June 20, 2013
New Hubble Image Shows Two Galaxies Getting Up Close And Personal
Lee Rannals for www.redorbit.com — Your Universe Online
Arp 142 was named after the American astronomer Halton Arp, who created the Atlas of Peculiar Galaxies. This atlas is a catalog of weirdly-shaped galaxies that was originally published in 1966. He compiled the catalog while trying to understand how galaxies evolved and changed shape over time.
Below the center of the newly released image you can spot galaxy NGC 2936, which is one of the galaxies interacting. This galaxy, nicknamed "the Penguin" or "the Porpoise," used to be a standard spiral galaxy before meeting NGC 2937.
The remnants of the Penguin's spiral structure can still be seen, almost forming the shape of an "eye." Around this you can see where the galaxy's pinwheel arms once existed. These arms now shape a "body" figure in the form of bright streaks of blue and red across the image. The arms streak down towards NGC 2937, which is a bright white oval.
The upper part of the image features two bright stars, both of which sit in the foreground of the Arp 142 pair. One of these stars is surrounded by sparkling blue material, which is actually another galaxy thought to be too far away to interact with Arp 142.
Blue and red elongated shapes of other galaxies can be spotted in the background of the image. These galaxies are still far away from the interacting cosmic neighborhoods of Arp 142.
One theory of what happens when galaxies collide is gravitational forces from the larger galaxy strip its neighbor of its outer stars, leaving more mass in the galactic center. Another theory suggests dark matter distorts' astronomers' observations of both older and younger galaxies, making the centers more difficult to measure.
A video was released in 2010 of an animation showing the interaction of galaxies colliding. The video details how the interaction creates violent tidal forces that tear the galactic discs apart, but also bridging the two bodies together at the same time.