Even though a galaxy collision sounds destructive, it is not. In fact, it triggers new generations of stars, and a recent Hubble image shows this cosmic marvel. It captures newborn clusters of stars that form along a stretched-out tidal tail for thousands of light-years, and they look like a cosmic string of pearls.
Hubble Space Telescope has made an incredible discovery of 12 interacting galaxies. These galaxies have long tails of gas, dust, and stars resembling tadpoles. Hubble’s advanced technology detected 425 clusters of newly born stars along these tails, each looking like strings of holiday lights containing as many as a million blue newborn stars. But other than stars, astronomers presume that these collisions also result in planets accompanying the newborn stars.
Astronomers combined stored data and recent observations to determine the ages and masses of star clusters in tidal tails. The clusters are relatively young, only 10 million years old, forming consistently along tails stretching for thousands of light-years.
“It’s a surprise to see lots of the young objects in the tails. It tells us a lot about cluster formation efficiency,” said lead author Michael Rodruck of Randolph-Macon College in Ashland, Virginia. “With tidal tails, you will build up new generations of stars that otherwise might not have existed.”
The tails look like they are taking a galaxy’s spiral arm and stretching it out into space. The exterior part of the arm gets pulled like taffy from the gravitational tug-of-war between a pair of interacting galaxies.
“Before the mergers, the galaxies were rich in dusty clouds of molecular hydrogen that simply may have remained inert, NASA explains in a post. “But the clouds got jostled and bumped into each other during the encounters. This compressed the hydrogen to the point where it precipitated a firestorm of star birth.”
“This string-of-pearls star formation may have been more common in the early universe when galaxies collided with each other more frequently. These nearby galaxies observed by Hubble are a proxy for what happened long ago, and therefore are laboratories for looking into the distant past.”
Other interesting space photos
Sometimes, we see images of earthly things and animals up there in the stars. We recently shared a cute “penguin and egg” galaxy photo. There are also festive clusters nicknamed the “Christmas Tree Cluster” and a Halloween-esque Bat nebula. We also saw “stellar fireworks,” as well as a space merry-go-round.