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Mar 23 2013 11:06am
A couple days ago, a couple dozen papers were published from the Planck Explorer project and made freely available online (don't need any kind of journal access to read them).
http://www.sciops.esa.int/index.php?project=PLANCK&page=Planck_Published_Papers

And I see I misspelled Planck in the title, like I always do. :(

This post was edited by Azrad on Mar 23 2013 11:08am
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Mar 23 2013 11:21am
what is the planck mission?
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Mar 23 2013 11:26am
this might help
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Mar 29 2013 09:21am
how do we messure the time of the big bang? my guess is looking at the farthest objects we can see and caculate how long the light would take to reach us...so if we can only see 16 billion light years away then they guess it is 16b years old? because thats how long it took the light to reach us? We can't see past the speed of light that got too us so everything farther then 16billion lights years away is out of our sight?

thx for posting this if you can answer some of those for me I bet you would know..

Well we now know that first there was things moving at the speed of light before matter could form... the particals needed to slow down..soo 80 billon years after the big bang some how a switch came on that slowed everything and matter started forming from smaller bits...that was lets say 16 billion years ago or some where around there we believe.
soo what we thought was a big bang 16b years ago now is a what ? slow down period? Dam we change our minds a lot. Well some of us do when enough evidence points to a better theory at the time.

This post was edited by doomchaser on Mar 29 2013 09:23am
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Mar 29 2013 12:04pm
Quote (doomchaser @ Mar 29 2013 08:21am)
how do we messure the time of the big bang? my guess is looking at the farthest objects we can see and caculate how long the light would take to reach us...
One way it can be done is by reversing the Hubble constant. Every object in the universe (outside the local group, where gravity is strong) is receding from every other object, at a rate that is correlated with its distance from that object. If you reverse this, every object will be in the same location about 13 billion years ago.
http://en.wikipedia.org/wiki/Hubble's_law

Another way (which yields the same answer) is by temperature. At about 3000k, hydrogen gas is ionized. Ionized hydrogen has a huge cross section for scattering photons (it is opaque, like a shower door). The entire univese appears to have been filled with ionized hydrogen gas in the distant past at essentially the same temperature (making the entire universe opaque). The point where this gas ceased to be ionized (the instant the universe became essentially transparent) is called the surface of last scattering. By taking measurements of this surface you can work out how long ago this transition happened. This surface also puts an upper limit on how far back anything can be measured though the use of photons, photons that existed while the surface was intact can not be used to form images because they were scattered by the surface (like how you can't see though a shower door, it is just a haze).
http://en.wikipedia.org/wiki/Cosmic_microwave_background_radiation

Quote (doomchaser @ Mar 29 2013 08:21am)
so if we can only see 16 billion light years away then they guess it is 16b years old? because thats how long it took the light to reach us? We can't see past the speed of light that got too us so everything farther then 16billion lights years away is out of our sight?
This is essentially right except it isn't quite that simple. Since the further an object is away from the us, the faster is it moving away, there is a distance where objects are moving away faster than the speed of light. New light emitted from these objects can never reach us, but light emitted a long time ago can be seen. It is a difficult concept. Image a straight toy race car track:
A-----------B
You push a toy car at B towards A. But every second someone inserts a new piece of track between every existing piece of track. Will the car make it to the other end? It depends on how long the initial track was (and how fast the car is moving, but we are talking about the speed of light so that is fixed). If the initial track is too long, enough pieces will be inserted during the trip that the car will never make it. But if the initial track is short enough, the car can make it. At a certain length the car will just barley make it. Let's assume this is where we started it. When the car reaches point A we ask how far away is B? Is it the original distance between A and B (a distance shorter than the car's trip), is it the current distance between A and B (a distance longer than the car's trip which is now so large no future cars can be received from B), or is it the distance the car moved (the car's speed multiplied by the time it was moving on the track)? The distance the car moved would be analogous to 13 billion light years.

