Density of space

whozum

Temperature is the measure of kinetic energy of the particles in an atom.

In space, pressure is nearly nonexistant due to the lack of atmosphere, this will cause your body to explode because the inside of your body is pressurized, my guess is at a pressure of 1 atm.

misskitty

So wait, if space has a lack of atmosphere, then how and why does it form around the planets and how they pull matter into them when they first start out?

turbo-1

if you are commenting on the statement about freezing to death while you are being irradiated, here's an analogy.

If someone touched your skin with a thin accupuncure needle at 300 degrees F, you would feel it like a prick on the skin and the temperature of the needle would rapidly approximate that of your skin. If someone touched your skin with a 16 penny nail at 300 degrees F it would hurt. If you put your hand on an anvil that is at 300 degrees, you would suffer severe burns. The damage is a function both of the energy level of the source and the mass (or flux in the case of radiation) of the source. Another example: You can go skiing on a bright (not even fully sunny) day and freeze your toes off all day long and end up with a severe sunburn if you're not careful. It's worse on more northern mountains with colder temperatures and less atmosphere to protect you from the UV. You don't even realize the UV is cooking you until it is too late.

whozum

Space doesnt form around plantes, planets form in space. Planets attract matter towards them via gravity.

Atmosphere is the collection of gasses and matter. For example, earth's atmosphere is made up of nitrogen, oxygen, carbon dioxide, etc.

misskitty

Ah, ok. Makes sense, I think. Pretty sure. The first part of my question was just asking how atmosphere forms around planets in space.

Whozum, you must think I am a complete and utter air head.

Turbo, great analogy. I guess I'll ahve to be more careful with my little pyro tendencies. just kidding.

Whozum, where does the matter that "starts" the planet get the gravity to attract smaller particles and eventually larger particles? Does it just have it?

whozum

If I remember correctly, the big bang didnt disperse matter perfectly evenly, so there were regions of space that were relatively denser than others. From there, the gravity in this region brought these particles together, and those particles, now armed with a stronger gravitational force, brought more together, and so forth.

Air head? Nonsense. A student. :)

misskitty

Glad to know you don't think I'm an air head.

What would cause the big bang to unevenly distribute the matter?

Chronos

It didn't, which is fortunate for us. The entire universe would have recollapsed back upon itself before we had a chance to come into being had the initial distribution of matter not been extremely smooth.

timothyjr

These posts seem to be more about the density of matter IN space. What about any thoughts to the density OF space. There must be some value of space itself that gives the speed of light its constant value?

DaveC426913

This thread has been bumped after 4 years of minding its own business. Nothing wrong with that in and of itself...

... but it did cause me a bit of a start to see Self-Adjoint again...

Chronos

See permissivity and permitivity, but, the larger question is harder. It takes a lot of fancy math and observational evidence to pin it down, and no one knows why c is c, or h is he. It is clear, however, such values are necessary to permit observers like us ask the question. Im not a multiverse fan, but, it is logical. In an infinite universe, at least one patch must permit physical parameters conducive to life to exist. Any theory that forbids our existence is illogical.

Wallace

Thems be the line of thinking that lead to the aether theory that was busted by a combination of the Michelson and Morley experiment and the theoretical advances of Einstein, Hilbert and others.

Space itself is not a thing in General Relativity. That's actually a really important (and tricky) concept to try and get your head around. You can't uniquely talk about that some region of space does without specifying a co-ordinate system, which General Relativity demands not be unique. Therefore anytime you try and pin down a property of some region of space, you have to make arbitrary co-ordinate choices which make your interpretations equally arbitrary.

I'm getting a little long winded, but the important thing is that space does not have a density, the constants of nature are what they are for reasons not yet understood. There is the question of a possible non-zero vaccuum energy density, but that is a different question not related to the speed of light (at least as far as we know!).

As an aside, holy threadcromancy Batman! I thought for a moment that Space Tiger was back, but not to be....

timothyjr

Density is probably not the right word... maybe a coefficient of space would be better... and not of a unique region, but of allspace. I think it exists and I am going to keep looking for "the reasons not yet understood".

Ich

You can attribute some kind of an index of refraction to space, which defines the speed of light. That wourks perfectly for light, but not for other things. For the complete theory, you need six numbers (I think).