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Interstellar Visitor Found to Be Unlike a Comet or an Asteroid

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

#31

Post by huhtenberg »

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.

For the book, the reviews on Goodreads aren't very good :-/

https://www.goodreads.com/book/show/18268008-alien-encounter

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

#32

Post by Cthulhu_ »

DaveSapien wrote: post #18

Would gravitational pull account for the acceleration? Meaning if it were made (or part of it) of some very dense element like Iridium, there would be an unexpected attraction to our sun?

Nope; gravity is very predictable and very constant (see also the difficulty in detecting gravitational waves), they calculated how much it should accelerate under influence of gravity and found the actual acceleration to be different.

As for the unexpected attraction, as one of the moon astronauts displayed, objects of different mass are attracted (fall) equally quickly by gravity in a vacuum.

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

#33

Post by Cthulhu_ »

kranner wrote: post #14
xrayzerone wrote: post #4

I'll ask what everyone is thinking but won't say. If the acceleration is in fact being caused by artificial thrusters, what kind of thruster configuration can produce prograde acceleration while maintaining the observed tumble? And why would someone engineer this configuration?

> And why would someone engineer this configuration? To make its being engineered seem implausible, surely.

You're saying instead of magic cloaking devices, the aliens used camouflage? Makes sense to me!

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

#34

Post by holografix »

_ph_ wrote: post #13
newnewpdro wrote: post #9

It's too bad we're not ready to launch probes to visit and explore such transient objects at a moment's notice.

I think it would make sense to plan a probe mission where the probe would be put into storage to stand by for these kind of events. It would still be a challenge and might be impossible to find a launch window and reach the passing object in time, but it would be worth trying. Just imagine how tragic it would be, if an ancient artifact of an alien civilization drifts by earth and we don't manage to have at least a lo…

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

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

#35

Post by Cthulhu_ »

_ph_ wrote: post #13
newnewpdro wrote: post #9

It's too bad we're not ready to launch probes to visit and explore such transient objects at a moment's notice.

I think it would make sense to plan a probe mission where the probe would be put into storage to stand by for these kind of events. It would still be a challenge and might be impossible to find a launch window and reach the passing object in time, but it would be worth trying. Just imagine how tragic it would be, if an ancient artifact of an alien civilization drifts by earth and we don't manage to have at least a lo…

Yeah and then you'd need the delta-V to match the object's velocity as well, which would be solar escape velocity and then some. Although having probes scattered around the solar system that could be trained onto the object to get observations from multiple simultaneous angles would be neat.

I hope one day we'll get a solar system wide observation network. Like the current arrays of radio dish observatories, but on a solar system scale.

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

#36

Post by RobertoG »

azernik wrote: post #15
szilardboy wrote: post #7

Earlier quoted context omitted.

What’s special about 0.163 AU? Does it have a mathematical significance?

Just that it's unusually close.

As we are in paranoid mode (and it's fun to be, isn't it?): not only it's unusually close, but it seems that Earth is the planet it pass closer in all the Solar System.

Maybe somebody should check if that "slightly acceleration" bring it closer or farther to Earth.

Maybe we have been photographed. I hope it's not that somebody shoot us and failed.

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

#38

Post by TheOtherHobbes »

xrayzerone wrote: post #4

I'll ask what everyone is thinking but won't say. If the acceleration is in fact being caused by artificial thrusters, what kind of thruster configuration can produce prograde acceleration while maintaining the observed tumble? And why would someone engineer this configuration?

It's maybe worth pointing out the tumbling is a hypothesis used to explain variable brightness measurements and not something that was observed directly.

https://arxiv.org/pdf/1712.00437.pdf

For all anyone knows the intrinsic brightness was variable.

(This is probably not very likely without some supporting spectroscopic anomalies. But still.)

As for thrusters - that's the same problem as the comet and outgassing hypothesis. No known mechanism can explain the acceleration.

And if you were alien race and wanted to look at a planetary system without attracting attention, something that looks like a tumbling rock with a plausibly improbable trajectory would be ideal.

It could just be a coincidence that the first large proven extra-solar object slingshotted around the Sun in a way that happened to pass close by the Earth.

But considering the size of the Solar System and the convenient phasing of the Earth's orbit, what are the odds? It's certainly very curious.

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

#39

Post by elorant »

jobigoud wrote: post #19
newnewpdro wrote: post #9

It's too bad we're not ready to launch probes to visit and explore such transient objects at a moment's notice.

Let's say it takes us another 50 years to fund and prepare a mission, could we still catch up with it?

In 50 years it would be some 41bn kms away (it travels at a speed of 26km/s). Say you want to reach it within a five year span that would mean we'll need to build a spacecraft that could travel 0,1% the speed of light. Probably within our future capabilities considering all the theories that have been proposed for interstellar travel. For example the Breakthrough Starshot project has predictions for 10%-20% of the speed of light.

Of course reaching it and landing on it, especially at these speeds, are two completely different things.

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

#40

Post by _ph_ »

holografix wrote: post #34
_ph_ wrote: post #13

Earlier quoted context omitted.

I think it would make sense to plan a probe mission where the probe would be put into storage to stand by for these kind of events. It would still be a challenge and might be impossible to find a launch window and reach the passing object in time, but it would be worth trying. Just imagine how tragic it would be, if an ancient artifact of an alien civilization drifts by earth and we don't manage to have at least a lo…

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.
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