NASA’s Kepler Mission Discovers Bigger, Older Cousin to Earth • Hacker News Board

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

#201

Post by pdonis » Thu, Jul 23, 2015, 9:59 PM UTC

unchocked wrote: post #184

pdonis wrote: post #172

Earlier quoted context omitted.

> 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. But we've only been working on that for a few decades. 2 billion years is a lot longer. If there is a civilization there at all, it's extremely improbable that it hasn't figured out how to do exploration on a scale of thousands of light-years.

There's an implicit assumption running through most of this thread that if there's a civilization there, it's enjoyed 2 billion years of continuity. I suspect that's unlikely, even if there were advanced life there for 2 billion years.

> I suspect that's unlikely, even if there were advanced life there for 2 billion years.

Why do you think so? "Continuity" doesn't have to be having the same government or the same political structure, or even the same physical form (the article itself talks about uploads and nanomachines). It just means continuity of technological development. It doesn't have to mean steady progress either; our civilization hasn't had that, yet in ten millennia or so we have progressed from basic agriculture to space travel. For this planet, we're talking about two million millennia, or 200,000 times the time we've had. All the variables we've observed in our civilization's history become rounding error on that timescale.

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

#202

Post by morsch » Thu, Jul 23, 2015, 10:01 PM UTC

Cyph0n wrote: post #193

omonra wrote: post #179

Earlier quoted context omitted.

Was anybody but Arabs involved in the conquest of the early 7th century? Ie I'm sure other people took on Islam afterwards but he was talking about a specific point in history. We don't call the Spanish conquest of the Americas a Christian one even though they were Christians who ultimately converted everybody to Christianity.

Quite a few of the Prophet's companions were not Arabs, but yes the majority were. Nonetheless, it is more correct to identify as a Muslim before an Arab. What irritates me greatly is when historians refer to the Muslim scientists of the Islamic Golden Age as "Arabs", when most of them were not Arabs at all. It's such a simpleminded and sweeping generalisation that clearly shows the thoroughness of the so-called orie…

That seems like a silly thing to get greatly irritated about.

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

#203

Post by [deleted] » Thu, Jul 23, 2015, 10:05 PM UTC

[deleted]

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

#204

Post by danieltillett » Thu, Jul 23, 2015, 10:09 PM UTC

unchocked wrote: post #190

cstross wrote: post #70

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…

How would the physics of those three observations work, and what angular resolution would be required? I can see spectroscopy working for #3 and #2, #1 stumps me.

In theory #1 could be answered by looking for an atmosphere temperature that are similar to Earth’s despite being in an orbit that should make the planet cooler. If there is no plate tectonics then all the CO2 gets locked up in carbonates and the temperature falls (e.g. Mars) or you get a run away greenhouse like Venus. It is plate tectonics that have kept earth in the habitable zone. In theory we should be able to detect such a temp delta.

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

#205

Post by omonra » Thu, Jul 23, 2015, 10:12 PM UTC

Cyph0n wrote: post #193

omonra wrote: post #179

Earlier quoted context omitted.

Was anybody but Arabs involved in the conquest of the early 7th century? Ie I'm sure other people took on Islam afterwards but he was talking about a specific point in history. We don't call the Spanish conquest of the Americas a Christian one even though they were Christians who ultimately converted everybody to Christianity.

Quite a few of the Prophet's companions were not Arabs, but yes the majority were. Nonetheless, it is more correct to identify as a Muslim before an Arab. What irritates me greatly is when historians refer to the Muslim scientists of the Islamic Golden Age as "Arabs", when most of them were not Arabs at all. It's such a simpleminded and sweeping generalisation that clearly shows the thoroughness of the so-called orie…

I think it may be the preferred nomenclature in the Muslim world since all the people who were conquered are now Muslim - so they should have an easier time accepting the fact of being Islamicized as that's their culture now (whereas bringing up the fact that they were conquered by a foreign people might stir up tensions).

I agree with you about the second point. I guess it's due to the fact that they wrote in Arabic and many of the people they actually belonged to no longer exist (for example al-Khwārizm was from a Persian family but born in what is today Uzbekistan - I actually visited his hometown :)

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

#206

Post by omonra » Thu, Jul 23, 2015, 10:16 PM UTC

morsch wrote: post #202

Cyph0n wrote: post #193

Earlier quoted context omitted.

