Found space object may prove we are not alone

The E wrote:Also, if you insist on this "there are aliens on that rock" nonsense: They would know the state of interplanetary travel in this solar system pretty well. So there's no harm in being a rock because the chances of someone getting a probe on an intercept are nil.

I don't. I'm not in the camp that thinks that 'Ouamuamua is an alien probe. I'm just taking the proposal to its logical extension to make a proof-by-absurd.

(the probe would find that it's a rock)

How do you detect artificiality? What sensors can you pack on a probe that can make an intercept that can give you a definitive answer one way or the other that doesn't leave people who insist on believing that it isn't a rock (which is what it is) wiggle room?

You can't prove that a rock is artificial compared to a naturally-occurring rock. A rock is a rock. There may be specific crystalline alignments and other marks that could point to its creation being a doubtful natural occurrence, but like they say in cosmology, "it's never aliens" and we'd do everything to try and come up with a natural explanation for the occurrence before we blamed aliens.

What I meant was that if the object wasn't actually a rock, but merely pretending to be so, a probe that landed on it might note that it isn't a rock. Its density would be all wrong, it might have far more iron and other ferromagnetic alloys than it should. It might be putting out detectable radiation at close range that can't otherwise be explained.

(this rock was hiding in the way that all space travelling rocks do)

How would you know how significant this rock would be to the people looking at it?

That's the question, isn't it. If you're an alien intellegence trying to get more info on us, do you take this risk?

ThinksMarkedly wrote:What I meant was that if the object wasn't actually a rock, but merely pretending to be so, a probe that landed on it might note that it isn't a rock. Its density would be all wrong, it might have far more iron and other ferromagnetic alloys than it should. It might be putting out detectable radiation at close range that can't otherwise be explained.

Which would only be true if one assumes that such a vessel would not be (for the most part) a rock.
Using an asteroid as a basis for an interstellar probe is, after all, not that outlandish an idea.

That's the question, isn't it. If you're an alien intellegence trying to get more info on us, do you take this risk?

Why would you care?

A theoretical probe like this is incredibly slow. It's not going to reach another system, let alone one that is actually inhabited, for thousands if not hundreds of thousands of years.

After all, we don't care if someone intercepts the voyagers. Unless some pretty fundamental things we believe about the universe are wrong, by the time something non-human picks them up and identifies them as artificial, there will be nothing left that would be recognizably human to us, today.

The reason for why there is speculation that Oumuamua is an artificial object was the shape that was the best explanation for its light curve. That long, thin shape is not what you would expect from a natural object. BTW, I remember reading speculation that it was a rolled up light sail (discarded who knows how many years ago) drifting through space.

The E wrote:Which would only be true if one assumes that such a vessel would not be (for the most part) a rock.
Using an asteroid as a basis for an interstellar probe is, after all, not that outlandish an idea.

Very true. If you're going to spend tens of millennia travelling between the stars, a good rocky exterior is a very good armour against micrometeriorites. Add an internal layer of water and you've got good radiation insulation too.

A theoretical probe like this is incredibly slow. It's not going to reach another system, let alone one that is actually inhabited, for thousands if not hundreds of thousands of years.

After all, we don't care if someone intercepts the voyagers. Unless some pretty fundamental things we believe about the universe are wrong, by the time something non-human picks them up and identifies them as artificial, there will be nothing left that would be recognizably human to us, today.

Because either you care about staying hidden or you don't. If you do care, then being the single most remarkable discovery at the time in the system is not a good way to staying hidden. If you don't care, then the best way to get intelligence is to ask for and get a download of Wikipedia.

A civilisation that was trying to stay hidden would have kept the mothership way out in the outer system, where the chances of detection would be minimal. From there, send small probes to gather more intelligence, on wide ballistic courses and rendezvous with the mothership on its way out. From that outer system, they can capture some icy cores to use a heat sinks too. That's the strategy that Bob used in the new book in the Bobiverse (Heaven's River), which I recommend, BTW.

A thing as big as 'Oumuamua isn't stealthy. If itself is the probe, then has to have manoeuvring capability and some antennae or sensors. All those could be seen from close up, if the natives decided to send a probe.

Like I said, not a good strategy. It's not impossible, I'm just saying there are better and more effective ways, which the aliens would likely have tried first.