An update on Comet 2I/Borisov

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Overall, this second known interstellar object to pass through the solar system appears to be a very typical comet. They have found however that its nucleus is much smaller than at first thought, only 200 to 500 meters across, which means that radiation pressure from the Sun could cause its rotation to spin up, with the possibility that this spin could get fast enough to cause the comet to break up.

The comet made its closest approach to the Sun in December, and will spend the next year-plus flying outward to beyond Saturn.



  • Lee S

    The thought occurred to me today that if these interstellar visitors are genuinely more common than we ever thought, (2 detected in a few years seems to indicate this…), would it not be possible to have a mission ready and waiting to land on one and hitch a ride out of our solar system?
    I know there is talk of having something ready to go and analyse such an interloper, but surely a lander with the ability to just sit along for the ride… If equipped with a power source able to last a couple of hundred years ( a big chunk of plutonium, rather than the little ones still powering the voyagers) could send back invaluable data about the journey, and not just the destination

  • Gealon

    I know I am jumping on this a little late but I thought I’d weight in on Lee’s question of hitching a ride with the comet. Unless your goal is long term study of the comet as it leaves the solar system, there wouldn’t be much point to building a spacecraft with the delta V needed to reach it. If the comet is already traveling fast enough to escape the sun, then your spacecraft would have to have enough delta V to match that velocity and escape the sun it’s self. So you wouldn’t save anything by flying a rendezvous with the comet, your craft would more or less be trapped on what ever exit trajectory the comet takes.

    If you are looking to just leave the solar system however, then your best bet with current technology would be to combine a nuclear power source with electric propulsion and go for a few gravity assists around the solar system to achieve the highest delta V possible. Even then though you have the problem of where are you going to go? If Voyager 1 were aimed at Apha Centauri, it would take it about 40,000 years to get there. Even at 10% of the speed of light, which we can’t currently do, it would still take you 40 years to get there. So with today’s technology you would end up launching a very large, very expensive museum piece that we might pick up in a hundred years or so and bring back to Earth using a fusion powered vessel, or if we could solve some of the niggling problems with it, an Alcubierre White warp drive. My point being, with the current state of our technology, interstellar voyages aren’t on the table yet.

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