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Physics, Astronomy & Cosmology / how much would I weigh if there was no air?

« on: 08/03/2011 22:45:02 »

"how much would I weigh if there was no air?"

The same. Weigh is m*g and mass is the same, gravity is the same.

But if there's no air, then you would remove the mass of the air in your body, right? So this would mean that technically you weigh less... but then you can't breathe so I guess you won't be able to see your weight

The real question here should be "What would the scale say in a vacuum?"

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Physics, Astronomy & Cosmology / Have you seen this? Have you heard about this?

« on: 04/11/2010 21:27:34 »

http://listverse.com/2010/11/04/10-strange-things-about-the-universe/

That is all I have to say.

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Physics, Astronomy & Cosmology / Where does the energy go?

« on: 02/11/2010 02:37:49 »

Excuse me if this is a stupid question, but...

If one's chemical energy is being converted into kinetic energy, and that's helping you move up the ladder in the rocket that you're moving at the same speed as, is your kinetic energy (which is coming from chemical energy, being converted to body heat, as bill s. said) really going to change the center of gravity of a rocket that ways tons and tons more than you?

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Physics, Astronomy & Cosmology / Where does the energy go?

« on: 01/11/2010 19:21:25 »

Where did the climbing energy go?
 

I believe the energy went back to it's former potential state. Are your rockets in a frictionless, gravity free state? Or are they climbing out of orbit?

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General Science / How does a fushigi ball work?

« on: 31/10/2010 05:45:04 »

A fushigi ball works the same way a baseball or any other ball works.. It rolls around on your body. There's nothing special about it except for the fact that it costs 20 dollars and the people selling it call it by a fancy name.

Fushigi itself is an art form known as contact juggling.

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Physics, Astronomy & Cosmology / Does antimatter exist in its own \

« on: 30/10/2010 19:19:28 »

a photon is considered an antiparticle of an electron

I thought the positron was considered the antiparticle of the electron. Have I missed something?

Yes, you're correct. The positron is actually in my diagram, I made a crucial error. When the electron is moving back through time, it has a positive charge (I drew it with a negative charge.)

Here is a video showing positrons in a cloud chamber

This is our universe. I guess what I was trying to say is that antimatter is only a result of annihilation. You can still see antimatter, if only for a few seconds.

Watch this video as well, it explains the double slit experiment.

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Physics, Astronomy & Cosmology / Does antimatter exist in its own \

« on: 30/10/2010 09:34:08 »

Antimatter is an extension to the concept of the antiparticle to matter. (http://en.wikipedia.org/wiki/Antimatter)

For example, a positron is considered an antiparticle of an electron. A photon collides with an electron, creating what is called an annihilation. Now, the diagram shows photons moving backwards through time which suggests that they collide with the electron, but from what I understand (on a personal, futile level) is that it is the other way around.

Example using a Feynman diagram:

[diagram=604_0]

I can't draw. Anyway, basically what this says is that, the electron (the darker lines) are moving forward in time when their arrow is pointing up. A photon moving 'backwards' through time (notice how it stays in one spot in space) collides with the electron, sending it backwards in time (basically, it loops, allowing it to feel out it's path like in the double slit experiment). The positron then collides (hopefully!) with another photon, which causes it's spin to reverse again, causing it to land on a new more appropriate path.


Feel free to ask questions to clarify this post, it seems pretty solid to me but I don't mind editing to help make it more understandable.. Thanks

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Physics, Astronomy & Cosmology / Why can you not exceed the speed of light?

« on: 26/10/2010 06:15:48 »

So basically, in order to go the speed of light, you would need an infinite amount of mass to create an infinite amount of energy which you would be burning off for an infinite amount of time?

But the more mass you start with, the more energy you need to accelerate it...

Well, if you have an infinite amount of both, then that's not an issue... I understand what you're saying, I was just trying to reach a logical possibility based off of the information you provided.

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Chemistry / Do atoms have a gravitational pull?

« on: 25/10/2010 01:38:47 »

Do atoms have mass?

Yes

Does all mass have gravity?

Allegedly, yes

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Physics, Astronomy & Cosmology / Why can you not exceed the speed of light?

« on: 25/10/2010 01:32:40 »

So basically, in order to go the speed of light, you would need an infinite amount of mass to create an infinite amount of energy which you would be burning off for an infinite amount of time?

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Physics, Astronomy & Cosmology / Can you have two objects have equal density but not equal mass??

« on: 25/10/2010 01:02:15 »

Very interesting, thank you!!

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Physics, Astronomy & Cosmology / Can you have two objects have equal density but not equal mass??

« on: 25/10/2010 00:30:43 »

So technically, you could have something the size of the sun pulling equally on something the size of a basketball?

I won't ask for any math as long as you don't

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Physics, Astronomy & Cosmology / Can you have two objects have equal density but not equal mass??

« on: 25/10/2010 00:02:58 »

I was wondering if it was more about density rather than mass, because if two objects (made up of one substance each) are the same density, then they would have the same amount of mass, the only thing that would be different would be that one's diameter (in the case of beryllium and germanium) would be 8 times the size of the other...

Same density.. same amount of matter.. different size objects.. same gravitational pull? Right?

Even though one would be 1000 miles wide and the other is proportionally 8 times the size?

Ah, OK. For solid objects of uniform density, I think it's simply a question of the mass. The density has no effect.

I say that because, in Newtonian Mechanics at least, you can assume all the mass of a solid object acts at it's center of gravity, which, in the case of your spheres, would be right at the center of each sphere. So, the actual volume of the object does not matter. It's only the quantity of mass that has an effect.

