This week humanity may have the last chance to see a rare “green” comet: why (photo)
If you have not seen the long-period comet that has become famous over the past month, do not be discouraged. There is still a chance.

The comet closest to the Earth, which was last seen by Neanderthals, was already approaching on February 1 this year. But the too bright Moon prevented us from fully enjoying the flying “green” ice ball with a tail. But this week there will be a unique opportunity to see comet C/2022 E3 ZTF in the sky quite well. Given that the next time it may not fly back to the Sun in 50 thousand years, this may be the last chance for humanity to observe this space object, writes Forbes.
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Comet C/2022 E3 ZTF has been called “green” because of the characteristic hue seen in the sky during its flight. Focus has already written about this long-period comet , which last approached the Earth 50 thousand years ago. At that time, the last Neanderthals and Homo sapiens were still neighbors in parts of Europe, and we may be the last members of our species to see this comet.
This comet made the most buzz in the media in the middle of last week, because on February 1 it flew close enough to the Earth after it “met” with the Sun for a while. What does close mean? By space standards, a distance of 41.5 million km is so close. After this event, interest in her declined sharply. But the too bright Moon that day, and even during the following days, did not allow us to fully enjoy the flight of a very rare comet in the night sky.
By the way, the Czech astronomer Petr Horalek was able to make a unique image of a comet flying towards the Earth, which was located just between two famous constellations – Ursa Major and Ursa Minor.
When can comet C/2022 E3 ZTF be seen this week?
But this week there is a unique chance to still see comet C / 2022 E3 ZTF as clearly as possible at a time when it is gradually moving away from our planet. Given that by the end of the week the Moon will no longer shine so brightly, such an object that is not very prominent against the background of stars can become clearly visible.
Beginning Thursday evening, February 9, and for the next 10 days, the evening and night sky will be virtually devoid of moonlight, according to scientists. This means that the sky will be much darker and the green ice ball will become available for viewing. The only thing you need to have is binoculars, since, unfortunately, this object will not be visible to the naked eye.
According to scientists, the best time to observe Comet C/2022 E3 ZTF is the evening and night of February 10 and 11. By the way, this Saturday the comet will fly very close to Mars.
Why is Comet C/2022 E3 ZTF green?
The short answer is that it’s all about carbon. Comets are mostly ice, but only a fraction of that ice is ordinary frozen water. They also consist of frozen compounds such as methane and ammonia. When the ice evaporates under the heat of the sun, the sun’s radiation also breaks down some of the ice’s molecules, so the carbon in methane is in the form of two carbon atoms bonded together. It’s called atomic carbon, and it’s a very short lived molecule. But throughout its existence, it reflects light at wavelengths that give comet C/2022 E3 ZTF its characteristic greenish glow.
Where is comet C/2022 E3 ZTF headed?
Since the comet was discovered last March, scientists have been modeling its flight path. Some researchers believe that at least once more it will fly up to the Sun in 50 thousand years. But other scientists argue that the comet could escape the Sun’s gravitational influence and fly off into interstellar space. Focus has already written about what these vast stretches of space are .