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NASA’s Kepler Mission Discovers Bigger, Older Cousin to Earth

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Re: NASA’s Kepler Mission Discovers Bigger, Older Cousin to Earth

#61

Post by DanAndersen »

sktrdie wrote: post #18

Meh, given the hype for this press-release, I was hoping for something more extraordinary frankly. Not that finding other exoplanets isn't amazing, just that we're all waiting to find out whether we are alone or not in the universe. Finding out that other advanced civilizations exist out there would bring such an amazing new meaning to life. If I could ask for one wish, it would be to find out if we're alone or not.…

I can understand the disappointment. It's helpful to always keep in mind that when it comes to discoveries, it's easy to hype ourselves up excessively. Recognize that the PR arms of scientific organizations and universities are also somewhat responsible.

I find it helpful to remember that any Big Announcement like definite signs of life or advanced alien civilizations or asteroids hurtling toward Earth wouldn't be in such a small-scale announcement. You'd have the President appearing on TV or something.

Re: NASA’s Kepler Mission Discovers Bigger, Older Cousin to Earth

#63

Post by TheOtherHobbes »

Jweb_Guru wrote: post #41
camikazeg wrote: post #34

Earlier quoted context omitted.

Can't interstellar travel just be impossible?

Or at least, highly energy-intensive and fragile (due to problems like cosmic radiation) to the point of impracticality, particularly when it comes to something like panspermia (or, for that matter, sending high-energy signals directly at a planet that doesn't detectably have life from the perspective of the originating species). This possibility is not weighted nearly highly enough in most analyses.

Interstellar travel is perfectly possible if you're not in a hurry.

Assuming there's no way to sidestep GR, the real problem is the human lifespan (and attention span.)

If our culture moved at 0.1% of the current rate and we lived a thousand times as long, a 1400 year round trip wouldn't be problematic.

It's possible to imagine low-energy lifeforms that move that slowly. But they wouldn't be looking for Earth-like planets to colonise - they'd be looking for much colder and more stable locations.

And we wouldn't be looking for the right spectroscopic signals to give them away, because we don't know what they are.

Re: NASA’s Kepler Mission Discovers Bigger, Older Cousin to Earth

#64

Post by phantarch »

qrendel wrote: post #24
phantarch wrote: post #5

At 2 billion years older than Earth, I can't begin to imagine what kinds of things could possibly be living on this planet. Given, of course, that it's got the right ingredients for life to arise. What if it's suffered huge extinctions recently? What if there's a domineering species out to conquer the planet just like humans? What if there's a society there more sophisticated than us? It's a very exciting discovery.

I propose it's unlikely that any technological civilizations more advanced than our own have existed on this planet in the past few billion years, otherwise some subgroup of their species would likely have seeded the local universe with life (it's only ~1400 lightyears away) and they would be here instead of us. Unless of course the panspermia hypothesis is correct and that is indeed where life on Earth came from.

As a counter point, it's always possible that a civilization that developed past where we are now would have been masterful at space travel, but not advanced enough to completely figure out a 1400 light year long journey. We're still having hard times figuring how to get squishy meat sacks to Mars without being irradiated to death or creating a launch vehicle made of lead. Besides the engineering problems there's the social cost of a venture like that. Unless their societies would be structured in a wholly different way (which is likely) then there is significant political and social momentum that would need to go behind a project like a mission where the minimum acknowledgement time of success is 2800 years away. There's plenty of time to go extinct or make yourself die off.

Re: NASA’s Kepler Mission Discovers Bigger, Older Cousin to Earth

#65

Post by meatysnapper »

qrendel wrote: post #24
phantarch wrote: post #5

At 2 billion years older than Earth, I can't begin to imagine what kinds of things could possibly be living on this planet. Given, of course, that it's got the right ingredients for life to arise. What if it's suffered huge extinctions recently? What if there's a domineering species out to conquer the planet just like humans? What if there's a society there more sophisticated than us? It's a very exciting discovery.

I propose it's unlikely that any technological civilizations more advanced than our own have existed on this planet in the past few billion years, otherwise some subgroup of their species would likely have seeded the local universe with life (it's only ~1400 lightyears away) and they would be here instead of us. Unless of course the panspermia hypothesis is correct and that is indeed where life on Earth came from.

Perhaps they were wiped out by a virulent disease contracted from an unexpectedly dirty telephone?

Re: NASA’s Kepler Mission Discovers Bigger, Older Cousin to Earth

#66

Post by Jweb_Guru »

TheOtherHobbes wrote: post #63
Jweb_Guru wrote: post #41

Earlier quoted context omitted.

Or at least, highly energy-intensive and fragile (due to problems like cosmic radiation) to the point of impracticality, particularly when it comes to something like panspermia (or, for that matter, sending high-energy signals directly at a planet that doesn't detectably have life from the perspective of the originating species). This possibility is not weighted nearly highly enough in most analyses.

