{"id":15218,"date":"2026-03-24T09:01:23","date_gmt":"2026-03-24T13:01:23","guid":{"rendered":"https:\/\/theness.com\/neurologicablog\/?p=15218"},"modified":"2026-03-24T09:01:23","modified_gmt":"2026-03-24T13:01:23","slug":"what-happened-to-comet-3i-atlas","status":"publish","type":"post","link":"https:\/\/theness.com\/neurologicablog\/what-happened-to-comet-3i-atlas\/","title":{"rendered":"What Happened to Comet 3I\/Atlas"},"content":{"rendered":"

\"\"Last year the inner solar system had an interstellar visitor – 3I\/Atlas (which stands for the third interstellar object which was discovered by the Atlas telescope). The third ever of anything is by definition a rare event, and so this was scientifically exciting. The comet came into the inner solar system, passing close to Jupiter and Mars, but not to the Earth, went behind the sun, then emerged on its path away from the sun. It is now headed for the orbit of Jupiter and out of the solar system. At first 3I\/Atlas displayed a number of minor anomalies. It was behaving sort of like a comet, but with some differences. This fits well, however, with the main hypothesis that it is an interstellar comet – so it’s a comet, but may have a different composition from comets that were formed in our own solar system. This is not almost certainly the case – the comet comes from the thick disc of the galaxy, likely from a low metallicity star system, and has likely been travelling through interstellar space for billions of years, possibly being even older than our own star.<\/p>\n

Now that it is passing out of the solar system we can look at all the data that NASA collected<\/a> and make some fairly confident conclusions. There are a lot of sources of information, but Wikipedia actually has a pretty good summary<\/a> and list of references. In the end, 3I\/Atlas behaved mostly like a typical comet. It formed a tail heading away from the sun, brightened as it got close, then faded away as it moved away from the sun. Spectral analysis found that the comet was unusually rich in carbon dioxide (CO2), with small amounts of water ice, water vapor, carbon monoxide (CO), and carbonyl sulfide (OCS). It also had small amounts of cyanide and nickel gas, which is common in comets from our own solar system. In other words – it is a comet. It did originate from a part of the sky that we had previously calculated would have fewer such interstellar objects, which either makes it especially rare or means that our calculations are off.<\/p>\n

Every time we encounter a new interstellar object we gather more data about such objects – how frequent are they, where do they come from, and what is their nature. Right now we have just three data points. After the first one, Oumuamua, we had not idea how common they were because we had just one data point. Now we have enough instruments surveying the sky that we are better able to detect such objects, which are very fleeting. The question was – was Oumuamua a one-off, and we just got lucky to detect something that happens very rarely, or are such objects common. We now have three data points and can conclude that they are fairly common, and we should detect one every few years or so, perhaps even more often if we start looking more.<\/p>\n

Interstellar objects are a fairly new astronomical phenomenon, and what typically happens to new astronomical phenomena is that someone asks – could this be an alien artifact? So far the answer has been universally, no. The universe is a very big and complex place with lots of unusual phenomena. Historically speaking we have only just started to examine the cosmos, and are still encountering new phenomena on a regular basis. We have yet, however, to detect anything demonstrably, or even likely, alien. No one would be more excited than me if we discovered a genuine technosignature of an alien civilization. That is precisely why we have to be very careful before leaping to any such conclusions. But sure, ask the question, just don’t leap off the deep end.<\/p>\n

What I mean by that is – do not make bad arguments to prop up an alien hypothesis, do not mystery-monger, do not truck in conspiracy theories, and do not draw undue attention to such speculation or present it as anything other than speculation. Every generation seems to have someone, sometimes with a scientific background, who does all of these things. The allure of the alien hypothesis is just too great. It is genuinely fascinating. It is the fast track to fame and attention. You can portray yourself as just being open-minded, brave enough to ask the tough questions, and criticize your colleagues for being closed-minded. Of course, like many things, this is a continuum. A little\u00a0 is reasonable, more starts to get sketchy, and a lot makes you a crank.<\/p>\n

An example of something which I consider to be in the sweet spot of good scientific exploration of the possibility of alien technosignatures is SETI. SETI essentially uses radioastronomy to survey for potential radio signals of alien origin. But they are not just doing this – they are also doing lots of ordinary good radio astronomy. But mixed in with their radio astronomy are methods to screen for signals that might be technosignatures. They are also extremely careful not to make any premature or overblown claims, and they are their own most dedicated skeptics.<\/p>\n

