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Absolutely there could be. There could be a plausible explanation for why these aliens persistently appear to want to remain unobserved, too. But applying Occam's razor to the problem, is that the most likely explanation for the observations recounted so far? I'm willing to be convinced, but so far, I'm not hearing much beyond (some very cool, I admit) very speculative theorizing.Quote:
Originally Posted by DevilHorse
While I remain firmly in the "Yes they're out there, but no, we're not going to see them camp", I can make an argument against Fermi's Paradox just for the fun of it.
Whenever we here on earth think of investigating primitive societies that still function with near Stone Age technologies, or when we think of investigating life on other planets, the "Do Not Disturb" rule is usually considered to be of utmost importance.
So if you want to imagine that some amazing society has discovered flux capacitors and can now go wherever or whenever they want, you could maybe safely assume that their prime directive would be - don't let them know we've come to visit. Seems reasonable if you allow that they could have evolved ethically as well as technically.
And I'm thinking that short of "Sorry folks, we're building a new wormhole, and Earth's in the way", there could be nothing more disruptive than finding out about our new neighbors. So who knows, maybe they have been dropping by, and they're just being very proper about how they treat all us backwards folks.
I've seen this on Star Trek - Prime Directive and such.Quote:
Originally Posted by Ggallagher
Also, assuming we have had visitors, maybe they just aren't interested in us. :eek:
And finally, one explanation for the lights in the sky that have been seen is that is they are just uh, light. I don't think we can assume mass in "objects" that don't behave like they have mass.
There’s no point in acting surprised about it. All the planning charts and demolition orders have been on display at your local planning department in Alpha Centauri for 50 of your Earth years, so you’ve had plenty of time to lodge any formal complaint and it’s far too late to start making a fuss about it now. ... What do you mean you’ve never been to Alpha Centauri? Oh, for heaven’s sake, mankind, it’s only four light years away, you know. I’m sorry, but if you can’t be bothered to take an interest in local affairs, that’s your own lookout. Energize the demolition beams.Quote:
Originally Posted by Ggallagher
It may already be too late for mankind. It would be very 2020 for it to go down that way.
As we have been "noisy" for roughly 100 years, the most probable location for an ET that's interested in us is within 50 light years of Sol (50 years for our radio to reach them plus 50 years for them to get here). There are roughly 15,000 stars in a 50 light year radius of Sol.Quote:
Originally Posted by PackMan97
Radiation levels in the galactic core make intelligent life less likely there.Quote:
Originally Posted by jimsumner
Yes, Earth is clearly of interest for habitation, but wouldn't it be easier to find a habitable planet that doesn't have annoying sentient beings who have already harvested many of the handiest resources? Say, like Earth from 1,000,000 years ago?Quote:
Originally Posted by Wander
And if it turned out that the only habitable planet you could find was Earth, wouldn't it be a whole lot simpler to wipe out the intelligent life before you spend too much time randomly messing about with repeated low level flights? My strategy (if I were an ET), would be
1) Learn as much as possible from eavesdropping on our electronic communications, say from a vessel parked at the edge of the solar system
2) Send one landing party to gather up samples of DNA, viruses, plus some select scientists, say from China
3) Bring the landing party back to the vessel where they can engineer some virus deadly to humans but not to the ETs or other life on Earth
4) Send the virus back...wait.
So I conclude that ET is really just curious about us. Exo-anthropologists, if you will. Or COVID-19 was created by ET.
Is there a Goldilocks zone, i.e. a region where stars are close enough for a local cluster of civilizations but far enough from the galactic core to allow life to develop and thrive?Quote:
Originally Posted by Neals384
I've always noted the coincidence (unless it wasn't) that a number of high profile UFO sighting in New Mexico (e.g. Roswell) occurred just two years after the first atomic test in the New Mexico desert, only 150 miles away or so...does not seem beyond the realm of possibility that other civilization(s) were able to detect this, figured what the hell, that's a technological benchmark, let's go have a look at these guys. Probably found us to be self destructive and generally uninteresting...and not particularly flavorful.
This doesn't answer your question, Jim, but the sci-fi (and honest-to-god computer scientist) Vernor Vinge proposed in some of his stories that galaxies could be broken up into "zones" where faster-than-light travel was and wasn't possible: basically, as you got closer to the core, travel (and by consequence, processing) slowed down. He did not offer any good theoretical for the existence of such zones, but it does lead to some interesting settings, such as singularity events in the faster-than-light zones where god-like artificial intelligences can emerge, and natural sentient life surviving in the slower zones where AI isn't has powerful. I got a little fed up with his "anarcho-capitalist" viewpoint, but I really really enjoyed Vinge's books "A Fire Upon on the Deep" and "A Deepness in the Sky".Quote:
Originally Posted by jimsumner
Not to derail this thread, but let me ask/propose two things:
1) Regarding visits from alien life, I think one limitation in our current thinking (and one limitation we see in traditional sci-fi) is to always project our current technology forward by "speeding it up" or "increasing its power", etc (think Jetsons). Instead we need to think about about things we, well, haven't thought of! So we always assume we need to physically move bodies faster than light to "visit" places, but what if, instead, we use wormholes to send digital signals to each other, and then simply visit in some inter-system version of virtual reality or cyberspace?
btw, I really think our future is less about physical travel to other worlds and instead more and more immersion into virtual realities in which we can make up our own "laws" of physics, etc. The authors David Brin and Vinge both hint at this prospect (and perhaps another explanation for Fermi's paradox): as civilizations become more advanced, they eventually fall into a navel-gazing "senescence" and stop interacting with the outside world(s). With the way video-games are progressing, I think human society is getting pretty close! (E.g., my kids these days certainly spend more and more of their time immersed in games and interacting less with the "outside world" like their parents!...ha ha...)
