Mysterious interstellar object 3I\/ATLAS has reemerged from behind the Sun, allowing astronomers to once again get a glimpse at the rare visitor.<\/p>\n
The object, which is generally believed by experts to be a comet that\u2019s predominantly made up of carbon dioxide ice<\/a>, is continuing on its highly eccentric trajectory, and is expected to make its closest pass of the Earth just days before Christmas on its way back out of our star system.<\/p>\n And judging by the latest data, 3I\/ATLAS has survived its perihelion \u2014 or its closest approach to the Sun \u2014 largely intact, instead of breaking apart, as Harvard astronomer Avi Loeb had hypothesized<\/a> in a blog post<\/a> earlier this week.<\/p>\n New images of 3I\/ATLAS, taken by the Nordic Optical Telescope on the Canary Islands, \u201cshow a single body, with no evidence for breakup following the perihelion passage two weeks earlier,\u201d Loeb conceded in a Wednesday followup post<\/a>.<\/p>\n The images also show 3I\/ATLAS\u2019 prominent \u201canti-tail,\u201d an accumulation of jets that points towards the Sun, suspected to be made up of larger dust particles less affected by the Sun\u2019s radiation pressure.<\/p>\n However, to Loeb that\u2019s just one out of two possible scenarios. These jets could also be evidence of \u201cthrusters on a technological spacecraft,\u201d as he told NBC News<\/a> on Monday.<\/p>\n If so, Loeb suggests that if 3I\/ATLAS really is a visitor from a technological civilization \u2014 a possibility he\u2019s floated repeatedly \u2014 then it may be trying to boost its exit from the solar system to a breakneck pace. (Let\u2019s face it: getting away from Earth as rapidly as possible makes perfect sense these days<\/a>.)<\/p>\n \u201cTechnological thrusters which point their exhaust towards the Sun would accelerate away from the Sun,\u201d Loeb noted in his latest blog post. \u201cThis post-perihelion maneuver might be employed by a spacecraft that aims to gain speed rather than slow down through the gravitational assist from the Sun.\u201d<\/p>\n It\u2019s only one of several \u201canomalies\u201d Loeb has catalogued<\/a> to support his theory that 3I\/ATLAS could be some sort of alien spacecraft<\/a> visiting the solar system. Loeb had already discussed the object\u2019s \u201canti-tail\u201d in early September<\/a>. The appendage was first made apparent in August images<\/a> taken by NASA\u2019s Hubble Space Telescope, but has grown in length since then.<\/p>\n Of course, most of his peers think it\u2019s just a natural comet. Loeb\u2019s far-fetched theory has led to plenty of skepticism<\/a> from within the scientific community.<\/p>\n In a September 29 blog post<\/a>, Pennsylvania State University astronomer Jason Wright refuted Loeb\u2019s claim that 3I\/ATLAS\u2019 anti-tail was unique and could be alien technology, pointing out several previous observations of \u201csimilar sunward enhancement\u201d caused by large, ejected dust grains that \u201cdon\u2019t get swept up by the solar wind on the Sun-facing side of a comet.\u201d<\/p>\n Wright also pointed to a 1974 paper<\/a> that discussed the \u201canomalous tail of Comet Kohoutek,\u201d an object that was first discovered the year prior, in 1973.<\/p>\n But Loeb isn\u2019t ready to give up hope that we could be looking at an alien spacecraft.<\/p>\n According to his calculations, 3I\/ATLAS could be far more enormous than previously thought, based on the huge amount of mass it\u2019s shedding, with a surface area equivalent of a sphere with a diameter of 14.3 miles. That\u2019s four times as large as his\u00a0previous estimates<\/a>.<\/p>\n \u201cAlien-tech thrusters might employ yet higher exhaust speeds, reducing the required mass loss by several orders of magnitude and making the required fuel a small fraction of the spacecraft mass,\u201d he determined in a previous blog post<\/a>.<\/p>\n To Loeb, it\u2019s a matter of keeping an open mind, even in light of overwhelming evidence. Besides, if 3I\/ATLAS were to be an alien mothership, there\u2019s no saying what kind of risks it could pose to humanity.<\/p>\n \u201cThe foundation of science is the curiosity, the humility to learn,\u201d he told NBC News. \u201cLet\u2019s just wait a few more weeks, we\u2019ll figure it out, and let\u2019s hope that there will be no gifts from this object for the holidays on Earth.\u201d<\/p>\n