Happy Birthday Hubble: NASA Telescope Captures Five Galaxies Caught In A Gravitational Dance As It Turns 32

The Hubble Space Telescope telescope was deployed into Earth's orbit by NASA astronauts aboard the space shuttle Discovery, on April 25, 1990. 

NASA's Hubble Space Telescope celebrated its 32nd birthday by capturing the Hickson Compact Group 40, which is a menagerie of five galaxies caught in a gravitational dance

Source : NASA

New Delhi: NASA's iconic Hubble Space Telescope turns 32 years old today. Since its launch and deployment in 1990, Hubble has revolutionised astronomy. The telescope was deployed into Earth's orbit by NASA astronauts aboard the space shuttle Discovery, on April 25, 1990. 

Hubble has taken 1.5 million observations of approximately 50,000 celestial targets to date, according to NASA. 

The telescope celebrated its 32nd birthday with a mesmerising look at an unusual close-knit of five galaxies, called The Hickson Compact Group 40 (HCG 40).

All About The Tightly Grouped Galaxies

The isolated menagerie of the five galaxies is caught in a gravitational dance. The eclectic group includes three spiral-shaped galaxies, an elliptical galaxy, and a lenticular galaxy, which is a lens-like galaxy. The galaxies crossed paths in their evolution to create an exceptionally crowded menagerie. 

In about one billion years, the galaxies will collide and merge to form a giant elliptical galaxy. Hubble captured the eclectic bunch at a very special moment in the lifetime of the galaxies, as they fall together and continue their leisurely dance, before they merge.

According to NASA, the galaxies are so crowded that they could fit within a region of space that is less than twice the diameter of the Milky Way's stellar disc. Such cosy galaxy groupings can be found in the heart of huge galaxy clusters. The five galaxies captured by Hubble are isolated in their own small patch of the universe, in the direction of the constellation Hydra.

There are more than 100 such compact galaxy groups, but the eclectic bunch recently captured by Hubble is one of the most densely packed. In the early universe, such tightly grouped galaxies may have been more common. The superheated, infalling material of these galaxies may have fuelled very energetic black holes called quasars. By studying the details of galaxies in nearby groups, astronomers can determine when and where galaxies assembled themselves, and what they are assembled from.

Why Are The Galaxies Isolated In Their Own Small Patch?

A lot of dark matter, which is an unknown and invisible form of matter, is associated with the five galaxies. This could explain why the galaxies are isolated in their own small patch in the universe. 

The dark matter can form a big cloud within which the galaxies are orbiting, if they come closer. Due to the gravitational effects of dark matter, the galaxies feel a resistive force, which slows their motion and makes them lose energy. Eventually, the galaxies fall together.

The compact galaxy has been studied not only in visible light, but also in radio, infrared, and X-ray wavelengths. 

Almost all the five galaxies have a compact radio source in their cores, indicating the presence of supermassive black holes. 

Astronomers inferred from X-ray observations that the galaxies have been gravitationally interacting due to the presence of a lot of hot gas among the galaxies. 

Near star formation may be taking place within the galaxies, infrared observations suggest.

Hubble's unique capabilities are that it makes observations in visible and ultraviolet light, which are a critical scientific complement to the infrared-light observations of the recently launched James Webb Space Telescope.