Daily Archives: April 30, 2009

High Resolution Galactic X-ray Imagery

In today’s Nature, astronomers discuss the highest resolution imagery taken by the Chandra X-ray telescope of our own Milky Way galaxy. You’ll need a subscription, but there is a interpretive summary of the peer-reviewed paper available online now here (Nature has a great x-ray/visible composite image of M82 on the page), and if you want to see the astronomers’ data itself, you’ll find that online here. The Chandra mission team also has an announcement (available to all) about this published paper, here.

Remote Signs of Life

Scientists have long sought to develop a methodology by which they could detect life remotely, that is, at a distance, such as in orbit, or even further away. Many proxies for life’s detection have been debated, most recently the presence of methane in an atmosphere of a terrestrial type planet. Now a group of scientists believe that they have a way to detect life remotely, utilizing a technique known as circular polarization of light. This technique is directly related to the chirality, or handedness of biochemicals. For example, all life on Earth utilizes the “left-handed” (levo) amino acids, although we also utilize the right-handed (dextro) sugars. Light is polarized, just like a polarizing filter (like your sunglasses), and the biochemical causes the polarization because of the chirality of its atoms. Read more about this fascinating proposal for detecting life in this pre-print of the upcoming issue of the Proceedings of the National Academy of Sciences (PNAS), online now here.

In Search of Dusty Disks’ Nature

Conferences can often be an excellent way to catch up on the latest research in a field, and because astronomers know that they are addressing other astronomers who may not be well-versed in the presented material, they tend to provide explanations that you won’t find in the peer-reviewed literature. In a conference paper, given last month and released today, online here, Dr. Christine Chen of the Space Telescope Science Institute in Baltimore, outlines her research, and others, in an attempt to better understand what are called debris disks. Dr. Chen states that “debris disks are dusty disks around main sequence stars.” Furthermore, debris disks “are distinguished from proto-planetary disks by their small” gas to dust ratios. To better comprehend the nature of these debris disks, astronomers use multiple wavelengths in the electromagnetic spectrum as part of what is known as a spectral energy distribution analysis. In her presentation, Dr. Chen describes how astronomers know what they know about debris disks, and how they hope to learn more about the nature of debris disks after the servicing of the Hubble Space Telescope, and other future instruments.

April 2009
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