Astronomers have spotted a runaway supermassive black hole, seemingly ejected from its home galaxy and racing through space with a chain of stars trailing in its wake. - snip - The researchers discovered the runaway black hole as a bright streak of light while they were using the Hubble Space Telescope to observe the dwarf galaxy RCP 28, located about 7.5 billion light-years from Earth. Follow-up observations showed that the streak measures more than 200,000 light-years long — roughly twice the width of the Milky Way — and is thought to be made of compressed gas that is actively forming...