APOD: Earth size Kepler 186f (2014 Apr 19)

[APOD Robot]

Earth size Kepler 186f

Explanation: Planet Kepler-186f is the first known Earth-size planet to lie within the habitable zone of a star beyond the Sun. Discovered using data from the prolific planet-hunting Kepler spacecraft, the distant world orbits its parent star, a cool, dim, M dwarf star about half the size and mass of the Sun, some 500 light-years away in the constellation Cygnus. M dwarfs are common, making up about 70 percent of the stars in our Milky Way galaxy. To be within the habitable zone, where surface temperatures allowing liquid water are possible, Kepler-186f orbits close, within 53 million kilometers (about the Mercury-Sun distance) of the M dwarf star, once every 130 days. Four other planets are known in the distant system. All four are only a little larger than Earth and in much closer orbits, also illustrated in the tantalizing artist's vision. While the size and orbit of Kepler-186f are known, its mass and composition are not, and can't be determined by Kepler's transit technique. Still, models suggest that it could be rocky and have an atmosphere, making it potentially the most Earth-like exoplanet discovered so far ...

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[bystander]

viewtopic.php?p=224141#p224141

[billytt26@gmail.com]

What an amazing discovery! Congratulations to Prof. Justin Crepp and colleagues. Exiting times for astrophysics. I hope there is much more follow up data from astronomers, mass, composition etc. These discoveries certainly put our little blue dot into perspective. Looking forward to JWST.
Regards, Bill Tate, Cyprus

[supamario]

Love the concept art. Very nice and detailed. Makes for a great desktop wallpaper too!

It makes me wonder - what if humans made the great trip to this very distant planet, only to find that there were a very small amount of very primitive native inhabitants. Extremely incredible discovery aside, do we say, Oh, its taken, and leave? assuming we could leave? or what if we were unable to leave..

[somebodyshort]

Kepler identifies planets by looking for planets transiting their star. I assume any planets that do not transit their star cannot be identified. That being the case I would think that Kepler can only find a small fraction of planets. Also it would have great difficulty identifying planets with long orbits simply because the time required is long, especially because of the need to make observations of more than one transit. Taking all of that into consideration, the number of planets in close proximity must be huge.

[Case]

It makes me wonder - what if humans made the great trip to this very distant planet, only to find that there were a very small amount of very primitive native inhabitants. Extremely incredible discovery aside, do we say, Oh, its taken, and leave?

Human behavior from the past suggest that such an encounter won't end well for the lesser developed civilization, unless future generations formalize some kind of Prime Directive before making contact.

[supamario]

It makes me wonder - what if humans made the great trip to this very distant planet, only to find that there were a very small amount of very primitive native inhabitants. Extremely incredible discovery aside, do we say, Oh, its taken, and leave?

Human behavior from the past suggest that such an encounter won't end well for the lesser developed civilization, unless future generations formalize some kind of Prime Directive before making contact.

Yes, and lets hope that if there is an advanced race out there, that they would consider the same thing for us, if the roles were reversed. Depending on how desperate the visiting race may be (ability for advanced travel may not equate to ability to solve all other problems), it may be hard to simply pass up on taking resources from a fresh new planet..

[JohnD]

Whoa! Whoa!
Read the blurb. "While the size and orbit of Kepler-186f are known, its mass and composition are not"
We have no idea if this planet even has an atmosphere, let alone one that could, theoretically, support life.
John

[Boomer12k]

"Mr. Sulu, give me warp six to Kepler 186f."
"Captain to crew: Our mission is to explore the region in and around the Kepler 186 system, looking for new life forms. We are finally going to see what is out there".


At 500 ly, I think it is going to be awhile until we have anything near able to get there in a reasonable time frame. But at least we can detect other worlds.

Always a fascinating endeavor....


:---[===] *

[Boomer12k]

LOVE THE MANDELBROT INLAND SEA!!!!

:---[===] *

[Chris Peterson]

At 500 ly, I think it is going to be awhile until we have anything near able to get there in a reasonable time frame

Where "awhile" equals "never".

[Psnarf]

We'd better find someplace else very soon, considering the rate at which we are making this planet uninhabitable.

[Chris Peterson]

We'd better find someplace else very soon, considering the rate at which we are making this planet uninhabitable.

We will not find anyplace else. There is no place else. Not in our Solar System, and nothing beyond that is reachable.

The reality is, making Earth into a human paradise is a vastly easier solution than finding other places to live. If we can't manage the first, we surely aren't going to manage the latter. And frankly, we shouldn't.

[hakmul]

Yes, very nice artwork!
One thing though; Since this is a cool star, and the planet is very close, I would've expected the relative size of this 'sun' too be largerthan the Sun is to earth. With that small sun in the distance, I wouldn't expect any water to be liquid. As seen from that planets surface, I would assume it's sun to cover maybe something like maybe a stretched out hand, rather than the finger nail size or own sun covers...
BR
/Håkan Müller
Sweden

[astrobengt]

Is it really possible that an Earth-sized planet in the habitable zone could lack an atmosphere?

