The clumps of gas and stars may have meandered for 1 billion years
G. Beccari et al/Monthly Notices of the Royal Astronomical Society 2017
A pair of dark loners wander a distant cluster of galaxies. The two small gas clouds have been roaming the Virgo cluster, some 55 million light-years away, for at least a billion years. Such small, isolated clouds of gas shouldn’t be able to form stars on their own — and yet they are doing just that.
Astronomer Michele Bellazzini of the Italian National Institute for Astrophysics in Bologna and his colleagues found the small, dim clouds in 2014 in the SECCO survey, which looks for the building blocks of galaxies. The two are moving at the same speed and have the same chemical composition, so the researchers think they have the same origin story.
Together, the clouds, called SECCO 1, have just 160,000 solar masses' worth of stars, but 20 million solar masses of hydrogen gas—a lot more hydrogen than found in other small starry bodies. Dwarf