CASPER
THE FRIENDLY GHOST
A new image of a galactic pileup shows the vivid chaos of two colliding galaxies, giving astronomers a ringside seat to watch how the cosmic mergers can influence the evolution of the universe.
The spectacular new image was obtained by the European Southern Observatory. It shows the famous Atoms-for-Peace (NGC 7252) collision between two galaxies about 220 million light-years from Earth in the constellation of Aquarius.
By examining these cosmic smash-ups, scientists can unlock clues regarding galactic ancestry and can better understand how galaxy collisions shape the universe over time, astronomers said.
The new photo is a snapshot of the Atoms-for-Peace collision set against a rich backdrop of distant galaxies. The interplay of gravitational interactions can be seen in the shapes of the tails made from streams of stars, gas and dust.
The image also shows the spectacular shells that formed as gas and stars were ripped out of the colliding galaxies, and then became entwined around the collision's new joint core. While a good deal of material was ejected into space from the collision, some material in other regions is compressed, triggering bursts of star formation.
This has led to the birth of hundreds of very young star clusters, approximately 50 million to 500 million years old. These densely packed consortiums of stars, known as globular clusters, are distinguished from galactic clusters because of their ancient age and size (often 100,000 stars or more).
Since galaxy collisions are drawn-out events that last hundreds of millions of years, astronomers have ample time to study them. This is helpful, since Atoms-for-Peace may be a harbinger of our own galaxy's fate, researchers said in a statement.
Astronomers predict that in 3 billion to 4 billion years, the neighboring Andromeda Galaxy will slam into our own Milky Way, much like what happened with Atoms-for-Peace. Still, since the distance between stars within a galaxy is so vast, it is unlikely that our sun will end up in a head-on collision with another star during the merger.
Atoms-for-Peace, which is also known as NGC 7252 and Arp 226, is just bright enough to be seen by amateur astronomers as a small, very faint, fuzzy blob. The object's interesting nickname also has its own notable history.
In December 1953, President Eisenhower gave a speech that was dubbed "Atoms for Peace," in which he promoted nuclear power for peaceful purposes. The hot-button topic made waves in the scientific community and beyond, to such an extent that NGC 7252 was named the Atoms-for-Peace galaxy.
Yet, the moniker is oddly fitting, since the giant loops that are visible resemble a textbook diagram of electrons orbiting an atomic nucleus.
This image of Atoms-for-Peace was produced by the European Southern Observatory's Wide Field Imager at the La Silla Observatory in Chile.