Alpha Centauri could have a habitable Earth-like planet.
There could be an Earth-like planet within five light years of us. Not only that, but an Earth-like planet where you could see two suns in the sky (though one would be much brighter than the other). How cool is that?
>How cool is that?
It’s pretty cool. It could become intensely, overwhelmingly, absolutely cool if we found somebody there to strike up a conversation with.
While it is hard to say with much confidence, it’s plausible for now that we will live to witness the first contact between humanity and some other intelligent species. I mean, by radio or other massless communication, not by transportation.
The Drake Equation might as well have been called the Drake Equivocation. So much uncertainty. But there’s a roughly exponential growth in the amount of information that humanity has grabbed out of the air and tested to see if it originates in extraterrestrial intellegence. I’ve heard several pleasantly realistic interpretations of the things we do know about this, that have the first contact happening within the next 10 or 20 or 40 years (I’m leaving out for now how pleasantly realistic it is for me to hope I can witness something 40 years from now).
There’s a onesidedness to some of the possibilities. About cosmology in general - should I believe the universe is infinite in size? Because, if it is, given that we exist, given that the probability of intelligent life being near a star is greater than zero, there obviously must be infinitely many intelligent civilizations out there - no question. But the universe was, perhaps, closed and less-than-infinite when I was studying Astronomy. Is the number of years a scientific finding has been accepted some kind of predictive measure of how long I should assume it will still be accepted?
When I was first starting to get interested in Astronomy, I had a big poster of Mars on my bedroom wall, with all the canals marked with their names, and the hubs or nodes or cities where they connected also named. Thinking this was all silly, today, doesn’t really tell me much about how legitimate or silly it is today to think the universe is expanding at an increasing rate, or that it is open, or that there is dark matter and dark energy - is there still quintessence? Or did that get renamed as dark energy? I don’t remember.
Are there still an ever increasing number of theories about the ultimate fate of the universe? Or is the number of theories leveling off and starting to decline? This is the “big bang bang” theory of the universe, the “big metabang”…
I’m pretty sure I read in one of those WHAT IF astronomy threads in GQ that if a solar system had two suns, its planets would have an unstable figure-eight orbit that would eventually end up with the planet crashing into one of the suns.
It’s possible I’m misremembering, and of course it’s always possible that even if I’m remembering right, it was written by a crackpot who learned about astronomy from episodes of Marvin the Martian. Anne Neville, what’s the straight dope?
Either way, super cool.
Indubitably. That would be as cool as it must have been to be on one of Columbus’ ships. (Hopefully we could figure out how to do it this time around without all the disease, genocide, cultural destruction, enslavement, stealing of land and treasure, and religious persecution.)
IANACosmologist, but I don’t think any of them think the universe is really infinite. Vastly, hugely, mind-bogglingly big, yes, but it doesn’t have an infinite number of stars.
Even if it did, that wouldn’t necessarily mean that we weren’t the only intelligent civilization out there. The set of prime numbers is infinite, and there is one even prime number (2), so the odds that a prime number is even are not zero, but there’s only one even prime number. It gets less and less likely that we’re alone in the universe as the number of stars goes up, but it’s still possible.
Hoo boy, those are big ones for the philosophy-of-science types. I would say no to the first one, and “still an ever increasing number of theories” to the second, but that’s just my WAG.
You were studying astronomy in the first second of the Universe? Man, you’re old 
“Closed universe” didn’t refer to the number of galaxies overall, though. The terms “open universe” and “closed universe” referred to the ultimate fate of the universe. We used to think that the expansion of the universe was only affected by gravity, which would slow it down. If there was enough mass in the universe, the expansion might ultimately stop and reverse itself, and the universe would end in a reverse Big Bang called the Big Crunch. The open universe theory said that there wasn’t enough mass to do that, and the universe would keep expanding forever.
