The boundaries of our home galaxy may have to be redrawn.
Astronomers have discovered the farthest-flung stars yet known in the Milky Way. The two objects — known as ULAS J0744+25 and ULAS J0015+01 — are about 775,000 and 900,000 light-years from Earth, respectively, making them both about five times more distant than a satellite galaxy known as the Large Magellanic Cloud.
“The distances to these two stars are almost too large to comprehend,” study lead author John Bochanski, of Haverford College in Pennsylvania, said in a statement. “To put it in perspective, when the light from ULAS J0015+01 left the star, our early human ancestors were just starting to make fires here on Earth.” [Our Milky Way Galaxy: A Traveler's Guide (Infographic)]
The Milky Way extends far beyond its familiar disk, which is just 100,000 light-years or so wide. The galaxy is surrounded by a sparse “halo” of stars — perhaps stragglers left out there after the Milky Way’s many mergers with dwarf galaxies over the eons, researchers say.