The Edge of Space
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|Rick Pantaleo||March 20th 2012|
The WISE spacecraft launched Dec. 14, 2009. In 2010, it mapped the entire sky using equipment that was much more sensitive than that used on previous missions. Over the course of its mission, WISE collected more than 2.7 million images of everything from asteroids to distant galaxies. The mission team has also been processing more than 15 terabytes of data transmitted back to Earth by the WISE spacecraft. About a year ago, in a preliminary release, NASA offered its first bundle of WISE data to astronomers.
The observations made so far by WISE have led to a number of remarkable finds, including the discovery of a class of stars with temperatures as cool as the human body. Astronomers had been on the lookout for these elusive stars for more than a decade. Called Y-dwarfs, the stars have been cooling ever since they first formed. Unlike other, much hotter stars, they don’t shine in visible light and couldn’t be seen until the WISE mission used its infrared vision to map the sky. WISE made some other surprise discoveries, including what scientists call the first known Trojan asteroid, which shares the same orbit around the sun as the Earth.
A Trojan object, such as this asteroid, assumes the same orbital path of a major space object, such as a planet or a large moon. But since they sit at points within the orbital path that are approximately 60° ahead of or behind the planet or large moon, there’s no danger of collision. Given recent concern about asteroids possibly endangering our planet, WISE also polled near-Earth asteroids, finding many fewer mid-sized objects than previously thought, and that NASA has found more than 90 percent of the largest near-Earth asteroids.
At least 100 papers, based on the results from the WISE survey, already have been published, according to NASA. Now that scientists have access to data from the whole sky, even more discoveries are expected.
Rick Pantaleo writes for VOA, from where this article is adapted.