Interstellar travel is perfectly possible if you're not in a hurry. Assuming there's no way to sidestep GR, the real problem is the human lifespan (and attention span.) If our culture moved at 0.1% of the current rate and we lived a thousand times as long, a 1400 year round trip wouldn't be problematic. It's possible to imagine low-energy lifeforms that move that slowly. But they wouldn't be looking for Earth-like pl…

The problem isn't just sending something (or someone) to another star (though it would take far longer than 1400 years with any currently plausible technology and energy expenditure). It's sending something accurately to another star (can't use too much energy adjusting course, since fractional additions to weight require tremendously more power) with a payload that's still operational by the time it gets there. Think about the myriad problems NASA probes have after just a relative handful of years or so in space.

Also worth noting is that all deep space missions thus far have had to rely on nuclear power, usually using 238-Pu with a half life of less than 90 years. With such technology, a well-shielded, self-correcting computer system traveling at reasonable speeds and energies could not survive too long because it would simply run out of power. AFAIK, workarounds for this rely on exotic power sources and unproven physics--it's entirely possible that these don't pan out, and this provides our "Great Filter."

Re: NASA’s Kepler Mission Discovers Bigger, Older Cousin to Earth

#67

Post by ringshall »

coldpie wrote: post #49
stephengillie wrote: post #46

Earlier quoted context omitted.

I think "Kepler-452" is the star, and "b" is the 2nd planet in the system. I'm not certain of their naming convention. Edit: Another poster says "b" is the 1st planet found in the system, regardless of position in the system. Earth is 12,742 km in diameter, so "b" must be 20,387 km in diameter. Our Sun is 1,391,684 km in diameter, so Kepler-452 must be 1,530,852 km in diameter. Since the star is 10% larger and 20% br…

>I think "Kepler-452" is the star, and "b" is the 2nd planet in the system. I'm not certain of their naming convention. Yep, you understand it correctly.

I'm not sure this is correct. According to one source[1],

"The name of a newly discovered exoplanet is dependant on the name of the star which it orbits and also if any other exoplanets orbiting the same host star have been discovered. The first exoplanet discovered around a star is given its host star name with ‘b’ appended. The next exoplanet discovered in the same system gets the letter ‘c’ appended and so on. Planets in multiple planet systems are always labelled b, c, d… in the order of discovery."

It's not clear to me why they would begin with 'b' instead of 'a', but basing the order of names on the order of discovery makes intuitive sense. The largest planets would presumably be discovered first, even though they may be in the middle zone of their systems (such as in the Solar System).

EDIT: Kepler-26[2] is an example of the named order not matching the distance from the star. The planets in that system, in order of distance from their star, are: d, b, c, e

[1] https://www.paulanthonywilson.com/blog/how-are-exoplanets-na...

[2] https://en.wikipedia.org/wiki/Kepler-26

Re: NASA’s Kepler Mission Discovers Bigger, Older Cousin to Earth

#68

Post by cbhl »

king_magic wrote: post #42

So wouldn't a good next step be to point a bunch of radio telescopes at this system and start listening?

IIRC, the amount of radio waves leaking from Earth into space has decreased substantially over the last few decades. I wouldn't be surprised if energy efficiency gets to the point where, if a foreign alien civilization notices radio waves from Earth, by the time they transmit a round-trip back at Earth we'll have long since stopped leaking terrestrial radio waves by accident into space.

Re: NASA’s Kepler Mission Discovers Bigger, Older Cousin to Earth

#69

Post by camikazeg »

TheOtherHobbes wrote: post #63
Jweb_Guru wrote: post #41

Earlier quoted context omitted.

Or at least, highly energy-intensive and fragile (due to problems like cosmic radiation) to the point of impracticality, particularly when it comes to something like panspermia (or, for that matter, sending high-energy signals directly at a planet that doesn't detectably have life from the perspective of the originating species). This possibility is not weighted nearly highly enough in most analyses.

Interstellar travel is perfectly possible if you're not in a hurry. Assuming there's no way to sidestep GR, the real problem is the human lifespan (and attention span.) If our culture moved at 0.1% of the current rate and we lived a thousand times as long, a 1400 year round trip wouldn't be problematic. It's possible to imagine low-energy lifeforms that move that slowly. But they wouldn't be looking for Earth-like pl…

1,400 light years/~45,000mph (the speed of New Horizons) = 23,844,146.8 years of travel time. I guess that wouldn't be impossible, but if you've got a ship that can last that long in interstellar space, then what do you need a planet for? Or for that matter, a star?

Re: NASA’s Kepler Mission Discovers Bigger, Older Cousin to Earth

#70

Post by cstross »

I want answers to three questions before I get excited:

1. Does it have active plate tectonics?

2. Does it have a working deep carbon cycle?

3. Has its atmosphere hung on to its hydrogen (that is, has it managed not to lose it all to high-altitude UV splitting and solar wind)?

If the answer to all three of those is "yes" then this suddenly gets a lot more interesting, whether or not we can see any free oxygen in the atmosphere. And while we won't be able to get answers to them using current technology, next-generation direct-observation planet seeking telescopes might be able to deliver within the 15-30 year time scale (if the astrophysicists I know are correct).

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