View Full Version : Its the "Stump Fiz in Astronomy" Contest - Win X-Cash!
Hey guys, I figured that since I have 40 X-Cash sitting around, I might as well give it away.
Here's your chance to learn everything you wanted to know about astronomy, and try to win some X-Cash while you're at it!
I'm holding a short question contest to see who can stump me. You can ask a question related to astronomy or space or anything related (and it has to be a reasonable question, not something no human being can answer) and if you stump me, I'll give you 10 X-Cash! If there are too many questions, and I don't imagine there will be, and people start stumping me left right and center, then I may have to lower that limit. Hehe...
I just thought I could help you guys learn more about what goes on "up there" and give you a chance to ask a question that you've always been wondering about, or are having trouble with in school. Use your imagination! Make it easy, make it hard, but make it reasonable. ;) Most of all, try and win some cash!
If the question is really good, I may just give you more X-Cash. :) If no one asks anything, then I'm putting it all in the bank again...hehe...If I can't answer it by myself, I'll be honest...I want to give this cash away after all. ;)
lazy21236
10-27-2003, 07:04 PM
what is the big bang theory?
name 15 constellations.
if an asteroid that's 150 miles in diameter starts travelling through space at 15000 miles per hour and is 150 lightyears away from us, how long will it be until it hits earth?
lazy21236
10-27-2003, 07:08 PM
oops, the server messed up and double posted my thing. sorry
Hand of the Castle
10-27-2003, 07:23 PM
*clap clap* Ingenius idea fiz! Learning AND gaining Xcash! If ya need some funding, I'd gladly donate my 42(or 43) xcash that I've got left. :)
This has always been a question I've wanted answered...
How does the universe expand?
Afterburner
10-27-2003, 07:55 PM
Answer this...explain to me how black holes can give off radiation.
Explain to me why we haven't detected extraterrestrial life yet.
And if the universe is infinite, then how does it expand?
And if it's infinite, then how do you explain the fact that it therefore must contain anything imaginable, i.e. a physical manifestation of our world but with everyone's hair in a light bluish color, another world just like this but without anything ever from southern England other than grotesque sweaters?
Okay, lets start from top to bottom:
(1) What is the big bang theory.
The big bang theory is the scienific explanation of how the Universe was born. Scientists can determine everything that happened after time equals zero in the age of our Universe. Basically, at one time (roughly 12-14 billion years ago), the Universe was simply a single point of "infinite" density. I use the quotation marks loosely here. Something triggered the big bang and caused an outward force of expansion. Hydrogen and helium atoms were formed through complex processes, and particles slammed into each other to create slightly larger particles.
In the beginning of it all, the Universe was kind of a "soup". It was so dense that light could not penetrate through the material of the young Universe. After so many years (we're talking a large time scale here), the "soup" began to clear up, getting absorbed I guess you could say, and light could finally begin traveling across the expanse of the Universe.
Those particles that were slamming into each other eventually gave rise to more and more complex structures, giving birth to the stars and galaxies of stars. The same type of process took place when objects began rotating around stars, creating planets and solar systems like our own. These planets were formed by an accretion disc, where particles grouped together to create planetary orbits. And so the Universe was born. :)
(2) Name 15 Constellations.
Hoo boy. Okay. (1) The Big Dipper, (2) the Little Dipper, (3) Sagittarius, (4) Orion, (5) Ursa Major, (6) Ursa Minor, (7) Pegasus, (8.) Gemini, (9) Leo, (10) Pisces, (11) Taurus, (12) Capricorn, (13) Libra, (14) Aquarius, (15) Hercules
Phew! Thank God for birthsigns. Hehe...
(3) Ooh, a calculation question. Okay:
The only two pieces of information that we need to solve this problem is the velocity (15 000 mph) and the distance (150 light years) which equals about 8.8 *10^14 miles. The diameter of the asteroid is not significant. You didn't say it was accelerating, so I'll assume that its traveling at a constant speed.
d = 8.8 * 10^14 miles
v = 15 000 mph = 4.2 miles per second
t = ?
We can use the following formula:
d = 0.5(Vf + Vi)t
- where Vf is the final velocity (4.2 miles per second) and vi is the starting velocity at rest, which is just zero, and d is 8.8 * 10^14 miles
- we want to solve for time, so rearranging the formula, we get:
t = 8.8 * 10^14 miles / 0.5(4.2 miles/sec)
t = 4.19 * 10^14 seconds = 13 277 592 years
So the asteroid, traveling at 4.2 miles per second at a distance of 150 light years would arrive in a little more than 13 and a quarter million years.
(4) How does the Universe expand?
Okay. The expansion of the Universe is due to the outward force experienced from the time of the big bang. The Universe has continued to expand due to this event, and will continue expanding until it either reaches a point where it cannot expand anymore and collapses on itself, or will continue to expand forever, which is the accepted theory...the galaxies will drift farther and farther away from each other and the Universe will be one cold, dark place to live. Hope that answers it!
Hey! I love astronomy too, but i really love astrology, the study of the stories behind the stars. If someone can answer ths correctly i'll give them 15 xcash:
Who is pegasus's mother?
(5) Why do black holes give off radiation?
The reason why black holes give off radiation is because infalling matter swirls around the black hole and creates an accretion disc. When the matter passes the event horizon of the black hole, it cannot escape. The conservation of energy states that matter cannot be created or destroyed, and relativity states that when a particle enters a black hole, it is releases a pair particle that gets ejected back into the Universe. The X-ray jets seen being given off by black holes are a result of the energy produced by the black hole when it receives infalling matter.
(6) Why haven't we detected extra-terrestrial life yet?
That's a good question. In my opinion, from what I've learned anyway, our solar system is unique. Despite the fact that it is unique, we have also only charted a very small percentage of the sky. In charting this small percentage of the sky, we have only seen a very small percentage of our Universe.
The reason why we have life on Earth is due to the fact that the Earth is at a distance from the Sun where conditions are perfect to maintain life. The size, density, and radius of the Earth all present perfect conditions for life to exist. Throughout the rest of our solar system, we have not been able to find these conditions anywhere else. Extra-solar planets (planets around other stars) have been detected quite frequently, but these stars only harbor planets that are the size of Jupiter, and are as close as Mercury. These conditions are not suitable, for all we know, to harbor life.
We may still find life in our solar system. Jupiter's moon Europa may contain life under its icy surface, if there is an ocean under there. Scientists have predicted that there could be small, simple life all the way to whale sized creatures. On Earth, we have seen life survive in the most extreme underwater conditions with little oxygen and no sunlight. Hold your breath, we may find some in the next 20 years once drilling commences on Europa.
(7) If the Universe is infinite, then how does it expand? How do you explain the fact that it must contain anything imaginable?
I personally do not doubt the existence of alter dimensions within our own Universe. In fact, it has been theorized that in order for our Universe to work, there must be in excess of (I think it was) 8 or 10 extra dimensions that we cannot access.
The fact that our Universe is supposedly infinite is a "unique" statement. Let me propose this to you. We already know that our Universe is expanding. If it is indeed expanding, how can it be infinite? An infinitely large object cannot expand...it is a mathematical paradox.
If you agree with me then, I can conclude that point. Our Universe is finite in space, but expanding infinitely. If we were to draw the Universe on a plane, it would be a finite plane that is growing in all directions. The angle of the Universe's plane is very narrow, in fact, but this is complicated point.
In conclusion, I believe there are many dimensions within our own Universe. Take neutrinos for example. The Sun sends waves of these little particles around the solar system. Our bodies are bombarded with thousands or even millions of these every second. Neutrinos don't interact with normal matter, so why can't there exist another dimension made with particles that don't interact with our own matter on the same plane of our existence? The answer is that it is extremely possible, but not detectable.
We have only accounted for a small percentage of the mass of our own Universe...maybe 10%. The rest is hidden - dark matter. We'll leave that to another discussion. Hope that was okay!
HungryMonkey
10-27-2003, 08:38 PM
woah, um, explain in technical detail how a shuttle's systems work together
Hmm...that's a pretty vague question and has more to do with jet propulsion than astrophysics, but I can attempt to explain it from what I know in the physics sense and not the engineering sense. I'm assuming you're talking about a generic shuttle.
Okay, a shuttle is designed with one thing in mind. Get astronauts in space. A very basic explanation of a shuttle system consists of two major components. The fuel and the shuttle.
The shuttle, when stationary, is at equilibrium with the Earth. This means that the sum of all the forces acting on it equals to zero. The Earth has an escape velocity of 25 000 mph. That means that the shuttle must be able to generate enough force to accelerate beyond that escape velocity.
When the shuttle takes off, jet propulsion kicks in. The shuttle fires the rocket fuel perpendicular to the ground, and according to Newton's third law (action-reaction law) the force exterted on the ground by the fuel will cause an upward force in the opposite direction, sending the rocket into the sky.
The rocket cannot contain all fuel though. There has to be a balance between the amount of fuel weight and the rocket's weight so that the fuel can accelerate the rocket fast enough.