Quite a few of the Prophet's companions were not Arabs, but yes the majority were. Nonetheless, it is more correct to identify as a Muslim before an Arab. What irritates me greatly is when historians refer to the Muslim scientists of the Islamic Golden Age as "Arabs", when most of them were not Arabs at all. It's such a simpleminded and sweeping generalisation that clearly shows the thoroughness of the so-called orie…

That seems like a silly thing to get greatly irritated about.

Imagine if all the great Scottish scientists were referred to as 'the English'. That might piss some people off.

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

#207

Post by InclinedPlane » Thu, Jul 23, 2015, 10:21 PM UTC

toomuchtodo wrote: post #122

Gravityloss wrote: post #111

The significance is this: it's very likely that there are a lot more such planets a lot nearer to us. This is because Kepler can only detect planets which lie in the same plane as earth and the star so the planet occults the star. Assuming random distribution, there's probably thousand fold amount of off plane planets. There are 259 stars within about 30 light years. Communication could be conceivable with such dista…

> This is because Kepler can only detect planets which lie in the same plane as earth and the star so the planet occults the star. What would be necessary for a more comprehensive survey?

Likely something facilitating direct imaging, which would require canceling out almost all of the light from the parent star (diminishing it by a factor of at least 10^6:1).

While there are some techniques that could facilitate that (such as enormous star shades coupled with space telescopes) they wouldn't enable the sort of shotgun survey approach that Kepler has been able to do, but it would enable us to survey and extensively study stars one at a time for planets.

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

#208

Post by vectorjohn » Thu, Jul 23, 2015, 10:24 PM UTC

maaku wrote: post #144

vectorjohn wrote: post #117

Earlier quoted context omitted.

That's an unfounded presumption. It's like, nobody has considered that advanced life might not even feel a need to live on planets at all. It's expensive to get resources from, and there's a near limitless supply of easy to get smaller debris. Additionally, the difference a 2 billion year head start could make is hard to imagine. One thing that's not hard to imagine is that they don't live in meat bodies for most of…

We have sensitive telescopes. If there was life out there, we would have noticed. You would have astronomy conferences filled with people trying to figure out what all these weird spectra objects are, or trying to decipher all these structured radio observations.

What? No, absolutely no we would not just see them with sensitive telescopes. Perhaps, if you're thinking of some sort of interstellar space travel, maybe we'd see the engines? But no, even that seems unlikely.

Any space habitat of any plausible size will be completely undetectable, or at least indistinguishable from a planet. And I would think they'd be much smaller than that.

And structured radio? Lots of possible reasons not to see it. One, possibly not using radio. Two, encryption. Communication will likely look like noise. But even so, the distances involved means long range transmissions will need to be very directed and narrow beam. And even then, it's only a few light years before the signal is undetectable. I would suspect any really long distance communication would be bounced through relays. Also, why? You have to wait years for messages to go around. All of this means no, we're not likely to easily find stray radio signals.

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

#209

Post by InclinedPlane » Thu, Jul 23, 2015, 10:25 PM UTC

bpicolo wrote: post #182

guiomie wrote: post #165

"385-day orbit" ... Can't wait to have to take into consideration different "year" zone in my code.

seconds since January 1, 1970 on earth is still a valid strategy : )

Almost, but not quite.

While seconds since Jan 1, 1970 is a perfectly fine system, sadly unixtime has deviated from that simple definition, due to the introduction of leap-seconds.

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

#210

Post by evidencepi » Thu, Jul 23, 2015, 10:26 PM UTC

eastbayjake wrote: post #76

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.

It's jarring to think that if intelligent life were on Kepler 452-b and observing Earth, we're so far away that they would be seeing our "civilizations" in 615 AD: shrinking global population as the old Roman and Byzantine empires are overrun by barbarian hordes and Arab conquest, with some pockets of human progress in China. They would have no way of knowing that the descendants of those squabbling warlords just coo…

If they have the ability to telescope us before we do. They can probably guess that technology accelerates. In fact I feel more pessimistic of the human's future as we found more and more such older planets -- If their million or billion years older civilization cannot reach us, then we might not reach out that far as well in the next billion year, or ever.