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Tens of billions of potentially habitable, Earth-size planets in our galaxy

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Re: Tens of billions of potentially habitable, Earth-size planets in our galaxy

#61

Post by maaku »

gchokov wrote: post #42
nikcub wrote: post #35

I'm curious as to what is next, now that Kepler is dead what do we do to substantiate this data further? My impression is that there is not much more we can do to confirm outside of the statistical models giving us probabilities, it would take some much more advanced detection tech (or traveling there) to get further, which means we might be stuck at this point for a little while.

I guess pointing even more antennas to a star which is detected to have earth-like size and location (SETI like programs). With even larger telescopes - checking the light spectrum of the planet reflected light for chemical check of the planet (reflected light spectrum can show what the source is made from, to some extent).

We'd have to find them first.. Kepler was aiming at a distant part of the galaxy.

Re: Tens of billions of potentially habitable, Earth-size planets in our galaxy

#62

Post by maaku »

Pxtl wrote: post #54
unepipe wrote: post #29

Earlier quoted context omitted.

Honestly, I've come to disagree with the "paradox". The ability to send physical evidence of other intelligent life is based on a certain speed limit of the universe. So that doesn't serve as much of a lack of evidence. Habitable planets are too far apart for much interstellar travel to occur readily given that the speed limit is c. Beyond that, the power of a radio signal is inversely proportional to the square of t…

The Fermi Paradox doesn't necessarily say that intelligent life doesn't exist. The impossibility of interstellar travel is compatible with the Fermi paradox. The point is that if interstellar colonization is possible, the age of the universe practically requires galaxy-wide colonization as an inevitability. Yes, it would take millions of years to colonize an entire galaxy. Tens of millions, even. Guess what? 10 milli…

It goes beyond that. Even if interstellar travel is not plausible, you'd still expect to find solar systems completely transformed by intelligent life (think Dyson spheres, although maybe not so extreme). If interstellar travel were merely supremely difficult, then you'd expect regional clusters of stars exhibiting these properties. These would be bizarre astronomical oddities that we'd have likely noticed by now.

Re: Tens of billions of potentially habitable, Earth-size planets in our galaxy

#63

Post by repnescasb »

patmcc wrote: post #41
w_t_payne wrote: post #36

This raises the obvious question .... Where is everybody? It's like we were born on the Marie Celeste; a place that should clearly be brimming with intelligent life, yet appears (on the face of it) to be an empty desert. The more we learn that the extent to which the galaxy is chock-a-block with habitable worlds, yet apparently devoid of intelligent life, the more I get a truly creeped-out feeling that we are living…

I sometimes think the answer is both boring and sad: everybody is just really, really, unimaginably, far away. Even if we manage to continue for another 10,000 years without causing our own extinction, will we come up with anything capable of moving people even 10% of the speed of light? If we do, will we bother to go to the stars?

That. Why did I have to scroll down so far to find exactly what I was thinking all the time? I mean, I absolutely love Asimov and Mass Effect but they are entertainment stuff. The distances we are talking about here seem to be completely beyond everyone's mental reach. Even if we could upload ourselves into spacepods like Kurzweil suggests (or for that matter could just UDP our souls out into space) we would not break the speed of light - which makes interstellar travel possible but only in a very constraint range feasible. Plus the problem that during the four years it had taken me to get to Proxima Centauri, humanity on earth will probably have seen centuries pass...

Re: Tens of billions of potentially habitable, Earth-size planets in our galaxy

#64

Post by [deleted] »

gliese1337 wrote: post #51
thangalin wrote: post #48

Earlier quoted context omitted.

I was assuming conventional propulsion at 95% c. An Alcubierre warp field would be ideal, assuming the problems can be overcome: http://en.wikipedia.org/wiki/Alcubierre_drive#Difficulties http://arxiv.org/abs/1001.4960 http://arxiv.org/abs/1202.5708 I'd enjoy seeing your calculation of the number of years that would have passed on Earth for a round-trip of 100 light-years out.

You've seen it. 210.52 years. The passengers on the ship should only experience 65.7 years- (210.52)sqrt(1-.95^2). Hence the famous twin paradox- the twin who goes on a relativistic trip comes back younger than the one who stayed behind. What you calculated was how much time would pass on Earth for a trip that took 100 years and 100 light-years from the perspective of the people on the ship , which is not generally w…

[deleted]

Re: Tens of billions of potentially habitable, Earth-size planets in our galaxy

#65

Post by repnescasb »

codeboost wrote: post #34
marcosdumay wrote: post #22

Earlier quoted context omitted.

Probably, nothing changes untill we start communicating with them, what may take a while. If we start feeling less significant, well, list that in the benefits... But I doubt it'll happen. Rationaly, we should start looking hard for the explanation to Fermi's Paradox. Since it's not in our past, it must be in our future, what's very bad. But we are not rational, so we probably won't.

So we meet the aliens, we communicate with them, we become friends, they share a bunch of technological discoveries with us.. Then what ? We travel some more ? If we can travel parsecs to meet them, wouldn't we be supremely technologicall advanced ? I mean, the human race is pretty technologically advanced today, too advanced actually and it's hurting us as much as it's helping. Will we some day realise that it is of…

Renouncing technology you say... Also Medicine? If not so, overpopulation would soon become a problem and if by then they still don't know how to colonize further into space they face a serious problem.

