Mercury, finally.
Published on Jan 13, 2008 at 12:49 pm.
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Filed under Mercury, planets, space exploration.
The MESSENGER spacecraft is now nearly to Mercury. It will pass that planet tomorrow, Monday, January 13, 2008, at about 1:05pm, Central Standard Time. I have published two other postings about MESSENGER (here and here). I am not going to restate all of that, so you can go back and read them if you wish. But, I will summarize the key points.
MESSENGER (the MErcury Surface, Space Environment, GEochemistry and Ranging spacecraft) is the first space probe to visit Mercury since Mariner 10 last passed that planet in 1975, over three decades ago. Technology and instrumentation have come a long way since then. MESSENGER is far more capable than Mariner 10 ever could have been. Furthermore, MESSENGER aims to do something that Mariner 10 never did: MESSENGER, after several flybys, will enter orbit around Mercury. Mariner 10 only flew past three times. MESSENGER will pass closest to Mercury tomorrow, and then again 266 days later, on October 6, 2008. This is important, because it is about 4.5 Mercury rotations. That means that on the second flyby, MESSENGER will see the opposite side of Mercury lit than the one lit on the first flyby. When Mariner 10 flew past, each time by was almost 3 exact rotations later, so nearly the exact same side of Mercury was lit each time by. As a consequence, half of Mercury could never be seen by Mariner 10. And, not even all of the side lit by the Sun was imaged, so less than half of Mercury has been photographed and mapped. MESSENGER will not have this problem. The MESSENGER website has several animations that show the launch, trip across the solar system, and approach for the spacecraft.
Already, MESSENGER has been collecting images of Mercury. I have one of the earliest released images posted above. That image was made early yesterday morning. I am looking forward to the findings from MESSENGER. But, despite how exciting pretty pictures are, what really interests me are the findings from the other instruments aboard the spacecraft. They will tell just as much, and likely much more, than the photographs. There are still a lot of unanswered questions about Mercury. Understanding Mercury may help us understand Earth. We still don’t have a firm grasp on how planets form. Many of the models of planet formation that became popular over the last couple of decades have become increasingly strained by the findings of extrasolar planets. Few of the extrasolar planetary systems match our own Solar System. Granted, we are finding the easy-to-find systems. Our own Solar System is much tougher to find using the technology employed up to this time. But, that should soon be changing. Then, we will know if our Solar System is typical or rather unique.
-Astroprof
Image courtesy of NASA/Johns Hopkins University Applied Physics Laboratory/Carnegie Institution of Washington
