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Interstellar Visitor Found to Be Unlike a Comet or an Asteroid

quantamagazine.org

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Re: Interstellar Visitor Found to Be Unlike a Comet or an Asteroid

#91

Post by bloopernova »

interfixus wrote: post #43
turbo_fart_box wrote: post #28

Earlier quoted context omitted.

Great series of books! Every time I see a thread about this big rock I think of Rama.

Beg to differ. Great book. Awful cheap hacks posing as sequels. I regret reading them - they've nearly ruined the original for me.

I agree with you, they were pretty awful and lost so much of the original's sense of wonder and incomprehension.

One favourite daydream of mine is to think about how the Rama aliens' second and third probes would be received. I read Rama around the same time as Eon by Greg Bear, so I've always had an affinity for spin-gravity habitats filled with unknown stuff :)

With The Expanse TV series showing us how good hard scifi can be exciting and wonderful, I'm hoping we one day get an Eon or Rama series. Rama especially would work well in a hard scifi miniseries format.

(That's actually a great thought: that many shows thought impossible a couple of decades ago will now be made. Let's just hope they're made with love and devotion like The Expanse!)

Re: Interstellar Visitor Found to Be Unlike a Comet or an Asteroid

#92

Post by godshatter »

mattlondon wrote: post #30
sjclemmy wrote: post #3

I'm still convinced this is an alien probe. I mean look at that trajectory. 0.163 AU from Earth - what are the odds? The spinning is irrelevant surely - I mean, it's all relative, so as far as ’Oumuamua is concerned, we're spinning. Maybe it was spinning that way to stay aligned with a distant companion for communication.

Looking at the images on that site, the trajectory doing a "fly by" of a lot of the planets did look remarkedly like the sort of thing we've being doing for decades in our own solar system [1]- line up a bunch of planets and use gravity slingshots to do a close fly-by to get a closer look. The thought makes me have goose-bumps. Did some alient race just take a close look at us? Was there a voyager-style plaque on it?…

I wonder if it's speed increased on it's way out. Maybe it's on a multi-system route, using gravity assist as it goes to cut the route time down by a few thousand years here or there as it circles back around to it's home system. Must be very patient aliens, assuming no FTL messaging tech.

Re: Interstellar Visitor Found to Be Unlike a Comet or an Asteroid

#93

Post by scottlegrand2 »

_ph_ wrote: post #40
holografix wrote: post #34

Earlier quoted context omitted.

Wouldn’t such an object be emitting radio signals that earth could receive?

Only if it is actively emitting them. So if the aliens sent an active probe, it might emit radio signals. But if it is some junk from an alien civilization, it would just be trash drifting by. It would still be increadibly interesting to catch such an artifact.

Just another roadside picnic?

Re: Interstellar Visitor Found to Be Unlike a Comet or an Asteroid

#94

Post by pilsetnieks »

rbanffy wrote: post #82
pilsetnieks wrote: post #11

Earlier quoted context omitted.

If one were so inclined, they could argue that the spinning is in fact very relevant, as it would allow a static camera or other observation device a full 360° view along all axes.

Any civilization capable of building an interstellar craft would certainly have mastered the ability to move a camera by then ;-)

Stealth. If you wanted to reveal yourself, you wouldn't need to disguise your probe as space debris.

Re: Interstellar Visitor Found to Be Unlike a Comet or an Asteroid

#95

Post by InclinedPlane »

This is a little misleading because it presents the idea that there is a firm separation between "comets" and "asteroids", each of which have very different properties. In reality we've discovered in recent decades that there is significant overlap. Pure comets were formed in the outer solar system beyond the frost line, and they are composed of a mixture of primarily chondritic grains and ices. As noted such bodies are not very structurally strong so if they approach the Sun too closely they will break up from the stress of gravity as well as from the intensity of off-gassing vaporizing gasses. On the other hand you have classic asteroids which are formed inside the frost line and are made up of either chondritic material, stone, or metal (depending on their histories). Such asteroids can be much stronger but they lack the ices which might off-gas during a close solar encounter.

Except, that dichotomy is a simplified fiction. The reality is that there are objects in the middle, sometimes called "iceteroids" which we've discovered over the years. These could be the cores of comets which have lost most of their ices or these could be objects with more complicated histories, such as asteroids which have accreted surface layers of ices through various processes.

So this is a mystery but it's not some enormous mystery it's a small mystery. The idea that an asteroid could have acquired a small amount of ices on its surface isn't exactly world shattering news but because we don't know the history of the object we don't know the process by which it ended up with its observed properties.

