CRACK made by quakes FOUND ON MOON
Paparazzo probe's pic hints at smoking hot insides
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. Credit: NASA/Goddard/Arizona State University/Smithsonian Institution
The moonquakes occurred some time in the last 50 million years, which in Moon time is pretty recent since the rock is over 4.5 billion years old.
The valleys, known as graben, are narrow cracks on the surface that show the lunar crust is being pulled apart along two bounding faults.
"We think the Moon is in a general state of global contraction because of cooling of a still hot interior," said Thomas Watters, lead author of a paper on this research appearing in the journal Nature Geoscience.
"The graben tell us forces acting to shrink the moon were overcome in places by forces acting to pull it apart. This means the contractional forces shrinking the moon cannot be large, or the small graben might never form."
The findings raise questions about how the Moon evolved and whether or not it is still in the process of completely forming.
Scientists had assumed that the Moon was all done with tectonic activity, because the youngest geological markers on the surface were thought to be about a billion years old.
The graben show that the interior of the Moon could still be smoking hot and molten. If the core was cooling, the surface of the Moon would be wrinkling up, not cracking to form valleys.
"It was a big surprise when I spotted graben in the far side highlands," said co-author Mark Robinson, principal investigator of LROC.
"It's exciting when you discover something totally unexpected and only about half the lunar surface has been imaged in high resolution. There is much more of the Moon to be explored." ®
Re: Very cool...
'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.
Re: Drill baby, drill...
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...
Re: I don't care...
Anything FOUND ON MOON is worth shouting about.