Eta Carinae was cataloged in 1677 by Edmond Halley. By all means, it's a big old star.
There's also a lot of fuss now that it appears to be at the end of its life. Actually, it could have already met its end -- only that it's 7,500 light-years away from Earth, so evidence may take a while before astronomers see it. No one's really sure at this point, but there are two general views about what the star's end would mean for the people of Earth.
First, the more alarming version: should Eta Carinae end, it would release bursts of gamma rays, one of which may hit Earth. When it does, it would essentially sterilize the planet and wipe out life, starting from the side facing the star. This is what is assumed to have happened nearly 450 million years ago when the Ordovician period ended and with it the life of 80 percent of species on Earth. Calling Eta Carinae a "Death Star" would be truly fitting.
The second and less threatening version claims that Eta Carinae would not be unleashing gamma ray bursts. Even if it did, one wouldn't hit Earth because the polar ends from which the rays would emanate from are not facing the direction of the planet. Even if those poles were facing Earth, by the time a gamma ray burst of average quality gets to the planet, it would have dissipated mostly after having traveled so far. After a journey lasting 7,500 light-years, a gamma ray burst would no more be menacing than a full moon in the sky.
Eta Carinae weighs 120 times heavier than the sun, dwarfing the center of the solar system by 240 times. It has a companion star with a mass 30 times more than the mass of the sun, and it is scheduled to orbit Eta Carinae in five-year intervals. Should the gravitational interaction between the two stars shift, it's possible for the Eta Carinae's orientation to change, possibly aligning its poles with the Earth, putting the planet directly in the way of a gamma ray burst. Again, the star is located 7,500 light-years away. Even if the gravitational interaction between the two stars were to remain the same, the companion star could influence the evolution of the more massive heavenly body, affecting the timing and manner of Eta Carinae's end.
There are just so many variables at play concerning the end of Eta Carinae that astrophysicist Stan Woosley from the University of California, Santa Cruz calls it "our biggest embarrassment today."
"No one knows just what's going on there ... It could die tomorrow or a long time from now," he said.
