The discovery was made by an worldwide team of astronomers who had been utilizing the Hubble to observe some of the oldest and faintest white dwarf stars within the globular cluster NGC 6752. And after carefully measuring the brightness and temperature of the background stars, they realized they had found something special - an entire galaxy that was hidden by the glare of NGC 6752. Relative to other galaxies in the universe, NASA says that Bedin 1 is essentially in our planet's own "cosmic backyard". Dwarf spheroidal galaxies are defined by their small size, low luminosity, lack of dust and old stellar populations.
The Hubble Space Telescope has discovered thousands of galaxies throughout its lifetime, but many of those galaxies are billions of light-years away, in the most distant parts of our visible universe.
The IAC researchers said: "Recovering this light, emitted by the stars in these outer zones, was equivalent to recovering the light from a complete galaxy".
While dwarf spheroidal galaxies are not uncommon, Bedin 1 has some notable features. Due to these, scientists have determined that it is a dwarf spheroidal galaxy, according to a report published in the journal Monthly Notices of the Royal Astronomical Society: Letters. They wanted to measure the age of the cluster but instead found a dwarf galaxy.
This video takes the viewer on a journey to the globular cluster NGC 6752. 36 galaxies of this type are already known to exist in the Local Group of Galaxies, 22 of which are satellite galaxies of the Milky Way.
It's estimated to be roughly 13 billion years old based on the properties of its stars, meaning it is nearly as old as the universe itself. This makes it possibly the most isolated small dwarf galaxy discovered to date. Perhaps the most isolated small dwarf galaxy discovered so far, the Bedin 1 is located 30 million light-years away from the Milky Way galaxy and two million light-years from NGC 6744, its nearest plausible galaxy host.
The astronomers also note that a survey planned for the upcoming Wide Field Infrared Survey Telescope (WFIRST, planned to launch in the mid-2020's) may find more of these small, hermit-like galaxies.
This isn't the space telescope's first headline of the year, though.