*The time has arrived...the 3rd interstellar object ever recorded about to make its closest approach to the sun...and there is plenty of mystery surrounding 3I/ATLAS*
Paul Dorian
Interstellar comet 3I/ATLAS caught streaking through the solar system on Aug. 27 by the Gemini South telescope in Chile. (Image credit: International Gemini Observatory/NOIRLab/NSF/AURA/Shadow the ScientistImage Processing: J. Miller & M. Rodriguez (International Gemini Observatory/NSF NOIRLab), T.A. Rector (University of Alaska Anchorage/NSF NOIRLab), M. Zamani (NSF NOIRLab))
Overview
3I/ATLAS was discovered by telescope on July 1st, 2025, and it has been classified as interstellar because its trajectory is hyperbolic meaning it is not gravitationally bound to our solar system. It will pass closest to the Sun sometime later today or early tomorrow, at about 1.4 astronomical units (AU) or about 130 million miles, and then make its nearest approach to Earth on December 19th, 2025, at about 1.8 AU or about 170 million miles. NASA has been tracking the object for months, noting unusual movements and energy signatures that don’t match the behavior of typical comets. It is the third interstellar object ever recorded, quite likely the oldest, largest, and fastest moving, and this is the first time through our solar system.
Background of 3I/ATLAS
Speculation is running rampant as there is plenty of mystery surrounding an interstellar object officially known as “3I/ATLAS” which is going to come closest to the sun in its orbit sometime later today or early tomorrow (perihelion). This object was first detected by the NASA-funded ATLAS (Asteroid Terrestrial-impact Last Alert System) survey telescope in Chile on July 1st, 2025...hence the “ATLAS” is part of its official name. The letter “I” in the name stands for “interstellar” indicating the object came from outside our solar system, and it is the third known interstellar object, hence the “3” in the name. Astronomers have categorized this object as “interstellar” because of the hyperbolic shape of its orbital path (it does not follow a closed orbital path about the sun). The first two interstellar objects that were observed include “1I/Oumuamua” in 2017 and “2I/Borisov” in 2019.
NASA’s James Webb Space Telescope observed interstellar comet 3I/ATLAS Aug. 6, with its Near-Infrared Spectrograph instrument, revealing that the comet appears to be unusually rich in carbon dioxide. The research team has been analyzing insights from Webb’s data, and a preprint is available online. Webb is one of NASA’s space telescopes observing this comet, together providing more information about its size, physical properties, and chemical makeup.
Plenty of mystery surrounding 3I/ATLAS
Plenty of mystery has surrounded 3I/ATLAS beginning with its large size and unusually high speed. It is at least a thousand times more massive than either of the two previous interstellar objects observed and some have made the claim that it may be a million times as large (e.g., Dr. Avi Loeb, Harvard Astrophysicist). 31/ATLAS is roughly the size of Manhattan and is estimated to weigh over 33 billion tons. Its high density, as suggested by its mass relative to its size (estimated to be around 5.6 kilometers in diameter), challenges the typical characteristics of a comet. The object has an extremely high velocity of approximately 130,000 miles per hour - the highest velocity ever recorded for a solar system visitor. Its speed suggests it has been on a journey for billions of years through interstellar space and is due to it being on a one-way hyperbolic trajectory that is not gravitationally bound to our sun.
Interstellar comet 3I/ATLAS is following an orbit path through the inner solar system that includes close encounters with Mars, Venus an Jupiter. After passing Mars in early October 2025, it reached its closest point to the Sun around October 29-30, just inside the orbit of Mars. The comet is then predicted to pass Venus in early November 2025 and Jupiter in March 2026. Courtesy NASA/Google AI
Another mysterious feature regarding 3I/ATLAS involves its tail which is expected to face away from the sun as it closes in on the perihelion, but this object has exhibited a sunward-pointing tail, a characteristic that defies the norm for comets. Furthermore, the chemical composition of 3I/ATLAS is certainly strange and is baffling to many scientists. To begin with, it appears to include a high ratio of carbon dioxide ice to water ice...one of the highest ratios ever recorded. Specifically, the object’s gas plume, or ‘coma’, is itself a paradox. Data from the James Webb and SPHEREx telescopes revealed the gas is comprised of 95 percent carbon dioxide and only 5 percent water which is the inverse of what we would expect from a “dirty snowball”, which should be rich in water ice. In addition, some observations of the object reveal hints of nickel alloy which is not at all unusual; however, nickel is always found together with iron – kind of ‘cosmic twins’ - and 3I/ATLAS appears to be completely devoid of iron. Another note of interest, while 3I/ATLAS has been officially added to the “International Asteroid Warning Network”, NASA has remained rather tight-lipped about its unique characteristics...adding to the speculation and mystery surrounding this object.
Comments by a well-known theoretical physicist, Dr. Michio Kaku
Noted theoretical physicist Dr. Michio Kaku has said that the astronomical community is sharply divided over the nature of this object and that by later October 29th or the 30th, scientists could determine whether the interstellar object is simply a rock - or something far more intelligent. Dr. Kaku, a professor at the City College of New York, is author of the book named Quantum Supremacy. Kaku explained in a recent television interview that as the perihelion approaches in just a couple of days, telescopes around the world will be focused on the sun’s edge to see if 3I/ATLAS behaves like a natural object – or defies the rules of physics altogether. Specifically, “if it picks up extra energy as it whips around the Sun, that would be outside the ordinary bounds of conservation of energy. That would mean – in no uncertain terms – that some intelligence is guiding it.”
Stay tuned...the time has arrived.
Meteorologist Paul Dorian
Arcfield
arcfieldweather.com