February 20, 2012
By Charles Q. Choi
“If you think the moon is dead – think again. ‘These new findings raise questions about how the moon formed and evolved.’ Well of course. The moon is still a mystery. Doesn’t it make you curious why we never went back? What did they find that scared them so badly that we stopped traveling to the moon? If we would have continued the Apollo program, you and I would have been able to travel to the moon and back by now. But nope, let’s stay on Earth and fight with each other instead.” –KTRN
The moon’s crust was apparently active far more recently than previously believed, scientists say.
These new findings raise questions about how the moon formed and evolved, researchers said.
Although the Earth’s crust is still shifting, driven by the churning semimolten rock underneath it, researchers had thought the moon had cooled off much too long ago to still have any such tectonic activity. For instance, the youngest known tectonic features on the lunar landscape until now — small cliffs in the lunar highlands resulting from wrinkling of the surface as the moon’s interior cooled and shrunk — are thought to be less than 1 billion years old, although by how much is uncertain.
Moon graben are troughs formed when the lunar crust was stretched and pulled apart. This stretching causes the near-surface materials to break along two parallel normal faults, the terrain in between the twin faults drops down forming a valley.
Now, images collected by the Lunar Reconnaissance Orbiter hints the moon has probably seen tectonic activity within the last 50 million years.
In these photos, researchers spotted a dozen or so narrow, trenchlike features known as graben in the lunar highlands and in the dark plains of volcanic rock known as the mare basalts. Graben are essentially troughs with two faults or cracks in the surface on either side of them. They are thought to have formed as the lunar crust was stretched. [10 Coolest Moon Discoveries]
“Overall on the moon, you have this contracting, shrinking environment, but in some places, apparently there’s this stretching extension of the crust,” said study lead author Thomas Watters, a planetary scientist at the Smithsonian Institution in Washington.