APOD: Io's Surface

One of Jupiter's moons, Io, pictured above, is the solar system's most volcanically active body. The surface of Io is constantly being formed and reformed by lava. Io lacks craters, which indicates that the lava flow is so consistent that craters don't have time to form and remain before they are covered by lava. Astronomers speculate that strong tides are what cause Io's volcanic activity. Space seems like something that stays constant and unchanging because usually when discussing geological or universal time we talk in millions or billions of years. The fact that Io changes so constantly makes it a universal anomaly.

APOD: Trifid Nebula

The Trifid Nebula pictured above lies around 5,000 light years from Earth near the constellation Sagittarius. Also known as M20, the Trifid is a place where stars can be formed. Three kinds of nebulae exist within the Trifid and they are the red emission, blue reflection and dark nebulae. Red emission nebulae are dominated by light emitted by hydrogen atoms. Blue reflection nebulae are produced by dust reflecting starlight and dark nebulae are where dense dust clouds appear in silhouette. The nebula is about 40 light years across.

NASA Photo of the Day

The Crab Nebula is the remainder of a supernova left behind after the death of a large star. The supernova was noted in the constellation Taurus nearly one thousand years ago. The Crab is the strongest persistent source in the sky, with measured flux exteneding to above 10 TeV. I chose this photo because of the nebula's resemblance to veins in the human body. That's pretty cool.