A shuttle's system relies heavily on computer programs to determine whether it can lift off with enough force. If a single calculation is wrong, or if a program attempts to divide by zero (which has happened, causing a lift-off disaster), the shuttle will burn up or explode due to excessive forces and other factors.
I don't know how else to explain it without typing a huge 10 page paper, but I hope that answers your question. :)
I'm still offering 15xcash for whoever knows who was pegasus's mother. Here's another question for 15 xcash: How many wives did Zeus have?
Ah, I remember the answer to the second question from my Classics course in my first year. I believe he had 4 wives. I don't remember their names, but Hera was the most famous of them.
I have no idea about the first question. :)
kevinok
10-28-2003, 12:11 AM
Okay I have a couple questions for you.
1. How is and what is studyed with radio telescopes?
2. Why is it that you will age a different rate when you are traveling at the speed of light?
3. Where is the biggest telescope located, and then where have the 3 before that been located?
4. Who created the first telescope (IT was not galleo he only improved on it.)?
5. Explain why Pluto and Neptiune swith from being in between being the 8th and 9th planets?
I have more if you want them.
Whew, maybe I should have a one question per person per day limit...lol...okay.
(1) What is studied with radio telescopes, and how do they work?
Light comes in different wavelengths. Humans can only see visible light, so we cannot detect the majority of the wavelengths that our Universe emits. In order to see things in different wavelengths, we must use different types of telescopes. Radio telescopes can see the band of radio wavelengths in light. The way they work is like any other telescope. They capture the light in the wavelength it is emitted at and converts it into the visible spectrum that we can see. Basically anything that emits radio waves can be seen with these telescopes. I'm not much of an expert on telescopes, so I hope my answer suffices. :)
(2) Ah, the old "who ages faster, a person on Earth or a person in space traveling at a certain percentage of light speed" question.
First of all, for the sake of consistency, nothing but light can travel at light speed. Light has the unique property of having both wave and particle properties, making it essentially masseless but still behave like a particle. If anything else could travel at light speed, it would get bombarded by the particles it passed during its flight and not survive. (Yes, there are theories about virtual particles and stuff, but lets not get into that)
That being said, the explanation for this question is quite simple without getting into general or special relativity. A person standing stationary on Earth experiences what we consider "normal" time passing. There is no significant bending of space-time or anything else that would warp our perspective of time, so it passes normally.
Time and space dialation explain why a person traveling at some percentage of light speed experiences youthfulness upon returning to Earth. Suppose you leave on a rocket ship traveling at 90% of light speed. The mere act of this velocity would cause space to warp (differently depending on the point of view), and time to warp as well (same reason). For you in the space ship, all would seem normal. Traveling at this percentage of light speed, however, causes the time passing on your ship to be slower than normal time on Earth. Therefore, when you return to Earth some 50 000 years later, you will have only aged a percentage of that, and all the people you knew when you left would have all passed on. This is the idea of time dialation and the atomic clock.
(3) The biggest telescope? I don't know if this would count as a physics question, but more of a trivia question... :) The largest telescope in the world is located in Hawaii. They did studies on the expansion of the Universe and supernova hunting there. The other part of your question is a little vague, because there are different types of telescopes. If you mean optical, then technically there are 3 telescopes in Hawaii...hehehe...the other large ones are in Texas and Chile.
(4) Who created the first telescope?
Actually, Galileo improved on a few things that he was credited in inventing. If I remember correctly from my Astronomy 122 class, the person who invented the telescope was Hans Lippershay.
(5) The reason why Pluto and Neptune have cross-over orbits is due to Pluto's highly irregular orbit. Pluto is closer to the Sun during a period of its orbital motion than Neptune, but they never collide because Pluto's orbit is highly angular compared to the other planetary orbits.
Okay, now I'm going to bed... :lol: Thanks for the questions guys, keep 'em comin', but try to keep them to 3 questions per day each...hehe...I don't want to cut my answers short if it means having to make the posts shorter. :) I know no one likes to read looong posts. ;)
Actually Zeus had a total of 21 wives, some were actually mortals.
Wow, really? I thought he had 4 true wives and the rest were affairs! :)
Diamond187
10-28-2003, 01:10 PM
Alright, here's where I put my wonderful Relativity and Quantum Mechanics class to use *laughs evilly*.
First, just a simple explanation question.
One of Einstein's postulates is that you cannot tell who is moving and who is still because there is no perfect frame of reference. And if we have a pair of twins (twin A and twin B) and twin A leaves to go on an interstellar journey for a few years, he'll come back to twin B who is now older than he is. But twin A could say that he never moved, instead twin B and the planet rocketed away at close to light speed for a few years and then came back and so twin A should be older. Resolve this paradox.
Secondly, another paradox, but this requires some simple calculations.
If I have a cylinder with a mirror on a 45 degree angle inside of it, light will come into the top of the cylinder and reflect out a whole on one side. But, if I get this cylinder up to .866c then the height of the mirror should shrink by 1/2 and the angle will change, causing the light to miss the whole. But no matter what speed the cylinder is going, an observer in its frame should still see the light going through the hole and that must be true in all frames, so how does the light make it out of the hole according to someone in a stationary reference frame?
Good luck, hehe, and if you need a hint for the second question, I can give you one.
lazy21236
10-28-2003, 03:51 PM
if an asteroid that's 160.98 miles in diameter starts travelling through space at 15078 miles per hour and is 146.46 lightyears away from us, how long will it be until it hits earth?
that's the original part, slightly modified, and here's some more
*it accelerates at 12.459 mph every ten seconds
*there are 200 stars that it passes in which slow it down by 15% each time
*after it passes the 140th star, it loses an extra 4%
i have no clue what i'm saying, but if you're really smart then you might actually understand it...
have fun!!! :lol:
(1) Wow, that's a noodle scratcher! Hehe...okay, here's my explanation to resolving this paradox. Lemme know if this is the type of answer you were looking for, and if not, I'll ask you to be a bit more specific about what you were looking for.
If I remember this correctly, it has something to do with two reference frames and having to use both general and special relativity. So, we assume that Twin B is on Earth and Twin A is on the shuttle, accelerating away at some percentage of light speed. Since we know that Twin B (on Earth) is accelerating with the Earth around its orbit, we can safely (I hope) conclude that Twin A is the one who is accelerating away (for now). That part is okay, up until we look at Twin B's reference frame when he/she arrives back at Earth.
Okay...the time span of one second is measured by the number of vibrations in a Cesium atom. This is how we define it. During time dilation, everything "lives longer" because the time it takes for elements and such to decay is less. I would assume that the number of vibrations in a Cesium atom would also be elongated.
The idea that Twin A is accelerating away from Earth brings us to the conclusion that they must return to Earth, and to return to Earth they must turn around. Turning around would entail that the ship would have to slow down, turn around, and accelerate back to Earth. During this slowdown period, the time passing for Twin A would be the same as Twin B, and this is where the reference frames catch up to each other. Twin B (on Earth) would then have to "catch up" to twin B in age, and this is not possible. The clock references are different on the shuttle than they are for normal passing time on Earth, so this solves the paradox.
Is that what you were looking for there? Lemme know if it was or not. :)
(2) Actually, I think I can explain this question without having to do any sort of calculation, simply based on theory. And if I'm wrong, let me know, for I could very well be.
An stationary cylinder on Earth experiences very insignificant space dialation (or shrinkage) from the orbit of the Earth around the Sun, and the orbit of the Sun around the galaxy. The number is so small, its not important.
If the cylinder is accelerated to 0.866c, and the mirror shrinks to 1/2 of its original size, the light (traveling at a constant speed) would still enter the top of the cylinder. The angle will change with respect to the dialation of the mirror, but for the observer at a stationary reference point, the cylinder and the hole in the cylinder will have dialated by the same ratio as the mirror did, causing the angle at which the light deflects off of it to still exit the cylinder and hit the person's eye in the same place.
If that's not right, I will gladly a hint. ;)
(3) Asteroid question
I can't answer this question because you didn't give me enough information. ;) You need to tell me the distance of each star that it passes where it slows down, preferably how far each star is away from Earth, or you could say that each star is the same distance apart from each other. This question would be solveable then, but it would give some strange results based on the fact that the closest star to us in real life is 4 light years away, and you gave me a total distance of 146 light years. That means that each star would have to be really close together to fit 200 stars in that distance. Still solveable though! It would just take an extremely long time for the asteroid to get here. :lol:
Diamond187
10-29-2003, 01:25 AM
Hmm, well I think you might be on the right track. Admittedly, it's an annoyingly difficult question, but I'll tell you that there are three things going on which play with where the light beam ends up hitting the side of the cylinder. This is a really tough question without a diagram so I suggest you draw yourself one just to make life a little easier. The first thing which alters the beams path is the shrinkage of one component of the mirror, it's height (think of the mirror as a right triangle at 45 degrees, which then has it's height shrunk by 1/2 to change the angle). The beam then reflects higher up on the cylinder, missing the hole which should be considered a point (just to simplify things a bit, it shouldn't matter how you consider it) located by drawing the lights path when the cylinder is stationary (it ends up perpendicular to its entrance path). Secondly, and this is the part a lot of people miss, is that the law of reflection changes slightly when the mirror is moving (this is the calculation part, and trust me it's not a fun one). Now, if you think about how the light is moving (*hint* components *hint*) it should become obvious why the light must go through the hole.
