The comet has delighted stargazers for months, but if you look up Comet<\/a> A3 Tsuchinshan-ATLAS online, there is one key detail that most reports get wrong \u2013 its orbital period, or how long it takes the comet to orbit our Sun.<\/p> While many report that the long-period comet<\/a> last visited our planet 80,000 years ago, the truth is that its orbit is much, much longer.<\/p> So long in fact, that this could be the comet\u2019s first \u2013 and perhaps last \u2013 visit to the inner Solar System.<\/p> \u201cA3 almost certainly has never been near Earth before, nor will it again,\u201d says Karl Battams from the Naval Research Laboratory<\/a> in Washington, who has operated the NASA funded Sungrazer Comets Project<\/a> since 2003.<\/p> \u201cOn its way in towards the Sun, the comet was following what appeared to be a very, very long elliptical path, with an orbital period somewhere up in the hundreds of millions of years long.<\/p> \u201cThis places its origins far outside the gravitational pull of our Sun. So it absolutely didn\u2019t spend its whole existence on the orbit we saw, but instead was nudged onto it, probably gravitationally, a long time ago.\u201d<\/p> This, however, does not mean that Comet A3 Tsuchinshan-ATLAS\u2019s orbit is still hundreds of million years long however.<\/p> When the comet passed through its closest approach to the Sun, known as perihelion, on 27 September 2024, our star\u2019s gravity altered the comet\u2019s trajectory, changing its eccentricity \u2013 meaning how \u2018squished\u2019 its elliptical path is.<\/p> \u201cNow it\u2019s following an orbit that appears more like a few hundred thousand years long,\u201d says Battams. \u201cBut even at a couple of hundred thousand years, this would ultimately place A3 back so far out into space that it would probably begin to feel minor gravitational effects from other star systems, and these would sway it off-course or steal it entirely.\u201d<\/p> The main issue is that we can only observe comets during the short window when they are within the inner Solar System and close enough to see.<\/p> \u201cAll we can do is look at the apparent path it is following during the relatively very short window we\u2019ve been observing it and use that information to guess at its complete orbit,\u201d says Battams.<\/p> By measuring the current motion of the comet on the sky, astronomers like those at the Sungrazer Comets Project are able to back track the comet\u2019s path and calculate its orbit. \u00a0<\/p> \u201cFor objects on short-period orbits<\/a> this is usually a very precise measurement, but for comets like this that go to\/from such insanely distant regions of space, uncertainties are unavoidable regarding its position in the distant past and future.<\/p> \u201cWe\u2019ve only followed the comet for a distance of maybe 7 or 8 AU [where 1 AU is the distance between the Earth and the Sun], on a path that is likely hundreds of thousands of AU in length \u2013 if it\u2019s even a closed loop to begin with.\u201d<\/p> With such long scales, even though the team have been able to measure the path to six decimal places of precision, there\u2019s enough wiggle-room that the path of the comet could be parabolic \u2013 meaning the comet was only passing Earth by, and will not return.<\/p> All this uncertainty means that the comet\u2019s orbital parameters are constantly being updated as more observations are taken.<\/p> With such changes constantly happening, its highlight likely that many media outlets picked up on an outdated measurement of the comet\u2019s orbit.<\/p> \u201cIt\u2019s conceivable that they saw a very early orbit prediction, shortly after the comet was discovered and we had little data to work with, but that was well over a year ago.\u201d<\/p> One of the biggest problems is that there\u2019s no centralised repository of information.<\/p> \u201cFor its orbit, I think NASA’s JPL Horizons<\/a> is the most reliable source of up-to-date data,\u201d says Battams.<\/p> \u201cFor data about its past, present, and predicted future brightness, the\u00a0Comet Observation Database<\/a>\u00a0is very nice.<\/p> \u201cAnd of course, there\u2019s a legion of highly skilled astrophotographers who are going to continue to have fun with this one for at least a few more weeks, despite it being too faint to see naked-eye now.\u201d<\/p> Take a look at our gallery of some of your best images of Comet A3 Tsuchinshan-ATLAS.<\/p> While the comet may have been stolen from another star, this is not the only explanation of its origin.<\/p> \u201cBy far the most likely scenario is that this comet has spent its entire life floating around in the Oort Cloud<\/a> \u2013 a theorised reservoir of comets that sit at the very distant reaches of our Sun\u2019s gravity,\u201d says Battams.<\/p> \u201cSomething, maybe a passing star, another comet, or even a collision, gave it just enough of a nudge that it started to fall into our Solar System.\u201d<\/p> This is a common occurrence.<\/p> ![\"Comet](\"https:\/\/c02.purpledshub.com\/uploads\/sites\/48\/2024\/10\/comet-a3-mount-etna.jpg\")
What is Comet A3 Tsuchinshan-ATLAS’s orbit?<\/h2>
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Why is there so much uncertainty when measuring a comet’s orbit?<\/h2>
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Where can I find the latest information on Comet A3 Tsuchinshan-ATLAS\u2019s orbit?<\/h2>
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Where did Comet A3 Tsuchinshan-ATLAS come from?<\/h2>
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