This Is What It Looks Like When 2 Galaxies Collide

The Hubble Space Telescope has been responsible for some pretty spectacular photos since it was launched into space 25 years ago, but a new image (above) of a celestial object astronomers call NGC 3597 is definitely one of its standouts.

NGC 3597 is essentially a cosmic mash-up of two “good-sized” galaxies that have collided and are on their way to becoming a giant elliptical galaxy, according to NASA. The object lies about 150 million light-years from Earth in the constellation Crater, aka The Cup.

The collisions of two sizable galaxies typically takes a few hundred million years, said Dr. Meg Urry, director of the Yale Center for Astronomy & Astrophysics.

“We know this because we can ‘watch’ galaxy collisions in computer simulations,” she said. “Because the time scales involved in the evolution of our universe are so huge, we do astronomy with snapshots like this image.”

“By piecing together the many mergers we see throughout the universe, in very different stages — and by modeling them in our computers — we have managed to figure out how things work over most of cosmic time,” Urry added. “Pretty amazing, really.”

The combined gas and dust of NGC 3597’s constituent galaxies has formed dozens of so-called proto-globular clusters, which appear in the image and will go on to become fully fledged globular clusters. Such clusters can be described as “mothball-shaped sets of tens of thousands of stars” that orbit the centers of galaxies, said Dr. Jay Pasachoff, an astronomer at Williams College in Massachusetts and co-author of The Cosmos.

Why do the contents of merging galaxies form clusters instead of violently smashing into each other?

“There is so much empty space in galaxies that the galaxies pass through each other with almost no chance of any stars actually hitting each other,” Pasachoff —> Read More