Re: Tens of billions of potentially habitable, Earth-size planets in our galaxy

#66

Post by thangalin »

gliese1337 wrote: post #51
thangalin wrote: post #48

Earlier quoted context omitted.

I was assuming conventional propulsion at 95% c. An Alcubierre warp field would be ideal, assuming the problems can be overcome: http://en.wikipedia.org/wiki/Alcubierre_drive#Difficulties http://arxiv.org/abs/1001.4960 http://arxiv.org/abs/1202.5708 I'd enjoy seeing your calculation of the number of years that would have passed on Earth for a round-trip of 100 light-years out.

You've seen it. 210.52 years. The passengers on the ship should only experience 65.7 years- (210.52)sqrt(1-.95^2). Hence the famous twin paradox- the twin who goes on a relativistic trip comes back younger than the one who stayed behind. What you calculated was how much time would pass on Earth for a trip that took 100 years and 100 light-years from the perspective of the people on the ship , which is not generally w…

I found the source of my confusion.

The post I replied to stated, "I don't know how much time would have passed on Earth though." You stated I calculated "how much time would pass on Earth."

The OP was wondering, "if a person on a ship visited a star 100ly away, how much time would have passed on Earth when they returned?"

However, the OP was wondering about time frames in terms of a warp drive, rather than a conventional almost-light-speed drive. Take my upvotes. :-)

Re: Tens of billions of potentially habitable, Earth-size planets in our galaxy

#67

Post by ceejayoz »

macspoofing wrote: post #57
Diederich wrote: post #13

In my mind, Fermi's Paradox looms very large. http://en.wikipedia.org/wiki/Fermi_paradox

Perhaps most (all?) advanced civilizations annihilate themselves (or get annihilated) before they have a chance to colonize other worlds?

That's one of many theories. One of the other popular ones is that we're in some sort of galactic natural park until we're ready to cope with joining the civilized folks.

Re: Tens of billions of potentially habitable, Earth-size planets in our galaxy

#68

Post by unepipe »

Pxtl wrote: post #54
unepipe wrote: post #29

Earlier quoted context omitted.

Honestly, I've come to disagree with the "paradox". The ability to send physical evidence of other intelligent life is based on a certain speed limit of the universe. So that doesn't serve as much of a lack of evidence. Habitable planets are too far apart for much interstellar travel to occur readily given that the speed limit is c. Beyond that, the power of a radio signal is inversely proportional to the square of t…

The Fermi Paradox doesn't necessarily say that intelligent life doesn't exist. The impossibility of interstellar travel is compatible with the Fermi paradox. The point is that if interstellar colonization is possible, the age of the universe practically requires galaxy-wide colonization as an inevitability. Yes, it would take millions of years to colonize an entire galaxy. Tens of millions, even. Guess what? 10 milli…

Damn, thank you for the informative response! This makes more sense, I misunderstood the Fermi paradox.

Re: Tens of billions of potentially habitable, Earth-size planets in our galaxy

#69

Post by unepipe »

maaku wrote: post #62
Pxtl wrote: post #54

Earlier quoted context omitted.

The Fermi Paradox doesn't necessarily say that intelligent life doesn't exist. The impossibility of interstellar travel is compatible with the Fermi paradox. The point is that if interstellar colonization is possible, the age of the universe practically requires galaxy-wide colonization as an inevitability. Yes, it would take millions of years to colonize an entire galaxy. Tens of millions, even. Guess what? 10 milli…

It goes beyond that. Even if interstellar travel is not plausible, you'd still expect to find solar systems completely transformed by intelligent life (think Dyson spheres, although maybe not so extreme). If interstellar travel were merely supremely difficult, then you'd expect regional clusters of stars exhibiting these properties. These would be bizarre astronomical oddities that we'd have likely noticed by now.

I'd still maintain we simply can't detect it.

Re: Tens of billions of potentially habitable, Earth-size planets in our galaxy

#70

Post by samoht »

1/5 seems to be the accepted number doing the rounds, but there must be other factors to consider too - I'm sure this number is still overoptimistic?

For example..how many of these habitable exoplanets also do the following earth things

1. Rotate around their axis as opposed to having one side facing the star.

2. have a stabilising moon to stop them from wobbling about.

3. Also how many of these exo solar sytems similarly have heavier elements and have evolved from spent star dust - using spent supernova explosions? To have enough water you need H and enough O

Some other important considerations that should perhaps be factored in?

The Earth went through a couple of "snowball-earth events" which resulted in a healthy % of oxygen being made available in the atmosphere.

We also have an outerlying and right-sized Jupiter to sweep away most of the asteroids and space debris.

Even with all the luck in the world, intelligent life only involved in the last million years of our 4 billion year plus Earth history... and we needed an asteroid, the right size again, to wipe out the dominant dinosaurs so that the evolutionary stage was set for our homo sapien species.

How much of this is repeatable?

We may indeed be the only intelligent life in our galaxy.

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