Ever seen a UFO?

[Mike OReilly]

Originally Posted by Russian007

Thanks. Cool comments. I presumed the other comments citing physics to dismiss the likelihood of aliens is based on the notion that the nearest solar system (approx 4 light years?) and the 186k mps posted speed limit make the time frames for travel prohibitive. But none of the naysayers said that exactly so maybe they have other reasons.
btw there some exotic theories that propose compressing space-time as a workaround for Einstein's speed limit and that the Casimir vacuum between parallel plates could fulfill the negative-energy requirement-- whatever that means... more here https://en.wikipedia.org/wiki/Alcubierre_drive

Fun... haven't heard of that one. I can't pretend to understand it, but it almost sounds like applying a doppler shift to space-time. Interesting...

Interstellar travel is certainly possible. It just takes a really long time to get anywhere. This is where all those cryogenic-freezing ideas come from in sci-fi, or the spaceships which start with one generation of people, but arrive with their great-great...progeny.

All this makes it very hard to travel interstellar distances. I find it hard to believe an alien species would put that much effort into coming here without making a big deal of saying "HI!" Instead, most of these so-called alien sightings are fleeting zippy things in the sky, or odd-balls claiming to have been abducted and (often) sexually assaulted. Just doesn't pass my sniff test for credibilty.

[capn_billl]

There is a problem with the "UFO's are aliens" theory.

Space is big, really really big.

Technology like Bussard drive would leave a signature detectable by deep space telescopes as they approach our part of the universe.

There are billions of stars, but developing space age technology from single cell life takes billions of years, and is likely one in a billion probability.

That leaves likely civilizations billions of light years apart, and approaches the age of the universe in probability.

That leaves a probable space civilization in one of the billions of nearby galaxies (measured in millions of light years apart), long odds of even considering whether the Milky way galaxy supports life, and deciding to visit.

We haven't even emitted enough RF to travel 100 light years from Earth, let alone the millions it would take for another race to pick it up.

Without building a superstructure Like a Dyson sphere, or Ringworld, it is unlikely even a nearby solar system would detect our presence.

The very first detectable emission we've sent is still light years away from the nearest star.

Thus we have Fermi's paradox.

If there is another intelligent civilization that has reached the space age, it is likely too far to visit, or even detect.

[Mike OReilly]

Originally Posted by capn_billl

The very first detectable emission we've sent is still light years away from the nearest star.

Mostly agree with your thoughts Bill, although we would quibble about the stats. We really can't say very much about the odds of life (intelligent or otherwise) showing up on other planets. We currently only have a sample size of one, so we have no way of assessing the odds.

But just to clarify, the nearest star to Sol is about 4 light-years away. There must be thousands of stars within 100 light-years of us. Since we've been emitting electromagnetic signals for a bit over 100 years now, our potential detectable sphere theoretically includes all these stars.

Of course, at about 100,000 light-years in diameter, this is only a tiny corner of our galaxy. And our galaxy is a miniscule drop of sand in a beach of galaxies.

[capn_billl]

The closest star with an Earth sized planet was 100 light years that I had heard of.

But there are 76 known stars within 100 light years.

4.5 light years to Proxima, practically next door.

That means we nearly have the technology to go check it out. A small nuclear powered probe could get there in 50 - 60 years, do a loop, and come back.

I'm not sure how we would get that funded, but I think it would be a worthwhile endeavor whether we find little green men there or not.

[Mike OReilly]

Originally Posted by capn_billl

The closest star with an Earth sized planet was 100 light years that I had heard of.

But there are 76 known stars within 100 light years.

4.5 light years to Proxima, practically next door.

That means we nearly have the technology to go check it out. A small nuclear powered probe could get there in 50 - 60 years, do a loop, and come back.

I'm not sure how we would get that funded, but I think it would be a worthwhile endeavor whether we find little green men there or not.

According to this database there are 76 Type A stars within 100 ly of Sol, but there are:

• about 250 giant and supergiant stars
• 4 Type B
• 303 Type F
• 512 Type G
• 947 Type K
• and over 2,000 Type M

Of course, if we're talking stars with Earth-sized planets, the numbers shrink dramatically.

Yes indeed, interstellar travel is certainly possible for us. As I said, we already have two human-made ships traversing interstellar space: Voyager I & II. It just takes a very long time, but it's certainly possible.

[jimbunyard]

Not only did Jimmy see (I mean report) one on this day in 1973, they're even showing up on the latest media-wide, (perhaps) sordid, cash-cow 'story'.

Look closely at the sky in this video of the 'lovebirds' from 6:54 to 6:56. Is that a tic-tac I spy?

Helps if you slow down playback speed to .25.

https://www.youtube.com/watch?v=GLpyOuqpcPI

Of course, it's really just the moon (I suppose), but in my mind, it's actually the real reason for Ms. Petito's disappearance. You know, alien abduction and all that. Even explains hubby's (or whatever his rating is) reluctance to spill the beans...

[GordMay]

Originally Posted by jimbunyard

Not only did Jimmy see one on this day in 1973 ...

FWIW: NO.
Jimmy filed a report, with the National Investigations Committee on Aerial Phenomena (NICAP) on September 18, 1973, claiming he had seen an Unidentified Flying Object (UFO) in October 1969.

[jimbunyard]

My bad. Fixed it. FWIW...

[jimbunyard]

About all that's left to say is that a lot of people seem to have a lot of problems determining the difference between science fiction and science fact...

A million miles an hour will put you 4 light years away in 2740 years. So what?

Ever heard about minimum population requirements for civilizational survival, let alone progress? What about species interdependence for biome perpetuation?

Again, it is extremely likely that humans will be forever moored to this planet, and certainly to this solar system, and the absence of evidence for 'little green men' can be taken as 'proof' that this is generally the case for the rest of the universe.


