I've watched a few scientifically-informed presentations on interstellar travel, and the figures involved - the amount of energy that has to be used, the threat of radiation in deep space, and above all the immense distances involved - seem to rule it out. I mean, aside from 'faster than light travel' which I'm sure is not possible as a matter of principle, you simply can't bridge gaps of 10's or 100's or 1000's of light-years in any meaningful time-frame. I'm of the view that terrestrial organisms such as ourselves are inexorably earth-bound, and that although we might get boots on Mars - very big 'if'! - we'll never escape the bounds of the solar system. And there's no other planet that seems remotely habitable (even Mars would be an enormous stretch).

although it's probably worth mentioning another initiative Avi Loeb is involved with - the Breakthrough Starshot project founded by Yuri Milner. The Starshot concept envisions launching a "mothership" carrying about a thousand tiny spacecraft (a 'swarm', each one on the scale of centimeters) to a high-altitude Earth orbit for deployment. After deployment a phased array of ground-based lasers would focus a light beam on the crafts' sails to accelerate them one by one to the target speed within 10 minutes, with an average acceleration on the order of 100 km/s2 (10,000 ɡ), and an illumination energy on the order of 1 TJ delivered to each sail. A preliminary sail model is suggested to have a surface area of 4 m × 4 m develop a proof-of-concept fleet of light sail interstellar probes named Starchip to be capable of making the journey to the Alpha Centauri star system 4.37 light-years away. The chips that the sails are carrying will only weigh a few grams.

Breakthrough Starshot was founded in 2016 by Yuri Milner, Stephen Hawking, and Mark Zuckerberg. Avi Loeb chairs an advisory board. See the wikipedia entry for more details; current news wrap here.

So what may appear might be simply concepts that are too complicated to understand, rather than concepts beyond what an idealized human mind might conjure up. — jgill

Can't any concept be broken down into smaller understandable sub-concepts? Is there a theorem on that?

Can't any concept be broken down into smaller understandable sub-concepts? Is there a theorem on that? — RogueAI

Not that I'm familiar with. I often bring up trying to teach my late Corgi mathematical concepts, to no avail. He passed away with not an inkling of calculus. Perhaps we are like Corgis, cute but limited as to intellectual depth. What is beyond our comprehension may remain that way. However, AI, coupled with the human mind might find a way to break the barrier. Even then we might just be relegated to following instructions, like "roll over". :cool:

Nobody would have been able to guess what, say, quantum theory would turn out like, prior to the pioneers actually doing the investigations and devising the math. A whole new conceptual vocabulary had to be developed along the way. And it was exceedingly difficult. Werner Heisenberg said he was reduced to tears in some of his dialogues/debates with Neils Bohr. Bohr and Einstein debated for 40 years and never really saw eye-to-eye. When you're dealing outer limits of understanding, it would be impossible to break it down in such a way that the untrained could fathom it.

Nobody would have been able to guess what, say, quantum theory would turn out like, prior to the pioneers actually doing the investigations and devising the math. — Wayfarer

Are you claiming that QM would have been impossible to understand for the Greek atomists using nothing but their language and concepts?

Are you claiming that QM would have been impossible to understand for the Greek atomists using nothing but their language and concepts? — RogueAI

I'm sure. I mean, we'll never know, but how would someone transported between two completely different epochs respond? I don't think they would be able to cope. You'd have to break their whole worldview right down and build it up again from scratch. Einstein had trouble coping with quantum physics.

I'm sure. I mean, we'll never know, but how would someone transported between two completely different epochs respond? I don't think they would be able to cope. You'd have to break their whole worldview right down and build it up again from scratch. — Wayfarer

I think you could explain the double slit experiment to them without too much trouble.

'Any sufficiently advanced technology is indistinguishable from magic' ~ Arthur C Clarke - especially true of the application of quantum physics, because nobody really understands how it works. So maybe there's something as far ahead of quantum physics as we are ahead of the technology of the ancient world.

There's also nothing new under the sun. If an advanced intelligence that has figured it all out tried to explain it to us, could we understand the explanation? Or at least get the gist of it?

You seen Contact? That's one pretty amazing attempt to explain what it would be like. Geez, even Close Encounters, and 2001: Space Odyssey have a go at it. One of the reasons I love a good sci fi film, although there's also a lot of trashy sci fi.

But, on a more serious note, I think the only plausible explanation for interstellar visitors, is they find some way to get here without actually travelling the distance. They dissappear there and turn up here. How that would be done, of course, is completely unknown to us. But I don't believe in interstellar travel, as I said, the distances are just too great to traverse with actual physical vehicles.

PBS SpaceTime has a good video on the logistics of interstellar craft. 'We don't see aliens because intestellar travel is just too hard.'

If an advanced intelligence that has figured it all out tried to explain it to us, could we understand the explanation? Or at least get the gist of it? — RogueAI

I doubt it, but how could we know? I did see an interview with (I think) Neil deGrasse Tyson and Richard Dawkins talking about potential alien intelligence with them suggesting that the difference between us and aliens might be comparable to the difference between us and chimpanzees. I guess it all hinges upon whether useful communication would even be possible between an advanced species and us.

There was a segment on last night's Media Watch about a respected Australian journalist, Ross Coulthart, who has gone all-in on the testimony of a UFO whistleblower, David Grusch. Grusch has made sensational claims that the US has, and is concealing, actual alien technology and even bodily remains. Grusch invariably deflects questions about his actual first-hand sighting of these, saying either that he's relying on other's testimony, or that he can't answer because it's classified. But one answer I did notice, was Coulthart saying that UFO's travel 'from another dimension'. Presumably, they can kind of materialise or de-materialise. (Which makes you wonder, as one of Grusch's congressional questioners asked, why they could be careless or incompetent enough to leave anything behind for the US Airforce to peruse.) I personally try to be open-minded, but I have to say I am extremely sceptical about this guy's testimony, short of actual proof.

As you would imagine, there's a good deal of money to be made out of the UFO speaking/writing circuit. I've watched Ross's various 'documentaries' he is careful, but it's clear he has an audience in mind and seems to have re-launched a flagging career. But some of his research is intriguing.

Nevertheless I am interested in the claims. There are several high profile whistle blowers - the other notable one is Luis Elizondo - Coulthart has used him too.

Presumably, they can kind of materialise or de-materialise. — Wayfarer

I think this is becoming accepted in the 'lore' now. And it goes back to earlier accounts. A famous one I have a slight connection to is Westall, which also seemed to feature 'vanishing and 'reappearing' back in 1966.

Well, the ability to materialize and the suggestion of 'other dimensions' which is what puts these claims in the category of occultism. Maybe I should revisit Carl Jung's book on it.