Kepler telescope spies 'most Earth-like' worlds to date

 
Artist's impression of Kepler-62 system Artist's impression: The outermost pair are the smallest exoplanets yet found in a host star’s habitable zone

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The search for a far-off twin of Earth has turned up two of the most intriguing candidates yet.

Scientists say these new worlds are the right size and distance from their parent star, so that you might expect to find liquid water on their surface.

It is impossible to know for sure. Being 1,200 light-years away, they are beyond detailed inspection by current telescope technology.

But researchers tell Science magazine, they are an exciting discovery.

"They are the best candidates found to date for habitable planets," stated Bill Borucki, who leads the team working on the US space agency Nasa's orbiting Kepler telescope.

The prolific observatory has so far confirmed the existence of more than 100 new worlds beyond our Solar System since its launch in 2009.

The two now being highlighted were actually found in a group of five planets circling a star that is slightly smaller, cooler and older than our own Sun. Called Kepler-62, this star is located in the Constellation Lyra.

The two planets go by the names Kepler-62e and Kepler-62f

Its two outermost worlds go by the names Kepler-62e and Kepler-62f.

They are what one might term "super-Earths" because their dimensions are somewhat larger than our home planet - about one-and-a-half-times the Earth's diameter.

Nonetheless, their size, the researchers say, still suggests that they are either rocky, like Earth, or composed mostly of ice. Certainly, they would appear to be too small to be gaseous worlds, like a Neptune or a Jupiter.

Many assumptions

Planets 62e and 62f also happen to sit a sufficient distance from their host star that they receive a very tolerable amount of energy. They are neither too hot, nor too cold; a region of space around a star sometimes referred to as the "Goldilocks Zone".

Kepler Mission

An illustration of Kepler
  • Launched in 2009, the Kepler space telescope is on a mission to find Earth-like worlds orbiting distant stars
  • It works by detecting periodic variations in the brightness of stars caused by orbiting exoplanets passing in front of them
  • In January 2013, astronomers used Kepler's data to estimate that there are at least 17 billion Earth-sized exoplanets in the Milky Way Galaxy

Given the right kind of atmosphere, it is therefore reasonable to speculate, says the team, that they might be able to sustain water in a liquid state - a generally accepted precondition for life.

"Statements about a planet's habitability always depend on assumptions," said Lisa Kaltenegger, an expert on the likely atmospheres of "exoplanets" and a member of the discovery group.

"Let us assume that the planets Kepler-62e and -62f are indeed rocky, as their radius would indicate. Let us further assume that they have water and their atmospheric composition is similar to that of Earth, dominated by nitrogen, and containing water and carbon dioxide," the Max Planck Institute for Astronomy in Heidelberg researcher went on.

"In that case, both planets could have liquid water on their surface: Kepler-62f gets less radiation energy from its host star than the Earth from the Sun and therefore needs more greenhouse gases, for Instance more carbon dioxide, than Earth to remain unfrozen.

"Kepler-62e is closer to its star, and needs an increased cloud cover - sufficient to reflect some of the star's radiation - to allow for liquid water on its surface."

Key signatures

None of this can be confirmed - not with today's technology. But with future telescopes, scientists say it may be possible to see past the blinding glare of the parent star to pick out just the faint light passing through a small world's atmosphere or even reflected off its surface.

This would permit the detection of chemical signatures associated with specific atmospheric gases and perhaps even some surface processes. Researchers have spoken in the past of trying to detect a marker for chlorophyll, the pigment in plants that plays a critical role in photosynthesis.

Dr Suzanne Aigrain is a lecturer in astrophysics at the University of Oxford.

She said ground-based experiments and space missions planned in the next few years would give more detailed information on distant planets like those announced by the Kepler team.

Astronomers would like to pin down the masses of the planets (information difficult to acquire with Kepler), as well as getting that data on atmospheric composition.

Dr Aigrain told BBC News: "What we do next is we try to find more systems like these; we try to measure the frequency of these systems; and we try to characterise individual systems and individual planets in more detail.

"That involves measuring their masses and their radii, and if possible getting an idea of what's in their atmospheres. But this is a very challenging task."

Kepler meanwhile will just keep counting planets beyond our Solar System.

It is equipped with the largest camera ever launched into space. It senses the presence of planets by looking for a tiny "shadowing" effect when one of them passes in front of its parent star.

Planets graphic

Jonathan.Amos-INTERNET@bbc.co.uk and follow me on Twitter: @BBCAmos

 

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  • rate this
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    Comment number 454.

    451.Akkarrin

    There are inaccuracies in your post. First God didn't just create two people and a talking snake, Eden was populated with all manner of beings. Adam and Eve were not considered brother and sister, He made Eve from Adam's rib, make what you will of that. And lastly the fruit from the The Tree of the Knowledge of Good and Evil was not an apple, it's just symbolised as such.

  • rate this
    0

    Comment number 453.

    448.shortpulse

    "God is a man not a woman. The bible always refers to God as He. God made a home for Adam and Eve here, nowhere else."

    Correction, God is beyond mortal concepts like gender. The reason why He is referred to as "He" in the bible is becuase for most of history "He" was considered a Gender neutral term when not referring to a male.

  • rate this
    +1

    Comment number 452.

