Green comet 2023 – live: How to see E3 in sky tonight before it disappears forever
C/2022 E3 (ZTF) comet is visible with the naked eye from certain locations
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A green comet is flying past Earth for the first time in 50,000 years, offering skygazers a one-off opportunity to witness the celestial spectacle before it disappears from our Solar System forever.
The C/2022 E3 (ZTF) comet made its closest approach to Earth on 1 February, 2023, but will continue to be visible throughout the week from anywhere in the northern hemisphere – weather permitting.
At a relatively close 42 million kilometres (26 million miles) from our planet, and with a brightness value of the magnitude of about +6, it will be possible to see it with the naked eye.
The comet is so rare that woolly mammoths and saber-toothed cats were still roaming the Earth when it last swept by our planet.
To find out where in the sky to look, and learn when conditions are best for viewing the comet tonight and over the next few days, you can follow our live coverage in the blog below.
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How green comet ZTF was discovered
The green comet C/2022 E3 (ZTF) was found in March 2022, the discovery largely attributed to astronomers Bryce Bolin and Frank Masci.
While it was initially thought to be an asteroid, the space rock’s condensed coma – its nebulous envelope – indicated it was a comet.
The comet was spotted in a twilight survey by the Caltech-led project the Zwicky Transient Facility.
For the survey, ZTF uses a special camera to take images nearly every 30 seconds through the Palomar Observatory’s forty-eight-inch telescope.
Researchers have taught machine-learning algorithms to detect moving objects in the sky by analysing these images.
“On March 2nd, all we knew was that we had found a moving object. We reported it to the Minor Planet Center – they are the clearing house for these things,” Tom Prince, one of the lead scientists on the project, told The New Yorker.
Nasa decodes distinctive shape of green comet
The green comet C/2022 E3 (ZTF) hurtling past Earth over the last month has been spotted to have not just one or two tails, but three.
Nasa notes in a blog post that the comet not only has a common dust tail, an ion tail, as well as a green gas coma, but also a rare distinctive anti-tail.
While the dust and ion tails are seen trialing comets, the ZTF’s anti-tail was seen seemingly leading the comet.
This anti-tail, seen in some photographs, is an illusion caused by the Earth moving through the comet’s orbital plane.
“The anti-tail does not actually lead the comet, it is just that the head of the comet is seen superposed on part of the fanned-out and trailing dust tail,” Nasa noted.
ZTF is currently visible all night long from northern latitudes, but is expected to fade from observation during the next few weeks and might never return to pass by Earth.
Some estimates suggest green comet may never again pass by Earth
Researchers say the green comet’s current orbit trajectory may see the space rock booted out of the inner Solar System to never return.
“Some predictions suggest that the orbit of this comet is so eccentric it’s no longer in an orbit—so it’s not going to return at all and will just keep going,” astronomer Jessica Lee from the Royal Observatory Greenwich told Newsweek.
While scientists do not yet have an accurate estimate of how far the comet could get from the Earth, they say if it does return, it may not for at least another 50,000 years.
Whether it returns or not may depend on the perturbations the comet may encounter from losing its mass or from any disturbances it might face while in the Oort cloud.
The green comet’s path through the sky
Tonight is not the only chance to see the green comet, so don’t lose hope if the weather near you is bad.
This handy map, courtesy of the MISAO Project, shows the path the comet will be taking across the sky over the coming days and weeks.
The early hours of 1 February will see Comet ZTF reach its perigee, meaning it is at its closest point to Earth, but it will still be visible with the naked eye for the next few days in case you don’t get a chance to see it tonight. For a few weeks it will also be possible to see it using binoculars or a telescope.
What we know about Oort cosmic cloud from where green comet originated
The green comet C/2022 E3 (ZTF) making its closest pass by Earth today originated from the Oort Cloud, a cosmic shell of debris encircling the farthest reaches of the Solar System.
Scientists have long known that this region, containing billions or trillions of space debris, is the origin site of long-period comets like ZTF.
This region is thought to be a giant spherical shell encircling the Solar System like a thick-walled bubble made of icy rocks.
It is likely at a massive distance of about one-quarter to halfway from the Sun to the next star, according to Nasa.
Scientists have theorised that this region likely formed as gravity from the Solar System’s planets shoved a vast number of icy rocks away from the Sun, and gravity from the galaxy may have caused debris to settle into a border shell.
The comets from this shell can shed light on the history of the Solar System and have been seen only once in recorded history since their orbital periods are very long.
Nasa to study green comet using Webb telescope
Nasa is planning to observe the comet with its James Webb Space Telescope to unravel clues about the Solar System.
The comet may shed light on the formation of the Solar System as it likely formed during its early stages, scientists say.
It was first identified by the wide-field survey camera at the Zwicky Transient Facility inside the orbit of Jupiter in March 2022 but was initially suspected to be an asteroid.
“We’re going to be looking for the fingerprints of given molecules that we can’t access from the ground,” planetary scientist Stefanie Milam of NASA’s Goddard Space Flight Center in Maryland said.
“Because JWST’s so sensitive, we’re expecting new discoveries.”
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