2) I really like good "hard" science fiction...anyone got any good recommendations of anything new? I've read most of Clark and Vinge, a bit of Scott-Card, some Brin, some Stephenson ("Anathem" was a real slog, but had a few interesting ideas)...and of course Liu's trilogy (still probably the most mind-blowing series I've read in a while). Anyone else I should check out?
From stuff I read a while back, we actually are in the Goldilocks zone for our galaxy.Quote:
Originally Posted by jimsumner
If we were closer to the center, greater radiation would be harmful to life, and higher gravity would be more likely to disturb orbits in our neighborhood.
If we had been dropped into one of the spiral arms, the risk of higher radiation arises from a higher rate of star formation.
If we're too far out in the galaxy, the problem is the reduced amount of heavy metals required to form a planet like Earth.
If we had failed to have a roughly circular orbit, we would increase the risk of passing through the galactic arms - see above.
So yep, I think this spot is "Just Right".
On the surface of this statement, I'd say no. I think light/intelligence/structure needs a medium to organize and propagate it has to organize/think, build stuff, consume, excrete. Otherwise, it is just particles. Me thinks aliens would have to share the same 4-space that we do. Cloaked maybe, but just light (photonic), I wouldn't think so.Quote:
Originally Posted by camion
Unless of course you're talking aliens occupying other dimensions that can peer into our dimensions; then you'd have something. Perhaps the Metrones from Star Trek; that's the ticket. But those guys had no sense of humor. If aliens have curiousity, a sense of "hands-off", then a sense of humor has to go with it too.
Larry
DevilHorse
You realize that Alpha Centauri is a star. Either the plans are burnt to a crisp, in a well made lockbox (thanks Al Gore), or sitting in a depot on a neighboring planet. Will Robinson and family, well, they needed to make some alternate plans anyway.Quote:
Originally Posted by PackMan97
Just Fact Checking.
Larry
DevilHorse
To answer the OP's question, NO -- I do not believe that the reports UFO's and ET's as evidence of the arrival of intelligent life from other planets -- or sent as robotic/drone devices. There are too many other causes -- known and unknown -- to jump to that conclusion.
Is there life elsewhere in the Solar System and on other planets around other stars? I'd say the likelihood is overwhelmingly YES. It would be pretty hard to have a combination of oxygen, water and heat/atmosphere that results in liquid water without somehow generating complex molecules that combine and transform to form what we would call "life." We'll probably find out (and confirm) this in our Solar System in the next few decades.
There are a few "Goldilocks zones" that you'd have to fit in. Some have short term lethalness and other long term. The answer above is a good one for where a planet needs to be located in a galaxy. These determine overall radiation and outside comet/object traffic. You may recall that about 2 years ago an object, nicknamed Oumuamua entered our solar system at an oblique angle and was (first thought to be an alien craft maybe because it looked alot like the alien craft from the movie Star Trek IV The Voyage Home - long cigar shape) determined to be the first non-solar system object observed. So it is a rare event. But at the center of our galaxy, we would expect significant traffic from outside of the solar system which could have had devastating consequences for our planet and the development of life.Quote:
Originally Posted by Ggallagher
https://en.wikipedia.org/wiki/%CA%BBOumuamua
There is a Goldilocks Zone, that we most often have heard of, around a star, that dictates the placement of a planet relative to a star. You really need a G type star (that H-R diagram again) that's a medium sized star like ours, where you can expect a planet that is around our size at about our distance (Bode's Law was mentioned). Mars and Venus are similar size and distance too, but perturbations of 50% have obviously dramatic differences in planet evolution. Stars appreciably different in mass than our star would probably not have a similar sized planet in the right place for tolerable sunlight (for us).
There is also a Goldilocks like Zone for moons around large planets. There is some talk about life on moons like Enceladus or Europa (all these planets are yours, but hands off Europa!). But these moons are situated around Jupiter and Saturn, gas giants with incredible Radiation fields. Jupiter is a couple of Big Macs short of being a star in its own right. Do you realize that most of the stars in the sky are double stars (stars with smaller companions). Our sun was almost a double star with Jupiter as its partner; but the radiation is there. If you were on Europa (Jupiter moon) [with warmth and breathing gear of course] the radiation from Jupiter would kill you in days. That is cell destroying radiation. Tough life would have to grow near there. The Earth does not produce that kind of radiation.