    If I am truly made in God's image, as the Christians say, then we are in big trouble. The chances are that planet Earth was something he started with a lot of enthusiasm, nearly finished and then left when he got bored and went onto something new. He is probably at this moment carving commandments for simpler folks in a galaxy far far away. Maybe the universe is full of his half finished jobs.

  • rate this
    0

    Comment number 451.

    448. Shortpulse
    the thought that we were placed on a planet by some distinctly masculine entity 6000 years ago with just two people and a talking snake who were expected to breed all of humanity even though they were brother and sister and exiled to death for eating an apple is so far beyond rediculous it belongs in a work of fiction... oh wait... its in a work of fiction

    Please stop trolling

  • rate this
    0

    Comment number 450.

    One of the best and most chilling short stories about space travel is Larry Niven's Bordered in Black. I'm not going to spoil the plot, but suffice to say that astronauts need to stay sane. At the same time, immediately you leave near Earth orbit your body decays rapidly. Astronauts wouldn't have the strength to put on their space suits months in. You'd lose your humanity very fast.

  • rate this
    0

    Comment number 449.

    My only fear is that once we discover new worlds, we will set on a campaign to colonize and we will screw those planets as we have done this one.

  • rate this
    0

    Comment number 448.

    447 Akkarrin God is a man not a woman. The bible always refers to God as He. God made a home for Adam and Eve here, nowhere else.

  • rate this
    +1

    Comment number 447.

    To all the people who are saying life cannot exist on other planets cause a old book says it doesnt.

    Does this mean that if we do ever find life up there you can all shut up about god and accept maybe she isnt real after all?

    Honestly after 2000 years all this religous nonsense is annoying...

    If aliens come here and go to the church, the aliens will leave rolling in laughter at our planet...

  • rate this
    0

    Comment number 446.

    441.Fiscal prudence

    I think the reason why most people assume that first contact will be with a benevolent being is becuase if they're not they'll either 1) destroy us before we even consider that aliens are attacking or 2) They'll just scoot off and leave us alone. And hopefully if they do come here and are benevolent they'll take terminal disease into account before making contact.

  • rate this
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    Comment number 445.

    I am struggling to understand religion's problem with discoveries like these. What is the problem with finding out first-hand what is in God's universe, and possibly even detecting more of his life from elsewhere? There is no evil in science. Science is fact. The laws of physics are here at God's command, and show the greatness of his creation. Otherwise, why would any matter exist at all?

  • rate this
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    Comment number 444.

    2.Jack
    "We can't stay on this dying rock forever!"
    This is the typical anthropogenic fallacy. Like all organic life, man is obviously subordinate to, and reliant upon, Mother Nature. I believe it was Fred Hoyle who noted that the distances between stars are so vast that it appears that stars are incubated from each other; so that life becomes an isolated experiment, not an infectious virus!

  • rate this
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    Comment number 443.

    439 Someonewhocares, don't forget to mention that God put Adam and Eve on Earth and not all these other fictional planets.

  • rate this
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    Comment number 442.

    @TonyL99

    As I pointed out before, the problem with this kind of time dilation space travel is that the chances are that in the time that passes at home, advances in technology will enable people who leave hundreds of years later to get there before you. In the limit there is no point going until you can get there instantaneously!

  • rate this
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    Comment number 441.

    Why do we always assume contact with alien life forms would be an enriching and beneficial event? It may at best expose us to terminal disease or at worst predatory violence. I'm not saying don't continue scientific & exploratory research but we need to recognise the dangers as well and take care.

  • rate this
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    Comment number 440.

    It may be possible to reach some of these other worlds within a lifetime. The key is 'relative velocity time dilation'. Close to c, the crew would experience time at a slower rate than us on Earth. Haven't done the maths but wondering if 1G acceleration for half the journey then similar deceleration would do the trick and also give the crew 'artificial gravity'. Physicist here to enlighten us?

  • rate this
    0

    Comment number 439.

    The Spirit moved over the earth, and said let there be light, and there was light. Now, the Spirit finding this dark planet with ice and water made some land,fish,trees etc made an image of himself,then eve. Since then all this happened lol. The fact this planet may have been alive before is not written but alluded to. Look at scar on mars? Something hit earth also. Maybe mars was alive?

  • rate this
    0

    Comment number 438.

    These planets can’t be real, it doesn’t say anything them in bible or any other religious text. God talked to Moses on earth and told Moses all that was really important, the Ten Commandments. God made the entire universe 6000 years ago, and the centre of it, is the planet earth. Stop talking scientific nonsense, all the truth you need is to be found in the bible.

  • rate this
    +1

    Comment number 437.

    Well, I guess thats it then.

    I like reading/commenting on HYS. But I'm finding myself feeling somewhat disappointed by our host the BBC. Surely it won't hurt to open a topic which actually has meaning to our lives.

    I think I'll leave you all (and my favourites) and say farewell. HYS has really become an exercise in futility.

  • rate this
    0

    Comment number 436.

    Back in the days of Isaac Asimov, Bob Heinlein, Fred Pohl we would just hop on our cruiser and go there but such is not to be.

    Not yet any way!

    After all its just "a matter of crude power to short circuit the continuum on the three parsec level" as they say in the film.

  • Comment number 435.

    This comment was removed because the moderators found it broke the house rules. Explain.

 

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