But 'ET' could show up tomorrow...

[GordMay]

Will it be safe for humans to fly to Mars?

A Mars Mission would be viable, if it doesn’t exceed four years, an international research team concludes.

This doesn't bode well, for interstellar travel.

Sending human travelers to Mars would require scientists and engineers to overcome a range of technological and safety obstacles. One of them is the grave risk posed by particle radiation from the sun, distant stars and galaxies.

Answering two key questions, would go a long way toward overcoming that hurdle:
Would particle radiation pose too grave a threat to human life throughout a round trip to the red planet?
And, could the very timing of a mission to Mars help shield astronauts and the spacecraft from the radiation?

In a article [1], published in the peer-reviewed journal Space Weather, an international team of space scientists, including researchers from UCLA, answers those two questions with a "no" and a "yes."

That is, humans should be able to safely travel to and from Mars, provided that the spacecraft has sufficient shielding, and the round trip is shorter than approximately four years.

And the timing of a human mission to Mars would indeed make a difference: The scientists determined that the best time for a flight to leave Earth would be when solar activity is at its peak, known as the solar maximum.

[1] “Beating 1 Sievert: Optimal Radiation Shielding of Astronauts on a Mission to Mars” ~ by M. I. Dobynde et al
➥ https://agupubs.onlinelibrary.wiley....9/2021SW002749

[OldManMirage]

Originally Posted by jimbunyard

About all that's left to say is that a lot of people seem to have a lot of problems determining the difference between science fiction and science fact...

A million miles an hour will put you 4 light years away in 2740 years. So what?

Ever heard about minimum population requirements for civilizational survival, let alone progress? What about species interdependence for biome perpetuation?

This is why I said IF we devoted the resources to it. And it is a hypothetical situation I used trying to demonstrate the Fermi paradox.

But I do believe that using even present technology it is possible. It would take cooperation on a global scale that is impossible to imagine at the moment. But the resources are there.

Generational ships the size of cruise ships could be built in orbit and populated with sufficient numbers of people and bio-matter. They could be launched toward likely destinations. Some would probably get lucky and hit habitable planets - IF there are such.

And again, this is crux of the Fermi paradox. IF - big IF - but if this and if that and if life is common, and if little old us could do it, then the odds are that other older and more advanced - and more cooperative - species' would have already done it.

I imagine a species with a more "hive-type" mentality would rule the galaxy.

"All hail the Queen Ant !"

And yeah...they certainly could show up anytime !

[AKA-None]

Originally Posted by OldManMirage

This is why I said IF we devoted the resources to it. And it is a hypothetical situation I used trying to demonstrate the Fermi paradox.



But I do believe that using even present technology it is possible. It would take cooperation on a global scale that is impossible to imagine at the moment. But the resources are there.



Generational ships the size of cruise ships could be built in orbit and populated with sufficient numbers of people and bio-matter. They could be launched toward likely destinations. Some would probably get lucky and hit habitable planets - IF there are such.



And again, this is crux of the Fermi paradox. IF - big IF - but if this and if that and if life is common, and if little old us could do it, then the odds are that other older and more advanced - and more cooperative - species' would have already done it.



I imagine a species with a more "hive-type" mentality would rule the galaxy.



"All hail the Queen Ant !"



And yeah...they certainly could show up anytime !

Enders Game?

[jimbunyard]

You're not even talking science fiction, you're talking science fantasy. A cruise ship-sized intragalactic colony vessel would probably be at least an order of magnitude too small, we have no known method of propelling, or, more importantly, braking it, and no way to get the materials to build it into space.

Even a cruise ship sized 'space ship' would take 2000 NEO launches, (not including construction equipment, fuel, consumable and population launches) if we were able to launch 100 ton payloads, which 'we' (any individual Earth organization) currently are not.

The 'resources' required would bankrupt an already bankrupt planet, economically, physically and energetically.


'Beliefs' do not connote reality; and quite often do the opposite.


Ever read the 'Ringworld' trilogy? The 'Puppeteers' had the right idea; they 'figured out a way' to move their entire planet (actually [in the books], five of them, along with an artifical sun).

Of course, imagination is not bound by the laws of physics...

[AKA-None]

Originally Posted by jimbunyard

You're not even talking science fiction, you're talking science fantasy. A cruise ship-sized intragalactic colony vessel would probably be at least an order of magnitude too small, we have no known method of propelling, or, more importantly, braking it, and no way to get the materials to build it into space.

Even a cruise ship sized 'space ship' would take 2000 NEO launches, (not including construction equipment, fuel, consumable and population launches) if we were able to launch 100 ton payloads, which 'we' (any individual Earth organization) currently are not.

The 'resources' required would bankrupt an already bankrupt planet, economically, physically and energetically.


'Beliefs' do not connote reality; and quite often do the opposite.


Ever read the 'Ringworld' trilogy? The 'Puppeteers' had the right idea; they 'figured out a way' to move their entire planet (actually [in the books], five of them, along with an artifical sun).

Of course, imagination is not bound by the laws of physics...

Oumuamua?

Rendezvous with Rama?

[Mike OReilly]

Interstellar travel for humanity right now is barely technologically conceivable (not achievable, but conceivable). But then there's even the question of, where would we go? We have no hint of any life out there yet. Heck, we haven't even found life outside of Earth in our solar system. So where would we go?

Besides, as I mentioned earlier, Fermi's Paradox might not be paradoxical at all. Given the only data point we currently have (us, on Earth), it is conceivable that we are at the early stages where intelligence can evolve and explore space. Given the necessity of having heavy elements, and given our own evolutionary history, it's possible we are one of the first intelligences to emerge in this galaxy.

So maybe we are one of the First Ones.