White dwarfs — the superdense, slowly cooling embers left behind when stars like our sun die — are usually quiet cosmic relics. A rare few, however, are anything but.

In recent years, astronomers analyzing data from the European Space Agency's Gaia spacecraft identified a handful of white dwarfs hurtling through the Milky Way at breakneck speeds of up to 1,240 miles per second (2,000 kilometers per second). That's fast enough to zip from New York to Los Angeles in under two seconds — and to escape the galaxy entirely.

These so-called hypervelocity white dwarfs have puzzled astronomers since their discovery in 2018. Their extreme speeds suggest they were launched by powerful, violent events, but no single theory has been able to explain both their breakneck velocities and their puffed-up,

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