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

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

#181

Post by antognini » Thu, Jul 23, 2015, 9:27 PM UTC

phantarch wrote: post #177

antognini wrote: post #131

Earlier quoted context omitted.

If the planet is not transiting there are two other ways to detect it: radial velocity measurements, and direct imaging. In the radial velocity technique you measure the wobble of the star due to the gravitational pull of the planet. This also requires that the planet be somewhat edge-on, but the requirement isn't nearly as strict as with the transit method. The difficulty is that Earth size planets have very little…

What kind of resolution is possible with direct imaging at 1400 ly away? I would imagine that it's probably milliseconds of arc within the field of vision of any telescope, so how close could we actually look at the planet?

With adaptive optics it's possible to achieve resolutions down to ~30 milliarcseconds. At 1400 ly that would subtend a distance of 13 AU, so you wouldn't be able to find Earth-like planets. But even if it's theoretically possible to resolve 13 AU separations at 1400 ly, in practice the light from the star is so much brighter than the planet that it bleeds all over the image and completely washes out the reflected light of the star.

To do direct imaging you really need to look at systems near the Earth, maybe a few tens of ly away. Then you can separate the planet from the star by enough that you can hope to mask the light from the star and still be able to detect the planet.

To get some idea of the techniques required to do this, take a look here: http://astrobites.org/2013/06/09/lowest-mass-exoplanet-disco...

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

#182

Post by bpicolo » Thu, Jul 23, 2015, 9:29 PM UTC

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 : )

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

#183

Post by humbertomn » Thu, Jul 23, 2015, 9:31 PM UTC

It IS great news... But it's terrible to see the media here in Brazil going like "We're finally close to discover life in another planet" and things like that... And even worse, people sharing like crazy around the internet, without even reading it or trying to understand what really was discovered.

EDIT: typing error

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

#184

Post by unchocked » Thu, Jul 23, 2015, 9:32 PM UTC

pdonis wrote: post #172

phantarch wrote: post #64

Earlier quoted context omitted.

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…

> 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.

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

#185

Post by personlurking » Thu, Jul 23, 2015, 9:32 PM UTC

wmeredith wrote: post #89

qrendel wrote: post #24

Earlier quoted context omitted.

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.

Maybe they are here and it IS us?

https://www.youtube.com/watch?v=N8hEwMMDtFY

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

#186

Post by mratzloff » Thu, Jul 23, 2015, 9:33 PM UTC

ryangittins wrote: post #162

tatterdemalion wrote: post #110

Earlier quoted context omitted.

It seems like UDP is probably a better protocol for this use case.

I've got a really good joke about UDP, but you might not get it.

That's fine. I've got a great joke about TCP, and I'll just keep telling it to you until you get it. I'll just speak slower each time...

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

#187

Post by IndianAstronaut » Thu, Jul 23, 2015, 9:34 PM UTC

humbertomn wrote: post #183

It IS great news... But it's terrible to see the media here in Brazil going like "We're finally close to discover life in another planet" and things like that... And even worse, people sharing like crazy around the internet, without even reading it or trying to understand what really was discovered. EDIT: typing error

Life could mean anything though. It could be bacterial life or advanced life. This discovery doesn't show otherwise, but it does indicate that there are other places which could harbor earth like life.

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

#188

Post by IndianAstronaut » Thu, Jul 23, 2015, 9:36 PM UTC

pi-rat wrote: post #152

Now, if only NASA would announce that Kepler-452b is full of oil, we would have warp engines in under a decade.

Why go that far? Titan, Saturn's moon, is loaded with far more hydrocarbons than are available on Earth.

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

#189

Post by baby » Thu, Jul 23, 2015, 9:36 PM UTC

humbertomn wrote: post #183

It IS great news... But it's terrible to see the media here in Brazil going like "We're finally close to discover life in another planet" and things like that... And even worse, people sharing like crazy around the internet, without even reading it or trying to understand what really was discovered. EDIT: typing error

I thought that was why we come on website like HN, to get above the average kind of discussions. I don't think complaining about normal channels of discussion is really relevant.

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

#190

Post by unchocked » Thu, Jul 23, 2015, 9:41 PM UTC

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.