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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

#51

Post by gliese1337 »

thangalin wrote: post #48
gliese1337 wrote: post #45

Earlier quoted context omitted.

That's not how Alcubierre-derived warp fields work. The time inside a warp bubble is predicted to remain synchronized with the time in the originating frame. Thus, if your warp bubble goes at .95c, it'll take you 105.26 years one way, 210.52 going there and back. And I'm sceptical of your calculation, anyway. From Earth's unchanging perspective, if your are going at .95c in a conventional manner relative to Earth, Ea…

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 what people mean when they say that a star is 100ly away.

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

#52

Post by gliese1337 »

dionidium wrote: post #25
VLM wrote: post #17

Earlier quoted context omitted.

"Spiritually, economically?" Community norms would be an interesting dynamic. Some groups of humans like to conform more than others. What does equal rights for beings with different numbers of tentacles mean to us? Humans think its hilarious good time to fight and kill each other over multinational corporations "owning" teams of grown men playing childrens ball games, so if you think humans aren't going to kill each…

Humans think its hilarious good time to fight and kill each other over multinational corporations "owning" teams of grown men playing childrens ball games... This is obviously tangential to your point, but it doesn't make you sound smarter or more evolved when you talk this way about sports. This sort of stuff is just tiring. As a software developer in one of the cities that sent a team to the World Series this year,…

In general, I agree, but I think it does serve a valid rhetorical point in this case- i.e., that is the way in which we are likely to view a lot of the weird, different, unexpected practices of an alien culture. And yet, there will be people who embrace those things in all seriousness.

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

#53

Post by yongjik »

ceejayoz wrote: post #33
lxmorj wrote: post #30

Earlier quoted context omitted.

Don't Earth-sized moons of gas-giants have a few others problems? Less consistent weather patterns due to a more complicated relationship with the sun, stripping of the atmosphere due to gas giants gravity, and crazy huge tidal forces from the same.

I'm not an expert, so take these with a grain of salt. There are plenty of spots on Earth with unusual weather patterns (not to mention extremophiles). I'm not sure what sorts of weather changes a gas giant moon would see but I'd imagine they're surmountable via evolution. Titan has a nice atmosphere, so it's possible for a gas giant moon to retain one. Gravitational force diminishes pretty quickly with distance, so…

Tidal force can be a blessing instead. Some says that plate tectonics plays a vital role in making Earth a habitable planet. It requires continuous source of heat from inside, which is supplied by radioactive elements[1] on Earth, but in a gas giant moon, tidal force could play the same role.

[1]: (Off-topic) The fact that our whole planet's life basically survived thanks to the gigantic amount of radioactivity buried inside, hot enough to keep the whole planet's core molten for 4.6 billion years, gives me endless amusement whenever I see someone ranting about how radioactivity has no place in nature and is a deadly scourge we're inflicting on Earth.

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

#54

Post by Pxtl »

unepipe wrote: post #29
Diederich wrote: post #13

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

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 million years is only 0.1% of the age of the universe. So if one civilization develops interstellar colonization, they experience geometric growth and claim the entire galaxy.

So either there is no civilization that has a 0.1% lead on us (which is statistically absurd if Earth-like planets are common) or interstellar colonization is impossible.

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

#55

Post by Pxtl »

VladRussian2 wrote: post #40
Diederich wrote: post #13

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

The Fermi paradox is "why a highly developed civilization isn't behaving like a Western colonialists or tourists toward primitive natives of some remote wilderness".

The universe is old. If habitable planets are common, then it's functionally inevitable that intelligent life exists with a billion year head start on us.

Would they eschew expansionism? Maybe. Would they always eschew it 100% of the time? Definitely not. And this is a Darwinean process - the ones that decided to stay home are the ones you don't meet.

And they've had a billion years to change their minds. Consider that the likelihood is numerous billion-year-head-starts, one species would inevitably try it.

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

#56

Post by VladRussian2 »

Pxtl wrote: post #55
VladRussian2 wrote: post #40

Earlier quoted context omitted.

The Fermi paradox is "why a highly developed civilization isn't behaving like a Western colonialists or tourists toward primitive natives of some remote wilderness".

The universe is old. If habitable planets are common, then it's functionally inevitable that intelligent life exists with a billion year head start on us. Would they eschew expansionism? Maybe. Would they always eschew it 100% of the time? Definitely not. And this is a Darwinean process - the ones that decided to stay home are the ones you don't meet. And they've had a billion years to change their minds. Consider th…

i'm not saying that they wouldn't pursue expansionism. A half-billion years ago they could have had a thriving colony on our planet. And, as you said, there is a plenty of time to change their mind, literally, and bodies, so planet surface existence isn't a key anymore, or at least it isn't a big deal to let go the planet which has potential for development of new civilization. We're just so low on the development ladder, that we're a national park, designated wilderness, off-limit for the ones who can reach us.

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

#57

Post by macspoofing »

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?

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

#58

Post by macspoofing »

lupatus wrote: post #43
codeboost wrote: post #6

But let's say what we really hope for is true. What if we somehow discover that a large number of these planets are teaming with life ? What then ? How would that help us ? Spiritually, economically ? Wouldn't that make us feel even less significant ? I'm just wondering, why are we hoping there is life out there and what would we do if we find it ?

"... and what would we do if we find it ?" Grill it. Even if it can talk to us. In all sincerity, that's what I honestly think will happen. Humans are the apex predators of Earth. Give us starships and we would be the apex predators of the galaxy in short order. For tens to hundreds of thousands of years, there have been no creatures on Earth about which some human didn't think, "I wonder what that tastes like?" For…

>Humans are the apex predators of Earth.

Probably most advance life would have evolved from predators. If you look at earth, the most intelligent animals are either predators or some sort of scavenger-predator hybrid. Which makes sense, predators need intelligence, cunning, sometimes pack awareness, to bring down prey. They need to be at the top or near the top of the food chain to devote some time to pursuits other than not being eaten.

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

#59

Post by radley »

Tuna-Fish wrote: post #14
JonSkeptic wrote: post #2

>One in five stars in our galaxy like the Sun have planets about the size of Earth and a surface temperature conducive to life That is a considerable claim that jars with most of the astronomical data I've seen. 1 in 5 is far more probable, perhaps an order of magnitude more probable than I've previously heard. Does anyone have studies that corroborate their claim? [EDIT] Later in the article data is cited that more…

> astrological UGHH. Astro nomical . The previous studies have mostly been lower bounds, not attempts to estimate the most likely count. We are still essentially terrible at locating earth-sized planets in earth-like orbits, we are much better at finding larger planets in closer orbits. Because of this, most of the planets that we do find are larger and/or closer, however, this obviously should not be used to deduce…

Psychics at Cal Tech...

http://www.youtube.com/watch?v=M3DoDMfDa_Q

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

#60

Post by maaku »

JonSkeptic wrote: post #2

>One in five stars in our galaxy like the Sun have planets about the size of Earth and a surface temperature conducive to life That is a considerable claim that jars with most of the astronomical data I've seen. 1 in 5 is far more probable, perhaps an order of magnitude more probable than I've previously heard. Does anyone have studies that corroborate their claim? [EDIT] Later in the article data is cited that more…

Our current methods of observation are resolution limited and have huge, huge blind spots. When you correct for that, you get the "1 in 5" number.
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