Larry
DevilHorse
But our nearest solar neighbors are more than four light years away. I'm trying to visualize a cluster of stars-not double systems--closer to each other than that, maybe several within a light year or so in which more than one star can produce a technologically advanced society in a chronologically over-lapped time frame with others that would enable some sort of interaction. Given the age of the universe and the uncertain life span of a technologically-advanced species, probably not. Who knows how many technologically advanced societies have come and gone in our galactic neck of the woods over several billion years?Quote:
Originally Posted by Ggallagher
Perhaps a more practical question involves an interstellar civilization with a bunch of life-friendly planets within a light year or so of home base, enough to colonize and reduce the odds of an extinction-level event ending the existence of said civilization. Is there a Goldilocks zone for that?
Jim, I think you're asking for trouble (astronomically speaking) at least with your scale. [Light Year - ly] Proxima Centauri (4.25 ly) and Alpha Centauri (4.35 ly) are pretty close to our sun (for perspective). But we are fortunate that we are no closer than than that.Quote:
Originally Posted by jimsumner
Consider these numbers. You are no doubt familiar with the Kuiper Belt, where many of our comets come from, extends out as far as 2 ly from our sun. That is as far as our suns gravity influence is known to extend. If you put another star within 1 ly, for a long time, that star won't be there for long unless it has a very specific orbit that keeps it from crashing into our sun, which makes it a double star. Now if you add a third star to the original 2, there is no known solution to that problem, but the effects are likely to result in just 2 stars really soon. My point is that I don't think that 2 stars, that are too close, would last that long, unless they are orbiting each other. Then there would be other problems in planet formation (a different view appears later).
Think about denser areas of stars and dust. The Orion Nebula, filthy with dirt, its 28 Light Years across; embedded in a spiral arm. A star system there would get pummeled with comets, asteroids, and no doubt bad TV shows for years. The Hercules Cluster, 10,000 of stars densely packed within 160 Light years; no doubt lots of gas as planetoids in between. Lots of fireworks, no doubt. So you can't have these areas for older civilizations to form.
Some of these Goldilocks zones are really probabilities for being able to survive without getting hit by comets and the like. You don't have to be in a Goldilocks zone to beat the odds. Other Goldilocks zones (like for radiation) you won't beat.
Gravity gets us all in the end. Andromeda and the Milky Way are going to collide, and we are 2.5 Million Light Years apart.
Earth actually has a big advantage with having Jupiter as a big sister in our solar system. Earth would have been hit with many more life/species ending events if not for Jupiter (and probably Saturn) sweeping out many of the space junk and catching stray comets/asteroids that come in from the Oort Cloud and Kuiper Belt.
Remember Shoemaker-Levy 9?
https://www.google.com/url?sa=t&rct=...cK4SX0Gsqo1a_n
That's compliments of Big Sister protecting the siblings.
Larry
DevilHorse
And this is the very impetus behind The (appropriately titled) Three-Body Problem :)Quote:
Originally Posted by DevilHorse
There are a few special case solutions, but they don't make sense on a planetary scale (i.e., two big ones and a very small one, perhaps acting like a moon).Quote:
Originally Posted by construe
Larry
DevilHorse
So, it's wormhole or bust.Quote:
Originally Posted by DevilHorse
I should have been more clear. In the last paragraph I wasn’t postulating aliens at all. I was just saying that the “objects” seen to move in ways that normal vehicles can’t might not be massive solid objects after all. One example of a known thing that moves with great speed and changes direction abruptly would be lightning. And, no, I’m not saying the sightings are lightning, just that we shouldn’t assume a large mass which would require a lot of energy to accelerate. A small or negligible mass wouldn’t need to break our current physical laws to change velocity abruptly.Quote:
Originally Posted by DevilHorse
Not a problem. I was attempting to keep things 'light' on some of these subjects while bringing enough facts into the discussion in an entertaining way. I hope I wasn't too dismissive or flippant with your statement/question. My attempt is to answer the specific and to pull in some other interesting factoids, and an occasional Duke connection if possible.Quote:
Originally Posted by camion
As an aside, and speaking of observing fast moving things, there have been quite a few observations of phenomena of 'physics breaking' motion of things before, that on closer inspection were found to be consistent with known physical laws. About every other year there is a headline in the New York Times about an observation of something, either in space or here on earth, of something that moves faster than the speed of light. No immediate explanation (by the measurer) is provided; but it is obviously noteworthy.
I remember one of these cases where a pulse of light (in an experimental setting) was presumed to move, from here to there, faster than C. But on closer examination, what they found was that the shape of the pulse changed and that the lead edge of the pulse got fatter (for lack of a better phrase) and the hind end thinner, rather than the hind end moving forward at C. I hope I explained that clearly. The trailing edge of a pulse did not move faster than the speed of light, the leading edge just masqueraded to look like the hind end. There always seems to be some measurement explanation behind these things.
Key:
C- Speed of Light
Hind End - horse talk for trailing part
Larry
DevilHorse