# First object from another solar system **URL:** \ **Category:** Miscellaneous and Personal Stuff I Must Share\ **Created:** [October 27, 2017, 7:55pm UTC](https://boards.straightdope.com/t/first-object-from-another-solar-system/800014 "2017-10-27T19:55:28Z")\ **Posts on this page:** 20\ **Page:** 2
**Author:** ![Sunspace](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/sunspace/32/1250_2.png) [@Sunspace](https://boards.straightdope.com/u/Sunspace)\ **Post date:** [October 28, 2017, 11:32pm UTC](https://boards.straightdope.com/t/first-object-from-another-solar-system/800014/21 "2017-10-28T23:32:15Z")
> [@Darren\_Garrison](#): > > Playing around with numbers a bit–[the estimate is](https://en.wikipedia.org/wiki/Interstellar_comet) that there are between 1 trillion and 10 trillion interstellar comets per cubic parsec. One cubic parsec is 2.72x10[sup]17[/sup] cubic astronomical units. So the chance of any interstellar comet to randomly be within one AU of the Earth is from 1 in 272,000 to 1 in 27,200. I think this is the first time I’ve seen “cubic parsec” or “cubic astronomical unit” before. And since an astronomical unit is 150 000 000 km, that’s bloody big. ---
**Author:** ![Quartz](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/quartz/32/267_2.png) [@Quartz](https://boards.straightdope.com/u/Quartz)\ **Post date:** [October 28, 2017, 11:45pm UTC](https://boards.straightdope.com/t/first-object-from-another-solar-system/800014/22 "2017-10-28T23:45:40Z")
I note that the eccentricity of this object’s orbit is not that far off 1, being only 1.18. ---
**Author:** ![Beckdawrek](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/beckdawrek/32/3647_2.png) [@Beckdawrek](https://boards.straightdope.com/u/Beckdawrek)\ **Post date:** [October 29, 2017, 12:22am UTC](https://boards.straightdope.com/t/first-object-from-another-solar-system/800014/23 "2017-10-29T00:22:11Z")
V-ger! Maybe it is some of our own junk that has gone rogue! ---
**Author:** ![dtilque](https://avatars.discourse-cdn.com/v4/letter/d/d6d6ee/32.png) [@dtilque](https://boards.straightdope.com/u/dtilque)\ **Post date:** [October 29, 2017, 12:28am UTC](https://boards.straightdope.com/t/first-object-from-another-solar-system/800014/24 "2017-10-29T00:28:21Z")
> [@Quartz](#): > > How do we know that it wasn’t kicked out of the Oort Cloud by a passing massive object? (That in itself would be interesting.) Huh? Every long period comet comes from the Oort Cloud. That’s how we know it’s there, since we can’t see any objects that are still in it. We know this one is interstellar because of its orbital parameters. Specifically, its eccentricity, which is 1.19. Orbits that are elliptical have eccentricity below 1; a parabola has eccentricity exactly 1; and for a hyperbola, greater than 1. There have been a few instances of comets with eccentricity slightly greater than 1, like 1.002 or something, but those could be caused by measurement error or the influence of planets. That is, it started out with e \< 1, but perturbations by Jupiter changed its orbit enough that it is ejected. Thus the slightly hyperbolic orbit. But this is way too high to ascribe to that. It definitely came from interstellar space. ---
**Author:** ![jtur88](https://avatars.discourse-cdn.com/v4/letter/j/e9c0ed/32.png) [@jtur88](https://boards.straightdope.com/u/jtur88)\ **Post date:** [October 29, 2017, 12:45am UTC](https://boards.straightdope.com/t/first-object-from-another-solar-system/800014/25 "2017-10-29T00:45:16Z")
> [@What\_Exit](#): > > Your nitpick is incorrect. What great authority are you falling upon except a mistaken pet peeve? If I change my mind, what great authority to I thank for enlightening me? I explained why I thought what I thought. Ad hominem responses are not informative. ---
**Author:** ![dtilque](https://avatars.discourse-cdn.com/v4/letter/d/d6d6ee/32.png) [@dtilque](https://boards.straightdope.com/u/dtilque)\ **Post date:** [October 29, 2017, 1:19am UTC](https://boards.straightdope.com/t/first-object-from-another-solar-system/800014/26 "2017-10-29T01:19:02Z")
As far as comets ejected from the solar system, there’s only been one that we’re certain about: [Comet Bowell (1980)](https://en.wikipedia.org/wiki/C/1980_E1_(Bowell)). It had the previously record eccentricity of about 1.06, but only after a fairly close pass near Jupiter. Before that, it was in an elliptical orbit. ---
**Author:** ![rbroome](https://avatars.discourse-cdn.com/v4/letter/r/838e76/32.png) [@rbroome](https://boards.straightdope.com/u/rbroome)\ **Post date:** [October 29, 2017, 1:24am UTC](https://boards.straightdope.com/t/first-object-from-another-solar-system/800014/27 "2017-10-29T01:24:04Z")
> [@Qadgop\_the\_Mercotan](#): > > Can we name it _ **Rama** _? Only if we hurry! The big question: What is it’s light curve? Does it have one? 🙂 ---
