Thursday, April 30, 2009

GRB 090423


NASA's Swift satellite last week recorded what they think is the most ancient event yet witnessed by man- GRB 090423, a burst of gamma radiation released in the annihilation a star some 30 to 100 times the mass of our sun. GRB 090423 was thought to have collapsed into a black hole some 13.1 billion years ago, when the universe was a mere 5 % of the age it is now, providing astronomers with a tantalizing glimpse into the distant past. With a redshift of 8.2, GRB 090423 is also the most distant visible object ever observed (the previous record was . Astronomers are counting this as conclusive proof of the existence of massive stars in the reionization period, and hoping it will help them to ascertain exactly when in the evolution of the universe galaxies formed.

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