Fifteen Eighty Four

That dark spot is where an earth-sized object collided with Jupiter

It was big news yesterday — an amateur astronomer in Australia, Anthony Wesley, snapped a picture of the aftermath of a major collision with Jupiter. I asked our amateur astronomy guru Paul Kinzer about this. Kinzer teaches folks about how to do effective backyard astronomy, and his Stargazing Basics covers, well, the basics.

“Are these events commonplace?” he asks. “I guess, in an astronomical sense, they are. The SOHO solar observing satellite has imaged lots of comets impacting the Sun, and lots more whipping around it. The latest total count is 1685! But the Sun is our giant vacuum cleaner, and keeps us relatively safe.”

Thank you, Sun! You’re good for more than just photosynthesis and otherwise sustaining life! He continues:

“Still, I’m thinking that folks much more knowledgeable than me are going to be re-assessing our understanding of planetary impacts; or, at least, our response to the potential threat. Jupiter is an effective vacuum cleaner, too, protecting us from the ‘rear’, where most of the potentially hazardous comets and asteroids come from. But to have two large impacts observed on Jupiter in 15 years (the other was Shoemaker-Levy 9, in 1994) seems, to my limited understanding, a reason for re-assessment. There may have been others that have gone unobserved, and there have almost certainly been many smaller bodies that have hit Jupiter, but that didn’t show effects from such a great distance. Many of these ‘smaller’ bodies, if they came toward us, wouldn’t seem small at all!”

Good point. Remember, whatever caused that earth-sized impact spot on Jupiter was hundreds of meters across. But it’s good to know that we’ve got a gas giant holding up the gravitational rear.

“Thank the heavens — literally! — that Jupiter is there, because, without it, I don’t think we would be.

PS: No, I didn’t get any images (wouldn’t that be cool!), but it looks like, if I had tried at the right time, I could have, even with my modest set-up.”

Sorry you missed the opportunity, Paul, and thanks for filling us in on our solar system’s vacuum cleaners. But it’s good to know, nonetheless, that even a modest scope can catch some very amazing stuff out there, even before NASA had the chance. Keep it up, amateur astronomers!