| ▲ | criddell 8 days ago |
| > We show that 3I/ATLAS approaches surprisingly close to Venus, Mars and Jupiter, with a probability of ≲ 0.005%. What probability are they talking about? |
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| ▲ | dvh 8 days ago | parent | next [-] |
| “You know, the most amazing thing happened to me tonight. I was coming here, on the way to the lecture, and I came in through the parking lot. And you won’t believe what happened. I saw a car with the license plate ARW 357. Can you imagine? Of all the millions of license plates in the state, what was the chance that I would see that particular one tonight? Amazing!” — Richard Feynman, Six Easy Pieces |
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| ▲ | baggy_trough 8 days ago | parent | prev | next [-] |
| I noticed that about the orbit as well. It does seem a little surprising. |
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| ▲ | pbmonster 8 days ago | parent | prev | next [-] |
| If you take a random trajectory through our solar system, your chance to pass this close to three planets is < 0.005%. |
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| ▲ | datadrivenangel 8 days ago | parent | next [-] | | Specifically a random angle. "The likelihood for such a perfect alignment of the orbital angular momentum vector around the Sun for Earth and 3I/ATLAS is π(5◦/57◦)2/(4π) = 2×10−3." Sloppy sloppy work. | | |
| ▲ | pbmonster 8 days ago | parent [-] | | I also misread that. The 0.005% is in relation to this: > In the following analysis we assume that 3I/ATLAS is on its current orbit but vary the time-of-entry into the Solar System (or equivalently the time of perihelion), assuming 3I/ATLAS could have come at any time into the Solar System, and happened to do so such that it came within the observed closest approaches of Venus, Mars and Jupiter. The probability of this is 0.005 So exact same trajectory, but analyzed over a long period of time. If it came any earlier or later, it would almost never get this close to exactly those three planets. |
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| ▲ | voidUpdate 8 days ago | parent | prev | next [-] | | isnt the chance only for those specific three planets, not any three planets? there are 56 ways to choose three planets from the 8 (sorry pluto) in our solar system, so the probability of passing that close to any three planets is 56x greater | |
| ▲ | taneq 8 days ago | parent | prev [-] | | How many objects go through our solar state each year? More than 200? Are their trajectories uniformly distributed? | | |
| ▲ | Perenti 7 days ago | parent | next [-] | | Given mass distribution of our galaxy is decidedly anisotropic I would expect the answer to be a resounding "no". The ((5/57)/ (4 Pi)) implicity assumes uniform incoming trajectories - I think. There's an odd mixing of radians and steradians in this formula, if the "4 Pi" represents the total solid angle of a sphere. | |
| ▲ | pbmonster 8 days ago | parent | prev [-] | | We don't know! We only got the telescopes to look for them with any chance of success in 2017. Since then, we saw three. Since they are often small and dark, it's very possible we missed a few. |
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| ▲ | Zigurd 8 days ago | parent | prev [-] |
| Evidently not the probability of all the other coincidences that could be the basis of post hoc ergo propter hoc analysis. |
