All these days we knew that our Milky Way has two best-known companions — the Magellanic Clouds, which are a pair of nearby dwarf galaxies. But, a recent observation of the dwarf galaxies has eventually upset this three-member family picture, i.e. they may be nothing more than strangers passing by.
The Large and Small Magellanic clouds are found to be moving with a velocity of 378 kilometres per second and 302 km/s respectively. This velocity reveals that they are ‘moving too fast’ to be considered as satellites of the Milky Way! This is discovered by comparing the Hubble Space Telescope images taken two years apart. This has helped make the most accurate measurements of the Magellanic Clouds velocities to date.
But, if the two galaxies were orbiting the Milky Way, their velocities would have to be about 250 km/s, the researchers believe. Nitya Kallivayalil of the Harvard-Smithsonian Center for Astrophysics said,
I really wasn’t expecting them to be moving so fast.Hats off to the astronomers at the Harvard-Smithsonian Center for Astrophysics (CfA) in Cambridge, Massachusetts, and the Space Telescope Science Institute (STScI) in Baltimore, Maryland (both in the US) for making this discovery.
Image Credit: AURA/NOAO/NSF
