Post by Ginnie on Jan 15, 2008 21:06:27 GMT -4
I've been reading a fascinating book by Patrick Moore - 'On the Moon', and came across some very interesting observations:
"There is a trace of atmosphere, but the density is so low that it corresponds to what we normally call a good laboratory vacuum. The total weight of the entire lunar atmosphere is no more than 30 tons"
"Take the whole of the Lunar atmosphere, compress it to the density of the Earth's air at sea level - and it would just about fill a cube with a side length of 200 feet. It may be considered as a collisionless gas. The density is no more than one ten-thousand-millionth of that of our atmosphere."
Apollo 15 and 16 orbiters detected small quantities of radon and polonium gas seeping out below the Moon's crust, produced by the radioactive decay of uranium. Lots of that in the moon rocks. Apollo 17 did the LACE experiment and found helium and argon. Argon seeped out more a few hours before each lunar sunrise. The helium came from the solar wind.
In the Leonid meteor shower of 1998 meteor impacts on the moon created a cloud of sodium gas which then escaped from the moon's surface. Sodium atoms were 'pushed away' by the pressure of sunlight and reached the vicinity of Earth two days later.
A meteor approaching the moon would have to be about 600 feet in diameter to be seen by an Earth telescope and apparently there are no recorded pictures of a meteor hitting the moon.
Moonquakes happen all the time. The seismographs set up by Apollo astronauts recorded 1300 moonquakes per year. Most originate 500 to 600 miles below the surface. Meteorite impacts were also recorded. Some moonquakes were man-made, caused by the impacts of discarded lunar modules.
A one ton meteorite hit the moon in July 1972 and was recorded by the Apollo seismograph.
I find this fascinating because it indicate that stuff does happen on the moon. Perhaps some of the 'rolling' boulders are caused by a moon quake?
Added: He doubts that any moonquake would register more than 3 on the Richter scale.
Some examples of the force equivalents:
0.5 5.6 kg (12.4 lb) 23.5 MJ large Hand grenade
1.0 32 kg (70 lb) 134.4 MJ Construction site blast
1.5 178 kg (392 lb) 747.6 MJ WWII conventional bombs
2.0 1 metric ton 4.2 GJ late WWII conventional bombs
2.5 5.6 metric tons 23.5 GJ WWII blockbuster bomb
3.0 32 metric tons 134.4 GJ Massive Ordnance Air Blast bomb
So if the equivalent of a 'Massive Ordnance Air Blast' happened 500 miles below the surface of the moon, could it move a few rocks on the surface?
A MOAB bomb : "MOAB length is 30 feet (9.17 m), diameter is 40.5 inches (102.9 cm), weight is 21,000 lb. (9.5 tonnes), of which 18,700 lb. (8.4 tonnes) are high explosives. Blast radius is 450 feet (137.61m, 150 yards), though the massive shockwave created by the air burst is said to be able to destroy an area as large as nine city blocks."
"There is a trace of atmosphere, but the density is so low that it corresponds to what we normally call a good laboratory vacuum. The total weight of the entire lunar atmosphere is no more than 30 tons"
"Take the whole of the Lunar atmosphere, compress it to the density of the Earth's air at sea level - and it would just about fill a cube with a side length of 200 feet. It may be considered as a collisionless gas. The density is no more than one ten-thousand-millionth of that of our atmosphere."
Apollo 15 and 16 orbiters detected small quantities of radon and polonium gas seeping out below the Moon's crust, produced by the radioactive decay of uranium. Lots of that in the moon rocks. Apollo 17 did the LACE experiment and found helium and argon. Argon seeped out more a few hours before each lunar sunrise. The helium came from the solar wind.
In the Leonid meteor shower of 1998 meteor impacts on the moon created a cloud of sodium gas which then escaped from the moon's surface. Sodium atoms were 'pushed away' by the pressure of sunlight and reached the vicinity of Earth two days later.
A meteor approaching the moon would have to be about 600 feet in diameter to be seen by an Earth telescope and apparently there are no recorded pictures of a meteor hitting the moon.
Moonquakes happen all the time. The seismographs set up by Apollo astronauts recorded 1300 moonquakes per year. Most originate 500 to 600 miles below the surface. Meteorite impacts were also recorded. Some moonquakes were man-made, caused by the impacts of discarded lunar modules.
A one ton meteorite hit the moon in July 1972 and was recorded by the Apollo seismograph.
I find this fascinating because it indicate that stuff does happen on the moon. Perhaps some of the 'rolling' boulders are caused by a moon quake?
Added: He doubts that any moonquake would register more than 3 on the Richter scale.
Some examples of the force equivalents:
0.5 5.6 kg (12.4 lb) 23.5 MJ large Hand grenade
1.0 32 kg (70 lb) 134.4 MJ Construction site blast
1.5 178 kg (392 lb) 747.6 MJ WWII conventional bombs
2.0 1 metric ton 4.2 GJ late WWII conventional bombs
2.5 5.6 metric tons 23.5 GJ WWII blockbuster bomb
3.0 32 metric tons 134.4 GJ Massive Ordnance Air Blast bomb
So if the equivalent of a 'Massive Ordnance Air Blast' happened 500 miles below the surface of the moon, could it move a few rocks on the surface?
A MOAB bomb : "MOAB length is 30 feet (9.17 m), diameter is 40.5 inches (102.9 cm), weight is 21,000 lb. (9.5 tonnes), of which 18,700 lb. (8.4 tonnes) are high explosives. Blast radius is 450 feet (137.61m, 150 yards), though the massive shockwave created by the air burst is said to be able to destroy an area as large as nine city blocks."