When a star ten times the Sun's mass explodes, it crushes down to the size of Manhattan. Whether we can still see its blinding light 50 million years later depends entirely on where you stand.
Stars below eight solar masses gently shed their envelopes as white dwarfs, while those above twenty collapse into black holes. A ten-solar-mass star takes the middle road: it detonates in a core-collapse supernova, leaving behind a neutron star.
During the explosion, the star’s outer layers blast into space at thousands of kilometers per second, dispersing gas enriched with oxygen, neon, and magnesium into the interstellar medium. Gravity crushes the remaining core into a sphere barely twenty kilometers across. In that compact ball, protons and electrons merge into neutrons, creating an object with more mass than our Sun, spinning hundreds of times per second and generating intense magnetic fields. The Crab Nebula, created by a supernova recorded in 1054 CE, originated from a star in this exact mass range.
If the supernova occurred fifty million light-years away—in the Virgo Cluster, for instance—the answer is yes. Light travels at roughly 300,000 kilometers per second, covering one light-year each year. The blinding burst from that star’s death would take exactly fifty million years to cross intergalactic space, meaning telescopes on Earth would witness the explosion right now.
If the explosion occurred locally in the Milky Way fifty million years ago, the original flash is long gone. The optical flare fades within months, and the glowing nebula of debris disperses into interstellar clouds within a few hundred thousand years.
The surviving neutron star remains, but it would be nearly impossible to spot today. Over fifty million years, its surface cools from millions of degrees down to tens of thousands. Because its surface area is so small, its total thermal brightness drops to negligible levels. At the same time, the star’s rotation slows until it crosses the pulsar death line, cutting off the radio beams that once swept across space and leaving behind a cold, dark cinder drifting through the galaxy.