3I/ATLAS: A View from Planet EarthNow outbound after its perihelion or closest approach to the Sun on October 29, Comet 3I/ATLAS is only the third known interstellar object to pass through our fair Solar System. Its greenish coma and faint tails are seen against a background of stars in the constellation Virgo in this view from planet Earth,…Read More

Alnitak, Alnilam, MintakaAlnitak, Alnilam, and Mintaka are the bright bluish stars from east to west (upper right to lower left) along the diagonal in this cosmic vista. Otherwise known as the Belt of Orion, these three blue supergiant stars are hotter and much more massive than the Sun. They lie from 700 to 2,000 light-years away, born of Orion’s…Read More

Chamaeleon Dark NebulasSometimes the dark dust of interstellar space has an angular elegance. Such is the case toward the far-south constellation of Chamaeleon. Normally too faint to see, dark dust is best known for blocking visible light from stars and galaxies behind it. In this 11.4-hour exposure, however, the dust is seen mostly in light of…Read More

Comet Lemmon’s Wandering TailWhat has happened to Comet Lemmon’s tail? The answer is blowing in the wind — the wind from the Sun in this case. This continuous outflow of charged particles from the Sun has been quite variable of late, as the Sun emits bursts of energy, CMEs, that push out and deflect charged particles emitted by the comet itself. T…Read More

Crossing Saturn’s Ring PlaneIf this is Saturn, where are the rings? When Saturn’s “appendages” disappeared in 1612, Galileo did not understand why. Later that century, it became understood that Saturn’s unusual protrusions were rings and that when the Earth crosses the ring plane, the edge-on rings will appear to disappear. This is because…Read More