Tsangaridis: Greenish comet close to Earth after 50.000 years

A greenish comet, a unique traveler, is visiting the neighborhood of our planet these days, after 50.000 years when people still lived in caves.

As Astrophysicist Dr. Stelios Tsangaridis stated at KYPE, comet C/2022 E3 (ZTF) will reach its closest distance to Earth on February 1, 2023, when it will be 42 million km from our planet. In dark areas it will be visible as a faint, cloudy object.

It was discovered on March 3, 2022 by astronomers Bryce Bolin and Frank Masci (Zwicky Transient Facility, USA), when it was still en route to the inner solar system. Almost a year later, the comet has already orbited the Sun and will soon pass close by the Earth.

What are comets?

Icy, small solar system bodies, comets are composed mostly of water ice with a dense, metallic core. As they approach the Sun, stellar radiation vaporizes their surface material, creating the nebulous halo around their center that diffuses the starlight and gives them their name.

Mr. Tsaggaridis mentioned that the venting and disposal of material from their surface also creates two queues. One is composed of ice particles that mirror starlight, giving them the majestic appearance they are known for. This tail is straight and radiates from the comet into space, in line with the Sun.

The second tail consists of dust particles, which do not reflect light as efficiently and make it difficult to observe. But, being heavier, the dust tail curves so that it partly radiates from the comet and partly follows its orbit, Mr Tsangaridis continued.

The "green" comet visits us every 50.000 Earth years

What arouses interest in C/2022 E3 is its greenish color, which, as Mr. Tsaggaridis explained, is caused by the presence of molecular carbon (C2) on its surface, and that, as a long-period comet, an orbit of around the Sun may take about 50.000 Earth years.

"This means that the last time they were in our neighborhood - if there was a previous time - people were still living in caves and not even oral historical records have survived - the oldest of which, the songs of the Australian aborigines, are estimated to be around 40.000 years old", Mr. Tsangaridis told KYPE.

There is also a possibility, he added, that it will be "hurled" into interstellar space after its passage, therefore, its observation is a unique opportunity.

At its closest distance to Earth on February 1st

The greenish traveler has already passed its perihelion when, on January 12, 2023, it approached within 166 million kilometers of our star.

“It will reach its closest distance to Earth on February 1, 2023, when it will be 42 million km from our planet. It will become visible to the naked eye, but at the limits of human vision, as a faint, nebulous object - that is, a celestial smudge - near the north celestial pole in the constellation of the Giraffe," said Mr. Tsangaridis.

Then, he said, on February 10-11, it will pass close to Mars (within 1.5º – 2.0º of the red planet) and on February 13-15 it will pass in front of the Hyades star cluster in Taurus.

Faintly visible in dark skies

For those who would like to see it with the naked eye, its dim appearance and the fact that the Moon will be more than half - on February 5th is the full moon -, will make it invisible from the cities, with their intense light pollution.

“It may only be visible from the areas of our island with the darkest skies, so an expedition will be required to observe it. To the brave who will attempt it, the saying "ad astra per aspera" fits and our wishes for good success", concluded Mr. Tsangaridis