Quick Updates: Kepler, Saturn, Perseids, Jupiter
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Perseids:
The Perseids peak tonight after midnight. They’re dust- and sand-sized debris left in our path from comet Swift-Tuttle. The air compressing in front of each meteor generates enough heat that the debris burns up and we see a streak of light.
Kepler:
The Kepler mission (looking for Earth-like planets around other stars) has just proved it definitely can detect planets, with more detail and precision than other methods. Kepler observed the planet HAT-P-7, which orbits its star once every 2.2 days, and was able to detect the atmosphere of the planet, and measure the daytime temperature at 4310 degrees F. Ouch.
Saturn:
Saturn’s rings are edge-on from our point of view, which happens every 15 years when Saturn reaches its equinox. According to JPL that day was yesterday, August 11, though the rings will stay mostly edge-on for a while yet.
Jupiter:
I’m quite late off the mark on this one, but something crashed into Jupiter not too long ago. On July 19th an amateur astronomy (Anthony Wesley) found this extra dark spot on Jupiter, and later professional astronomers followed up on his observations with Hubble. With Hubble they can watch as the debris plume evolves, and make better estimates about the size of the impacting object (several hundred meters across).
There is a standing hypothesis that Jupiter, being large, helps clean up the debris in the solar system. It attracts more asteroids and comets, leaving the inner solar system clearer and thus making impacts on Earth less likely.
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~ A l i c e !
Dear Alice,
I don’t like to disagree with NASA, but I think they’re wrong that the disappearance of Saturn’s rings from our point of view is because the Sun is shining directly at their edge. If this were so, we would still see the rings because Saturn has an albedo of 47% and that is easily enough sunlight to reflect off the rings and make them visible. Rather, the rings are invisible because their edge is aimed directly at our line of sight. This occurs when the rings are lined up with the plane of the ecliptic. The orbit of Saturn itself is inclined 2.485 degrees to the ecliptic (I had to look this up) so the disappearance of the rings is not the same as Saturn’s equinox. Howard
Howard,
I saw the date of September 4th on another NASA site as the date of the ring plane crossing. It was an older article, so I used the newer one instead. What you say makes sense though, so perhaps the two dates are just so close together that they didn’t choose to differentiate.
-Alice