Re: Interstellar Visitor Found to Be Unlike a Comet or an Asteroid

#96

Post by [deleted] »

sjclemmy wrote: post #66
tonmoy wrote: post #60

Earlier quoted context omitted.

> The spinning is irrelevant surely - I mean it’s all relative That is incorrect. All motion is not relative, only intertial motion is relative. Spinning implies acceleration on a body which is measurably different from any reference frame compared to a body that is not accelerating

What I meant was, the origin of the object may have been in a different inertial frame of reference to our solar system, so the 'spin' as far as it is concerned is not spin.

[deleted]

Re: Interstellar Visitor Found to Be Unlike a Comet or an Asteroid

#97

Post by divbzero »

nrjames wrote: post #27

This reminds me of Rendevous with Rama, which I’m currently reading with my daughter.

’Oumuamua’s “mysterious thrust” [1][2] is obviously from rocket thrusters which undoubtedly come in threes.

1: [’Oumuamua] was being slightly accelerated by an unseen force, which they argued could only be attributed to comet “outgassing” acting like a thruster.

2: Now in a new study that is currently under peer review, Roman Rafikov, an astrophysicist at the University of Cambridge, argues that the same forces that appeared to have accelerated ’Oumuamua — the same forces that should have also produced a tail — would have also affected its spin. In particular, the acceleration would have torqued ’Oumuamua to such a degree that it would have spun apart, breaking up into smaller pieces. If ’Oumuamua were a comet, he argues, it would not have survived.

Re: Interstellar Visitor Found to Be Unlike a Comet or an Asteroid

#98

Post by rbanffy »

notsofastbuddy wrote: post #90
rbanffy wrote: post #79

Earlier quoted context omitted.

My personal theory is that Clarke's writing partners sedated and tied him inside a closet until the book was finished. That's the only way to explain how awful some of his last books were. Having said that, I liked Richter 10. Too bad the co-author died before they could write another one.

My heuristic is that anything co-written by Gentry Lee is not worth my time.

I even wonder why they insisted on it so much.

Re: Interstellar Visitor Found to Be Unlike a Comet or an Asteroid

#99

Post by crocal »

p2detar wrote: post #17
sjclemmy wrote: post #3

I'm still convinced this is an alien probe. I mean look at that trajectory. 0.163 AU from Earth - what are the odds? The spinning is irrelevant surely - I mean, it's all relative, so as far as ’Oumuamua is concerned, we're spinning. Maybe it was spinning that way to stay aligned with a distant companion for communication.

This has always fascinated me. We can actually build giant spaceships (space stations) inside asteroids and use them for interstellar travel. All the resources we need, including ice would be at our disposal. Like traveling with your own mini-planet. Dirk Schulze had taken that as a subject into his sci-fiction book - Alien Encounter.

Also mentionned in Legend of Galactic Heroes by Yoshiki Tanaka. The founder of the Free Planet Alliances escape from its prison world by using ice asteroids as vessels for interstellar travel.

Re: Interstellar Visitor Found to Be Unlike a Comet or an Asteroid

#100

Post by Balgair »

InclinedPlane wrote: post #95

This is a little misleading because it presents the idea that there is a firm separation between "comets" and "asteroids", each of which have very different properties. In reality we've discovered in recent decades that there is significant overlap. Pure comets were formed in the outer solar system beyond the frost line, and they are composed of a mixture of primarily chondritic grains and ices. As noted such bodies…

To me, the interesting thing is that this iceteroid (love the term!) is definitively extra-solar and that means that it is likely that other systems have both asteroids and comets. Though we've seen asteroids in other systems like Fomalhaut [0], we've not been up close and personal with the compositions of extra-solar material.

Here in the Sol system, we have a pretty strange arrangement of planets [1], with big ones all in the outer system and smaller ones in the inner system. So looking at just our system is not very indicative of 'typical' system evolution, in terms of iceteroids. Once we figure out where Oumuamua came from, that'll give us some idea of the compositions and evolutions of other systems (data point of 1 is better than 0), like the frost line. Oumuamua should be viewed as awesome and exciting, but as the tip of the ... iceberg ... when it comes to the real questions of stellar evolution and all the awesome stuff happening there.

[0]https://en.wikipedia.org/wiki/Fomalhaut

[1]https://en.wikipedia.org/wiki/Nice_model

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