This post was edited by Azrad on Mar 29 2013 12:05pm
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Mar 29 2013 01:43pm
Quote (Azrad @ Mar 29 2013 11:04am)
One way it can be done is by reversing the Hubble constant. Every object in the universe (outside the local group, where gravity is strong) is receding from every other object, at a rate that is correlated with its distance from that object. If you reverse this, every object will be in the same location about 13 billion years ago.
http://en.wikipedia.org/wiki/Hubble's_law

Another way (which yields the same answer) is by temperature. At about 3000k, hydrogen gas is ionized. Ionized hydrogen has a huge cross section for scattering photons (it is opaque, like a shower door). The entire univese appears to have been filled with ionized hydrogen gas in the distant past at essentially the same temperature (making the entire universe opaque). The point where this gas ceased to be ionized (the instant the universe became essentially transparent) is called the surface of last scattering. By taking measurements of this surface you can work out how long ago this transition happened. This surface also puts an upper limit on how far back anything can be measured though the use of photons, photons that existed while the surface was intact can not be used to form images because they were scattered by the surface (like how you can't see though a shower door, it is just a haze).
http://en.wikipedia.org/wiki/Cosmic_microwave_background_radiation

This is essentially right except it isn't quite that simple. Since the further an object is away from the us, the faster is it moving away, there is a distance where objects are moving away faster than the speed of light. New light emitted from these objects can never reach us, but light emitted a long time ago can be seen. It is a difficult concept. Image a straight toy race car track:
A-----------B
You push a toy car at B towards A. But every second someone inserts a new piece of track between every existing piece of track. Will the car make it to the other end? It depends on how long the initial track was (and how fast the car is moving, but we are talking about the speed of light so that is fixed). If the initial track is too long, enough pieces will be inserted during the trip that the car will never make it. But if the initial track is short enough, the car can make it. At a certain length the car will just barley make it. Let's assume this is where we started it. When the car reaches point A we ask how far away is B? Is it the original distance between A and B (a distance shorter than the car's trip), is it the current distance between A and B (a distance longer than the car's trip which is now so large no future cars can be received from B), or is it the distance the car moved (the car's speed multiplied by the time it was moving on the track)? The distance the car moved would be analogous to 13 billion light years.


Best attempt we will see most likely thx...but 1 question now...if something is comming at you faster then the speed of light..When would you not see it anymore the instant it passed you? OR would you still see the path it took?
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Mar 29 2013 02:22pm
Quote (doomchaser @ Mar 29 2013 12:43pm)
Best attempt we will see most likely thx...but 1 question now...if something is comming at you faster then the speed of light..When would you not see it anymore the instant it passed you? OR would you still see the path it took?

Accelerating a object to that velocity would require an infinite amount of energy. Light emitted from it would be infinitely blue shifted on its approach meaning it would hit you with photons that have an infinite amount of energy which would result in your death. After it passed, further light emitted would be infinitely red shifted, containing 0 energy and would be undetectable (there is no difference between a photon with 0 energy and no photon at all).
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Mar 29 2013 02:24pm
nvm mind by the time you see it ...it has already passed you lol

guess we can see the path of light but the object is gone...i had too think of that last question...yes soon as we detect something moving faster it is only the path of light we see
the speed of light slows down to the constant we know soo yes we see the path of light as you call it constant but not the object. coming or going...the path there either way

This post was edited by doomchaser on Mar 29 2013 02:35pm
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Mar 30 2013 09:33am
I break your laws because I always have a camera ahead of the object in question to see the track ,,,you do not use enough in your equations,,why you never see the full possible answers.
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Mar 30 2013 05:06pm
Quote (doomchaser @ Mar 30 2013 08:33am)
I break your laws
They are not my laws, they are the laws of nature.

Quote (doomchaser @ Mar 30 2013 08:33am)
because I always have a camera ahead of the object in question to see the track
No you don't. You haven't done the experiment. "Unperformed experiments have no results (Peres)." Since you haven't done the experiment, you can only calculate what the results should be based on experiments that have actually been done and the properties of light (which you have demonstrated you know nothing about).

Quote (doomchaser @ Mar 30 2013 08:33am)
you do not use enough in your equations,,why you never see the full possible answers.
Because of your fundamental ignorance of the subject, any criticism you offer is worthless. The equations are not mine. You don't know the equations. Even if you did, you wouldn't know how to use them. You've never done the experiments. You have no results. Yet you criticize the process you don't understand or know the results of...

Your criticism of something you are fundamentally ignorant about makes about as much sense as any criticism I might offer someone who istranslating 15th century French poetry. The reality is, I wouldn't have a clue if they were translating it perfectly or totally wrong. Since I have no way of comparing their output with the input.

This post was edited by Azrad on Mar 30 2013 05:10pm
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