Interstellar Comet Borisov Makes Closest Approach to the Sun

rod

Oct 22, 2019
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I enjoy these reports on 2I/Borisov comet. Starry Night Pro Plus 8 software is updated, showing the comet and sky chart views. At my location below 39 degrees north latitude, the comet currently rises near 0130 EST. Looking ahead to 28-Dec-19 close approach to Earth, this comet is visible with large telescopes 0300-0530 EST. I love looking at 0400 comets. So much fun to be outdoors with the deer, foxes, owls, and skunks moving around :)
 

dpc

Dec 12, 2019
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This story is nice. Super interesting. But you need to correct a major mistake.

This is not correct: "Comet Borisov is only the second interstellar minor body to enter our solar system..." It is the second *observed* interstellar body. It's predicted that these pass through frequently. In the history of our solar system, millions or perhaps billions have passed through. As our ability has improved to observe, we've already seen two in just a couple years. This happens all the time! Super cool that we are finally observing and studying them, but it is *not* only the second one to happen. (Or, when a tree falls in a forest, and no one is there to observe it... it's still fallen. When a comet or other body swings through the solar system from afar and no one observes it (or before humans even evolved to bear witness), it was still happening.)

Thanks for the interesting story. Sorry to nitpick, but that really is a major error of fact that should be corrected. Easy mistake to make (a lot of reporting now and a couple years ago did the same), but also important to do better.
 

rod

Oct 22, 2019
2,284
915
3,560
This story is nice. Super interesting. But you need to correct a major mistake.

This is not correct: "Comet Borisov is only the second interstellar minor body to enter our solar system..." It is the second *observed* interstellar body. It's predicted that these pass through frequently. In the history of our solar system, millions or perhaps billions have passed through. As our ability has improved to observe, we've already seen two in just a couple years. This happens all the time! Super cool that we are finally observing and studying them, but it is *not* only the second one to happen. (Or, when a tree falls in a forest, and no one is there to observe it... it's still fallen. When a comet or other body swings through the solar system from afar and no one observes it (or before humans even evolved to bear witness), it was still happening.)

Thanks for the interesting story. Sorry to nitpick, but that really is a major error of fact that should be corrected. Easy mistake to make (a lot of reporting now and a couple years ago did the same), but also important to do better.
Models of comets entering our solar system that originated from other stars - are models, not scientific fact. The two comets confirmed or interpreted as interstellar today are understood as such because of their orbits and eccentricity (very hyperbolic), this is an actual comet sighting but the parent star is not clearly established as to where the comets came from. A comet originating at a star 13 light-years distance for example and traveling at 20 km/s, will take 195,000 earth years to reach our solar system - if it does.
 

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