Comet-kazi: Sun-observing spacecraft spots a comet's demise
The Solar and Heliospheric Observatory (SOHO), launched in 1995 by NASA and the European Space Agency to study the sun and its environs, has delivered an auxiliary benefit—discovering more comets than any other mission in history. Most of the more than 1,500 comets SOHO has spotted are sun-grazing fragments of larger bodies, which themselves may have split off a common progenitor relatively recently, less than 2,000 years ago. That progenitor would have had an orbit that brought it from the outer solar system and past the sun only every several hundred years.
On March 12, SOHO spied a bright comet, likely from that same sun-grazing lineage, in its final hours as it streaked toward a fatal encounter with the sun. The inbound comet is visible below and to the left of the sun in this SOHO image. (The blinding disk of the sun itself is blotted out by an instrument called a coronagraph, which allows researchers to observe the solar atmosphere.) The bright point within the horizontal streak just below the sun is the planet Mercury.