# Space temperature question

obvek
Posers and Puzzles 10 Oct '05 01:01
1. 10 Oct '05 01:01
I just thought of this today and it kinda stumped me, and i suddenly knew exactly where to ask it- the rhp forums.

There is no mass in space, yet scientists say that space is a few degrees above absolute zero. Correct me if I'm wrong, but it takes mass to have temperature, right? How can space be massless and still have temperature?
2. 10 Oct '05 01:106 edits
Originally posted by obvek
I just thought of this today and it kinda stumped me, and i suddenly knew exactly where to ask it- the rhp forums.

There is no mass in space, yet scientists say that space is a few degrees above absolute zero. Correct me if I'm wrong, but it takes mass to have temperature, right? How can space be massless and still have temperature?
I think you mean zero-gravity, right?
Because you can't feel the affect earth's gravity pulling you, but it still is actually.
Weight is a measurement of gravity on mass. Mass does not change with gravity, weight does.

Temperature is just measurement of kinetic energy of atomic particles.
All matter has no kinetic energy "freezes/stops" at absolute zero. in theory.
This explains why objects expand and contract with temp.
Also why elements or compounds are more reactive with higher temps.

So yes, you must have mass to have a measurable temp, basicly.

Or is mass and temp is a property of matter? So matter is needed. I thinks thats a better answer.

I have no degree on the topic. So you and I will be set straight soon.
3. 10 Oct '05 01:18
Originally posted by obvek
I just thought of this today and it kinda stumped me, and i suddenly knew exactly where to ask it- the rhp forums.

There is no mass in space, yet scientists say that space is a few degrees above absolute zero. Correct me if I'm wrong, but it takes mass to have temperature, right? How can space be massless and still have temperature?
Well, your average bit of space isn't completely devoid of matter; it has bits of dust and stuff in it too. And, of course, your thermometer ðŸ˜µ.
4. 10 Oct '05 01:43
So what is the temp of a single free proton or neutron as it flies through your skull like a bullet.

Astronauts say they see flashes of light when free particles like this pass trough their retinas.

All solid matter is mostly empty space.
5. XanthosNZ
Cancerous Bus Crash
10 Oct '05 05:23
Pressure in space is in the order of 10^-20 Pa (Pascals).
It's not zero.
6. Suzianne
Misfit Queen
10 Oct '05 06:07
Correct. Space is obviously not mass-less. There are things like insterstellar dust, comets, and meteors, and asteroids, and planets and stars and galaxies and stuff in it. Not to mention nebulas and stuff given off by supernovas and quite a bit more free hydrogen than you'd expect. AND not to mention somewhat hypothetical stuff, like dark matter.

While the local tempurature, like inside star systems, is quite a bit above absolute zero, there is a heck of a lot of space between galaxies that is relatively matter-free, and therefore a lot closer to absolute zero. So much so that the hypothesis is that the overall average temp of the universe ends up being slightly above absolute zero.
7. Bowmann
Non-Subscriber
10 Oct '05 16:061 edit
Originally posted by obvek
I just thought of this today and it kinda stumped me, and i suddenly knew exactly where to ask it- the rhp forums.

There is no mass in space, yet scientists say that space is a few degrees above absolute zero. Correct me if I'm wrong, but it takes mass to have temperature, right? How can space be massless and still have temperature?
The "vacuum" of space is essentially mass-free. There's around 1 atom of hydrogen per cubic centimetre.

The reason why the temperature is not absolute zero is very simple. Absolute zero, or 0 Kelvin, does not exist anywhere. It's a theoretical temperature, if you like. Heat travels from a warm area to a cooler one. That's how things cool down. So, for absolute zero to exist, there would have to exist a place which is cooler still. And this is not possible.
8. 12 Oct '05 02:13
So what you're saying is that the scientists, when they give the average temperature of space, are actually giving the average temperaturo of the gas, dust and other particles floating around out there?
9. XanthosNZ
Cancerous Bus Crash
12 Oct '05 05:41
Originally posted by obvek
So what you're saying is that the scientists, when they give the average temperature of space, are actually giving the average temperaturo of the gas, dust and other particles floating around out there?
Replace the second temperature with average velocity and yes.
10. 12 Oct '05 13:11
What the heck!! Cant we discuss issues that could feed the hungry, I love space and everything in it but this discussion has no relevence to any of our lives.

How can we feed the hungry?
11. PBE6
Bananarama
12 Oct '05 14:02
Originally posted by Alan "Soylent" Green
What the heck!! Cant we discuss issues that could feed the hungry, I love space and everything in it but this discussion has no relevence to any of our lives.

How can we feed the hungry?
We could feed you to them. That would help a little bit.
12. sonhouse
Fast and Curious
12 Oct '05 17:56
rOriginally posted by obvek
I just thought of this today and it kinda stumped me, and i suddenly knew exactly where to ask it- the rhp forums.

There is no mass in space, yet scientists say that space is a few degrees above absolute zero. Correct me if I'm wrong, but it takes mass to have temperature, right? How can space be massless and still have temperature?
What the temperature of space means there is a background of
microwave radiation that would heat something very cold, say at 1
degree Kelvin, up to the tempurature of 2.73 degrees Kelvin.
It has nothing to do with mass, its just microwave radiation which
is the leftover radiation from the big bang but because the universe
has expanded to billions of light years across, this radiation has
been stretched out by the same amount, so it originally was a much
higher frequency, shorter wavelength, and thus a higher tempurature
but if you make the wavelength longer, the energy content per
packet of radiation (each wavelength) goes down. I am not sure what
the original wavelength was, ten times higher, hundreds of times,
not sure but its been measured at 2.73 degrees Kelvin.
It also doesn't matter which direction you point your antenna, its nearly
the same in all directions. Thats what won the Nobel prize for Pensias
and his buddies.
13. XanthosNZ
Cancerous Bus Crash
12 Oct '05 19:22
Originally posted by sonhouse
What the temperature of space means there is a background of
microwave radiation that would heat something very cold, say at 1
degree Kelvin, up to the tempurature of 2.73 degrees Kelvin.
It has nothing to do with mass, its just microwave radiation which
is the leftover radiation from the big bang but because the universe
has expanded to billions of ...[text shortened]... nearly
the same in all directions. Thats what won the Nobel prize for Pensias
and his buddies.
14. sonhouse
Fast and Curious
12 Oct '05 19:29
Originally posted by Alan Green
What the heck!! Cant we discuss issues that could feed the hungry, I love space and everything in it but this discussion has no relevence to any of our lives.

How can we feed the hungry?
What about those hungry for information?
15. sonhouse
Fast and Curious
12 Oct '05 21:41
Originally posted by XanthosNZ