For the first time ever, astronomers have observed how the colliding of two spiral galaxies quickly extinguishes both their star-making powers. By focusing a suite of telescopes on galaxy NGC 3801, an elliptical galaxy which resulted from the recent collision of two spiral galaxies, scientists were able to watch the early results of the cosmic shakeup. They observed that the supermassive black holes, lurking at the center of each galaxy, began consuming nearby star-making clouds of gaseous elements, rapidly aging both spiral galaxies by preventing new stars from forming.
What’s the Big Idea?
Our Milky Way is one such spiral galaxy and it is on a collision course with its neighboring galaxy Andromeda, sitting a relatively short distance of 2 million light years away. Thanks to the gravitational attraction between their outward spiral arms, astronomers estimate that they will begin to collide in about 3 billion years. “When that happens, observers on Earth will be able to watch from within the very thick of things as two youthful galaxies merge and grow suddenly old.” Of course, it would surprise us if there were still observers around to see the event.