Only attempt this if you have some time to kill, hehe.
lazy21236
10-29-2003, 03:21 PM
okay, then it passes 86 stars, each is twice as far from earth as the previous one. and forget about the so and so many lightyears away from the original post, just use the closest star is 4 lightyears away and is starting from the last star. and now that i look at it, it's not that hard, just a lot of wierd numbers like you said. but i want you to do it anyway, just to make you work hard. and if there's anything that i'm missing just throw in what's most convenient.
oh, and put in in terms of years for mercury. just one more simple little calculation to bug you.
Diamond, I gave you 5 X-cash, cuz I was on the right track but you still had me thinking hard about it for a while! I think I misunderstood a part of your question because I asked one of my physics profs and he said the same thing I did...ah well...hehe...when I have some time to kill I'll think about it some more.
Actually, I the first thing I did was draw a diagram...hehe...
kevinok
10-29-2003, 11:36 PM
Okay some more questions now.
1. Explain the theory of worm holes?
2. Explain how the red spot (It's a hurrican I think) on jupiter has been able to keep going for the past 300 years?
3. Who made the first concave and convex lens and how were they made?
I still have more.
Vagrant
10-30-2003, 12:48 AM
1) How is light affected by mass?
2) If the 'big bang' supposedly contained all mass in the universe, why didn't it just collapse into an ulta-massive black hole?
3) Does it seem ironic to you that if you want mass destruction, you go into the tiniest of research?
4) Do stars have megaton yields?
5) How were most stars named?
Okay, lemme reword this question for my convenience - I'm going to convert everything into metric units because that's the way science does things. :)
An asteroid (diameter is not important) travels at 6 740.5 m/s and has an acceleration of 2 011.7 m/s^2. During its trip, it encounters 86 stars, each one being twice as far as the original one is from the Earth, and upon passing each one, the asteroid slows down by 15%. When it passes the 60th star, it loses an extra 4% of its velocity. (I just used a ratio from the 140th star from the original question with 200 stars) The closest star to Earth is 3.76 *10^16 m away.
How long does it take for the asteroid to hit the Earth?
This is by far the strangest question I've ever encountered, but I'll attempt it anyway...hehe...
Okay, so...if we know that each star is twice the distance away from Earth than the previous one, then we know that each star is 3.76 *10^16 m away from the previous one. That means that every 3.76 *10^16 m of travel, the ship loses 15% of its velocity. Good.
I'll assume that the ship starts at a distance of 3.76 *10^16 m away from the furthest star. We know that the acceleration of the ship is 2 011.7 m/s^2 (about 205 times greater than gravity!).
To find the final velocity of the ship when it reaches the furthest star, we can use this formula: d = (Vf^2 - Vi^2) / 2a (where d is the distance, Vf is the final velocity, Vi is the initial velocity, and a is the acceleration)
Vf = SQRT(Vi^2 + 2ad)
We get that the velocity of the ship after it has accelerated for 4 light years at a rate of 2 011.7 m/s^2 is 1.23 * 10^10 m/s. (this is obviously a ludricously large number for a velocity)
Wow...okay...we just violated the laws of physics already...hehe...
Anyways, so, the question says that when it passes this star, it loses 15% of its speed. That means, by the time it reaches the furthest star, it is now at a speed of 1.05 * 10^10 m/s.
In order to calculate the changes in velocity for 86 stars and having the ship accelerate by the same percentage between those 86 stars, then lose 15% of their velocity, I had to write a computer program to simulate the numbers. I found that the rate of which the velocity is decreasing is smaller than the rate of acceleration. This means that the asteroid is getting faster as it passes each star. The 60th star slowing it down by 4% is insignificant. Eventually, the number actually stablizes and the final velocity on approach to Earth is 1.99 * 10^10 m/s.
To calculate the time it takes, we use the formula: t = d / 0.5(Vf - Vi)
The time value we get is 3 778 895.8 seconds which is absolutely nuts, because that means it would take the asteroid 0.12 years to get to Earth!! That means that if it takes light to travel 300 000 m/s, this asteroid accelerates to such great speeds, that by the time it is within 4 km of Earth, it would be traveling in excess of 66 000 times faster than light speed!!
Of course, this question is completely out of bounds in everything we know and hold dear in physics. :) It turns out that the closer you get to light speed, the larger your relativistic mass becomes and the greater the force you need to apply to keep yourself traveling at that speed. This asteroid would never exist.
I'll do the other questions tomorrow when I get a chance. :)
The First
10-30-2003, 07:27 AM
Something I've truly been wondering about:
Why does your relative/relativistic mass increase when you approach the speed of light, when the speed of light is only the speed at which the light "particles" move. Sure, you'd move so fast that no one could actually see your actual progress or speed, but why does it change anything about your own mass and the time that "passes" (the person-traveling-at-light-speed-doesn't-age-as-quickly problem).
link64
10-30-2003, 03:47 PM
if i need science help u the one im askin fiz..
lazy21236
10-30-2003, 04:17 PM
wow, you are good!!!! i didn't have a clue on what you just said for the answer, but i trust that you're right... i didn't realize that my question was physically impossible either. oh well, i tried to confuse you but i'm too stupid to even make up a plausible question. *sigh* i give up...
Kevinok's Questions:
1. Explain the theory of worm holes?
The idea of wormholes is simple. A wormhole is a point in space that, due to the "ripping of space-time", can allow an object to travel from point A to point B in the Universes that make up the entire theoretical physical system without having to travel the linear distance - which would be impossible otherwise.
Of course, the idea of wormholes will likely never be proven due to the fact that upon entering a black hole, one would be stretched to death and would never be physically able to pass through and out of the white hole. (A white hole is the opposite of a black hole. Black holes don't let matter escape, white hole spit matter out. Notwithstanding that a typical wormhole would be too unstable to exist for long.
Personally, I don't follow worm hole and white hole theory as closely as I'd like to, but its an interesting concept. In my non-professional opinion, our Universe could very well be a inside an extremely large "black hole" type object that essentially does not allow light to escape from it, and this "black hole" type object is expanding in size. If we were able to escape from our Universe, it could very well be like escaping our solar system or our galaxy. We would then be in inter-Universe space...the space between Universes...this is a weird idea, but something to think about. :) Just remember that everything has an escape velocity...our Solar System has one (basically the escape velocity of the Sun), our galaxy has one, and our Universe could possibly have one as well. Who knows. :)
2. Explain how the red spot on Jupiter has been able to keep going for the past 300 years?
Actually, the great red spot on Jupiter is not a hurricane, but a cyclone. This has to do with the coriolis affect, which I will not get into because its kind of a dry subject. :) On Earth, a hurricane (or cyclone) dissipates because it comes into contact with land. Jupiter's structure does not allow the Red Spot to stop, because Jupiter doesn't have a "surface" like Earth does. That's basically the answer.
3. Who made the first concave and convex lens and how were they made?
Actually, this is a history of optics question and not an astrophysics question, and I don't know much about optics. Sorry! :) I'll give you 5 X-Cash anyway, even though its not astronomy. :)
Vagrant's Questions
1) How is light affected by mass?
Light is not actually affected by "mass" per se, but it is affected by gravity, which is related to mass. Weight is defined as mass times gravity. The weight of an object is the downward pulling force it feels with respect to the ground. Light, on the other hand, has no rest mass, but due to its wave-particle duality, does have momentum. Since a massive body bends the curvature of space time around it, light will follow this bend on while on its path. This is why light bends around black holes. A photon of light traveling near a black hole will follow the curvature of space-time that the black hole creates around itself, and therefore rather than going through the black hole, the photon will curve around it and continue past. That's why stars behind black holes appear to be in front of them. This is called gravitational lensing. Hope this answers your question!
2) If the 'big bang' supposedly contained all mass in the universe, why didn't it just collapse into an ulta-massive black hole?
The reason why the early Universe didn't re-collapse on itself is due to the outward force that the big bang caused. When something collapses, the gravitational force is greater than the expanding force. In the case of the big bang, the force pushing outward was greater than the collapsing force inward. The reason why the Universe chose to expand from a single point in the first place is still a mystery.
3) Does it seem ironic to you that if you want mass destruction, you go into the tiniest of research?
No, this doesn't seem ironic to me at all. Large structures in the Universe only exist because of small structures. The electromagnetic force is actually a much larger force than gravity. Gravity is an extremely weak force compared to electromagnetism, but because electromagnetism only affects particles that are very small and close together, gravity controls the large scale structures of the Universe. If the EM force was magnified so it could control large scale structures, we would be in trouble. Therefore, just because something is small doesn't mean it can't pack a punch. A supernova is one of the most powerful and violent occurrences in our Universe, and the only reason it happens is due to small particle interactions.
4) Do stars have megaton yields?
