Evolution of Guidesites and Planets

The Physics Guidesite continues to grow, as I add more content for my readers. Here's are some of the articles added in the last couple of days, although feel free to look around the site for other useful links, as well.

• What Is Physics?
• The Fields of Physics
• Study Guide: Know Your Variables

In other news, those who were interested in the galaxy simulation earlier might want to keep their eyes open on Thursday for the new issue of the science journal Nature, in which an article will describe how MIT scientists have discovered, for the first time, an arrangement of space debris which appears to match an early formation phase the Earth is believed to have once gone through.

MIT scientists, using the Spitzer Space Telescope, discovered a burst of radiation from a disk of matter near a pulsar that is 13,000 light-years from Earth. Previous research as far back as 1992 has discovered planets and planetary systems circling pulsars, but those were established planetary bodies. The disk appears to be composed of dense material released in the supernova explosion that created the pulsar 100,000 years ago, but not imparted with enough energy to escape the gravity of the remaining pulsar.

Unfortunately, current technology lacks the ability to see whether any planets are forming or have formed within the cluster, but scientists indicate that this sort of arrangement of matter fits precisely with models of how other planets, including the Earth, have formed.