The Milky Way Might Never Become An Elliptical Galaxy

“We will continue to slowly form new stars for many trillions of years. Our Local Group won’t become “red and dead” for many times the present age of the Universe. And, perhaps most importantly, we’ll still have a Milky Way-like feature in the night sky of whatever planets are around in the far future. There may come a day where our spiral features are no more. But since the turn of the century, we’ve learned that day won’t come when the Milky Way and Andromeda merge, but rather much farther out into the distant future.”

In about 4 billion years, the Milky Way and Andromeda will merge. Gravitational interactions will trigger the collapse of gas, new stars will form, stellar winds will blow, gas will get ejected, stars will be gravitationally disrupted, and our galaxy will transition from a spiral to an elliptical. Devoid of gas, our post-merger galaxy, now named Milkdromeda, will become what’s known as “red and dead.”

Only, that was the story 20 years ago, and those last parts of it aren’t true! As it turns out, we’re unlikely to become an elliptical galaxy. Here’s what we’ve learned will happen instead.