“You really need to take a look. Because if you don’t do it now, you’ll have to wait 50,000 years for your next chance.”
The advice is from Floris-Jan van der Meulen, retired journalist and passionate amateur astronomer. He’s talking about comet C/2022 E3 (ZTF), popularly known as “the rare green comet” that is skimming past Earth these weeks.
Birdwatcher is enough
Van der Meulen speaks enthusiastically about the celestial body. “You can’t see it with the naked eye, but simple binoculars are enough. The advantage of this is that you look wide into the sky, so you can easily find it. If you want to see it sharper, you can of course with a better viewer, and especially with a telescope.”
On the night of Wednesday, February 1 to Thursday, February 2, it will come closest to Earth – still 43 million kilometers, but that is a stone’s throw by cosmic standards. The comet can grow up to 50 kilometers in size and drag a tail of a million kilometers behind it.
Astronomer and science journalist Lucas Ellerbroek is also enthusiastic. “I look up every night these days.”
Ellerbroek explains what the comet is exactly: “It is called a ‘dirty snowball’, a dirty snowball of rock, ice and gas. Leftover Lego bricks from the early formation period of our solar system have clumped together to form this comet. Stones become pebbles and dust. held together in a ball of ice. As the comet gets closer to the sun, the ice evaporates. The tail you see are grains of dust breaking off the surface.”
Gifwolk
Amateur astronomer Van der Meulen says that two tails can regularly be seen on the comet. “A tail of dust, which is gray. And a tail of gas, which is blue-green. The nice thing is that they can both point in different directions. The gray dust tail is always behind the comet, but the blue-green gas tail points away of the sun, so it can also point straight ahead.”
He also has a nice anecdote about that gas tail: “The green color is caused by the substance cyanogen. You already hear: that is related to the deadly poison gas cyanide. In 1910 another comet, called Halley, also came close to the earth. The whole world was in turmoil, because if the earth came through the gas cloud, we could be poisoned. Pills and special umbrellas were sold for that. But that turned out not to be necessary at all.”
The green comet that has gripped astronomers this month does not move in a nearly circular, slightly elliptical orbit around the sun like Earth, says astronomer Ellerbroek, but in an elongated oval orbit. “It takes it far beyond our solar system, even into the Oort cloud. But now it skims right through our system.”
According to the scientist, the cosmic visit is a special event. “I find it fun and exciting myself because it shows that the universe sometimes unpredictably turns out. We will see more of such comets in the next hundred years, suddenly racing through our solar system.”
Celestial bodies ‘not on collision course’
The chance that one of those unexpected visits will cause a head-on collision with the Earth is very small, says Ellerbroek. “We generally have a very good idea of celestial bodies that could be a danger to us. You see them coming a long time in advance.”
At present, there are no comets in view that are “on a collision course for the next several decades,” he says. “Of course you could be surprised, never say never, but that chance is really very small. And even then we wouldn’t have a chance: recently a NASA mission pushed an asteroid off its course by flying into it with a space probe. So if we see one coming, there’s still time to do something.”
Here are images of the green comet taken with a telescope:
Both stargazers will be regularly peering at the sky in the coming days and weeks, they say. Ellerbroek: “The moon is currently very present in the sky, which is a pity. But I will try it more often with my telescope in the coming days. It will be visible until the end of next month, so there is still plenty of chance.”
Tonight, when the green comet is closest to Earth, Van der Meulen will be ‘certainly looking up’ with some other stargazers from the local Arnhem association Presikheaven.
1 degree from Mars
“Incidentally, we are organizing a viewing evening for interested parties on February 11,” says Van der Meulen. “Then the comet will be a little further away, that’s right, but there are three advantages to that date: the moon will then be less present, which will sharpen the contrast against the dark sky; the comet will be a little higher in the sky, so that you have to look through less atmosphere; and third, the comet is 1 degree away from the planet Mars that evening, so you can see both of them in one image, which will be wonderful.”
He also has a tip: “First look online, for example on Hemel.waarnemen.com, to see where you should look. Find a dark spot with little light. And then fingers crossed for a cloudless sky.”
Lucas Ellerbroek recommends Hanno Rein’s app, available in the Apple store: “It’s a handy map of the sky with a red circle around the comet. Couldn’t be simpler. And then indeed look for a dark spot.”
Weather conditions not ideal
“The weather conditions are not ideal for stargazers in the coming days,” says William Huizinga, meteorologist at Buienradar. “It looks quite cloudy in the coming nights. Coming night you have the best chance of local gaps in the cloud cover in the northern half of the country.”
Huizinga does point out that the weather, and certainly the clouds, is always erratic at this time of the year. “Check the forecast every day, because the weather can change quickly.”
What also doesn’t help is that ‘prominently’ present moon. Huizinga: “We are on our way to a full moon. Tonight the moon is 81 percent full. It rises in the afternoon, and therefore gives a lot of disruptive light in the evening and early night. It will be full on Monday.”
He thinks the date February 11 for the viewing evening of Presikheaven in Arnhem is ‘not bad’. “The moon will then rise later, in the late evening. It will also be less high in the sky. Therefore, it will be less disruptive in the sky in the evening and early night.”
