Ancient Stardust

When our galaxy was born, around 13,000 million years ago, a plethora of clusters containing millions of stars emerged. But over time, they have been disappearing. However, hidden behind younger stars that formed later, some old and dying star clusters remain, such as the so-called E 3. European astronomers have now studied this testimony to the beginnings of our galaxy.

An international team of astronomers has used a highly sensitive instrument on one of the world’s largest telescopes to witness a dominant galaxy, Messier 81 in Ursa Major, ingesting the stars of its near neighbours. The gravitational pull of M81 was shown to distort the shapes of adjacent galaxies, pulling their stars into long tails in a process called tidal stripping.

Many galaxies are chock-full of dust, while others have occasional dark streaks of opaque cosmic soot swirling in amongst their gas and stars. However, the irregular dwarf galaxy IC 1613 contains very little cosmic dust, allowing astronomers to explore its contents with great clarity. This is not just a matter of appearances; the galaxy’s cleanliness is vital to our understanding of the universe around us.