The Moons Atomosphere

[Theredbarron]

Why is it that people on here ignore that the moon has an atmosphere? 

https://en.wikipedia.org/wiki/Atmosphere_of_the_Moon

its says .3 npa which from all sources that converts to 4 psi just for easy comparison. Our atmosphere is at 14.7 psi. Mars atmosphere is at 14.6 psi. It may not be one just like ours but it is one. 

 

sorry that was 4 to the -14

Whats collecting the gasses that it does have is what I want to know

Mars is half the size of earth and has half the surface speed of earth approximately and has almost the same amount of psi as earth. Why isn't there a relationship between the atmospheres and the size and speed of the planets including the moon?

Conveniently about the same amount of hrs in a day on mars as it is here.

[Moontanman]

42 minutes ago, Theredbarron said:

Why is it that people on here ignore that the moon has an atmosphere? 

https://en.wikipedia.org/wiki/Atmosphere_of_the_Moon

its says .3 npa which from all sources that converts to 4 psi just for easy comparison. Our atmosphere is at 14.7 psi. Mars atmosphere is at 14.6 psi. It may not be one just like ours but it is one. 

 

sorry that was 4 to the -14

Whats collecting the gasses that it does have is what I want to know

Mars is half the size of earth and has half the surface speed of earth approximately and has almost the same amount of psi as earth. Why isn't there a relationship between the atmospheres and the size and speed of the planets including the moon?

Conveniently about the same amount of hrs in a day on mars as it is here.

I'm not sure where you are getting your conversions to psi, mars has an atmosphere of less than 1% that of earth definitely not 14.6 psi and the moon's atmosphere is a very good vacuum compared to earth's. I suggest you recalculate your conversions.. 

[Strange]

37 minutes ago, Theredbarron said:

its says .3 npa which from all sources that converts to 4 psi just for easy comparison.

0.3 nano pascals is 4 x 10^-14 psi. https://www.wolframalpha.com/input/?i=0.3+nano pascals+in+psi

In other words the atmospheric pressure on Earth is about 400,000,000,000,000 times greater than the pressure on the moon. 

I do hope you were not about to claim that the Moon's almost non-existent atmosphere is responsive for its gravity.

42 minutes ago, Theredbarron said:

Whats collecting the gasses that it does have is what I want to know

Mainly, the fact that gasses are released from the surface.

"For most practical purposes, the Moon is considered to be surrounded by vacuum."

"Otherwise, the Moon is considered not to have an atmosphere because it cannot absorb measurable quantities of radiation, does not appear layered or self-circulating, and requires constant replenishment due to the high rate at which its gases are lost to space."

"One source of the lunar atmosphere is outgassing: the release of gases such as radon and helium resulting from radioactive decay within the crust and mantle. Another important source is the bombardment of the lunar surface by micrometeorites, the solar wind, and sunlight, in a process known as sputtering."

https://en.wikipedia.org/wiki/Atmosphere_of_the_Moon

 

41 minutes ago, Theredbarron said:

Mars is half the size of earth and has half the surface speed of earth approximately and has almost the same amount of psi as earth.

"The atmospheric pressure on the Martian surface averages 600 pascals (0.087 psi; 6.0 mbar), about 0.6% of Earth's"

https://en.wikipedia.org/wiki/Atmosphere_of_Mars

 

So every single fact in your post appears to be wrong.

 

Now, what was your point?

[Theredbarron]

Nope just trying to answer some questions is all

Where can I get the good information from?

[Strange]

1 minute ago, Theredbarron said:

Where can I get the good information from?

A good astronomy book?

Wikipedia is usually a pretty good starting point; you can follow up with the references for more details.

But a web search will produce plenty of other sources.

[Moontanman]

1 minute ago, Theredbarron said:

Nope just trying to answer some questions is all

Where can I get the good information from?

I would suggest you start by paying attention to the figures Strange gave you. I don't know how you got your conversions but it looks like your math was way way way off... 

[Theredbarron]

Is mars atmosphere that low due to the density of it?

nevermind

[Strange]

Just now, Theredbarron said:

Is mars atmosphere that low due to the density of it?

What? Is the density low because the density is low?

The density is lower because there is less pressure. There is less pressure because the surface gravity is lower.

[Moontanman]

1 minute ago, Strange said:

What? Is the density low because the density is low?

The density is lower because there is less pressure. There is less pressure because the surface gravity is lower.

It should be noted that even under earth's gravity mars would have very little pressure.. 

[Theredbarron]

1 minute ago, Moontanman said:

It should be noted that even under earth's gravity mars would have very little pressure.. 

Is that due to the composition?

[Moontanman]

1 minute ago, Theredbarron said:

Is that due to the composition?

It's due to the lack of mass, the atmosphere of Mars is far less massive than earth's. If you could give mars the same gravity as earth but keep it's current atmosphere the pressure would still be tiny compared to earth's (I'll go out on a limb and say the pressure would still be less than 3% of earth's)  then there is the fact that mars' atmosphere is just CO2, little to nothing of anything else... 

[Strange]

11 minutes ago, Moontanman said:

It should be noted that even under earth's gravity mars would have very little pressure.. 

True. It is not as simple as just gravity. There are sources providing gas to the atmosphere and there are variable factors that remove gas (temperature, solar wind, etc)

[studiot]

Interestingly the presence of water as ice on the surface of the Moon has just been announced.