Well, if the objects are more dense because their atoms are more heavily attracted to each other, wouldn't objects that are more dense in turn create a stronger gravitational pull? I mean, more dense means more mass in the area, but why are these objects more dense?

Is gravity making the atoms behave differently? Therefore, if an object is more dense, wouldn't that mean it has more gravity?

I mean, obviously yes, this is the case, sense more density = more mass which in turn = more gravity, but what makes objects more dense? (I guess this is finally the question I was trying to ask!)

Think of the objects having an equal number of mols

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Physics, Astronomy & Cosmology / Can you have two objects have equal density but not equal mass??

« on: 24/10/2010 23:40:49 »

Twice the volume* ?

For cubes, it will be eight times. The volume of a cube is, strangely enough, the cube of the length of a side.

The volume of a sphere is proportional to the cube of it's radius, so, if you double the radius, the volume will also be eight times greater.

so for theory's sake, Maybe it would be better if I used Beryllium and Germanium?

New set up: a sphere of Beryllium that has a volume of 160,000 m^3 and a sphere of Germanium that has a volume of 20,000 m^3... Am I there yet?

I think so, but I've kinda forgotten what the question was  []

Assuming you picked volumes that will result in spheres of equal mass, then I believe they will have equal gravitational effects (if that was the question of course).

I was wondering if it was more about density rather than mass, because if two objects (made up of one substance each) are the same density, then they would have the same amount of mass, the only thing that would be different would be that one's diameter (in the case of beryllium and germanium) would be 8 times the size of the other...

Same density.. same amount of matter.. different size objects.. same gravitational pull? Right?

Even though one would be 1000 miles wide and the other is proportionally 8 times the size?

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Physics, Astronomy & Cosmology / What is Dark Matter?

« on: 24/10/2010 23:25:03 »

As is Dark Energy; so where does that leave current cosmological thinking?

http://en.wikipedia.org/wiki/The_Cosmic_Landscape

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Physics, Astronomy & Cosmology / Can you have two objects have equal density but not equal mass??

« on: 24/10/2010 23:23:03 »

Twice the volume* ?

For cubes, it will be eight times. The volume of a cube is, strangely enough, the cube of the length of a side.

The volume of a sphere is proporttional to the cube of it's radius, so, if you double the radius, the volume will also be eight times greater.

so for theory's sake, Maybe it would be better if I used Beryllium and Germanium?

New set up: a sphere of Beryllium that has a volume of 160,000 m^3 and a sphere of Germanium that has a volume of 20,000 m^3... Am I there yet?

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Physics, Astronomy & Cosmology / Has the Universe expanded faster than light?

« on: 24/10/2010 23:16:20 »

Yes this is a mind melter indeed,

Firstly the universe has expanded faster than the speed of light (according to the most accepted view anyway). The time when expansion was at its fastest was a period called inflation.

We can only see back as far as aproximatly 13.75 billion years which tells us the known universe (i.e that which we can see) must be that big in radius. This does not mean the universe is that big in reality.Thanks to hubble we know that the universe is expanding and has done at an accelerating pace and its much bigger than the known size estimated by speed of light, therefore the space must have expanded faster than the speed of light.

At first glance this may appear to break some fundamental laws but its not matter thats moving that fast, just the space inbetween. So stars that are more distant than 14 billion light years may or may not be there but we have know way of telling at present as their light has not yet had enough time to reach us.

Hope this helps

Almost sounds as if the universe is rendering existence the same way a video game renders the levels/maps

Also, Chris, what if the universe has always been and we just popped out of the super massive black hole at the center of our galaxy? Doesn't matter shoot out of black holes? If I were to guess, I'd imagine that's how galaxies are formed (though who knows)

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Physics, Astronomy & Cosmology / At what speed does gravity move?

« on: 24/10/2010 23:07:50 »

Gravity moves at the speed of light !

That's the reason why Physicist around the world are in search of an evidence for Graviton !

If gravity "moves" at the speed of light, why doesn't it radiate/illuminate? If it really "moved" at the speed of light, couldn't light reflect off of it? Wouldn't this mean that gravity is "moving" faster than the speed of light? I placed the word move in quotes because as far as I am aware, there are no particles that make up gravity and therefore, nothing about gravity is 'moving' the way that light moves, or physical spacial objects move

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Physics, Astronomy & Cosmology / Can you have two objects have equal density but not equal mass??

« on: 24/10/2010 22:56:54 »

Twice the volume* ?

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Physics, Astronomy & Cosmology / Can you have two objects have equal density but not equal mass??

« on: 24/10/2010 21:45:03 »

Wow. Thank you for your responses. I feel much better now, haha.

I will give you guys a much clearer picture of what I was thinking because I was really excited initially and couldn't get my thoughts straight.

I'm picturing the two spheres, planets, whatever you want to call them, floating in a normal vacuum. Weightless space is unrealistic for this problem since even in a vacuum there is mass and energy defined as "quantum jitters", and if mass creates gravity then there is gravity everywhere, and therefore, weightless space is.. well, it doesn't make sense to me since weight is the measure of an object's reaction to gravity, etc etc.

I'm wondering about density because, if you think about it, the more dense an object is, the closer the atoms are together. So if an object made of manganese with an atomic number of 25 is twice the volume* as an object of tin with an atomic number value of 50, wouldn't this mean that the two objects would have an equal gravitational pull?

*Edit: used to say 'size'