**Author:** ![rbroome](https://avatars.discourse-cdn.com/v4/letter/r/838e76/32.png) [@rbroome](https://boards.straightdope.com/u/rbroome)\ **Post date:** [October 29, 2017, 1:26am UTC](https://boards.straightdope.com/t/first-object-from-another-solar-system/800014/28 "2017-10-29T01:26:12Z")
> [@John\_Mace](#): > > There are _three_ of them??? 😉 Lets keep our eyes open. After all they didn’t all come by at once… ---
**Author:** ![Bullitt](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/bullitt/32/5725_2.png) [@Bullitt](https://boards.straightdope.com/u/Bullitt)\ **Post date:** [October 29, 2017, 1:39am UTC](https://boards.straightdope.com/t/first-object-from-another-solar-system/800014/29 "2017-10-29T01:39:21Z")
> [@dtilque](#): > > Huh? Every long period comet comes from the Oort Cloud. That’s how we know it’s there, since we can’t see any objects that are still in it. > > We know this one is interstellar because of its orbital parameters. Specifically, its eccentricity, which is 1.19. Orbits that are elliptical have eccentricity below 1; a parabola has eccentricity exactly 1; and for a hyperbola, greater than 1. There have been a few instances of comets with eccentricity slightly greater than 1, like 1.002 or something, but those could be caused by measurement error or the influence of planets. That is, it started out with e \< 1, but perturbations by Jupiter changed its orbit enough that it is ejected. Thus the slightly hyperbolic orbit. > > But this is way too high to ascribe to that. It definitely came from interstellar space. Not just eccentricity, but also its velocity, right? If its velocity is great enough, greater than the escape velocity to escape our solar system, then it must come from outside. ---
**Author:** ![AI\_Proofreader](https://avatars.discourse-cdn.com/v4/letter/a/8dc957/32.png) [@AI\_Proofreader](https://boards.straightdope.com/u/AI_Proofreader)\ **Post date:** [October 29, 2017, 2:48am UTC](https://boards.straightdope.com/t/first-object-from-another-solar-system/800014/30 "2017-10-29T02:48:42Z")
> [@Bullitt](#): > > Not just eccentricity, but also its velocity, right? If its velocity is great enough, greater than the escape velocity to escape our solar system, then it must come from outside. Not necessarily. An object from within our solar system could be accelerated to system escape velocity from an impact or a gravity assist from a close encounter with a planet; that’s how the Voyager probes reached system escape velocity, slingshotting around gas giants. Something like that can happen naturally with a comet or asteroid coming too close to a gas giant at the right angle and getting hurled out of the system. ---
**Author:** ![dtilque](https://avatars.discourse-cdn.com/v4/letter/d/d6d6ee/32.png) [@dtilque](https://boards.straightdope.com/u/dtilque)\ **Post date:** [October 29, 2017, 2:53am UTC](https://boards.straightdope.com/t/first-object-from-another-solar-system/800014/31 "2017-10-29T02:53:36Z")
> [@Bullitt](#): > > Not just eccentricity, but also its velocity, right? If its velocity is great enough, greater than the escape velocity to escape our solar system, then it must come from outside. That certainly helps confirm it. [S&T](http://www.skyandtelescope.com/astronomy-news/astronomers-spot-first-known-interstellar-comet/) says that it entered the Solar System at 26 km/sec, which is typical of relative velocities between stars. ---
**Author:** ![dtilque](https://avatars.discourse-cdn.com/v4/letter/d/d6d6ee/32.png) [@dtilque](https://boards.straightdope.com/u/dtilque)\ **Post date:** [October 29, 2017, 3:05am UTC](https://boards.straightdope.com/t/first-object-from-another-solar-system/800014/32 "2017-10-29T03:05:58Z")
> [@dtilque](#): > > That certainly helps confirm it. [S&T](http://www.skyandtelescope.com/astronomy-news/astronomers-spot-first-known-interstellar-comet/) says that it entered the Solar System at 26 km/sec, which is typical of relative velocities between stars. Just want to note that the high velocity is reflected in its hyperbolic orbit. It wouldn’t have such a high eccentricity without that velocity. ---
**Author:** ![bibliophage](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/bibliophage/32/7615_2.png) [@bibliophage](https://boards.straightdope.com/u/bibliophage)\ **Post date:** [November 20, 2017, 10:08pm UTC](https://boards.straightdope.com/t/first-object-from-another-solar-system/800014/33 "2017-11-20T22:08:43Z")
> [@Qadgop\_the\_Mercotan](#): > > Can we name it _ **Rama** _? Like Rama, it appears to be roughly cylindrical [cue Twilight Zone theme]. Sadly, they decided to name it 'Oumuamua instead. The artist’s rendition looks vaguely obscene to me, but I have a dirty mind. [Bizarre shape of interstellar asteroid](http://www.bbc.com/news/science-environment-42053634) ---
