Good Saturday everyone! We are going to stay with the astronomy lectures this week.As an update, the SEB on Jupiter that we reviewed last week is continuing to form. Here are some additional images from ALPO-Japan, this group is worth the review. We will update on this later when the images are more striking.
I ran across the following article last night, it is a new theory on where some of the comets come from.
The Sun Steals Comets from Other Stars:
Nov. 23, 2010: The next time you thrill at the sight of a comet blazing across the night sky, consider this: it’s a stolen pleasure. You’re enjoying the spectacle at the expense of a distant star.
Sophisticated computer simulations run by researchers at the Southwest Research Institute (SWRI) have exposed the crime.
“If the results are right, our Sun snatched comets from neighboring stars’ back yards,” says SWRI scientist Hal Levison. And he believes this kind of thievery accounts for most of the comets in the Oort Cloud at the edge of our solar system.
“We know that stars form in clusters. The Sun was born within a huge community of other stars that formed in the same gas cloud. In that birth cluster, the stars were close enough together to pull comets away from each other via gravity. It’s like neighborhood children playing in each others’ back yards. It’s hard to imagine it not happening.”
According to this “thief” model, comets accompanied the nearest star when the birth cluster blew apart. The Sun made off with quite a treasure – the Oort Cloud, which was swarming with comets from all over the “neighborhood.”
The Oort cloud is an immense cloud of comets orbiting the Sun far beyond Pluto. It is named after mid-20th century Dutch astronomer Jan Oort, who first proposed such a cloud to explain the origin of comets sometimes seen falling into the inner solar system. Although no confirmed direct observations of the Oort cloud have been made, most astronomers believe that it is the source of all long-period and Halley-type comets.
Recently, we had a close flyby of Comet Hartley 2 with some very interesting results:
Comet Snowstorm Engulfs Hartley 2
Nov. 18, 2010: NASA has just issued a travel advisory for spacecraft: Watch out for Comet Hartley 2, it is experiencing a significant winter snowstorm.
Deep Impact photographed the unexpected tempest when it flew past the comet’s nucleus on Nov. 4th at a distance of only 700 km (435 miles). At first, researchers only noticed the comet’s hyperactive jets. The icy nucleus is studded with them, flamboyantly spewing carbon dioxide from dozens of sites. A closer look revealed an even greater marvel, however. The space around the comet’s core is glistening with chunks of ice and snow, some of them possibly as large as a basketball.
For those of you that missed the beautiful flyby pics of Harley 2, here is EPOXIs Home page.
Tags: astronomy, comets, saturday lecture series
