• Space/Science
  • GeekSpeak
  • Mysteries of
    the Multiverse
  • Science Fiction
  • The Comestible Zone
  • Off-Topic
  • Community
  • Flame
  • CurrentEvents

Recent posts

Retirement home Spirit cover -- yeah, we had better music. ER July 26, 2025 7:31 am (Off-Topic)

Maxwell's Silver Hammer ER July 26, 2025 6:58 am (CurrentEvents)

♫ I tell you to enjoy life I wish I could but it's too late ♫ BuckGalaxy July 22, 2025 1:32 pm (Off-Topic)

How Groupthink Protected Biden and Re-elected Trump, or put another way... BuckGalaxy July 19, 2025 2:32 pm (Flame)

Why Trump Can’t Shake Jeffrey Epstein BuckGalaxy July 18, 2025 8:07 pm (CurrentEvents)

Colbert cancelled. ER July 17, 2025 8:20 pm (CurrentEvents)

just passin' thru... ER July 16, 2025 2:08 pm (Space/Science)

Epic Epstein Magasphere Meltdown BuckGalaxy July 14, 2025 1:58 pm (CurrentEvents)

the June ice report ER July 10, 2025 7:34 pm (Space/Science)

Home » Space/Science

Our first visitor from the stars October 27, 2017 1:58 pm hank

Our sun is surrounded by a cloud of comets. In the past, there probably were a lot more of them, the debris left over after the formation of the solar system. Presumably, other stars also have their own cometary companions. But it is difficult for any comet to escape from the gravity well of its parent star; it would require an interaction in it’s own system with a another body which could give it the additional gravitational boost needed to exceed stellar escape velocity.

Comets approaching the sun on hyperbolic orbits will never be captured by Sol unless some third body interacts with them, absorbing excess kinetic energy. So all the comets we have seen so far have either elliptical orbits, or parabolic ones (the parabola does not circle back on itself, it is the intermediate curve between ellipse and hyperbola, but it is extremely difficult to tell a parabola from an extremely skinny ellipse). We have detected several comets with apparently parabolic orbits, but they could be members of our own solar system.

This object is apparently in a true hyperbolic orbit, it must be an outsider, which according to the article is corroborated by other considerations. It is an interstellar visitor. I find this absolutely stunning.

http://www.skyandtelescope.com/astronomy-news/astronomers-spot-first-known-interstellar-comet/?utm_source=newsletter&utm_campaign=sky-jma-nl-171027&utm_content=978262_EDT_SKY_171027&utm_medium=email

  • Oumuamua by BuckGalaxy 2017-11-27 10:21:48
    • Path of Oumuamua by BuckGalaxy 2017-11-28 17:37:25
      • More artists' conceptions of Oumuamua... by BuckGalaxy 2017-11-28 17:20:34
        • No image by RL 2017-11-28 17:21:14
          • was editing still by BuckGalaxy 2017-11-28 17:25:30
      • Reading more and more like 'Rendezvous with Rama'... by RL 2017-11-20 18:52:16
        • Ramalama ding-dong by hank 2017-11-22 08:41:53
        • Read the "comments" section of that S&T link. by ER 2017-10-28 07:59:50
          • Is it slowing down? by Robert 2017-10-27 15:40:39
            • As a matter of fact, it is. by hank 2017-10-27 19:54:58
              • Ah, just rubberneckers, then by Robert 2017-10-27 20:37:28
                • Looking at the wreck in the third lane... by RL 2017-10-28 12:48:09
            • "The Ramans do everything in threes..." by RL 2017-10-27 14:43:05

              Search

              The Control Panel

              • Log in
              • Register