V838 Monocerotis is a star that blew up about 20,000 years ago, but whose light just reached Earth in 2002, when its sudden increase in brightness was noticed by an amateur astronomer. It became a million times brighter than the Sun, and the diameter of the explosion was as large as the diameter of Jupiter’s orbit around the sun.
In today’s New York Times, Dennis Overybye has a piece on this star, called one of the most stunning astronomical events ever seen. What is most stunning, though, is the 2.5-minute video, which you can access (as well as the article) by clicking on the screenshot below.
An excerpt from the piece:
Astronomers are still arguing and speculating about what happened. Measurements of the star’s light output showed that the explosion happened in three stages, flaring and then dimming three times from January to March 2002.
Some scientists have suggested that V 838 swallowed planets in its orbit. Others have proposed that V 838 was actually two stars orbiting each other, and that the explosions were a result of their atmospheres merging into a common envelope of gas.
The answer could be relevant to our plight. Someday, a few billion years from now, the sun will run out of fuel and become a red giant,swallowing Mercury and frying the Earth and Venus.
Whatever it was that made V 838 erupt, astronomers are still watching it go.
The star, it turns out, is embedded in a cloud of dust trillions of miles across. Most likely, astronomers say, these wreaths of dust gave rise to V 838 perhaps four million years ago. They would usually be invisible, but the pulses of light traveling outward from the explosion have illuminated shells of dust previously kicked off the star. The Hubble Space Telescope has recorded images of these so-called light echoes, and viewing them in succession calls to mind the explosion of Darth Vader’s Death Star — except that in this case, nothing is moving but the outward-rushing light wave; the dust is standing still.