Number Zero

Credit: NASA and The Hub­ble Her­itage Team (STScI/AURA)

We’re start­ing a new series here at Starry Crit­ters; num­bers and let­ters. Today’s image is brought to you by the num­ber zero.

Hot, blue stars form a halo around the yel­low cen­ter of a galaxy known as Hoag’s Object. From Earth it appears as the huge num­ber zero as we view this odd galaxy face-on in this image from NASA’s Hub­ble Space Tele­scope.

The ring of young, mas­sive stars stretches about 120,000 light-years across; slightly larger than our Milky Way Galaxy. The ring may be the result of new star for­ma­tion caused when one galaxy zoomed through the other. Sci­en­tists don’t see a sec­ond galaxy that could be respon­si­ble. Another idea is that the ring is the shred­ded remains of a galaxy that encoun­tered the older yel­low galaxy in the cen­ter. Astronomers believe this encounter took place two to three bil­lion years ago.

Explore the the bil­lions of stars that make up this galaxy. The halo con­sists of blue stars grouped together in giant clus­ters. They are recently born out of huge clouds of gas and dust. These mas­sive, new stars won’t live long. Within a cou­ple mil­lion years they will start to explode in super­nova brighter than the entire galaxy. The gap in the cen­ter may not be entirely empty. Faint star clus­ters or indi­vid­ual stars may be sprin­kled lightly in this area. Can you pick out dis­tant spi­ral galax­ies and another ring galaxy shin­ing through this area?

Light from Hoag’s Object has trav­eled a long time to reach Earth, tak­ing nearly 600 mil­lion light-years to reach us. This unusual ring galaxy is found in the con­stel­la­tion Ser­pens, the Ser­pent. It is named after Arthur Allen Hoag who dis­cov­ered it in 1950. Hoag believed it to be either a plan­e­tary neb­ula or a pecu­liar galaxy.