A space
94. oddity
In this image by the NASA/ESA Hubble Space Telescope, an unusual, ghostly green
blob of gas appears to float near a normal-looking spiral galaxy.
The bizarre object, dubbed Hanny’s Voorwerp (Hanny’s Object in Dutch), is the
only visible part of a streamer of gas stretching 300 000 light-years around the
galaxy, called IC 2497. The greenish Voorwerp is visible because a searchlight
beam of light from the galaxy’s core has illuminated it. This beam came from a
quasar, a bright, energetic object that is powered by a black hole. The quasar
may have turned off in the last 200 000 years.
This Hubble view uncovers a pocket of star clusters, the yellowish-orange area at
the tip of Hanny’s Voorwerp. The star clusters are confined to an area that is a few
thousand light-years wide. The youngest stars are a couple of million years old. The
Voorwerp is the size of the Milky Way, and its bright green colour is from glowing
oxygen.
Credit: NASA, ESA, William Keel (University of Alabama, Tuscaloosa), and the
Galaxy Zoo team