arch49

A spectacular head-on collision between two galaxies, known as Arp 143, has fueled the unusual triangular-shaped star-formation frenzy as captured by the NASA/ESA Hubble Space Telescope. The interacting galaxy duo Arp 143 contains the distorted, star-forming spiral galaxy NGC 2445, at right, along with its less flashy companion, NGC 2444, at left. Their frenzied collision takes place against the tapestry of distant galaxies, of which some can be seen through the interacting pair. Astronomers suggest that the two galaxies passed through each other, igniting the uniquely shaped firestorm of star formation in NGC 2445, where thousands of stars are bursting into life. This galaxy is awash with new stars because it is rich in gas, the raw material from which stars are made. However, it hasn't yet escaped the gravitational clutches of its partner at left. The pair is waging a cosmic tug-of-war, which NGC 2444 appears to be winning. That galaxy has pulled gas from NGC 2445, forming the oddball triangle of newly minted stars. NGC 2444 is also responsible for yanking strands of gas from its partner, stoking the streamers of young, blue stars that appear to form a bridge between the two galaxies. These streamers are among the first in what appears to be a wave of star formation that started on the galaxy's outskirts and continued inward. Researchers estimate the streamer stars were born between 50 million and 100 million years ago. But these infant stars are being left behind as NGC 2445 continues to pull slowly away from NGC 2444. Stars no older than one million to two million years old are forming closer to the centre of NGC 2445. Hubble's keen vision reveals some individual stars, the brightest and most massive in the galaxy. Most of the brilliant blue clumps are groupings of stars and the pink blobs are glowing gas clouds enshrouding young, massive star clusters. Although most of the action is happening in NGC 2445, it doesn't mean the other member of the interacting