Monday, May 23, 2011

The Unstable Crab Nebula


On the 4th of July 1054 or maybe even earlier, in April or May that year, a new bright star near the Sun was observed in the constellation of Taurus by witnesses in Italy, Armenia, Iraq, China, Japan, and North America. The unusual object appeared with a magnitude between –4 and –7.5 and was visible to the naked eye, even in the daytime sky. Apparently, maximum brightness coincided with the solar conjunction. Chinese astronomers observed the star in daylight until the 27th of July 1054, and they were able to see it in the night sky until the 17th of April 1056, before it faded from naked-eye visibility. In Europe, sightings of the supernova were probably censored, since the catholic church saw this celestial event as a bad omen in connection with the split from the orthodox church in the same year.

Friday, May 20, 2011

Kepler's Latest Hunting Trips

Torrents of likely new exoplanets are pouring in from NASA's Kepler space telescope - more than 1,200 of them so far, large and small, including weird worlds and systems that no one expected. The Kepler science team unveiled its latest batch of findings on February 2nd, based largely on data from just the first four months (May 12 to Sept. 17, 2009) of Kepler's planned 3½-year mission. The Kepler scientists highlighted two themes. One was the sheer number and variety of likely planets being found, especially small ones, including several small ones in their stars' habitable zones. The team also highlighted one system in particular. A 14th-magnitude star dubbed Kepler-11 seems to have six super-earths and Neptunes transiting it. All are orbiting in nearly the same plane, five of them in compactly nested orbits closer to the star than Mercury is to the Sun. Two or three of these planets have such unexpectedly low average densities that they would float in water.

Thursday, May 19, 2011

Listening to black holes

The lowest note ever produced in the universe is B flat !

Ever wondered what a black hole "sounds" like? As NASA's Chandra X-ray telescope recently discovered, is B flat.
Unfortunately there's no way of listening to it because the note is 57 octaves below middle C.
That's a million billion times lower than the limit of human hearing, making it the deepest note that's ever been detected in the universe.