That question has been settled in favor of the open universe, because there’s some force other than gravity acting on the universe. We don’t really know what’s doing it, but something is working against gravity and making the universe expand at an accelerating rate. I suspect this force also has something to do with socks disappearing from the dryer and a pot lid disappearing from my kitchen last night 
This is very cool, but it is still worth noting that we have only had the means to communicate through space for little more than hundred years and we have been around only a few hundred thousand. So not only does a nearby star need to be capable of supporting life, but life needs to start, and then develop into a tool using, radio transmitting society and sustain their technological period long enough to overlap our own very recent entry into this tech. This also assumes that possible societies that are more advanced have not moved beyond looking for and sending radio signals. What is the useful sphere for actual two-way communication?
I would guess no more than 40 light years at the most and more like only 10.
All this said, I still do not expect anything more than to maybe pick up someone else’s communications and to be unable to actually hold an exchange of ideas in a meaningful way in our lifetimes.
Jim (BTW: I hope I am wrong, I used to be an optimist about these things.)
I don’t think what they’re proposing here is a figure-eight orbit. They’re proposing that the planet orbits one of the stars, but the other one is close enough to be brighter than the full moon in our sky.
I wonder about this, too. We do seem to be moving away from broadcasting signals out in every which direction and toward something more directed.
I also wonder how likely it is that a society will get on the path toward being a technological society. Something like what China did in the 1400s might be a more usual path for societies to take, and something more like what Europe did around then might be much rarer.
Very cool. Unfortunately, all we’ll find is xenofungus and mind worms.
I wouldn’t even expect that much, at least for the forseeable future. We don’t currently possess the technology, even with our most powerful radiotelescopes, to detect incidental leakqage emissions (things like our TV and radio broadcasts which aren’t intended for off-planet reception) even an order of magnitude stronger than our most powerful signals to date. A directed transmission of sufficient power would be a different matter, assuming we were looking at the right time.
Good point, but I meant, someone else’s attempt to send a long range message.
If they’re up to our level of technology, why not? I think the science-fiction mantra holds true here: aliens can do (almost) anything.
Also, imagine what it would be like to live on Alpha Centauri…
Hot. Really, really, hot, since that’s a star you’re talking about.
Didn’t you really mean “imagine what it would be like to live in orbit around Alpha Centauri”?
:smack: :smack: :smack: I had two hours of sleep previous to today! I swear!
(Yes, it would be very cool to live on the planet orbiting Alpha Centauri. Really quite cool. thumbs up, goes to put paper bag over head)
I guess it is time to dust off those old plans for a for a mission to Alpha Centauri.
The thought of an Earth-like planet so relatively close is exciting but I have my doubts on the prospects of intelligent life being found there or anywhere else for that matter. I started a thread here discussing some of the know circumstances leading to intelligent life on our world. It was far from being a inevitable outcome here and, in my opinion, an unlikely one within the sphere of discovery I discussed; 50 light-years as a practical distance for two-way communication or eventual travel.)
Often I see people (not here) misconstrue “extraterrestrial life” to mean alien intelligence. I tend to see the probability of life as in decreasingly likely degrees of intelligence. I think it highly likely we will eventually find life in it’s basic forms and is microscopic life or even fungus or algae. Somewhat less likely is more advanced life like the plants and animals that are commonplace here. Next level would be what we consider to have a form of intelligence like the Great Apes, whales and the like. Lastly, and least likely, are the civilizations in the sense of “city builders” and tool makers.
It is this last group that I think most people think of when Life In Space comes up and the group I feel least likely to be discovered. That is not to say that in a near infinite universe there is no such life, only that given the limits on speed of travel and communication that if a civilization exists now it would take millions of years to get a signal here or from us to them and if we receive one from there now, what are the odds of them being there when we hear it.
Just one mans thoughts and ones I personally hope are not true.
I think the real story here is that these guys have shown that it’s possible for planets to be in the habitable zone, or even likely. That makes Alpha Centauri a target for advanced telescopes. We’re not expecting to communicate with another civilization (the odds have to be literally astronomical). But we might be able to design experiments to detect bio-markers in the atmosphere of the planet, or even image it directly with large orbiting interferometry arrays. If we could find a planet worth studying at Alpha C, it would be a boon because it’s the easiest system to study, and we’d have the best chance of resolving features on an orbiting planet.