Please explain "megaton yields"...I'm assuming it has something to do with nuclear physics. If you can tell me what you mean, I'll answer your question.
5) How were most stars named?
Since stars are so numerous in our Universe (estimated to be more than the number of grains of sand on every beach on Earth), we cannot give each of them a name like you would name your pets. :) Instead, catalogue naming systems are used. These systems use a number after the catalogue's abbreviation to catalogue the star. Some stars are given actual names, but these are reserved for the brightest or closest stars. Other objects are also named this way like nebulae, galaxies, and clusters of galaxies.
Dark Reality's Question:
Why does your relative/relativistic mass increase when you approach the speed of light?
Good question. The speed of light is simply, as you said, the speed at which light travels. This is different than saying that an object with mass travels at light speed. Light speed is nothing special if you take it away from the fact that a photon of light is different from any other molecule or particle that contains mass. Light's ability to move at the speed of 300 000 km/s is still a stumper for scientists. It could very well be that light speed was set when the big bang happened. The fact that light travels at a finite constant speed tells us something about how special this speed must really be if nothing else can come close to it.
So the question is, why do we expect strange things to happen when an object that has an actual mass approaches light speed, assuming that light speed is just another number corresponding to how fast something can travel? The truth is, it doesn't matter how fast the speed is, you will always experience some form of mass gain. Even when you are walking, you're mass is being affected by the acceleration your body is experiencing.
In order for an object to accelerate, energy must be put into the system. If you agree with me there, then you have your answer already.
We know that nothing can travel faster than light speed. Therefore, since this is true, an object traveling closer and closer to light speed will never be able to (theoretically) reach it. As an object's velocity increases closer and closer to light speed, its mass goes to infinity. If you know Calculus, this can be defined as the limit as velocity approaches light speed. Its an asymptotic relationship. If we graph this relationship with mass on the y-axis and velocity on the x-axis, we will find that the line curves upwards but will never cross velocity = light speed. This means that the mass of an object must equal infinity for it to travel at the speed of a photon of light, which has no definable mass. You could (dangerously) say that light has an infinite mass...this would kind of help you understand what's going on here.
The best way to explain this is using Einstein's famous equation:
E = mc^2
Think of it this way. If I told you to push a pebble up a hill, you would be able to do it. Why? Because the amount of energy required to push that pebble is extremely small, since the pebble is small in mass. If I told you to push the pebble faster and faster, you would require slightly more energy to do this. No problem. If I told you to push a larger rock up a hill, you'd still be able to do it, but you'd need more energy because the mass has increased. If I then told you to push it faster, you'd need even more energy. The faster you have to push it, the more energy you would need. Einstein proved that in relativity, mass and energy are equivalent. Therefore, the more massive an object is, the more energy is required...the more energy is required, the more massive the object is. The equation tells us the amount of energy released from a system if the mass of an object could be converted into energy.
Hope that doesn't confuse you more! If you still are confused, I'll try to explain it better.
wow, you are good!!!! i didn't have a clue on what you just said for the answer, but i trust that you're right... i didn't realize that my question was physically impossible either. oh well, i tried to confuse you but i'm too stupid to even make up a plausible question. *sigh* i give up...
:lol: Your question was interesting! It really made me think, actually, cuz I honestly didn't think that the result would be what it was. I actually had to write a computer program to calculate the reduction and acceleration of the asteroid as it passed each star. I hardly think that this merits an invalid question. :) It was great fun! I actually started solving it the night you posted it and had to stop halfway through to go to bed, and the next day I actually was waiting to get home from school so I could find out what the answer was...lol!
I wouldn't give up if I were you, rather, I would think of questions you've been wondering about. When you look up at night, I'm sure there are things that boggle your mind...it happens to me every day. :) Math questions are all well and good, and they can really make you think, but its the stuff that we are still trying to understand that makes thinking about these things worthwhile. :)
Diamond187
10-31-2003, 02:25 AM
Alright, here's an interesting one. Prove that the planets must orbit in a plane (approximately) and then provide a physical reason for this. The plane proof requires some simple vector calculus (Think gravitation). If you've ever tried to prove Kepler's laws, then this should be easy.
Afterburner
10-31-2003, 07:42 AM
Very good!!!
Prove the sun is spherical.
bionic_2100
10-31-2003, 08:14 AM
a way to know it is sphereical is to look at the ultraviolt rays
Vagrant
10-31-2003, 09:52 AM
OR just think of gravity....
but anyways, what I meant by a mgeaton yield, is that atom bombs have a 'megaton' yield. Is there a yield for stars?
The First
10-31-2003, 04:00 PM
Back to the light speed question: E= mc^2, yes, but light speed isn't an infinite speed. Us not being able to reach it only has something do with our energie supply methods. We can't create enough energy to move light as fast as light moves, since nothing we have has such a small mass as light (the fact that it does have a finite speed in a vacuum makes it possible to assume that light has a close to infinitely small mass). But as said, it should be possible to move at that sort of speed, if we could bring up the kind of energy needed.
What confuses me more is the speed at which you age depending on the speed at which you constantly travel. Since the equater has to move more quickly than the north pole (since it has a larger diameter etc.), can we assume that africans age more slowly than eskimos? :p
a way to know it is sphereical is to look at the ultraviolt rays
Oh? Really? I didn't know that... how do ultraviolet rays tell us the sun is spherical? I would have said something along the lines of a sphere being the most stable shape and every point on the sphere is equally close to the center of the sun, because it's gravitational pull holds it in that shape...
Vector calculus is not the way I would prove it, but I do know the theory behind this proof. I would use the conservation of angular momentum and the origins of our solar system to show that all the planets orbit in the same plane.
The conservation of angular momentum in the case of our Sun states that the Sun does not induce torque on any of the planets in our system. Since this is true, and since we know that in the physics of "work", where force equals mass times distance, that the total work done for a planet to make one full orbit around the Sun is equal to zero (because the sum of all the work done is equal to zero), and since angular momentum works like linear momentum, the angular momentum of any planet is constant. This means that all the planets were formed in the same disk, and all their angular momentums must be constant, and explains how it can be that they all are on the same plane.
In the early years of our solar system's life, the Sun rotated very slowly, and it was surrounded by a large cloud of dust. Over time, the conservation of angular momentum caused the cloud of dust to collapse into a disk around the Sun, and this disk would be the same plane where all the planets would orbit. Pluto is the exception, and this leads astronomers to believe that Pluto was not one of the original bodies that orbited the Sun, but was captured some time later, and is actually a member of a group of orbiting asteroids some distance outward in our solar system. Hope that was sufficient!
You guys are on the right track about the Sun being spherical due to gravity...its more involved than that, however, and has to do with hydrostatic equilibrium. The Sun isn't perfectly spherical though...all stars bulge at their equators.
Vagrant, the time dialation discussion is a page or two back, but its hard to understand if you are new to relativity. At speeds like the rotation of the Earth, the time changing factor is practically non-existent.
Actually, this goes back to the topic discussed earlier (can't remember if it was in this thread or not) about the moon's orbit decaying...I gave an explanation about what could happen if the moon's orbit did decay, theoretically speaking...the moon's orbit actually will never decay...in fact, its distance from the Earth is actually getting further! This goes back again to angular momentum. The Earth is losing angular momentum (slowing down by something like 10^-8 seconds per day) to the moon, but the moon gains this angular momentum, making its orbit larger. Eventually though, its believed that the Earth will stop slowing down and keep the same face to the moon at all times, just like the moon is locked in synchronous orbit with the Earth. Therefore, when this happens, if there is a full moon, we will always see a full moon every single night. If its a new moon, we will never, ever see the moon again. ;)
The Megaton Yield Question:
Okay, so atom bombs have a megaton yield. I think I know what you mean now...this is the "power" of the bomb, basically. The larger the megaton yield, the more powerful the bomb blast.
Stars undergo nuclear fusion and fission. Therefore, a star is not unlike a nuclear bomb if it becomes a supernova. My educated guess, then, would be yes...stars do have megaton yields. The larger the supernova-bound star, the larger the supernova intensity.
HungryMonkey
11-01-2003, 11:10 AM
My brain is hurting now. Prove that other galixes that we con't see exist.
lazy21236
11-01-2003, 12:17 PM
OWWWWWWWWWWWWWWWWWWWWW it won't stop hurting!
i've downed a bottle of advil, two of tylenol, and five of some *special* medicine.
my brain won't stop twitching, i can feel it moving, i'm seeing beautiful new colors everywhere, the giant pink elephant just ate me and i'm being digested, i'm getting cold, now i can see the space elves all over the place, they keep poking me for some reason. (starts to stumble on the ground) i can fly now! this is fun! (falling down the stairs)
*THUMP* (now laying down passed out and starting to foam at the mouth)
lol you people are really starting to confuse me! IT'S FUN!!!!!!!!!!
that's a quote from me back in "How do you think the world began" thread. i think it's relevent enough to bring it back here...
anyway, i'm done with confusing math questions and now i just want some simple answers to some simple questions...
What's the possibility of another planet that can support life?
