Welcome back Steemians! In the last episode of "Trolls on the moon" we learned that there is no atmosphere above the lunar surface, well, more correctly, there is only it's super thin. But it hasn't always been like that. Follow me...
(Image source:pxhere.com)
In the long past (around 4 billion years ago)
When our earth and moon were still at their infancy stage, they went through the "Late Heavy Bombardment". At the time, our solar system was a dangerous place to be because activity was very high. Space rocks and asteroids would regularly spank them to teach them some discipline.
When the incidents of celestial violence stopped, the moon still had lots of negativity, anger and wrath inside it. Inner conflicts would show in the form of volcanic activity and blustery outbursts of gases would dress the irritated moon in a gaseous mantle, thick enough to provide it with an atmosphere, layers of yellowish or brownish gases (because of the high sulfuric presence). Scientists also presume that in a great part of this atmosphere there could be water.
On the lunar surface you could see seas of molten lava (AKA maria from latin) coming out of its volcanoes. After analyzing data and specimens from various lunar missions, scientists came to the conclusion that the moon would burp violently creating an atmosphere of pressure almost 1% of the present atmospheric pressure at sea level on the earth.
(Image source: commons.wikimedia.org)
This rageous puberty probably lasted for 70 million years. As the moon started to get anger out of its system and cool down, volcanic activity diminished and the gassy explosions stopped. Lunar maria (the huge seas we see through telescopes or the naked eye) filled up with hardened lava remained on its surface as a memento of the wild past. The weak gravitational forces failed keeping this atmosphere around the moon and the gas particles were swept away in space.
The ancient atmosphere of the moon is a recent discovery and means a lot to scientists. By getting to know more they will deduct a lot about the primary stages of our planet too.
From the long past to the present
Today the lunar atmosphere is so weak it cannot be considered an atmosphere but an exosphere. This means that unlike the earth's atmosphere where particles are relatively close and collide with each other, on the moon the gas particles are so far away, wandering independently and bouncing on the lunar surface. See the comparison for yourselves: at sea level the earth's atmosphere has about 100 billion billion molecules per cubic centimeter (cm3) (10^19 is a lot of digits, I know), whereas for the lunar atmosphere the number is 100 molecules per cubic centimeter.
(Image source: pixabay.com/)
Why is it so weak?
The moon cannot hold an atmosphere because of several reasons:
- It's mass is too little to apply gravitational forces enough to retain gas particles around it.
- The gases on the moon consist of lighter particles, meaning that they can move around more easily.
- The escape velocities of gas particles rise when the sun heats the lunar surface (during daytime), so they can get away very easily.
- Solar wind also sweeps away those gases (although it may help replenish them in a different time).
Composition
According to NASA, the Apollo 17 mission found traces of helium, argon, and possibly neon, ammonia, methane and carbon dioxide. Through telescopes scientists have also detected atoms of sodium and potassium, but the list awaits to be completed.
What feeds it?
This is still a mystery, but the various hypotheses include:
- Strikes of solar wind and high energy photons that scratch atoms from the lunar soil (sputtering).
- Celestial bodies (comets and asteroids) that hit the moon and release atoms (sputtering).
- Chemical reactions of the lunar soil atoms and solar wind.
- Evaporation of lunar soil ingredients.
- The moon's interior by outgassing (often during moonquakes), when the surface temperatures drop (during night-time), the escape velocities lower and gas particles can't get away that easily.
And a short video to revise what we've learned:
References
skyandtelescope.com
popularmechanics.com
csep10.phys.utk.edu
space.com
nasa.gov
Thank you for stopping by and giving this post a read. I hope you enjoyed it! If you please, feel free to pay a visit to my blog and check out my short stories along with plenty of educational posts and of course my bizarre natural phenomena series.
Until my next post,
Steem on and keep smiling, people!
