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

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

#41

Post by Jweb_Guru » Thu, Jul 23, 2015, 5:09 PM UTC

camikazeg wrote: post #34

uptown wrote: post #19

Earlier quoted context omitted.

Read: "Where are all the aliens?" http://qz.com/452452/where-are-all-the-aliens/ "We’re rare, we’re first, or we’re fucked."

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.

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

#42

Post by king_magic » Thu, Jul 23, 2015, 5:10 PM UTC

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

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

#43

Post by lucozade » Thu, Jul 23, 2015, 5:10 PM UTC

mentos wrote: post #32

niels_olson wrote: post #23

> 1,400 light-years away Very cool that we can find it, but I don't think we'll be visiting this one any time soon...

http://www.universetoday.com/15403/how-long-would-it-take-to...

So best case about 28,000 years.

Which is a bugger as I'm out that week.

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

#44

Post by Sharlin » Thu, Jul 23, 2015, 5:12 PM UTC

dr_zoidberg wrote: post #36

peeters wrote: post #20

Earlier quoted context omitted.

One thing to keep in mind is that there is one thing that happens with exoplanets that can never happen with Pluto: the planet can pass between its star and us (i.e. eclipse the star). This gives a lot of information about the planet's composition, because light from the star will scatter/change color according to the planet's composition. See this image: http://seagerexoplanets.mit.edu/images/transitschematic.gif .…

As I understand, star transits by Pluto helped to better estimate its size before NH. But as you said, it's complicated to get a full spectrographic analisys of its atmosphere this way. Kepler is a mission that mostly works with photometric measurements of planet transits in front of their stars.

And indeed the fact that the observed transits were "fuzzy" told us that Pluto has a (very tenuous) atmosphere. Indeed, Pluto's diameter had considerable uncertainty before New Horizons arrived due to this (unlike Charon's whose transits were always tack sharp.)

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

#45

Post by pxndx » Thu, Jul 23, 2015, 5:12 PM UTC

phkahler wrote: post #38

How big is it? They have 2 numbers: >> Kepler-452b is 60 percent larger in diameter than Earth and is considered a super-Earth-size planet. And then: >> Kepler-452 is 6 billion years old, 1.5 billion years older than our sun, has the same temperature, and is 20 percent brighter and has a diameter 10 percent larger. I noticed the lack of "b" on that second one, but they seem to be talking about a single planet.

The second reference talks about the star, which is named Kepler-452.

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

#46

Post by stephengillie » Thu, Jul 23, 2015, 5:12 PM UTC

phkahler wrote: post #38

How big is it? They have 2 numbers: >> Kepler-452b is 60 percent larger in diameter than Earth and is considered a super-Earth-size planet. And then: >> Kepler-452 is 6 billion years old, 1.5 billion years older than our sun, has the same temperature, and is 20 percent brighter and has a diameter 10 percent larger. I noticed the lack of "b" on that second one, but they seem to be talking about a single planet.

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% brighter, but the same temperature, does that mean it is burning fuel 20% faster, and will enter its later stages earlier?

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

#47

Post by BWStearns » Thu, Jul 23, 2015, 5:14 PM UTC

phkahler wrote: post #38

How big is it? They have 2 numbers: >> Kepler-452b is 60 percent larger in diameter than Earth and is considered a super-Earth-size planet. And then: >> Kepler-452 is 6 billion years old, 1.5 billion years older than our sun, has the same temperature, and is 20 percent brighter and has a diameter 10 percent larger. I noticed the lack of "b" on that second one, but they seem to be talking about a single planet.

Kepler names are numbers for stars and numbers followed by a letter for planets. 452 -> star, 452b -> that star's second planet.

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

#48

Post by verytrivial » Thu, Jul 23, 2015, 5:14 PM UTC

peeters wrote: post #20

jpreiland wrote: post #10

To rephrase another comment in the other submission - how do we know/can we infer so much about a planet so far away when we are just now getting reasonable pictures of Pluto? Looking at the images (aside from the artist interpretation), it looks like they're just guessing based on size and location?

One thing to keep in mind is that there is one thing that happens with exoplanets that can never happen with Pluto: the planet can pass between its star and us (i.e. eclipse the star). This gives a lot of information about the planet's composition, because light from the star will scatter/change color according to the planet's composition. See this image: http://seagerexoplanets.mit.edu/images/transitschematic.gif .…

Indeed this is exactly what New Horizons did very recently. After shooting past Pluto, the probe spun around to view it with the sun behind it. http://pluto.jhuapl.edu/Multimedia/Science-Photos/image.php?...

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

#49

Post by coldpie » Thu, Jul 23, 2015, 5:15 PM UTC

stephengillie wrote: post #46

phkahler wrote: post #38

How big is it? They have 2 numbers: >> Kepler-452b is 60 percent larger in diameter than Earth and is considered a super-Earth-size planet. And then: >> Kepler-452 is 6 billion years old, 1.5 billion years older than our sun, has the same temperature, and is 20 percent brighter and has a diameter 10 percent larger. I noticed the lack of "b" on that second one, but they seem to be talking about a single planet.

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.

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

#50

Post by psykovsky » Thu, Jul 23, 2015, 5:15 PM UTC

phkahler wrote: post #38

How big is it? They have 2 numbers: >> Kepler-452b is 60 percent larger in diameter than Earth and is considered a super-Earth-size planet. And then: >> Kepler-452 is 6 billion years old, 1.5 billion years older than our sun, has the same temperature, and is 20 percent brighter and has a diameter 10 percent larger. I noticed the lack of "b" on that second one, but they seem to be talking about a single planet.

Kepler-452 is the parent star around which Kepler-452b is orbiting.