How big is the green comet and how often can it be seen?
The once in a lifetime viewing of the comet is coming up meaning astronomers will need to keep their eyes peeled.


Skywatchers can already get their first glimpses of C/2022 E3 (ZTF). The once-in-a-lifetime opportunity will be hungrily snapped up by astronomers as missing out will mean no chance of a human seeing the phenomenon for another 50,000 years.
Scientists have calculated that the comet is 3,281 feet (1,000m) wide, over half a mile. For some context that is 11 Statue of Libertys stacked on top of one another. The Burj Kahlifa, the world’s tallest building, doesn’t come close to being the same height.
A dazzling green comet not seen since the Stone Age has stargazers thrilled in these amazing photos https://t.co/7v8QufCrti pic.twitter.com/1J3jLuG8h1
— SPACE.com (@SPACEdotcom) January 13, 2023
The size is known but an unknown variable is how bright the comet will be. The characteristic green colour is created by minerals thought to be at the front of the comet. It won’t be as bright as other comets like Halley’s.
“The brightness of comets is notoriously unpredictable, but by (1 Feb) C/2022 E3 (ZTF) could become only just visible to the eye in dark night skies,” NASA said in its blog.
It will be possible to view the comet every day from 12 January until 10 February, if the conditions are right. Travelling so far away, and at such speed, means the comet will traverse the locations of a number of famous constellations such as Gemini as well as near to Mars.
How can the green comet be viewed?
While the comet can already be seen in the night sky, unless you are living in an area with bad light pollution, the clearest it will be visible will be closer to the end of the month. 1 and 2 of February are expected to be the clearest days.
PASS IT ON: A green comet will appear in the night sky for the 1st time in 50,000 years! Comet 2022 E3 (ZTF) will appear through early February & make its closest pass of Earth on February 1st & 2nd. You may need binoculars but should spot it near the North Star. #Comet #Space pic.twitter.com/6AZsl0g7bb
— Mark Tarello (@mark_tarello) January 17, 2023
A telescope will be necessary to see it or you can turn to YouTube to watch a live feed.