Galactic Antennae

Credit: NASA, ESA, SAO, CXC, JPL-Caltech, and STScI

Star­ing at the stars doesn’t get much bet­ter than this. Explore this beau­ti­ful image of the Anten­nae galax­ies by NASA’s Great Observatories.

From Earth, astronomers saw stream­ers arc­ing far into space. The arcs of stars looked like the anten­nae of an insect, so astronomers called them the Anten­nae galax­ies. Closer up, what do the galax­ies look like to you? This image of the Anten­nae galax­ies show a com­pos­ite of images from Chan­dra X-ray Tele­scope (in blue), the Hub­ble Space Tele­scope (in gold and brown) and the Spitzer Space Tele­scope (in red).

The fea­tures we see in the image are of galax­ies col­lid­ing. The col­li­sion began about 200 mil­lion to 300 mil­lion years ago. As the stars and gas of the galax­ies move together, new stars are born, mostly in star clus­ters. The most mas­sive of these young stars have lasted only a few mil­lion years, end­ing in spec­tac­u­lar and bright super­novae explo­sions. The X-ray image from Chan­dra shows huge clouds of hot gas that include the remains of these explo­sions. The gas is rich in oxy­gen, iron, mag­ne­sium and sil­i­con; the build­ing blocks for plan­ets and humans. Bright pin-points of light in the image are made by mat­ter falling into black holes and neu­tron stars.

The Spitzer Space Tele­scope shows the galax­ies in infrared. Warm dust clouds, heated by new­born stars, over­lap in areas between the galax­ies. The Hub­ble image shows the galaxy as we see it with our eyes. We see the two galac­tic cores glow­ing orange-yellow. These are full of mostly older stars criss­crossed with brown dust. Sur­round­ing these areas are bright blue star–form­ing areas. Vast clouds of hydro­gen gas glow hot pink near these young, blue stars. As you explore, look for super-clusters of stars. Most of these clus­ters will prob­a­bly break apart. The stars will drift away from each other to find their own places in the galaxy. Many, how­ever, will stay together, form­ing a halo of glob­u­lar clus­ters like those we find around the Milky Way.

The Anten­nae Galax­ies, or NGC 4038 and NGC 4039, are found in the south­ern con­stel­la­tion Corvus the Crow. The galax­ies are about 63 mil­lion light-years away. When light left the Anten­nae Galax­ies, dinosaurs had recently died out on Earth fol­low­ing a sus­pected aster­oid or comet impact.