Whale of a Galaxy

Credit: NASA & ESA and J. Dal­can­ton and B. Williams (Uni­ver­sity of Wash­ing­ton, Seattle)

This galac­tic whale is actu­ally a spi­ral galaxy. But in this image of NGC 2976 from NASA’s Hub­ble Space Tele­scope, it sure doesn’t look like one.

Explore the image. Dusty fil­a­ments run through the disk. No clear spi­ral struc­ture can be seen. What look like grains of sand are actu­ally indi­vid­ual stars. Hubble’s tele­scope vision is that sharp. The blue dots in the image are young, blue giant stars born in the active star-birth regions at the outer edge of the galaxy. The explo­sion of new stars and the lack of spi­ral arms are due to a col­li­sion, or near col­li­sion, with other galax­ies. But while new stars were being born at the outer edge of the galaxy, the gas and dust that fueled this birth was drawn away or fun­neled to the cen­ter of the galaxy. Now, a burst of star for­ma­tion is using up all the fuel in the inner part of NGC 2976.

What will hap­pen when this galaxy runs out of gas? Astronomers will be watch­ing. Study­ing indi­vid­ual stars in the galaxy helps astronomers find their col­ors and bright­ness. From that infor­ma­tion, sci­en­tists can recon­struct the stars’ lives as well as the rest of the galaxy.

NGC 2976 is located at the edge of the M81 group of galax­ies in the con­stel­la­tion Ursa Major, the Great Bear, or Big Dip­per. These galax­ies are pretty close. Their light only took about 12 mil­lion years to reach Earth. The clos­est large galaxy that we can see with our naked eye, the Androm­eda Galaxy, is about 2 mil­lion light years away.