Are there any suspected planets to have life or support us? and one for fun
Are there any asteroids that have a threat to earth? just to go along with my previous more confusing question.
Vagrant
11-01-2003, 03:04 PM
My brain is hurting now. Prove that other galixes that we con't see exist.
Considering the light we get from them is about a couple billion years old, we can't prove that the exist as of now.
kevinok
11-01-2003, 05:10 PM
Well how I understand worm holes they are basicly just folds in space. The best way to explain it is with a piece of cloth. When you fold the cloth the distance srinks. I think that is right.
Prove that other galaxies that we can't see exist.
Vagrant is correct. Since light travels at a finite speed, it does take the light emitted from a distant galaxy a certain time to get to Earth. Galaxies that formed when the Universe began that have already collided with other galaxies or simply "died out" are just now being seen by our eyes. We can prove that galaxies undergo changes and collide with each other by seeing the light that distant galaxies emit. Since these processes take millions and millions of years, we only have "snapshots" of each phase of a galaxies development.
The more relevant question would be to prove that a galaxy we are seeing actually doesn't exist anymore. :) Good question though. The whole "seeing something that went out eons ago" baffles some people. In essense, we are actually looking back in time. If you want to, you could even say that when you look at someone standing 100 meters away, you're actually seeing them a very short distance in the past, and they're seeing you a very short distance in the past. On the surface, its another relativity "paradox".
(1) What's the possibility of another planet that can support life?
Another planet in our solar system? Not very likely from what we know, but there are exceptions. Jupiter's moon Europa has a thick, icy surface which could very well contain water underneath. Water, as you know, can harbor life, even in extreme conditions where oxygen and sunlight are non-existent. Astronomers have been talking about drilling Europa's surface to see what could possibly be a moon that supports aquatic life.
Everyone has probably heard the theory that Mars once supported life. There is evidence on Mars that suggests it had water at one time. We can see this when we look at the poles of the planet, and the dried riverbed-like features the planet has. Unfortunately, Mars has a temporary atmosphere that comes and goes. Life would not be able to develop without a stable atmosphere.
(2) Are there any suspected planets to have life or the ability to support us?
The only planet that we could possibly go to if something were to force us to leave Earth is Mars. If we could somehow figure out how to make the atmosphere permanent and terraform the land so we could grow food on it and introduce a natural water source, we could have a new home. Of course, the conditions on Mars are harsh, and humans would have to figure out a way to survive in extreme changing temperatures, amongst other things.
All the other planets are not ideal to live on. They're either way too hot, way too cold, or don't have a surface. The inner planets are rocky and have land surfaces (for the most part), because they formed within a certain distance of the Sun and were able to capture heavy elements. The outer planets were too far out and could not capture heavy elements, making them large gas giants. Another reason why Pluto is not considered a true planet. It does not fit with the descriptions of our other outer planets.
(3) Are there any asteroids that have a threat to Earth?
Hehe...if I told you how many potential colliders there are crossing Earth's orbit, you'd start worrying about how long you have to live. There are literally hundreds of thousands of near-Earth objects (or NEOs, as they're called) that cross our orbit around the Sun. A small portion of these are at least one kilometer in diameter, which would cause devestating results.
Of course, its rare that we would be hit by one any time soon (I think its like 1 in 10 000), however, its happened a few times in Earth's short history and it is inevitiable that it will happen again. Don't hold your breath though. :)
Oh, and also...we can thank Jupiter for the fact that we even have life on Earth. Jupiter has been called the solar system's vaccuum cleaner. If it weren't for this planet, asteroids would have hit Earth with great success and we would never have been able to evolve. Jupiter's gravitational field essentially "sucks" these asteroids in, as we saw a few years back in the Shoemaker-Levy disaster on Jupiter.
kevinok
11-01-2003, 07:18 PM
Fiz was my comment on worm holes right.
Yes Kevin, you can definitely look at it that way. This is an accepted explanation on what limited theory there is on this subject.
Diamond187
11-02-2003, 02:33 AM
Just out of my idle curosity (and that scene from Total Recall) what's the mean surface temperature of Mars during the day? At night? And if you feel like being really informative, what are the other atmospheric conditions?
Total Recall - that movie rules! I wanted to watch it on TV today, but I also wanted to watch hockey. Hehe...
I don't remember the exact numbers, but I believe the warmest it gets on Mars averages around 20 degrees Celsius and the coldest is about -70 degrees Celsius. (between +70 and -70 farenheit) During the Martian winter it can get twice as cold.
The atmospheric composition is almost exclusively carbon dioxide, with fractions of percentages in other gases. Funny thing is that this is how the Earth was in its early days. :) Again, I can't remember the exact numbers here.
theundeclinable
11-03-2003, 03:43 PM
Fiz. i have a question.
Why is it impossible, at this point in time, to convert energy into matter.
knowing that its not why cant we turn it back?
how fast do gravity waves travel?
How does anti matter react to the gravity of normal matter?
why if 90% of universal substance is anti matter where are they hiding it all?
theundeclinable
11-03-2003, 05:31 PM
fiz, more to the point. and this one may be a little trickier :)
why the permitivity of a vacuum is not 1
you will prolly get it. but i know it fairly high end quant stuff so most people wont know it :D
lazy21236
11-03-2003, 08:58 PM
well, for the energy into matter thing i think i can answer that, maybe, i don't really know but i'm gonna guess....
from what i know, which isn't that much, no matter can be created or destroyed. all that matter can do is change states making it appear like it's being created or destroyed to some people, like me. and i think, not sure at all though, that energy is just how active a state of matter is, so you can't turn energy into matter since it's a measurement of a sense for matter itself.
i'm sure i got something if not everything wrong but i'm bored and i'm coming out of my siezure so i can work my brain a little until i start foaming again...
I'll try to answer these questions later if I can but this is a hellish week for me. :) It may take me about 15 hours to respond... :lol:
I will say that energy cannot be seen whereas matter can. We can only see the effects of energy in how it relates to matter. Think about that for a while as I continue to plunder away at my computing science assignment. :(
Diamond187
11-04-2003, 02:03 AM
Hehe, alright, for all the ppl with some quantum backgrounds: What shape does psi have in a parabolic potential well?
lazy21236
11-04-2003, 04:37 PM
ooooo i know this one, it's the shape of a cat, no a dog. that's it, a dog!!!!
i am soooooooooooooooo confused right now...
i think it's time for me to siezure out again *starts foaming at the mouth*
HungryMonkey
11-05-2003, 10:57 PM
A metor orbits earth, constantly stayin 19 lightyears away at 25,000 mph. every 22 and a fourth years its orbit decays 1.038466%. How long until it hits earth?
Galactus
11-05-2003, 11:53 PM
A meteor would never orbit earth at 1,000 light years away.
Sorry :(
HungryMonkey
11-06-2003, 03:52 PM
shh, he doesn't know that!
:lol: Unfortunately, I do...hehe...
Sorry for the lack of responses guys...I have a big midterm exam Friday morning and I'm studying my brains out. After that's over, I have a four day long weekend in which I will use to catch up on these question...stay tuned!!
HungryMonkey
11-06-2003, 07:58 PM
So don't overload Fiz here, do you want to break his brain after a midterm?
No, its okay, by all means keep them comin'! Just know that I won't be able to respond until Friday or Saturday. :) I'm actually looking forward to being done my exam so I can get back to discussing astrophysics with you guys. :)
stickfighter7
11-07-2003, 08:01 PM
Ok i got one on the moon
1) name what gas we will use to be successful colonised on the moon
Why is it impossible, at this point in time, to convert energy into matter?
We can't turn energy into matter for one very simple reason. We cannot produce the amount of energy needed to cause this change to occur. This goes back to the question I answered about gaining mass at high velocities. I think that explanation will do you good. :) Just think of it this way. To create matter from energy, you would have to cause a particle to travel close to light speed, and even then, it would be very hard to work with it.
Knowing that its not why can't we turn it back?
I don't think I understand what you're asking here. Knowing that its not possible, why can't we turn what back? Matter into energy you mean? If that's what you mean, then you can totally turn matter into energy. Just heat something up (heat energy), break something in half (sound energy), or do other things to matter to cause it to produce energy.
How fast do gravity waves travel?
Anything that behaves like a wave will travel at the speed of light. Gravity waves, EM waves, etc.
How does anti-matter react to the gravity of normal matter?
Actually, anti-matter is not equivalent to normal, everyday matter. When you say that matter reacts to gravity, you are really saying large matter, like clumps of matter. You need to watch the terms in this case, because anti-matter particles are just the opposite of matter particles. They're the opposite charge. So to answer your question, anti-matter particles are governed by the force of electromagnetism, just like matter particles such as electrons and protons. Its just the way they move around in a magnetic field that makes them different from each other.
If 90% of universal substance is anti-matter, where are they hiding it all?
Okay, as far as my knowledge takes me, the going theory used to be that for every matter particle there is an anti-matter particle. That means that there should be just as much anti-matter as there is matter.
