The US space agency NASA’s iconic Hubble Space Telescope (HST) has uncovered hidden side of a galaxy named NGC 24 located 25 million light years away. The 40,000 light-years wide galaxy was discovered by astronomer William Herschel back in 1785.
Advanced Camera for Surveys, known as ACS for short, aboard HST was used to snap the shot. It shows NGC 24 in detail, highlighting the blue bursts (young stars), dark lanes (cosmic dust), and red bubbles (hydrogen gas) of material peppered throughout the galaxy’s spiral arms. Numerous distant galaxies can also been seen hovering around NGC 24’s perimeter.
However, there may be more to this picture than first meets the eye. Astronomers suspect that spiral galaxies like NGC 24 and the Milky Way are surrounded by, and contained within, extended haloes of dark matter. Dark matter is a mysterious substance that cannot be seen; instead, it reveals itself via its gravitational interactions with surrounding material. Its existence was originally proposed to explain why the outer parts of galaxies, including our own, rotate unexpectedly fast, but it is thought to also play an essential role in a galaxy’s formation and evolution. Most of NGC 24’s mass — a whopping 80 percent — is thought to be held within such a dark halo.
Hubble Space Telescope is a joint venture of NASA and ESA. The telescope was launched in 1990 and since then it is the largest telescope in space. HST has helped scientists in exploring the deepest corners of the universe and has beamed back millions of stunning shots in its entire career. However, HST will be replaced by the James Webb Telescope in 2018 as it has thrice larger lens when compared to HST.