1998 SH2: A Near-Earth Object Reclassified as a Comet, Illuminating Planetary Defense
Astronomers using NASA radar and decades of precise astrometry determined that the near-Earth object 1998 SH2 is actually an active comet with a faint tail. The discovery, supported by observations from the Very Large Telescope and CFHT and published in Nature Astronomy, shows nongravitational forces from outgassing that can alter an object's orbit, improving how we identify hidden comets among near-Earth objects and assess potential impact risks.