Cruising silently through space, a comet is headed straight toward the planet. Nothing can stop the inevitable impact. It sounds like the setup for yet another disaster movie. But about a week ago, it really happened. However there was never any need to call Bruce Willis. The planet in peril was Jupiter. And far from being a disaster, the impact (probably by a comet, although scientists don’t know for sure) has been a boon for astronomers observing the dark mark left in Jupiter’s atmosphere. Even the testing and calibration of the upgraded Hubble telescope was put on hold to get pictures of the rare event. More information about the impact and Hubble’s picture taking can be found in this SPACE.com article.
To the backyard astronomer, the most important question about the mark left by the impact is “Can I see it?” The answer is a clear and definite maybe. The good news is that Jupiter is currently in prime viewing position for us in North America, shining brightly in the southern sky. But whether the impact mark (estimated to be the size of the Pacific Ocean) can be seen depends on the quality of your telescope and the viewing conditions. My advice is to go with the highest magnification the seeing allows, put in a dark blue filter (to heighten contrast) if you have one, and give it a try. Of course, with Jupiter rotating on it’s axis, there’s always the risk that even if everything else is good, the mark will be on the “wrong” side of the planet. But at worst, you can still spend some time looking at Jupiter’s cloud bands and large moons, always interesting telescopic targets in their own right.
visible to the naked eye, can have an interesting story to tell. Such is the case with Antares (aka Alpha Scorpii), a red giant star at the heart of the constellation Scorpius. In fact it’s old Arabic name, Ķalb al Άķrab, translates as the “Scorpion’s heart.” However it’s name Antares translates as “rival of Ares”, Ares being the Greek name for Mars. The reason for the name is obvious, seeing it’s similarity in color and brightness to the red planet. But unlike Mars, Antares is roughly 600 light-years away. And that distance is a good thing. If Antares were at the center of our solar system, it’s outer edge would extend beyond the orbit of Mars. But despite it’s immense size, it’s mass is estimated at only 15 to 18 solar masses. And so it has the very low average density typical to red giants.
