Joe Velaidum and his partner, Laura Kelly, set out to walk their dog when their doorbell camera captured a meteorite striking their front walkway — where Velaidum had been standing moments before.

For the homeowner, Joe Velaidum, the video did not just capture something of value to science but also recorded a brush with luck. Just before the meteorite hit, Mr. Velaidum and his partner ...

Scientists think they may have come from space. For years scientists had been finding organic compounds in meteorites, but could not rule out the possibility that they were Earth-based contamination.