Sotiris Savvides on Unsplash
Save
On Tuesday night, a newly discovered comet will be at its closest point to the Earth, and if the clear skies continue, the unique green glow could be visible to those in the Bay Area. The comet, called C/2025 A6 (Lemmon), is the brightest of the year. Once it passes by Earth, it won’t appear again for another 1,000 years.
The green comet is predicted to be at its brightest tonight, but will continue to pass over the skies until the beginning of November. The brightness isn’t the only thing that makes this comet unique; the green hue is also a notable sight to look out for. The comet has diatomic carbon (C2), which breaks down and emits a green light, causing the unique glow around the comet. Comets are often visible with a long exposure camera or binoculars, but some hope the comet will be visible to the naked eye. Predictions for the comet’s visibility are uncertain, as it is hard to determine how bright a comet will be accurately.
—To see the comet, it’s best to look for it just after sunset and when the sky is clear. The green glow should be visible between the constellations Scorpius and Libra, or on the low western horizon. October 21st will be the best night for viewing, and the comet’s brightness will fade as it moves farther from the Earth.
What are comets?
According to NASA, comets are “cosmic snowballs.” They are comprised of frozen gases, rock, and dust, and orbit the sun. When a comet’s orbit is close to the sun, it starts to heat up, releasing the dust and gases that give it a glowing head and a trail that stretches on for miles. Comets are common, and NASA estimates it’s likely billions are orbiting the sun.
So far, the weather in San Francisco has clear skies, but slight rain is predicted for later tonight, so clouds could obstruct the view of the comet.