**Author:** ![Qadgop\_the\_Mercotan](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/qadgop_the_mercotan/32/83_2.png) [@Qadgop\_the\_Mercotan](https://boards.straightdope.com/u/Qadgop_the_Mercotan)\ **Post date:** [November 20, 2017, 10:40pm UTC](https://boards.straightdope.com/t/first-object-from-another-solar-system/800014/34 "2017-11-20T22:40:03Z")
> [@bibliophage](#): > > Like Rama, it appears to be roughly cylindrical [cue Twilight Zone theme]. Sadly, they decided to name it 'Oumuamua instead. My mind wants to parse that as “Yomama” for some reason. Rendezvous with Yomama? I don’t think so . . . Fascinating! I’ve put my copy of Clarke’s book on the topic to the forefront of my reading list to peruse yet again. ---
**Author:** ![CalMeacham](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/calmeacham/32/35_2.png) [@CalMeacham](https://boards.straightdope.com/u/CalMeacham)\ **Post date:** [November 21, 2017, 12:45am UTC](https://boards.straightdope.com/t/first-object-from-another-solar-system/800014/35 "2017-11-21T00:45:02Z")
Years ago, when some astronomers was trying to account for the huge explosion from the Tunguska meteorite, he theorized that it was an extrasolar object. That, he figured, is how it had so much energy – it had more velocity than a solar object ought to have, and that meant that its mass wouldn’t be outrageous. This explanation doesn’t fly today – it’s believed to be a fragment from the Pons-Winnecke comet train of debris. But for a while, it looked like it might be the first extrasolar object to come close. A little too close. ---
**Author:** ![jasg](https://avatars.discourse-cdn.com/v4/letter/j/f0a364/32.png) [@jasg](https://boards.straightdope.com/u/jasg)\ **Post date:** [November 21, 2017, 2:49am UTC](https://boards.straightdope.com/t/first-object-from-another-solar-system/800014/36 "2017-11-21T02:49:43Z")
> [@bibliophage](#): > > Like Rama, it appears to be roughly cylindrical [cue Twilight Zone theme]. Sadly, they decided to name it 'Oumuamua instead. The artist’s rendition looks vaguely obscene to me, but I have a dirty mind. [Bizarre shape of interstellar asteroid](http://www.bbc.com/news/science-environment-42053634) That representation looks like a cylindrical ship with a badly ablated protective coating, worn away over eons by interstellar dust 😃 ---
**Author:** ![Ethilrist](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/ethilrist/32/4604_2.png) [@Ethilrist](https://boards.straightdope.com/u/Ethilrist)\ **Post date:** [November 21, 2017, 4:59am UTC](https://boards.straightdope.com/t/first-object-from-another-solar-system/800014/37 "2017-11-21T04:59:17Z")
> [@jasg](#): > > That representation looks like a cylindrical ship with a badly ablated protective coating, worn away over eons by interstellar dust 😃 Just so long as it’s not made of neutronium. If it starts cutting Mars apart with an anti-proton beam, we got problems. ---
**Author:** ![dtilque](https://avatars.discourse-cdn.com/v4/letter/d/d6d6ee/32.png) [@dtilque](https://boards.straightdope.com/u/dtilque)\ **Post date:** [November 21, 2017, 5:16am UTC](https://boards.straightdope.com/t/first-object-from-another-solar-system/800014/38 "2017-11-21T05:16:52Z")
> [@Ethilrist](#): > > Just so long as it’s not made of neutronium. If it is, our friend Qadgop will make short work of it, I’m sure. ---
**Author:** ![iiandyiiii](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/iiandyiiii/32/7924_2.png) [@iiandyiiii](https://boards.straightdope.com/u/iiandyiiii)\ **Post date:** [November 21, 2017, 1:25pm UTC](https://boards.straightdope.com/t/first-object-from-another-solar-system/800014/39 "2017-11-21T13:25:04Z")
That space rock is definitely not a cleverly disguised alien invasion ship. And this article definitely is not the type of news story that would be played over the opening credits of a sci-fi movie. And The Rock and Will Smith are definitely not kissing their kids goodbye on their way to what they assume will be a typical work day at the military base… ---
**Author:** ![digs](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/digs/32/14889_2.png) [@digs](https://boards.straightdope.com/u/digs)\ **Post date:** [November 21, 2017, 1:50pm UTC](https://boards.straightdope.com/t/first-object-from-another-solar-system/800014/40 "2017-11-21T13:50:55Z")
> [@iiandyiiii](#): > > That space rock is definitely not a cleverly disguised alien invasion ship. And this article definitely is not the type of news story that would be played over the opening credits of a sci-fi movie. And The Rock and Will Smith are definitely not kissing their kids goodbye on their way to what they assume will be a typical work day at the military base… Ok, I made a big tub of popcorn with “movie butter-esque topping”. What happens next? Do we get some foreshadowing? Or do we meet the nerdy young astrophysics intern who no one will listen to? Ooh, or maybe the plucky prostitute with a good heart (and a cute kid) (and a dog) (and it’s a blind service dog… three days away from retirement)! [Previous page](https://boards.straightdope.com/t/first-object-from-another-solar-system/800014.md?page=1) [Next page](https://boards.straightdope.com/t/first-object-from-another-solar-system/800014.md?page=3)