There is an old adage that goes, “If a tree falls in a forest and no one is around to hear it, does it make a sound?"
A similar question was answered on Friday, “If a star blew up some 6 billion years ago when no one was on Earth, would anyone have seen it?”
The answer to that question is yes, we could see it, last week in fact. A star in a distant, previously unknown galaxy, exploded when the universe was about half its current age, some 6 billion years ago. This star was according to NASA about 40 times larger than our sun.
The explosion of the star resulted in a gamma ray burst that originated 7.5 billion light years away from Earth. It has taken these billions of years for the light from that explosion to reach Earth. NASA’s Swift satellite first detected the gamma rays at 2:12 a.m. Wednesday March 18, 2008.
The light from the explosion would have been visible by the naked eye if anyone had been outside to see last week. So bright was the light that it set a new record for the most distant object to be seen from Earth by the naked eye.
CNN quotes Neil Gehrels from NASA as saying, “Someone would have had to run out and look at it with a naked eye, but didn't.” The light would have appeared in the sky as bright as some of the stars in the handle of the Little Dipper constellation according to astronomer David Burrows. Burrow’s says that “This [explosion] is roughly halfway to the edge of the universe.”
Gehrels added that the explosion would have vaporized any planet nearby. Likely, the gamma ray burst would have eradicated anything in its path for thousands of light years. Earth dwellers had little to worry though, as the explosion took place so far away.