NASA’s Hubble Space Telescope (HST) was launched into space on 24 April 1990. It is a sophisticated observatory, exploring the universe from an Earth orbit. It has acquired hundreds of thousands of images of numerous celestial objects, and yielded startling discoveries that revolutionized modern astronomy.
Celebrating the 21st anniversary of the launch of HST, astronomers at the Space Telescope Science Institute (STScI) recently slewed Hubble, to image a system of two curious spiral galaxies, whose shapes have been fantastically distorted, due to their mutual gravitational attraction. This system is known technically as Arp 273, as it is the 273rd entry in the Atlas of Peculiar Galaxies, compiled by the American astronomer Halton Arp. HST’s image of Arp 273 was obtained, applying the telescope’s Wide Field Camera 3 device.
When two or more galaxies pass close to each other, they are said to be in interaction, as each galaxy is then disturbed by the gravitational fields of the other galaxies. Some interacting galaxies may eventually collide, or merge, forming a larger galaxy. Interactions of galaxies are believed to have played a significant role in the evolution of the cosmos, since they may trigger an active star formation process in the interacting galaxies.
The Arp 273 system lies roughly 300 million light years from Earth. It consists of a large spiral galaxy, designated UGC 1810, and a smaller companion spiral galaxy, designated UGC 1813. In HST’s image, UGC 1810 shows a disk that is distorted into a rose-like shape, due to the gravitational pull of UGC 1813. UGC 1813, visible below center, shows distinct signs of active star formation at its core, perhaps induced by the gravitational influence of its larger companion. The image also reveals a faint bridge of material, extending between the two galaxies, that are tens of thousands of light-years apart.
"For 21 years, Hubble has profoundly changed our view of the universe, allowing us to see deep into the past while opening our eyes to the majesty and wonders around us," said NASA Administrator Charles Bolden. "I was privileged to pilot space shuttle Discovery as it deployed Hubble. After all this time, new Hubble images still inspire awe and are a testament to the extraordinary work of the many people behind the world's most famous observatory."
Hubble was launched aboard the Space Shuttle Discovery, into a low Earth orbit, about 600 km high. It is one of the largest spacecraft ever deployed, measuring 13 m in length, and weighing over 11,000 kg. It is expected to remain operational till at least 2014, when a new successor space telescope will be due for launch.
References
NASA
www.nasa.gov/
HUBBLESITE
http://hubblesite.org/
NASA's Hubble Celebrates 21st Anniversary with "Rose" of Galaxies
http://hubblesite.org/newscenter/archive/releases/2011/11/
Shuttle Orbiter Discovery
http://science.ksc.nasa.gov/shuttle/resources/orbiters/discovery.html
Wikipedia