Cheesus Chrust!
The moon lives!
NASA's Lunar Reconnaissance Orbiter (LRO) has snapped shots showing that the Moon's crust has been stretched and pulled fairly recently to form tiny valleys on its surfaces. Recent valleys on the Moon's surface Recent valleys on the Moon's surface. Credit: NASA/Goddard/Arizona State University/Smithsonian Institution The …
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...or rather, very hot!
So, I was hanging on the edge of my seat... What's the scoop? Does the moon still have a hot core? Is there anyway to find out (from earth)? Probably not unless one observed some sort of Luna volcano??
Of course, if there's a heat source, then it could be harnessed when we (eventually) come to colonise the moon...
'Does the moon still have a hot core? Is there anyway to find out (from earth)? Probably not unless one observed some sort of Luna volcano??'
The exact state of the Moon's core is uncertain. Apollo left a series of ALSEPs packages on the surface to record heat flow from the interior and register impacts which could have revealed the structure of the interior. In their period of operation we found out the heat flow is very low, but nothing big enough to send a good shock through the core hit the Moon before the instruments were turned off. Having said that, some top notch seismic boffinry has been done on the Moon.
The best estimate is that the lunar core is tiny - no more than 350km across. It's probably nickel-iron alloy with sulfur and silicon like the Earth's core. It is suggested there is a solid or mostly solid inner core about half the diameter of the whole core. The outer core is probably liquid but not convecting violently like the Earth's (hence no appreciable lunar magnetic field), but this is somewhat disputed.
Over that is the mantle which is divided into two, a lower zone about 500km in diameter which appears to be either partially molten or highly plastic and might contain sizeable pockets of magma. The outer mantle is relatively cold, solid and appears not to contain any sizeable amounts of magma.
There has been some mathematical and laboratory modelling of the lunar interior by VU University Amsterdam which used the European Synchrotron Radiation Facility to examine the behaviour of postulated lunar magma under very high temperatures and pressures. Their discovery is that the titanium-rich magmas responsible for forming the rocks returned by Apollo and Luna are unlikely to be able to rise through the lunar mantle because they are denser than the warm mantle. However, if the mantle continues to cool and become denser, we could see a resumption of vulcanism on the Moon.
HTH.
Well, yeah - give us nukes!
You see, you hippies will be the first to complain if someone would start drilling holes in your backyard (and there will need to be *lots* of holes to get any meaningful geothermal energy unless you are living on a volcano).
You'll be complaining about it causing quakes, polluting ground water, killing earthworms and hurting Gaia and then in 10 - 20 years the wells' heat will be depleted and they will all have to be drilled again in different places...
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From memory, it's because of the difference in gravity between the nearside and farside of said satellite, rather than the pull between the host and the sun.
Thats the case with Jupiter and some of its moons at least, but the gravity is far stronger on Jupiter. I don't think the Earth is massive enough to have that sort of effect. Then again, what do I know.
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Has anyone determined the probability of a building on the moon, of a particular size, being hit by a meteor within a given time frame? I know that most of the craters will be very old, but a tiny high speed particle will not be burned up before impact on the moon, so it seems risky to me.
I personally suspect that those cracks are caused by tidal forces from the Earth's gravity acting on different densities of material on the moon. Given what we know about how the moon formed, it doesn't have enough dense radioactive material to have a hot core after 4 billion years, nor does the Earth apply sufficient tidal energy to directly cause volcanism (think Io). I'm going to expect this to be debunked pretty soon.
More likely they're down to the interior of the Moon contracting as it has cooled.
The range on the ages of these features is pretty wide; they're anywhere from 1.2 Gya to 50 Mya years ago (most probably towards the younger end of the scale). Lunar geologists have an especially broad definition of 'recent' - even compared to terrestrial geologists.
That there was much going on on the Moon after 1 Gya is interesting enough; the youngest feature with a firm(ish) date is the Compton–Belkovich thorium anomaly, a patch of highly evolved silicic rock on the lunar far side which has been estimated at 800 Mya - 1 Gya.
It'd be interesting to see if any of the glowing Transient Lunar Phenomena which are occasionally reported by astronomers can be tied to these faults. One of the explanations for TLPs is that gas might still be coming out of the interior of the Moon.
And that is why you would want to build your facility as deep underground as is feasible. Not only does it help protect against the inevitable small impacts, it also gives almost 100% protection from those nasty cosmic rays and other sources of radiation out there in space. Living long term on the surface of the moon seems like an excessively risky proposal.
... about cracks in the moon, but as I'm scanning down the page of headlines this one stood out. Why? Because of the inappropriate shouty-shouty BLOODY CAPITALS IN THE HEADLINE!!! STOP BLOODY SHOUTING, IT'S NOT BIG AND IT'S NOT CLEVER.
