Green comet, last near earth 50,000 years ago, makes closest approach to planet on Wednesday night

A comet not seen since the last ice age will make its closest approach to Earth on Wednesday, offering a once-in-a-geological-age opportunity for sighting the icy astronomical body. 

Comet C/2022 E3 (ZTF) last passed by Earth around 50,000 years ago, during a time when Neanderthals were still extant and wooly mammoths still roamed the planet. 

It will pass within about 26 million miles of our planet's surface on Wednesday night, offering potential naked-eye viewing opportunities under optimal conditions. 

The comet is observable as a green smudge with a long tail in the air, astronomers say. The object was first spotted in March of last year. 

Astronomers estimate that the comet is possibly "unbound" to our Solar System, meaning its orbit may carry it permanently away from Earth after its present passage, marking what may be the last time the object will be observable from our planet.