There is post on a sub I frequent that said there is going to be a [comet](https://www.npr.org/2024/10/10/nx-s1-5148895/how-to-see-comet-c-2023-a3-tsuchinshan-atlas) that won’t be seen for another 80,000 years.
How do we know this particular comet has an 80,000 year long orbit? What are those observations that tell us something like that?
80,000 years ago, as fas as I know, people weren’t writing down astronomical observations. And even if we did, we aren’t relying on their observations today. The post says they discovered this comet in 2023.
What’s our justification for saying something so definitive that this comet won’t be seen for another 80,000 years? I’m not understanding how they would even begin to determine something like that after having discovered it last year.
In: Planetary Science
Remember “objects in motion stay in motion” from school?
An object orbiting in space will *keep* orbiting. And it turns out that the math to calculate orbits is relatively straightforward, as these things go. So we can calculate the comets orbit, and look forward or back at any point in the math to see where it will be or was.
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