A green-hued comet is expected to be visible to stargazers tonight for the first time in about 50,000 years. It will make its closest approach to Earth since the age of the Neanderthals. The comet named C/2022 E3 (ZTF) will come within 26 million miles (42 million kilometres) of Earth on Wednesday before speeding away again, unlikely to return for millions of years.
According to EarthSky, the comet has been brightening the night sky since January and will pass between the orbits of Mars and Earth. It will travel at a speed of 128,500 mph (207,000 km/h).
The comet was first spotted in March last year by astronomers through the wide-field survey camera at the Zwicky Transient Facility. It was in Jupiter's orbit at the time and has grown brighter since then.
NASA plans to observe the comet with its James Webb Space Telescope (JWST), which could provide clues about the solar system's formation.
"We're going to be looking for the fingerprints of given molecules that we can't access from the ground," said planetary scientist Stefanie Milam of NASA's Goddard Space Flight Center in Maryland. "Because JWST's so sensitive, we're expecting new discoveries."
You can see the green comet by using binoculars on a clear night, the comet can be seen in the northern sky. On Monday, it appeared between the Big Dipper and Polaris, the North Star. And on Wednesday, it was positioned to appear near the constellation Camelopardalis, bordered by Ursa Major, the Big Dipper and the Little Dipper, Reuters reported.
Finding a remote location to avoid light pollution in populated areas is key to catching a nice view of the comet.
Nicknamed "dirty snowballs" by astronomers, comets are balls of ice, dust and rocks that typically hail from the ring of icy material called the Oort cloud at our solar system's outer edge. One known comet actually originated outside the solar system - 2I/Borisov, according to Reuters.
Comets are composed of a solid core of rock, ice and dust and are blanketed by a thin and gassy atmosphere of more ice and dust, called a coma. They melt as they approach the sun, releasing a stream of gas and dust blown from their surface by solar radiation and plasma and forming a cloudy and outward-facing tail.
Comets wander toward the inner solar system when various gravitational forces dislodge them from the Oort cloud, becoming more visible as they venture closer to the heat given off by the sun. Fewer than a dozen comets are discovered each year by observatories around the world.