Just being able to determine that life exists there would be momentous. Because even if we find life on Mars, it won’t really prove that life isn’t a unique event, because it could be that bombardments polluted both planets with any life that evolved on either one. Perhaps repeatedly over millions of years.
But if life is found in another star system, then we will have very good evidence that it can appear spontaneously and repeatedly. And if that’s the case, then the universe is alive. There is life everywhere, in varying stages of evolution. We might even be the only technologically advanced civilization within our light sphere, but there could still be life almost everywhere.
As for how big the universe is, the only facts we have that really allow us to estimate it are that within range of our vision it is isotropic, and showing no signs of any kind of boundary condition or change in distribution patterm of the galaxies and clusters. The other is that recent measurements show the universe’s topology to be extremely flat. Since there is no real reason for it to be flat, the other explanation is that it is so gigantic that whatever curvature there is, is too small to be measured within our own range of measurement.
>You were studying astronomy in the first second of the Universe?
Yes! It’s true! When I was taking astronomy classes, the Universe was less than a second old! Well, somewhere it was.
>The set of prime numbers is infinite, and there is one even prime number (2), so the odds that a prime number is even are not zero, but there’s only one even prime number. It gets less and less likely that we’re alone in the universe as the number of stars goes up, but it’s still possible.
Gee. I’m just sure there’s something wrong with your logic, but I don’t know what it is.
There are two ways to think about the scientific findings about the universe. One is more literal - the discoveries are this and that and the other, and the consequences have to be so and so. The other way is to worry that current scientific findings are sufficiently wrong that the conclusions are unwarranted, because we’re on the wrong track somehow. I propose that only a sense of history and of humor enable one to work properly with this way of thought.
A century ago Lord Kelvin demonstrated that the Earth couldn’t be many millions of years old, let alone billions, because its heat capacity and its rate of loss of thermal energy would have cooled the interior to a much lower temperature than we know exists. He was unappologetic and stern about this and his wrath was hard on younger scientists who proposed evidence of the Earth’s greater age. Trouble was, Kelvin did not appreciate the warming effect of atomic fission contributing to Earth’s temperature. So, he missed something, and headed off in the wrong direction. We can only be stern about the truths we were correct in finding, right? I guess I’m saying that, since the canals and cities on Mars were reasonable a while ago, I can’t have total confidence they won’t be again. Now, I know what Mars looks like up close, I’ve seen Spirit and Opportunity photos. What I’m really getting at is that there will be surprises, and they will be surprising.
Very cool. Let’s get cracking on building a FTL drive, and once we get there let’s all try, seriously try, not to screw up Nova Terra like we’ve screwed up Earth.
Cochrane? Zefrem Cochrane? Line 2.
Oh, Gawd. Ever had a conversation with a mind worm? Talk about boorish behavior!
Here’s another one. We know you can’t travel at speeds faster than c, the limiting relative velocity between objects that have mass. The so-called “speed of light”, as if light per se was somehow important in all this.
So, this absolutely and inflexibly rules out, say, a weekend jaunt to Alpha Centauri’s planets. To think otherwise you’d have to misunderstand physics, you’d have to be just plain incorrect.
But look at this in the historical perspective. It’s only been a century that the above statements about relative velocity were clear and true, or more accurately were the conventional wisdom.
So, pretend to be ageless, and think about whether to believe faster-than-c travel is possible. You would have spent all the millenia prior to 1905 thinking, sure, why wouldn’t it be possible, you keep going faster and faster until you’re going faster than c. Then, for the last about 103 years, you’re supposed to think otherwise. Now, ask yourself, prevailing opinion has only leaned this way for the last 100 out of all those thousands of years. Why should I be confident that it will continue to lean this way for the next 1000, let alone the next 1,000,000? And, in the grand scheme of things, what kind of miserable pittance is a wee tiny 1,000,000 years?
Forever is a long time for us not to change our minds.