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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

#41

Post by patmcc »

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?

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

#42

Post by gchokov »

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).

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

#43

Post by lupatus »

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 Pete's sake, our ancestors ate giant, super-fast cave bears to extinction using little more than sharp sticks. Eskimos hunt huge multi-ton whales in the open ocean in flimsy canoes with hooked spears.

Sure alien life will be examined in labs and some will go to zoos. But, eventually, Monsanto would sell you Venusian steaks with a side of Martian scrapple. And, the most telling thing is, I would buy some and eat it. My mouth is already watering.

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

#44

Post by melling »

thangalin wrote: post #27
dm2 wrote: post #16

Earlier quoted context omitted.

We're (other people, not me) at least working on it. http://www.nasa.gov/centers/glenn/technology/warp/warp.html http://en.wikipedia.org/wiki/100_Year_Starship http://en.wikipedia.org/wiki/Faster-than-light If they're successful and you warp to a planet that's 100 light years away then warp back, I don't know how much time would have passed on Earth though.

Depends on their velocity. Assuming a warp of 95% the speed of light, then ~640 years (~320 years one direction). See: http://www.fourmilab.ch/cship/timedial.html http://physics.stackexchange.com/questions/31105/how-to-calc... http://www.phy.olemiss.edu/HEP/QuarkNet/time.html t / 2 = 100 / (1 - (0.95 * c)^2 / c^2)^(1/2) Where t is the time for a one-way trip and c is the speed of light.

A lot sure will have changed. Imagine going back to the year 1370 and arriving today. Before Kepler, Galileo, before the discovery of America, or the printing press. Heck, a lot can go wrong in 640 years too.

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

#45

Post by gliese1337 »

thangalin wrote: post #27
dm2 wrote: post #16

Earlier quoted context omitted.

We're (other people, not me) at least working on it. http://www.nasa.gov/centers/glenn/technology/warp/warp.html http://en.wikipedia.org/wiki/100_Year_Starship http://en.wikipedia.org/wiki/Faster-than-light If they're successful and you warp to a planet that's 100 light years away then warp back, I don't know how much time would have passed on Earth though.

Depends on their velocity. Assuming a warp of 95% the speed of light, then ~640 years (~320 years one direction). See: http://www.fourmilab.ch/cship/timedial.html http://physics.stackexchange.com/questions/31105/how-to-calc... http://www.phy.olemiss.edu/HEP/QuarkNet/time.html t / 2 = 100 / (1 - (0.95 * c)^2 / c^2)^(1/2) Where t is the time for a one-way trip and c is the speed of light.

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, Earthlings will see your trip as taking the same 210.52 years. Time dilation will only affect the time that passes for the people on board, which will make it seem shorter, not longer. So, really, if your warp drive can't break c, it's better from the passengers' perspective not to use one. This is explained in the StackExchange article you linked to- you put the factor of gamma in the wrong spot (http://physics.stackexchange.com/questions/31105/how-to-calc...).

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

#46

Post by splitrocket »

Diederich wrote: post #13

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

As far as we understand physics, actually traveling through interstellar medium is very very slow. Light itself takes next to forever to go from here to there. Most likely, intelligent species realized it was much more fun to explore inner space rather than outer space. I'd wager we won't see them: they've surrounded their local stars with Dyson Spheres, communicating with highly directed, encrypted, massively wide-band, low power communications that would look rather like background radiation unless they were pointed right at us and we were meters away.

Think about how important latency is to high frequency traders. In an information ecosystem, the laws of physics become paramount: latency and bandwidth are king. Physically being far from the action is essentially choosing to banish yourself to the hinterlands when everything exciting/valuable is happening at the hot core as close to the ball of fusion in the middle.

update: Thinking further, if anyone has in fact developed FTL, you can bet your ass they don't want anyone else to have it. In space, Sir Isaac Newton is the deadliest MotherF&@$%^# around. A baseball going 99% C is a weapon of mass destruction (http://what-if.xkcd.com/1/), much less a ship, which would essentially be a planet destroyer you literally couldn't see coming.

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

#47

Post by gliese1337 »

devx wrote: post #24
melling wrote: post #11

Unfortunately every single one of them is unreachable within several lifetimes. We're going to be pretty much trapped in our solar system until we try to solve some of the more difficult problems.

We can visit up to a few tens of solar systems in a few hundred years, if we could develop a space-ship powered by a black hole, antimatter, or some advanced or innovative hybrid fusion engine (there were talks about one from the 60's around here). Colonizing a few solar systems out of the 100 or so we can visit with such a ship that reaches a large fraction of the speed of light, should be "enough" for the next 1,00…

Black holes naively look like a great way to get 100% mass-to-energy conversion, but when you really look into it, things aren't that great. To get more energy output, you want the black hole to be small (to have a high curvature in the event horizon); but, black holes that are small enough to give reasonable output are also too small (smaller than an atom) to reasonably feed new matter into.

Meanwhile, black holes big enough to feed fuel into have an incredibly terrible power-to-weight ratio.

And that's assuming that black holes even work the same way when they get that small. Quantum gravity could easily screw things up even more (or make them more convenient; who knows?)

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

#48

Post by thangalin »

gliese1337 wrote: post #45
thangalin wrote: post #27

Earlier quoted context omitted.

Depends on their velocity. Assuming a warp of 95% the speed of light, then ~640 years (~320 years one direction). See: http://www.fourmilab.ch/cship/timedial.html http://physics.stackexchange.com/questions/31105/how-to-calc... http://www.phy.olemiss.edu/HEP/QuarkNet/time.html t / 2 = 100 / (1 - (0.95 * c)^2 / c^2)^(1/2) Where t is the time for a one-way trip and c is the speed of light.

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.

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

#49

Post by repnescasb »

thangalin wrote: post #27
dm2 wrote: post #16

Earlier quoted context omitted.

We're (other people, not me) at least working on it. http://www.nasa.gov/centers/glenn/technology/warp/warp.html http://en.wikipedia.org/wiki/100_Year_Starship http://en.wikipedia.org/wiki/Faster-than-light If they're successful and you warp to a planet that's 100 light years away then warp back, I don't know how much time would have passed on Earth though.

Depends on their velocity. Assuming a warp of 95% the speed of light, then ~640 years (~320 years one direction). See: http://www.fourmilab.ch/cship/timedial.html http://physics.stackexchange.com/questions/31105/how-to-calc... http://www.phy.olemiss.edu/HEP/QuarkNet/time.html t / 2 = 100 / (1 - (0.95 * c)^2 / c^2)^(1/2) Where t is the time for a one-way trip and c is the speed of light.

I wonder how much of a perception you have of this trip though... if you're just radiation floating through space you might just was well think you just "instantly jumped" as soon as you arrive and "assemble" (whatever that process may consist of)

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

#50

Post by gliese1337 »

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…

Titan is a good existence proof that moons can retain dense atmospheres, but the exact reasons for it are complicated. Why don't any of Jupiter's large moons have dense atmospheres? Maybe radiation around Jupiter causes more atmosphere loss. Maybe it's just random. There's actually an argument that gas giant moons might be more capable of retaining atmospheres, all other things being equal, than equivalent free bodies, because gas molecules they lose will remain in orbit about the gas giant and eventually re-join the moon.

So, moons with atmospheres are clearly possible, but it's very unclear how frequent they might be, or how their prospects compare to those of regular planets.

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