 

https://www.bbc.co.uk/news/science-environment-45251370

 

Also interestingly these pressures are similar to the sublimation pressure of ice at lunar surface temperatures.

The pink arrow shows the sublimation line from ice to vapour.

 

 

source

https://www.nist.gov/sites/default/files/documents/srd/jpcrd402011New.pdf

 

 

[Janus]

2 hours ago, Theredbarron said:

Is mars atmosphere that low due to the density of it?

nevermind

It is believed that Mars once had a thicker atmosphere.  But because of it smaller mass, Mars has a lower escape velocity than the Earth does. (less than 1/2) and this made it easier for Mars to lose its atmosphere over time, especially once its geological processes slowed the venting of gasses to replace it. (Again, at just 1/10 the mass of the Earth, Mars' interior cooled faster.)  The loss of of an active interior also could have resulted in a severe weakening of its magnetic field which protected its atmosphere from being stripped away by the solar wind.

Whether the loss of the majority of it atmosphere is just due to a slow bleeding/stripping away over time, or could have been helped by a catastrophic collision with a another body is still an open question.

[Theredbarron]

2 hours ago, Janus said:

It is believed that Mars once had a thicker atmosphere.  But because of it smaller mass, Mars has a lower escape velocity than the Earth does. (less than 1/2) and this made it easier for Mars to lose its atmosphere over time, especially once its geological processes slowed the venting of gasses to replace it. (Again, at just 1/10 the mass of the Earth, Mars' interior cooled faster.)  The loss of of an active interior also could have resulted in a severe weakening of its magnetic field which protected its atmosphere from being stripped away by the solar wind.

Whether the loss of the majority of it atmosphere is just due to a slow bleeding/stripping away over time, or could have been helped by a catastrophic collision with a another body is still an open question.

By interior are you referring to the core?

[Janus]

2 hours ago, Theredbarron said:

By interior are you referring to the core?

Core, magma layer, anything below the crust.   Mon Olympus is a giant shield volcano that is evidence that Mars was much more geologically (areologically) active in its past, producing the type of lava flows needed to build such a volcano,  which in turns suggests a past magma layer beneath under the crust.

[Theredbarron]

Is the moons surface in a vacuum or is it technically not a vacuum?

[beecee]

1 hour ago, Theredbarron said:

Is the moons surface in a vacuum or is it technically not a vacuum?

From your own link in the OP....

"The atmosphere of the Moon is a very scant presence of gases surrounding the Moon. For most practical purposes, the Moon is considered to be surrounded by vacuum. The elevated presence of atomic and molecular particles in its vicinity compared to interplanetary medium, referred to as "lunar atmosphere" for scientific objectives, is negligible in comparison with the gaseous envelopes surrounding Earthand most planets of the Solar System. The pressure of this small mass is around 3×10⁻¹⁵ atm (0.3 nPa), varying throughout the day, and in total weighs less than 10 metric tonnes.^[2][3] Otherwise, the Moon is considered not to have an atmosphere because it cannot absorb measurable quantities of radiation, does not appear layered or self-circulating, and requires constant replenishment due to the high rate at which its gases are lost to space".

[StringJunky]

1 hour ago, Theredbarron said:

Is the moons surface in a vacuum or is it technically not a vacuum?

it has no atmosphere that is retained. Pressure is pretty much the same as interstellar space. On earth, it would be called a vacuum if you created that here. There's only about a million molecules per cubic metre.

[Strange]

6 hours ago, Theredbarron said:

Is the moons surface in a vacuum or is it technically not a vacuum?

It is pretty much a vacuum. (There is no such thing as a perfect vacuum, it is a relative term. If you created that little pressure in a lab you would consider it a pretty good vacuum.)

[Ghideon]

9 hours ago, Theredbarron said:

Is the moons surface in a vacuum or is it technically not a vacuum?

I think you can get different answers depending on the situation. On one hand I immediately agree with @Strange, the pressure is low enough to have minimal impact on experiments that requires vacuum.
But on the other hand, assuming identical pressure; does the small amount of air in the vacuum lab on earth have a different mixture of gasses than the vacuum on the moon? Are there some other types of experiments where that would make a difference?

 

[Strange]

13 minutes ago, Ghideon said:

But on the other hand, assuming identical pressure; does the small amount of air in the vacuum lab on earth have a different mixture of gasses than the vacuum on the moon? Are there some other types of experiments where that would make a difference?

Good point. I'm sure there are experiments where the composition matters: measuring the absorption of difference wavelengths of light, or the breakdown voltage or ...

[Theredbarron]

Ok so what would 30 in hg be in comparison to?

[Strange]

3 minutes ago, Theredbarron said:

Ok so what would 30 in hg be in comparison to?

What?

30 inches of mercury (if that is what you mean) is roughly standard atmospheric pressure on Earth: https://www.wolframalpha.com/input/?i=30+inches+mercury+in+psi

Edited August 28, 2018 by Strange

[Theredbarron]

Did I state that wrong? Is 30 in hg different from what I read on a vacuum gauge? 

Found it

So couldn't you put a chamber inside a chamber and drop the vacuum lower in the inner chamber?

So I'm still interested in playing with this concept. Maybe I can find a use but I would like to get it in a chamber with 30in pumped down. What should I use to measure what its doing? Or what would be a good idea to put inside that I can get an accurate measurement or weight of? I've got a pretty good idea of what it can do but I would like to test it out and see what else it can do.