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| Image credit: NASA |
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| You've Got to Be Fast to Spot Burst Afterglows |
| Sep 15, 2003 - Until recently, astronomers thought that nearly two-thirds of gamma ray bursts - the most powerful known explosions in the Universe - don't seem to leave an afterglow. It turns out, they just weren't looking quickly enough. Gamma-ray bursts explode suddenly, last for only a few fractions of a second and then disappear. All that's left is the afterglow, which astronomers can study to try to understand what caused the explosion. NASA's HETE spacecraft has quickly determined the positions of 15 gamma-ray bursts and passed this info along to astronomers to follow up with optical telescopes. In this case, only one hasn't had an afterglow. So, it appears afterglows are common, you just need to look quickly. |
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| Image credit: NASA |
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| Satellite Photo of Hurricane Isabel |
| Sep 15, 2003 - NASA's Aqua satellite took this overhead view of Hurricane Isabel on September 14, 2003 while it was 650 km north of Puerto Rico. The image was acquired using Aqua's Moderate Resolution Imaging Spectroradiometer (MODIS). Isabel is currently a category 4 hurricane, with winds as high as 220 km/h - this is about 15 km/h slower than they were on the weekend. Residents, businesses, and even the military are taking precautions in case Isabel doesn't lose strength and hits the coast of the North America. |
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| Image credit: NASA/JPL |
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| Coldest Temperature Ever Created |
| Sep 15, 2003 - Researchers from NASA and MIT have cooled sodium gas to the lowest temperature ever recorded - one-half billion degrees above absolute zero. At absolute zero (-273 degrees Celsius), all molecular motion would stop completely since the cooling process has extracted all energy from the material. The gas needed to be confined in a magnetic field; otherwise it would stick to the walls of the container and be impossible to cool down. The researchers used a similar methodology that led to the Nobel Prize for Physics in 2001with the discovery of Bose-Einstein condesates (where the molecules move together in an orderly way at low temperatures). |
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