And now I return you to your regularly scheduled commentards
Let's get up there and get a core sample. We'll just jump in one of our Space Shuttles and ... wait ... I forgot - President O'screwu ended the Space Program. Now we have to fork over 50 million US a pop to hitchhike with the Soviets ? We screwed ourselved by voting for the first FAILED black president, Obama, so now we can't get a moon core sample without a Soviet chaperone. There is always a price for voting stupidly, and this is only a tiny fraction of the price we paid, and continue to pay. Thank God November elections are almost here. Obama, you're FIRED !!! (That will be soooo sweet)
You, off course do realize that even if you had the Space Shuttle you wouldn't be able to get to the moon. It never was capable of leaving earth's orbit. So, in essence it was not him that screwed you out of it, but don't let that impeach you in your bloated non-factual rant frivolously including something as unimportant as the skin colour...
Empire state building: 0.381km.
Space shuttle orbit altitude: 300 km average, sometimes 600 km.
Lunar orbit: 362,600km to 405,400km.
Thinking that the Space Transport System (AKA shuttles) would get us to the moon makes as much sense as trying to get to the International Space Station by going to New York City and getting on an elevator.
Aliens? And why are aliens using the same units of measurements as we do? It lends credence to the fact that Earth was colonized by aliens. And that they are still running things behind the scenes.
As if the machinations going on in Brussels wasn't enough to convince you that some strange, unearthly force was behind all the recent political activity.
I'm going to suggest crater rates. You will be able to work out the age of a surface if craters are superimposed on any feature, the assumption is that different epochs have different (reducing) impacts just due to less stuff flying around the inner solar system over time. So if the number of craters since the event can be counted, its age can be derived. From my armchair though I find the photo difficult to see if any craters superimpose or are crossed by the faults.
But we are talking about a stretching or pulling apart of the areas...
There are 3 situations:
1. ground stretches, later a meteor impacts.
2. meteor impacts, later ground stretches.
3. ground stretches as a meteor impacts.
#3 is unlikely; unless the crater caused the ground to shift.
Which leaves 1 and 2.
If a meteor impacts prior to stretching then the best you can do is date the impact and state that the crater formed sometime before that..
If a meteor impacts after the stretching then the best you can do is say that the stretching occurred sometime before the stretching was photographed up to the date the crater is dated...
Dating events like this is such crap.
And whereas they look kind of like aquatic features.....
And whereas surface features on the moon have been named for everyone from Tycho Brahe to Marilyn Lovell.....
I hearby move that these cracks be christened as the "Joan Rivers"!!
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What are all those hemispherical pock marks caused by?
It can't be incoming unless they were all aimed expertly to hit at an angle of 90 degrees.
Wouldn't meteorites hit at anything between tangential to perpendicular in a 360 degree plane?
And wouldn't some of them hop and/or gouge and/or fail to embed fully?
Didn't the astronauts take a pick and shovel with them to dig for samples?
Question: What are all those hemispherical pock marks caused by?
Answer: Meteorites.
Statement: It can't be incoming unless they were all aimed expertly to hit at an angle of 90 degrees.
Correction: Yes, they can.
Querstion: Wouldn't meteorites hit at anything between tangential to perpendicular in a 360 degree plane?
Answer: Close enough, not entirely so, but close enough.
Question: And wouldn't some of them hop and/or gouge and/or fail to embed fully?
Answer: No, not really. It depends on course, but at least it is very unlikely.
Question: Didn't the astronauts take a pick and shovel with them to dig for samples?
Answ...: What are you talking about?
You could just try google, you know that? I just did a search for the words why, are, craters and round. But anyhow, here goes. Imagine the biggest baddest gun you can think of, then try to shoot at a soft target at an angle. The angle has to be extremely low for it to bounce. Now, imagine that you are shooting a piece of porous rock and not metal into a layer of dust. Then try to multiply the velocity from the gun with several orders of magnitude. I have no idea on how fast bullets go, but a supersonic bullet at Mach 3 would travel at 1 km/s, meteorites travel at 50 (last number I saw on one, obviously they all hit with different velocities). Now, multiply the mass with even more orders of magnitude so that you remove any chance of an elastic impact.
To sum it up impact craters are round because basically it is equivalent to bury a large bomb deep under the surface and detonating it.
In a nutshell, because of the speeds involved, such impacts have a different dynamic than bouncing a soccer ball down the street. The energy difference between your ball bouncing to a meteor impact is greater than that of a small black powder firework (banger or firecracker, depending on which side of the pond you are on) to a large thermonuclear blast. The ground vaporizes at impact, and the energy is dispersed spherically. Thus, even low angle impacts produce round craters.
Yes, the astronauts carried basic excavation tools. For values of "excavation" that roughly equal "cat in a litter box", and turning over rocks..