However...if that was the case, then there would be nothing left, since matter and anti-matter collisions cause a non-existence of both particles as they are converted into light energy. That means that there is either more matter or more anti-matter.
My thought would be that there is more matter in the Universe. We can see matter, but we can't see anti-matter. That means that the anti-matter isn't actually hiding, its actually not there. (Well, there is some, but not as much as we think)
I think you are referring to dark matter. Dark matter is something that is there that we cannot see. Its the reason why our galaxies still have their outer stars. The stars in our galaxy are orbiting much too fast to stay within the system. There must be more mass that we cannot see in our galaxy that causes the orbits to remain stable. Dark matter is still quite a mystery to astronomers, but there are a few theories out there being developed.
Why is the permittivity of a vacuum not equal to 1?
Hmm, well as far as I know (I hope this is the answer you were looking for), the permittivity of a vacuum is related to Coloumb's constant, and its relationship brings out a value that is extremely small. Some billionths of negative magnitudes. I can't remember the actual value though.
What gas would allow us to colonize the moon?
Actually, this is likely a trick question...hehe...in my view it is, anyway. There is no gas we could introduce to cause the moon to generate an atmosphere.
The moon is much too small to maintain an atmosphere. Look at Mars...it has the same problem. Solar winds would not allow any kind of atmosphere to stick around on the moon. However, it is possible to create an atmosphere if there was enough water on the moon.
This is not practical, and almost a pipe dream of an idea though.
Of course, if you really want an answer to this question, you would need to introduce lots of oxygen into the moon's atmosphere and somehow allow the oxygen molecules to be converted into ozone molecules, and you would need to keep the ozone molecules stable in the atmosphere. :D
stickfighter7
11-07-2003, 10:24 PM
no there is a rare form of gas on the moon that we would use to create engery through with radiation but it leaves no radioactive trave
I know there are jets of gas that come from cracks in the moon's surface, and even though these have been thought to be proof of sub-surface icy water, its very unlikely that any kind of atmosphere could be created on the moon, simply due to its size and closeness to the Sun.
theundeclinable
11-08-2003, 05:35 AM
hey fiz, you really know your stuff. i was asking one of my mates at cambridge some questions to stump you. i wrote that darm matter wrong and you even spotted it (it wasnt deliberate)
i havent got the foggiest about most of that stuff. i am a mathematician as oppose to a astrologer :P i mean astronomer :P
ok. a little question. does astrology and the reading of the planets make any sense to a scientific astronomer?
thats a bit more subjective for you :P
how do you know all this stuff?
:lol: Wow, Cambridge huh? Cool! Dark matter has always been something I've been interested in. That and black hole physics...my favorite subject...hehe...
To answer your question about astrology and its ties to astronomy, in my opinion, astrology and astronomy are completely disjoint. The only real thing they have in common are the constellations and names. Of course, way back in the day, the ancient Greek astronomers were looking into the heavens, and others looked up into the sky after them through the ages. Stories were created about the stars according to how they were viewed.
I like reading about constellations and their stories from time to time (as I always loved Greek Mythology), but astrology and astronomy aren't related much in any way.
How do I know all this stuff? :lol: I've been interested in this stuff for years. Whatever I knew theoretically before I came to University was purely through my own readings, and my own curiosity when I myself went out onto a dark hill and stared up at the sky. That's when I decided to pursue physics, astronomy, and astrophysics in some form in University.
So that's my story. :)
theundeclinable
11-08-2003, 05:19 PM
so where are you now?
Education-wise? I'm still in University - going to major in Computational Physics.
Diamond187
11-09-2003, 03:15 AM
Hey, you skipped my quantum physics question! I understand if you've never taken a course in quantum physics, I just wanted to see if anybody knew what I was talking about.
:lol: Sorry Diamond! Yep, I'm not too well versed in Quantum physics, but I have to think about it using the fact that (I think) a parabolic potential well follows simple harmonic motion. I'm still not sure about the shape of psi...can you elaborate?
Diamond187
11-11-2003, 05:34 PM
Yeah, you're right about the SHM, a parabolic potential well is pretty much the definition of harmonic oscillation is subatomic particles. So obviously it's going to be a sin/cos function, but it has some special features as it moves out towards where the energy equals the potential and after the energy equals the potential, those are what I'm looking for.
Tiki2day
11-17-2003, 04:50 PM
Eh Fiz thought you might like this,
http://www.mwscomp.com/sounds/mp3/galaxy.mp3
Heeeey, that's Monty Python Flying Circus right?? :lol:
HungryMonkey
11-25-2003, 04:39 PM
Yep, none other then the heros of the earth, Monty Python.
The strange thing is that I saw that just last night on TV...hehe...that very same skit.
HungryMonkey
11-25-2003, 07:35 PM
Well, today I heard the Spam Skit in Spammerland, then saw it on TV, strange things.... THE EARTH IS COMING TO AN END!
*runs away screaming*
kanammo3
12-09-2003, 05:06 PM
lol what happen to astronomy :?:
:lol: Everyone is all Astro-ed out...
HungryMonkey
12-16-2003, 08:49 AM
Fiz is good, too good...
The First
12-16-2003, 03:13 PM
Yes. Fiz just knows too much.
I'd love to join the Friar's club, I don't want to die, but somehow, my application has been forgotten
"Yeah, you're right about the SHM, a parabolic potential well is pretty much the definition of harmonic oscillation is subatomic particles. So obviously it's going to be a sin/cos function, but it has some special features as it moves out towards where the energy equals the potential and after the energy equals the potential, those are what I'm looking for."
I just noticed, that sounds like the kind of thing you say when you try to sound smart... no one else understands it. Or you just are smart, and no one understands it. Or they pretend they don't understand it and you're just pretending to be smart... dun dun dun...
right.
Diamond187
12-16-2003, 03:34 PM
Well, it's very hard to discuss quantum mechanics in layman's terms. I've tried, but it's just as confusing as using the physics terms.
Afterburner
12-16-2003, 03:48 PM
What was that great quote from Niels Bohr...
"Anyone who thinks he understands quantum mechanics does not understand quantum mechanics."
Second best quote:
Einstein: "God does not play dice."
Einstein: "God is not malicious."
Bohr: "Einstein, stop telling God what to do."
The First
12-17-2003, 06:10 PM
well i figured it was hard to talk about, i never really expected to understand it. I'm sure it made sense, in some way or another. But I know i don't understand quantum physics/mechanics.
Ieattacos
12-18-2003, 09:01 PM
how many meteors have hit the ground in the last day?
put in order from smallest to biggest comets, asteriods, meteors
how hot does the suns core burn? (in f.)
wut part of the sun is visible during a solar eclispe?
how much less gravity does the moon have compared to the earth? compared to the sun?
how much mass does the moon have compared to the earth?
at wut speed does the moon travel around the earth?
at wut speed does the earth go around the sun?
at wut speed does the sun move?
Hmm, wow, I didn't know there was still an outstanding post here! Hehe...okay, here we go:
(1) How many meteors have hit the ground in the last day?
None. Meteors are just flashes of light that occur when meteoroids interact with the atmosphere.
(2) Put in order from smallest to biggest comets, asteriods, meteors
This question isn't valid, because of two reasons. The first being the same answer as above, and the second being that comets and asteroids come in many different sizes. Some comets are larger than some asteroids, and the other way around.
(3) How hot does the suns core burn?
In Farenheit, the core temperature of the Sun is almost 30 million degrees.
(4) What part of the sun is visible during a solar eclispe?
The Corona is the only part of the Sun visible during a total eclipse.
(5) How much less gravity does the moon have compared to the earth? Compared to the Sun?
The gravitational force on the moon is 1/6th that of Earth's. The Sun's gravitational force is much greater, about 28 times greater than the Earth, and almost 170 times that of the moon.
(6) How much mass does the moon have compared to the earth?
The moon's mass is about 1% the mass of the Earth.
(7) At what speed does the moon travel around the earth?
The moon's orbital velocity around the Earth is a little over 1 km/second. (0.62 miles/second)
(8 ) At what speed does the earth go around the sun?
The Earth's orbital velocity is about 30 km/second. (a little over 18 miles/second)
(9) At what speed does the sun move?
The Sun is really fast. About 240 km/second! (That's 150 miles/second)
The First
04-01-2004, 11:05 AM
*blinks* how do you measure the speed of the sun?... wouldn't you need some sort of fixed point to measure it?
To keep it simple, because I'm notorious for long-winded posts, every object in the solar system as an orbital velocity. The moon orbits the Earth (and the Earth techinically orbits the Moon - but that has to do with another topic called center of gravity), the Earth orbits the Sun, and the Sun revolves around the galaxy. Galaxies, as you may well know, also have a velocity. With this information, knowing that the Sun makes one full revolution around the galaxy once every 200+ million years, we can estimate the orbital velocity of the Sun as it makes its way around the galaxy.
Since the Sun is only about 5 billion years old (small in astronomical ages), it has made only 20 trips around the galaxy since it was born, and will only go around another 20 or so more times. Some scientists have linked the revolution of the Sun to certain mass extinctions, as a sort of pattern. It seems that once we hit a certain point, boom, something devestating happens...strange huh?
