Comet NEOWISE has been mesmerising stargazers across the northern hemisphere as the giant ball of ice produces a stunning gaseous tail visible to those of us on Earth. So clear are the colours coming from the comet, astronomers have been able to determine what exactly the icy rock consists of.
As comets approach the Sun, the chemicals react to the heat producing an array of colours.
According to astronomy site Space Weather, the comet’s head is green, meaning diatomic carbon, C2, is present which “emits a verdant glow in the near-vacuum of interplanetary space.”
The tail of the comet is blue, which shows one of the most abundant gasses in the comet is carbon monoxide (CO).
Space Weather said: “When CO flows away from a comet’s nucleus, it is ionised by solar UV radiation. Carbon monoxide ions (CO+) glow blue when they recapture electrons from the solar wind.”
The dust tail of the comet is yellow, which is just a reflection of the Sun’s light.
Space weather stated: “The two tails are nicely separated, revealing their individual colours because they are guided by different forces.
“The gaseous ion tail is shoved directly away from the Sun by solar wind; it acts as a kind of interplanetary windsock. The heavier dust trail, however, isn’t so easily pushed around.
“Specks of dust are like bread crumbs dropped on the comet’s orbit; they curve away from the ion tail, tracing the comet’s ‘footsteps’ instead of the local breeze.”
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Some scientists have warned Comet NEOWISE could be the last comet which could be visible to the naked eye.
Light pollution is increasingly making it difficult for astronomers and amateur stargazers alike, as artificial lighting is constantly on the increase, a team of researchers say.
According to the Natural History museum, light pollution caused by artificial lighting is increasing by an average of six percent a year.
And as things get lighter here on Earth, the sky at night seemingly gets darker.
Gareth Dorrian, post doctoral research fellow in Space Science at the University of Birmingham, and Ian Whittaker, senior lecturer in physics from Nottingham Trent University, said everyone should take advantage of the current comet, the first to be visible from Earth since the 90s, as it could be our last.
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The pair wrote in The Conversation: “So comet NEOWISE will only be seen for a few weeks near Earth while it is near perihelion (its closest approach to the Sun).
“It will then spend thousands of years moving slowly near the other end of its orbit.
“It’s aphelion (farthest point) is estimated at 630 astronomical units (AU), with one AU being the distance between the Earth and the Sun.
“With the constant increase of light pollution in the night sky the observation of comets with the naked eye is becoming much rarer.
“For now, though, NEOWISE presents a fantastic opportunity for millions of people to see a night sky phenomenon which typically only presents itself perhaps once in a decade or more. Enjoy the view!”