The Search for Distant Worlds
The astronomical community was surprised a few years ago with the discovery of a "planet" in orbit around a distant star. The discovery started an international search for these distant worlds that continues to this day. Astronomers presently know of 50 extrasolar planets that orbit stars other than the Sun. The latest discovery of 3 planets was reported only last month by a team using the Anglo-Australian Telescope.
The technique used to discover distant planets relies upon the detection of a small wobble in the motion of the parent star, an effect caused by the gravitational interaction between the orbiting bodies. The mass and orbital properties of extrasolar planets can be calculated from the wobble data. Plots of stellar wobble data can be seen at http://exoplanets.org.
Click Here for Information or to Buy this Poster
Nearly all the extrasolar planets discovered to date are more massive than Jupiter because the nature of the technique favors the detection of large planets. At present it is not possible to detect the very tiny wobbles associated with Earth-sized planets around distant stars. The question as to whether Earth-like planets are common or rare in our Galaxy remains unanswered.
NASA's Terrestrial Planet Finder is an ambitious project designed to detect Earth-like planets around nearby stars. Instead of trying to detect gravitational wobbles the TPF will use the combined light from 4 space telescopes to block, or null, the glare from a central star with a planetary system. This will allow direct observation of near-star regions where theory says small planets tend to exist but which cannot be observed at present due to the surrounding stellar glare. The TPF will also have the ability to examine the spectra of those planets to determine if their atmospheres contain signs of life.
January's Lunar Eclipse
A total eclipse of the Moon will occur on January 9th starting at 18:42 UT and ending at 21:59 UT (mid-eclipse at 20:20 UT). The eclipse is caused by the Earth's shadow sweeping across the face of the Moon. During totality the Moon will take on a red-orange color due to the effect of light being refracted into the Earth's shadow by its own atmosphere. Observers in Europe, Africa, and Asia are well-placed to view the entire event.
Clear skies till next month!