New Delhi: On 30 October, the interstellar comet 3I/ATLAS, which has piqued the interest of the global science community, will reach its closest point to the Sun, at a distance of about 1.4 astronomical units (au) or about 210 million kilometres.
“The closest it will approach our planet is about 1.8 astronomical units, about 170 million miles, or 270 million kilometres,” said the National Aeronautics and Space Administration’s (NASA) latest update about the comet’s movement.
It added that when the comet reaches its closest point to the Sun around 30 October, it will be just inside the orbit of Mars. “3I/ATLAS should remain visible to ground-based telescopes through September, after which it will pass too close to the Sun to observe. It will reappear on the other side of the Sun by early December 2025, allowing for renewed observations.”
Amid curiosity around the rare characteristics of the comet, ThePrint explains why its continued observations promise to enhance humanity’s understanding of the universe.
Discovery
When 3I/ATLAS was first spotted by scientists in Chile earlier this year, it was described as having a “teardrop-shaped cocoon of dust coming off its solid, icy nucleus.”
The NASA confirmed that when the orbit of 3I/ATLAS was first traced, it originated from outside our solar system, making it the third known interstellar object from outside our solar system [the first two being Oumuamua (2017) and 2I/Borisov (2019)] to be discovered passing through our celestial neighbourhood.
The comet is named after the NASA-funded ATLAS (Asteroid Terrestrial-impact Last Alert System), which first reported the observation. The comet’s orbital path is a hyperbolic shape, which means that it does not follow a closed orbital path about the Sun.
The European Space Agency (ESA) and the NASA have confirmed that it poses no threat to the Earth and will remain far away from the planet’s orbit. The closest it will approach the Earth is about 1.8 au, which comes to about 270 million km or 170 million miles before reaching its closest point to the Sun.
Conspiracy theories
The social media rumour mill started when some news reports by a few US-based websites published clickbait stories stating that this “massive”, “city killer” that was hurtling towards the Earth, seemed like a spaceship because of its peculiar characteristics.
While 3I/ATLAS has some unique characteristics that astronomers have not seen before, these are not unnatural in such objects.
For instance, initial observations were that the comet had a high carbon dioxide-to-water ratio, which was later published in a recent study in the Astrophysical Journal Letters. Researchers explored water activity on the comet and provided the first clear evidence that it was shedding water far from the Sun.
Observations have detected hydroxyl gas, an ultraviolet by-product of water, coming off the comet when it was nearly three times farther from the Sun than the Earth, which is much farther away than the region of our solar system where water typically turns to gas on passing comets.
Researchers calculated that the comet was shedding about 40 kg of water per second, equivalent to a fire hose running at full blast, according to a statement released by NASA researchers last month.
(Edited by Insha Jalil Waziri)
Also Read: How NASA’s 10-minute flight to study the Sun may help unlock the mysteries of solar astrophysics