Announcement

**Drake Tungsten** · January 10, 2004, 02:25

So what causes leakage in the first place? Do small amounts of oxygen get accelerated past escape velocity somehow? Or is there some other process that my physics-impaired ass doesn't know about? I'm intrigued...

**KrazyHorse** · January 10, 2004, 02:30

Not all molecules are at rms velocity

They follow a Boltzmann distribution.

exp (-E/kT)

so there are always some greater than escape velocity.

How many that is depends on temperature, mass of molecule and what escape velocity

rms velocity of H2 at stp is ~1700 m/s IIRC (it has to be 4X that of O2), which is much less than earth's escape velocity which is into the tens of km/s

But there's no H2 in earth's atmosphere (or hardly any)

**KrazyHorse** · January 10, 2004, 02:31

Sorry. escape velocity on moon is actually ~2.5 km/s
Earth's is the one at 11 km/s
Point still stands.

**KrazyHorse** · January 10, 2004, 02:37

Situation is even more complicated than that, because the mean free path of molecules in an atmosphere as dense as the earth's is very small, so not all molecules at escape velocity will make it all the way out.

Those already in outer reaches of atmosphere will have best chance.

**Drake Tungsten** · January 10, 2004, 02:38

Interesting. Thanks.

**Agathon** · January 10, 2004, 03:42

Originally posted by TCO
dEAN IS ALREADY THERE.

**Starchild** · January 10, 2004, 06:51

Is my quality of life on Mars significantly better than I would have on Earth? I don't want one of those damn frontier communities with weirdly asymmetrical economies and no doctors. Pioneers die young. Let Mars settle down into civilised society for a few hundred years and then I'd think about it.

I'm patient after all.

**The Mad Monk** · January 10, 2004, 07:03

One interesting point about establishing a breathable atmosphere on the Moon or on Mars that I had not considered until very recently is that, thanks to the lower gravities, it would have to be much thicker than Earth's to achieve the same pressure.

**KrazyHorse** · January 10, 2004, 07:06

"Thicker"?

I'm assuming you mean heightwise.

That is true.

**The Mad Monk** · January 10, 2004, 07:11

Yes, heightwise.

I don't like the idea of terraforming an atmosphere. It would take a lot of work, and would remove many of the advantages of colonizing the Moon in the first place.

**KrazyHorse** · January 10, 2004, 07:16

Terraforming is in distant future, AFAIK

And it migh remove some advantages, but provide a hell of a lot too.

Think about how much cheaper and safer it is to work under 100 kPa than it is to work under 0

**TCO** · January 10, 2004, 07:19

I woke up. too much drinking. caps lock came off too.

**The Mad Monk** · January 10, 2004, 07:19

Think the of view from Lunar Observatories once that extra-thick atmosphere is in place.

**KrazyHorse** · January 10, 2004, 07:20

Easier to keep satellites in orbit, no?

Especially for large mirrors. Gravity is chief problem with current large mirrors.

**KrazyHorse** · January 10, 2004, 07:20

Originally posted by TCO
I woke up. too much drinking. caps lock came off too.

How much you have, sailor?

Feel okay or sick?

Announcement

If you could emigrate to Mars, but could never come back to Earth, would you go?

Comment

Comment

Comment

Comment

Comment

Comment

Comment

Comment

Comment

Comment

Comment

Comment

Comment

Comment

Comment