2.5 APOD Iridescent Cloud Over Colorado

Looking like a three tiered rainbow, an iridescent cloud sits over Boulder, Colorado. This is a pretty rare event, but an iridescent cloud can show a whole spectrum of colors simultaneously. These clouds show colors when the clouds are relatively thin and the droplet sizes are about the same size. The light diffracts throw them, much like a rainbow. However, this only works if the sun is in exactly the right spot and mostly hidden by thick clouds. Sometimes iridescent clouds will start to form but then the cloud gets too thick or too far away from the sun. You can see why this would only occur rarely. One of the links (clouds) brings you to a page with a poem about clouds by William Wordsworth. Yay clouds.

2.4 APOD

For picture go to : http://apod.nasa.gov/apod/image/0711/cr_auger_big.jpg
For centuries astronomers have wondered where cosmic rays (energetic particles that begin in space and impinge on Earth's atmosphere and now the Pierre Auger Observatory in Argentina may have an answer. Auger suggests that 12 out of 15 ultra highhigh energy cosmic rays come from the direction of nearby active galactic nuclei (a compact region at the center of an active galaxy). These galactic centers emit large amounts of light and are probably feuled by a blackhole. The Auger Observatory believes that the highest energy rays are protons because any higher energy raywould be deflected by the Milky Way Galaxy's magnetic field and we wouldn't be able to figure out which direction the ray was coming from. The APOD picutre is of a ray striking Earth's atmosphere, with an active galaxy (Centaurus A) in the background as the galaxy from which the ray might have come.

2.3 APOD

This is a movie of an X-Class Flare Region (X-Class fares are the biggest ones) on the sun, and of a flare erupting there over a period of four hours. These violent flares can affect satellites and astronauts. This particular flare reached over ten million degrees Celsius and was probably caused by violently unstable magnetic reconnection events above the Sun (magnetic field lines interact and splice into one another, according to Wikipedia). The movie was capture by the TRACE (Transistion Region and Coronal Explorer) satellite, which is orbiting the Sun the study the connection between magnetic lines and plasma events on the Sun.

2.2 APOD Three Nebulae in a Narrow Band

These are three Nebula found in Sagittarius, two of them the Nebula we have to remember for the constellation quiz - M8 (the Lagoon Nebula) and M20 (the Trifid). The Nebula in the upper right hand corner is NGC 6559 (who didn't make Messier's list. Poor baby.). This is a false color photo, with a color scheme apparently made common by the HUbble Telescope. The color scheme works for land based telescopes because it allows the astronomer to ignore urban light pollution. M8 is 30 light years LONG and about 5000 light years away. It's actually very pretty with the false color palete, a pretty blue, and is a star forming region.