Sightseers in the northern hemisphere will be lucky enough to catch a glimpse of a solar system comet as the celestial object streaks through space very close to Earth for the first time in 50,000 years.
Look up to the sky Wednesday night through Thursday as the comet named C/2022 E3 (ZTF) was previously visible to the naked eye nearly 50,000 years ago, around the time of the Neanderthal man. If you miss it this time, you’re unlikely to get another chance.
Haven’t seen the ZTF green comet in the last few weeks yet? Tonight is the perfect moment, because on February 2, 2023, the historic comet passes closest to our planet.
A relative proximity, of course, because it passes a little over 42 million kilometers from Earth. At its closest, the comet will be within 26 million, according to the Adler Planetarium.
As it approached Earth, the comet became increasingly brighter and more visible. This Wednesday, it passes between the orbits of Earth and Mars around the Sun, at a speed of 207,000 km/h.
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Since January 19, it could be observed without a scientific instrument and on Wednesday evening it will be bright enough to be seen through telescopes and binoculars.
Comets can be hard to spot in the night sky, but the cosmic intruder has been steadily brightening through its movements, which should help people spot it, according to NASA.
Astronomers estimate that the comet has a nucleus 1.6 km in diameter and its tails stretch for millions of kilometres. The green comet poses no risk to the planet.
C/2022 E3 (ZTF) was discovered in March 2022 by astronomers using the surveillance camera at the Zwicky Transient Facility, north of San Diego in California, USA.
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Fairly common to scientists, comets are icy remnants of the formation of the solar system 4.5 billion years ago.
Comet C/2022 E3 (ZTF) holds a long orbit that will continue to take it on its journey around the sun and deep into the vast solar system for thousands of years.
How to see it?
To observe the passage of the green comet, you will have to look at the correct stars. It is advisable to observe the sky towards the northeast direction from a very dark place and to look for a spot in the sky, or in the hours before dawn, after the moon has fallen below the horizon.
According to EarthSky.org, the comet will pass below Polaris, the pole star at the tip of Ursa Minor, and will be visible near the star. And on February 10, the comet will be very close to the planet Mars. If you can locate Mars bright in the sky, look around for the comet.
Maps are available online to help you locate reference points, such as Hercules, Polaris, and Mars, in the night sky. You can also try your hand at stargazing apps, which will make it easier for you.
Why is it green?
With binoculars, the comet will appear as a faint green glow in the sky. According to NASA, it also has “a short, wide dust tail and a long, weak ion tail.”
Its emerald tones come, according to astronomy experts, from the presence of diatomic carbon in the gas cloud that surrounds its core, interacting with sunlight.
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When diatomic carbon, an unstable gaseous form of the element in which carbon atoms are bonded in pairs, is excited by ultraviolet rays, it emits light, causing the green cloud seen around the comet’s nucleus .
However, ultraviolet light can also cause diatomic carbon to break down. This explains why the tail of the comet is not green, but white.
For those unable to see the Green Comet in person, real-time images from robot-controlled telescopes in Italy and Spain will be webcast.