The First
04-01-2004, 02:28 PM
Hmm... interesting. But I mean, how do you measure the speed that the sun travels? Or at least how long it takes for the sun to make one revolution around the galaxy center? I mean... if everything starts spinning and revolving, it's somewhat hard to measure any speed, isn't it?
Nope, its not difficult to measure. Its just like measuring the velocities of the planets in our solar system. Everything on the large scale works the same as the small scale, as well. For example, we have great knowledge of electrons orbiting a nucleus, and in principle, it works essentially the same way.
When an object travels in an orbit, the linear velocity at any point can be measured using certain factors, such as centripetal acceleration and the centrifugal force. I won't get into it unless you want me to, but basically an object in orbit has a velocity that is tangent to the circle. If the object was released from its orbit, it would travel exactly perpendicular to the point where it was in orbit. Therefore, the velocity of that object can be determined from this fact.
That's basically how we can obtain the velocity of an object or body such as the Sun.
EDIT: Under further investigation of your question, I think I may know what you really mean. You're saying that if everything is moving relative to everything else, how can we measure a velocity? If that's right, then remember that we are moving in a fixed orbit around the Sun, so from our reference frame, we technically aren't really "moving" (That is, we're just changing our position around a fixed orbit). We are part of a system of planets that revolve around a central point, the Sun, which is moving. Its like if I held two weights and traveled around a room in a circle, and at the same time, spinning in circles. The weights would have their own velocities around my body, but they would also share the same velocity around the room that I am producing.
I really hope I didn't make the explanation worse with that addition... :lol:
The First
04-02-2004, 08:09 AM
No, it made sense :-) I think I just made it more complicated than it was when I thought about it.
:lol: It usually is. The human race prides itself on making simple things complicated.
Diamond187
04-06-2004, 08:01 PM
Alright, here's an interesting set of questions:
What are all the orbital modes possible, either the geometric subset or each shape individually?
Why are these the only possible shapes?
Bonus:
If gravity was proportional to the the inverse cube of the distance, what would the orbital modes be?
Afterburner
04-06-2004, 08:20 PM
I remember the first two....but I can't be bothered (sadly) to pull out that chem book.
My questions, something that's puzzled me:
You are standing on a scale in your physics room, minding your own business, when suddenly your evil physics teacher sucks all of the air out of the room. Before passing out, you notice the scale reading. Is the new scale reading higher than, lower than, or identical to the reading prior to the removal of the air?
As an ice cube in a glass of water melts, does the level of the water in the glass rise, fall, or stay the same?
(Oh, and btw, you two (Fiz/Diamond) I respect immensely. You guys are two of my three favorite members)
Diamond187
04-06-2004, 08:48 PM
Ooo, ooo, these ones are mine. Phys-Chem hybrid stuff is my specialty.
Ok, for the first question:
If the evil teacher sucks all the air out of the room, your weight will actually increase because the bouyant force the air exerts on you will disappear. Of course, unless your scale reads 4 decimal places or so, you aren't going to notice this.
For the second question:
This one is a bit of a trick for a couple of reasons. First, water is actually an exception to the rule in that it is one of the very few chemicals which is denser in the liquid phase than it is in the solid phase. An obvious way to see this is if you look at the ice in the glass, you'll notice it is floating, not sinking. This means that ice actually takes up more room than water, so the volume does go down. But again, this affect is going to be in the order of 4 decimals of accuracy.
Note on the first question: The problem of air pressure pushing down on you just occured to me. I know this will not affect your weight. Or, it is at least negligible compared to bouyancy. This is obvious if you think about deep-sea divers, who need many, many weights in order to stay at the bottom, despite being underneath several tons of water. I'll have to resolve this problem somehow, but I can't think off the top of my head how.
If all the air was sucked out of a room and it was made into a perfect vaccuum, the air in your lungs would also be removed, which would make your current lung capacity equal zero, and thus change your weight as well. ;)
Diamond, I have no idea about your questions...I've never even heard of orbital modes before. :lol: Never did take chemistry.
Jshall
04-07-2004, 06:12 PM
what star was the first to be seen oing supernova
Diamond187
04-07-2004, 06:30 PM
Hehe, actually, I mean gravitational orbits. ie. If you have arbitrary mass and velocity object near an arbitrary mass which is stationary, what are all the possible paths it could follow?
The first supernova to be witnessed took place in what is now known as the Crab Nebula. Ancient astronomers documented this event in the year 1054. As far as I know, this is the first supernova ever documented...
Ohh, I getcha now...my educated guess would be parabolic. If any moving object comes near a stationary object in orbit, the path it would follow would be a parabola, and as long as it remains in orbit, it will form and ellipse. Not sure if that's right, but that's my guess.
As far as why this is...hmm...I would have to use the idea of how the moon orbits the Earth. The moon is actually falling towards the Earth, but since it has a velocity, it moves a distance in the x direction every time it falls in the y direction. This causes the orbit to be formed and allows it to be maintained. Is that the answer you were looking for? If I'm reading you correctly, you are asking why gravitational orbits form ellipses only, and not any other shape. I'm sure you're looking for something more complex, so let me know...hehe...
Bonus: No clue. 2 X-cash for you... :)
Diamond187
04-07-2004, 09:34 PM
You are mostly right for the orbital path, actually. A parabola is the minimum possible trajectory to escape the planet's gravity. If you're going faster, you actually end up travelling in a hyperbola. And, if you know some geometry, you'll recognize those shapes as the conics.
I was actually trying to use the bonus as a bit of a hint. It all comes about because the gravitational force is proportional to 1/r^2. So, you were on the right track in thinking, about falling and all. If you actually wanted to prove it, you would need more math than could possibly be represented here.
As for the bonus, I actually don't know myself for sure. I know there are three different possible modes, and I believe that they are spiralling outwards, spiralling inwards, and a perfect circle, but if you asked me to prove it, I'd be in trouble.
Jshall
04-08-2004, 04:59 PM
what was the name of the second star to be seen going nova
It doesn't have a name, but its remnants should have a catalog number, which I don't know. Technically, the name of the star would be unknown, but the after affect, known as the supernova remnant, would have been given a letter-number combination for a name. I can tell you it was sighted in the year 1181 though.
what is self combustion?
where did the first cells come from?
where does heat come from?
sorry their sciece thought you might want something new
:lol: Well, they are physics related, and somewhat astronomy related, so its all good...I'll do my best!
(1) I'm guessing self-combustion is similar to spontaneous combustion, which is when an object ignites by itself without any external source acting upon it. Someone correct me if I'm wrong. :)
(2) From an astronomical point of view, the first cells were created when the Earth was still young, sometime after the proto-Earth stage. Astro-biologists (if that's what they're called) claim that cells formed from particles ejected by the remnants of a supernova explosion, which is related to the creation of our solar system. These supernova remnants, mixed with the gases and other debris on the young Earth, caused chemical and biological reactions to occur. To make a long story short, and to fill in my inexperience in astro-biology, this is how the first cells were formed.
(3) Heat is just a form of energy. Since energy must be conserved (according to the conservation of energy laws), heat is given off from a source when a transformation of energy occurs. For example, the Sun produces heat energy from the many nuclear processes that go on within it. Fission (when two elements are formed from one element) and fusion (when two elements combine to form another element) both give off energy when they occur. In the instance of our Sun and other stars, hydrogen is converted into helium, and this process gives off energy which can be heat energy. This heat energy is radiated through space and received by the planets.
Jshall
04-17-2004, 03:37 PM
What is the Decay rate of Urainum 238??
What is the hafl life of steel?
These aren't astronomy questions, but from what I can remember from my nuclear physics section in introductory physics, Uranium 238 has a half life of some 10^9 years in magnitude. I think its under 5 000 000 000 years.
Steel is made out of iron, and as far as I know, the majority of iron is stable and does not decay. Therefore, it has no half-life, or at least one that is not measurable in our time frame.
Jshall
04-18-2004, 09:00 PM
Man your good.
griffey04
04-19-2004, 10:35 AM
how many stars in the solar system??
There's only one in the solar system...that's our Sun. If you meant in the galaxy, then there are billions.
Jshall
04-20-2004, 05:05 PM
How old is the oldest star?? HAHA bet you can't get that one . So you should just send me the xcash now.
Afterburner
04-20-2004, 08:09 PM
Actually....................that's extremely easy. Besides, theone, that's a silly question.
Weeeell, actually, its not a question that you can give a precise answer to. The answer really is that no one really knows. We can predict that its somewhere between 14-10 billion years old, but we don't have the age of the Universe figured out to an exact number. Since star formation is an extremely long process, no one can really say with certainty what the exact age of the oldest star is. We don't even know the exact age of our Sun. We estimate that its approximately 4.5 billion years old, but we don't know it to the exact certainty that we know the mass of an electron.
Its not a silly question, its just one that no one has an exact answer to. But the accepted answer is somewhere between 10 and 14 billion years.