[Chris Peterson]

Is it really possible that an Earth-sized planet in the habitable zone could lack an atmosphere?

Being in the habitable zone is irrelevant. The question is whether an Earth-massed terrestrial planet can lack an atmosphere. And the answer is, we don't know. But it seems probable.

[Ann]

Yes, very nice artwork!
One thing though; Since this is a cool star, and the planet is very close, I would've expected the relative size of this 'sun' too be largerthan the Sun is to earth. With that small sun in the distance, I wouldn't expect any water to be liquid. As seen from that planets surface, I would assume it's sun to cover maybe something like maybe a stretched out hand, rather than the finger nail size or own sun covers...
BR
/Håkan Müller
Sweden

Indeed, isn't it true that the star should look bigger relative to Kepler 186f than our own Sun does to the Earth? In order to be in the habitable zone of a cool star, a planet has to be (considerably) closer to its star than the Earth is to the Sun.

Ann

[Anthony Barreiro]

We'd better find someplace else very soon, considering the rate at which we are making this planet uninhabitable.

We will not find anyplace else. There is no place else. Not in our Solar System, and nothing beyond that is reachable.

The reality is, making Earth into a human paradise is a vastly easier solution than finding other places to live. If we can't manage the first, we surely aren't going to manage the latter. And frankly, we shouldn't.

I hereby nominate Chris Peterson for Secretary General of the United Nations.

[Anthony Barreiro]

I saw this same image of Kepler 186f on the front page of yesterday's San Francisco Examiner, with a teaser headline along the lines of "Have Astronomers Discovered Earth's Twin Planet?" and a subhead pointing to a page five story about SFSU Professor Stephen Kane, who is involved in the research. There was no indication on the front page that this image is an imaginative illustration rather than, say, a Hubble Space Telescope photograph. These sorts of pictures are open to misinterpretation by a casual viewer who could easily conclude that we know a lot more than we really do.

[ta152h0]

fertile APOD to be jumping sharks on !!

[BDanielMayfield]

Kepler identifies planets by looking for planets transiting their star. I assume any planets that do not transit their star cannot be identified. That being the case I would think that Kepler can only find a small fraction of planets. Also it would have great difficulty identifying planets with long orbits simply because the time required is long, especially because of the need to make observations of more than one transit. Taking all of that into consideration, the number of planets in close proximity must be huge.

You assume correctly. Kepler’s initial mission looked at about 156,000 stars. Depending on the size of an exoplanet’s orbit, the orbital plane must be very closely aligned with our line of sight to produce transits. Of Kepler’s large star field, to date 413 stars have been shown to have one or more confirmed planets, and another 2540 more Kepler stars give evidence that they might host one or more planets but await confirmation.

Let’s say, just for the sake of discussion that most of the unconfirmed aren’t found to be false positives and that the total numbers of planet hosting stars in the original Kepler field turn out to be something around 2800. But there are many reasons why an exoplanet in Kepler’s field might have been missed, including orbital non-alignment, planet too small, planet too far from star, star too variable, orbit of transiting planet in synch with Kepler down time, etc. So let’s estimate the found by Kepler rate at something like 2% of the theoretical total of planet hosting stars. That would mean that the detection of 2800 planet hosting stars would actually imply the existence of 2800/.02 planet hosting stars, which would equal 140,000 planet hosting stars out of 156,000. This is why the Kepler results imply that most stars host at least one planet.

[rj rl]

LOVE THE MANDELBROT INLAND SEA!!!!

:---[===] *

wait, where? Can't see ;;

[metamorphmuses]

"Mr. Sulu, give me warp six to Kepler 186f."
"Captain to crew: Our mission is to explore the region in and around the Kepler 186 system, looking for new life forms. We are finally going to see what is out there".


At 500 ly, I think it is going to be awhile until we have anything near able to get there in a reasonable time frame. But at least we can detect other worlds.

Always a fascinating endeavor....


:---[===] *

This was my first reaction, too - as a destination for if and when we have FTL travel. (Unlike C. Peterson, I don't think we can be sure that we won't have such a thing, only that it seems improbable given what we know right now. But in 1500 AD, it would have seemed improbable to travel to the Moon.)

[Anthony Barreiro]

"Mr. Sulu, give me warp six to Kepler 186f."
"Captain to crew: Our mission is to explore the region in and around the Kepler 186 system, looking for new life forms. We are finally going to see what is out there".


At 500 ly, I think it is going to be awhile until we have anything near able to get there in a reasonable time frame. But at least we can detect other worlds.

Always a fascinating endeavor....


:---[===] *

This was my first reaction, too - as a destination for if and when we have FTL travel. (Unlike C. Peterson, I don't think we can be sure that we won't have such a thing, only that it seems improbable given what we know right now. But in 1500 AD, it would have seemed improbable to travel to the Moon.)

300,000 kilometers per second. It's not just a good idea -- it's the law.

[Chris Peterson]

300,000 kilometers per second. It's not just a good idea -- it's the law.

And we have a vastly greater understanding of the law than we did in 1500.