December 14th, 2011
01:01 PM ET

Another cosmic mystery, solved

Scientists have used "standard candles," Type 1a supernovae, for years to measure the universe's rate of expansion. Thousands of Type 1a supernovae have been studied for their light, but until now, scientists have relied wholly on models - not direct evidence - to explain why these supernovae explode and what their star systems might have looked like ahead of the explosion.

On August 24, Peter Nugent of the U.S. Department of Energy's Lawrence Berkeley Laboratory (the Berkeley Lab), going through data from an automated telescope on California's Palomar Mountain, saw something notable: a confirmed, very young Type 1a supernova, officially named SN2011fe. This supernova is in the Pinwheel Galaxy, relatively close at 21 million light-years away.

SN2011fe was seen 11 hours after its explosion, allowing Nugent and other members of the multi-institutional Palomar Transient Factory (PTF) to calculate the moment of SN2011fe's explosion to within 20 minutes.
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Filed under: Discoveries • In Space • News
On this day: December 14, 1962
December 14th, 2011
12:23 PM ET

On this day: December 14, 1962

On this day in 1962, the US spacecraft Mariner 2 flew past Venus.

Mariner 2 was the first planetary spacecraft to fly, acting as a backup to Mariner 1, which failed shortly after launch. By the time Mariner 2 approached Venus, it had lost a solar panel and possibly collided with a small object.

At its closest, Mariner 2 was 34,773 km from Venus.

The spacecraft carried science instruments that discovered Venus' hot surface temperatures and high surface pressure. Mariner 2 also revealed that Venus has an atmosphere made up mostly of carbon dioxide and perpetual cloud cover.

Mariner 2 also helped determine that solar winds are continuously streaming in the space between the planets.


Filed under: On this Day
December 14th, 2011
09:40 AM ET

A Galaxy Cluster Gets Sloshed

"Like wine in a glass, vast clouds of hot gas are sloshing back and forth in Abell 2052, a galaxy cluster located about 480 million light years from Earth. X-ray data (blue) from NASA's Chandra X-ray Observatory shows the hot gas in this dynamic system, and optical data (gold) from the Very Large Telescope shows the galaxies. The hot, X-ray bright gas has an average temperature of about 30 million degrees.

A huge spiral structure in the hot gas - spanning almost a million light years - is seen around the outside of the image, surrounding a giant elliptical galaxy at the center. This spiral was created when a small cluster of galaxies smashed into a larger one that surrounds the central elliptical galaxy.

The smaller cluster passed the cluster core, the direction of motion of the cluster gas reversed and it traveled back towards the cluster center. The cluster gas moved through the center again and "sloshed" back and forth, similar to wine sloshing in a glass that was jerked sideways. The sloshing gas ended up in a spiral pattern because the collision between the two clusters was off-center.

The Chandra data show clear bubbles evacuated by material blasted away from the black hole, which are surrounded by dense, bright, cool rims. As with the sloshing, this activity helps prevent cooling of the gas in the cluster's core, setting limits on the growth of the giant elliptical galaxy and its supermassive black hole."

Source: NASA

Filed under: Light up the screen

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