At the other end of the spectrum, in my opinion, is Avi Loeb<\/a>. He has seemed to make a career now out of mystery mongering anything unusual as a possible alien artifact. He claimed that all three interstellar objects might be alien craft. Why is he at the crank end of the spectrum? Because he elevated this possibility prematurely and with a series of really bad arguments, sometimes distorting the data or making bad calculations. He said that Oumuamua might be alien because it was coming close to the Earth, to observe it. He then argued that 3I\/Atlas might be alien because it was not coming close to the Earth, to hide from us. He exaggerated its possible size, its apparent lack of a tail, its composition. He made a lot of the fact that the comet’s trajectory is close to the ecliptic, about 5 degrees off, committing a classic lottery fallacy argument. He calculated how likely this specific feature is, but only after knowing it, and did not adjust for all possible features that might be individually unlikely. He engaged in classic post-hoc reasoning. In the end, the predictions of NASA scientists all proved correct – 3I\/Atlas is a comet, and displays all the features of a comet. Loeb attracted attention by saying 3I\/Atlas might pivot toward the Earth once it emerges from behind the sun. When this prediction failed he did admit<\/a> it was “most likely natural”, but is still emphasizing its apparent anomalies.<\/p>\n

What he is doing is playing coy, which is a common strategy for those who are pushing fringe ideas but who are trying to seem reasonable. All along he said – the most likely explanation is that it is natural. But then follows up with – here are lots of (really bad) reasons why it is unusual and might be alien. This is a win-win for him – in the rare case that he turns out to be right, he is a genius and takes all the credit (keep in mind, if it were alien NASA would have found out all by themselves, with his prodding). If it turns out he is wrong, then he can claim he said all along it was likely to be natural. Either way he sucks up as much oxygen as possible from the media and distracts from the hard-working scientists at NASA doing good work. There is some great and interesting science here. The conclusion that this is almost certainly not an alien craft is a footnote at best, because there was never any good reason to hypothesize that it was.<\/p>\n

Loeb is at it again (or still) with a recent post<\/a> about a “mysterious” Mars cylinder (see the picture above the fold). This is also a common strategy of mystery mongers – comb through tons of data looking for anything unusual, then declare it a mystery. Again – looking for anomalies is a legitimate process of science. Blowing up apparent anomalies into a high-priority mystery is something that an attention-seeking crank would do. In this case others combed through NASA pictures from the Rover and then send it along to Loeb, so he is now a magnet for such things. And again – he admits this is most likely to be just a piece of debris from the Rover itself, or its landing, or whatever. There is now debris on Mars from all the spacecraft we have sent from Earth, so when we encounter a bit of what looks like ordinary debris, that is most likely what it is.<\/p>\n

But Loeb is saying that NASA should turn the rover around and travel a few days to go back and take a closer look at this debris. NASA has not responded or commented to Loeb’s statement. This is actually a good operational definition of making too much of an apparent anomaly. Thinking that such anomalies, even when they are likely mundane, should take high priority and redirect our limited resources away from other scientific priorities, is worse than grabbing attention. It is trying to commandeer precious public resources to go on your own wild-goose chases, not because it is good science, but because it serves your own personal agenda.\u00a0 NASA is perfectly capable of determining the proper priorities for their own rover. They don’t have to go chasing after every piece of space junk because Loeb is trying to grab attention and justify his own dubious professional existence.<\/p>\n","protected":false},"excerpt":{"rendered":"

Last year the inner solar system had an interstellar visitor – 3I\/Atlas (which stands for the third interstellar object which was discovered by the Atlas telescope). The third ever of anything is by definition a rare event, and so this was scientifically exciting. The comet came into the inner solar system, passing close to Jupiter […]<\/p>\n","protected":false},"author":7,"featured_media":15219,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[73],"tags":[],"class_list":["post-15218","post","type-post","status-publish","format-standard","has-post-thumbnail","hentry","category-astronomy"],"aioseo_notices":[],"_links":{"self":[{"href":"https:\/\/theness.com\/neurologicablog\/wp-json\/wp\/v2\/posts\/15218","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/theness.com\/neurologicablog\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/theness.com\/neurologicablog\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/theness.com\/neurologicablog\/wp-json\/wp\/v2\/users\/7"}],"replies":[{"embeddable":true,"href":"https:\/\/theness.com\/neurologicablog\/wp-json\/wp\/v2\/comments?post=15218"}],"version-history":[{"count":1,"href":"https:\/\/theness.com\/neurologicablog\/wp-json\/wp\/v2\/posts\/15218\/revisions"}],"predecessor-version":[{"id":15220,"href":"https:\/\/theness.com\/neurologicablog\/wp-json\/wp\/v2\/posts\/15218\/revisions\/15220"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/theness.com\/neurologicablog\/wp-json\/wp\/v2\/media\/15219"}],"wp:attachment":[{"href":"https:\/\/theness.com\/neurologicablog\/wp-json\/wp\/v2\/media?parent=15218"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/theness.com\/neurologicablog\/wp-json\/wp\/v2\/categories?post=15218"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/theness.com\/neurologicablog\/wp-json\/wp\/v2\/tags?post=15218"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}