I would like this blog to be about science in general so I wanted to resist the temptation of posting about Astronomy again so soon (fail!). Do forgive me but this is too cool not to comment on: “Did you know the moon is shrinking?”. Yes, the moon, the only celestial body humans have set foot on, that bright, big object in the night sky where satellites have been to so many times does not stop surprising us. New images from NASA’s Lunar Reconnaissance Orbiter show widespread wrinkle-like features in the moon’s surface. These scarps are interpreted as being due to global cooling and resultant contraction. The planets and their satellites formed in a violent environment: collisions (as well as radioactive decay) resulted in a hot primordial moon. If a hot object has no heat source to maintain its temperature it eventually cools down. That’s what is happening to the moon. What is surprising is that it is still happening even though the moon formed over 4 billion years ago! Indeed the scarps revealed by NASA’s spacecraft are relatively recent having originated in the past billion years or so showing that the moon has not stopped shrinking. Astronomers believe our satellite will keep on contracting until its interior is cool enough. But worry not, the moon is not going anywhere: since it formed it “lost” only about 200 metres of its 3476 km diameter.
|photo: Luc Viatour|