Okay, if the "Big Bang Theory" is true, then how come the 2 things that're said to have made the universe do absolutely nothing over any amount of time?
P.S. You've answered hella questions, either you cheat damned well or you're damned smart. :twisted: :twisted:
:lol: I like to think of it as that I've done my research and enjoyed it. :)
Can you rephrase your question? I'm not sure what you mean, or what two things you're talking about.
The two elements used in the "Big Bang Theory", why do they do nothing when placed together over any period of time?
Ahhh, okay. Firstly, let me just say that the theory of the Big Bang is quite complicated.
In short, however, microseconds after the Big Bang occurred, the Universe was extremely hot, but rapidly cooled down to a point where particles could interact with one another.
When particle interactions occurred, hydrogen nuclei were able to form. When hydrogen was fully formed, the temperature was still hot enough for fusion reactions to take place. Remember, fusion occurs when two elements are fused together due to large amounts of energy, which overcomes their need to repel each other. Fusion reactions are what fuels our Sun. Because the Sun is so hot, the temperatures allow large amounts of energy to overcome the repulsive nature of four positively charged hydrogen nuclei, which fuse together to form helium.
We know that fusion releases a large amount of energy because the four hydrogen nuclei have a larger mass before they are fused than after they have become helium. Since matter cannot be created nor destroyed, this lost mass has to have gone somewhere. Long story short, this is where the extra energy comes from.
Okay, I got a little sidetracked, but I promise, that blabber does go somewhere important. :)
If I understand your question correctly, you are asking why the elements (hydrogen and helium) do nothing when they are placed together, but still helped in the creation of the Universe, right? Well, the above stuff pretty much answers that. Under normal conditions, hydrogen and helium, both being positively charged, will repel one another. Multiple hydrogen nuclei also repel each other, and the only way they can be fused is through high temperatures.
That is why the Universe formed. High temperatures allowed the hydrogen nuclei to fuse together to form helium, but when the Universe cooled down, those reactions did not occur naturally anymore. The only place this happens now is inside stars like our Sun. Eventually though, the Sun will have converted all of its hydrogen into helium, decreasing in mass (for the reasons noted above, that 4 hydrogens are heavier than one helium) thereby ceasing to produce anymore energy. Things will become very cold then.
You can think of the early Universe as the inside of a star. As the star converts its hydrogen into helium, the radius of the star increases, similar to the fact that the Universe is constantly expanding. In the case of the Universe, the hydrogen into helium conversions only happened for a certain amount of time, until the temperature cooled to a point where hydrogen began repelling itself again, like it normally should.
On a side note, it is difficult for scientists to produce fusion reactions here on Earth because we cannot produce temperatures high enough to allow hydrogen to "stick". Also, there is no container that can sustain such tremendous heat. Everything melts on contact. ;)
Hope that answers your question! In short, hydrogen and helium repel each other, but hydrogen interacting with itself under tremendously high temperatures can fuse to form helium.
P.S. - Can you tell I'm done my final exams? ;)
Ermmmm..... You're pretty much unstumpable......... Wann make something a little easier for us? Lol.
Diamond187
04-23-2004, 03:58 PM
four positively charged hydrogen nuclei, which fuse together to form helium
Not to be picky or anything but, helium is element number 2, meaning it has 2 protons. And since hydrogen nuclei are just protons, it only takes 2 hydrogen nuclei to make helium. It does require 2 additional neutrons, however, to make helium.
Yeah, that's generally what I meant. 4 hydrogen nuclei fuse together to make helium, a positron, and a neutrino, but I just referred to the last bit as "energy" to simplify things.
Technically, you can't have helium without 4 hydrogen nuclei, regardless of whether helium only has 2 protons. The fusion reaction occurs with 4 hydrogen nuclei.
Chemistry was never my strong point, but this is as far as I know from nuclear physics. ;) If I'm still wrong, lemme know... :lol:
Diamond187
04-24-2004, 10:27 PM
That could be true, but you'd need two electrons to fuse with two of the protons to make neutrons. I know that process theortically happens in reverse in certain decays, but I don't know about fusing, so you could be right.
¿CRAZYØ¿
04-26-2004, 04:07 PM
name the three types of galaxies?
what is a binary star?
What is the main substance in a star?
Good questions.
(1) Three types of galaxies are spiral (which is what our galaxy is) elliptical, and irregular.
(2) A binary star system contains two stars that orbit each other around a center of mass. We have evidence of binary stars because when one of them passes in front of the other, we can observe (through spectral lines) a change in the spectrum that is emitted from that system. The star that is being eclipsed will become "dimmer". Also, when one of the star's orbits comes close to the other star, we observe an orbital acceleration, since when two gravitational bodies come close to one another in an orbit, there is a gravitational slingshot effect that creates an acceleration. This is how astronauts use space shuttles around the Moon. They use the Moon's gravity to slingshot them around, giving them speed, which allows them to conserve fuel and accelerate back to Earth.
The methods we use to find binary stars are also used to find planets around other stars. When we observe a small dimming on a star, we can predict what kind of planet is orbiting that star and learn a lot of properties associated with that planet. We have yet to find any planets around other stars that could contain life using this eclipsing method, though.
The first person who can tell me why that is will get 20 X-Cash. (try to guess first before you cheat...lol) Here's a hint: Keep in mind that the only reason we know those planets exist is because of the fact that the star gets dimmer every certain number of days, which is how often the hypothetical planet passes in front of the star.
(3) Stars are mainly composed of hydrogen and helium. It is approximately 90% hydrogen and 8% helium, with the rest of the composition being other things, like oxygen, carbon, and so on. The star uses the greater abundance of hydrogen to create more helium, and as this happens, the star becomes less massive and grows larger in size, which is what our Sun is doing right now.
¿CRAZYØ¿
04-27-2004, 03:03 PM
How do you tell what a star will become before it's life is over when it is just brand new?
Diamond187
04-27-2004, 03:40 PM
I'll take a wild guess that the slight dimming would be the planet passing between the star and ourselves. But that would be a really tiny effect unless the planet was really far from the star and a gas giant. There is no way that method would work for detecting planets like Mercury or Venus, maybe not even Earth-like planets. If I'm wrong on that, please correct me.
ripht|CoC
04-28-2004, 12:06 AM
What does the following symbol stand for?
http://www.symbols.com/pics/big/41a/41a26.gif
Also, what major historical event coincided with the discovery of this? (Not that the symbol stands for this, it in itself (:P))
Hey guys, sorry, I just started a new job and they are severely under-staffed...lotsa shifts means lotsa money...anyways!
Heh...ahh, signs...
That would be the symbol for the planet Uranus, which was discovered by a Mr. William Herschel.
And Diamond, you are pretty much right. Except, the ironic thing is that the planets that are being found are gas giants (like you said), but have periods of a few days! That means that these planets are Jupiter-sized, but are closer to the star than our inner planets. So along with not having a surface, they go against our ideal structure of a solar system where a gas giant forms far from the parent star. Interesting stuff. 20 X-Cash for you. :)
crusty
05-10-2004, 04:34 PM
Which moon of Saturn was almost shattered by the object that produced the Herschel Crater on its surface?
Answer that. You probably will..
I think remember this little piece of knowledge from my Astro 120 course on planets and solar systems. The moon is either Mimas or Enceladus, but I'm gonna say Mimas because I remember some pretty cool pictures of it, and also because Enceladus is always shown as being really smooth. The other moons are either too big or too small to be threatened by being destroyed upon impact. The smaller ones wouldn't survive at all, and the bigger ones would not be affected much.
crusty
05-10-2004, 06:05 PM
I hate you. :P
Hows about this;
'In 2136 B.C., the two Imperial Court astronomers in China were executed for not predicting a solar eclipse. Name them'
:lol: Hey, no fair. I dub that an invalid question! ;)
MercuryLime
05-14-2004, 07:45 AM
Yeah, that's way too hard.
Wait, why am I in this thread?
crusty
05-15-2004, 06:30 PM
Wrong. Hsi and Ho. You owe me XCash.
Proof, you say? Clickies (http://www.funtrivia.com/submitquiz.cfm?quiz=12439). Scrollifer down to question deux.
Diamond187
05-15-2004, 06:32 PM
Uh, what were they're last names? And were they related to the 7 dwarves? (Hsi Ho, get it? Hsi, Ho.)
crusty
05-15-2004, 09:11 PM
*Booo..* Get off the stage, Diamond! I believe those are their last names.. Not quite sure, however.
Fiz owes meh! :P
Hey dude, that's not an astronomy question, its a history question, so nyah! :)
crusty
05-16-2004, 11:19 AM
Since when have astronomers ceased relativity to astronomy? So nyah back!
Hmm, I never got a reply notification of this... :lol:
2 weeks later...hehe...okay, I'm not gonna argue anymore cuz its taking away from this thread, so I'll give you the X-Cash. For future reference however, let it be known that history is history and astronomy is astronomy. If you knew a lot about the science of violent weather and I asked you who the first person to discover a tornado was, I wouldn't expect you to know that. Kudos if you did, but that's not relavant to the actual science itself. Its just history. :)
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