Scientists Find an ‘Earth Twin,’ or Perhaps a Cousin

http://www.nytimes.com/2014/04/18/science/space/scientists-find-an-earth-twin-or-maybe-a-cousin.html?hp&_r=0

by joewee • 12 years ago

73 56 12 years ago

rhizome2• 12 years ago

Sad, but the first thing my sci-fi mind thought of was whether Earth would be able to establish relations with a perhaps-society there without establishing military superiority first, just starting off with a Cold War.

spcoll• 12 years ago

Any planet harboring intelligent life would likely be several hundreds (like this one) if not thousands or millions of light years away, making any contact impossible at human scale. Even with this relatively close example of a possibly habitable planet, communications would take 1000 years to go back and forth.

As for actual contact... many earth civilizations would rise and fall before a spaceship going at even 2% of the speed of light could reach such a planet.

rhizome2• 12 years ago

Well sure, that's the sci-fi part...

lugg• 12 years ago

Us humans, so self centered. What you say doesn't mean we can't send a probe that simply says hey what's up and you're not alone but probably are by the time you read this.

joe_the_user4• 12 years ago

You're making the mistake of confusing totally unknown with very unlikely. We simply do not know enough to prognosticate one way or the other.

Perhaps every habitable planet develops life but only our plant has developed intelligent life. Perhaps only our planet among all the planet in the universe has life. Perhaps every planet develops civilization life and all such civilizations destroy themselves within about 10,000 years, leaving only hunter-killer robots.

In any case, interstellar space is so vast we couldn't practically other civilizations even if they turned out to be quite common in other solar systems.

clef• 12 years ago

People can be wary of new neighbours, i don't see why it wouldn't apply to space neighbours. On a brighter note, maybe we should welcome with open arms anyone, after all, better be nice than not nice!

Houshalter6• 12 years ago

I'd be more concerned the aliens would be militarily superior to us, considering the millions to billions of years head start on technology.

Or that there are no aliens, raising concerns that most civilizations inevitably destroy themselves.

Or that there are, but they haven't made contact because they don't care about us. If they don't care they might wipe us out because they want our resources, or see us as a potential threat.

gagege• 12 years ago

Or they're just building a highway and Earth is in the way.

flatline• 12 years ago

Or that long-distance space travel or even communication is simply not feasible for any civilization at any level of technological advancement.

ufmace• 12 years ago

Or we don't try to contact them out of fear that they may be militarily superior to us and be inclined to attack us. And they don't try to contact us out of fear that we may be militarily superior to them and want to attack them.

KamiCrit• 12 years ago

I wonder what Kepler 186f thinks of Earth?

XorNot• 12 years ago

"Smaller, hotter, but in the habitable zone of it's star. Relpek 681f orbits a hot yellow star but far enough out to not be cooked by it. Yellow stars are so hot that they would turn our planet into a barren, semi-molten wasteland at the same distance.

Scientists have noted that the atmosphere of Relpek 681f would have to be very thin in order for it to maintain cool enough temperatures, but it's well known that plant life would probably have an easier time dealing with it's solar radiation output..."

FlailFast• 12 years ago

Now I want a subscription to the Keplerian Journal of Science.

rbanffy• 12 years ago

"It's also a very young system and there hasn't been enough time for it to develop any form pf intelligent life."

ksrm• 12 years ago

Side note: we would be Relpek 681d (b=Mercury, c=Venus).

Udo2• 12 years ago

Thinking about what Earth and its star system look like from the outside is indeed a very interesting exercise, and it gives you an idea how flawed many of our own assumptions about exobiology may be.

At these distances, our radio spectrum would be difficult to discern from random galactical noise - even if the radio waves had enough time to cross the distance. And in fact, so far it looks like the more advanced we get the less telling our radio signature becomes. There are no large-scale constructs or artifacts visible that hint at any technological activity in the solar system.

Looking at how crowded the solar system is, an onlooker might well assume it's too unstable for life to have developed. The Earth might be seen as too small to support life, its atmosphere too thin to shield against radiation and also too thin to allow for a comfortable temperature interval in which liquid water exists. Due to the difficulties of aerodynamic flight under these circumstances, they can safely assume there will be no winged lifeforms on Earth.

They might also think that any plant life on Earth would be extremely sparse and desolate - yet the abundance of oxygen hints at a world dominated by microbial life. The orbital and rotational instability of the planet leads to wild temperature variations which will likely prevent the rise of higher life forms.

The presence of several semi-unstable interplanetary debris fields suggests asteroid impacts will be frequent, and likely to extinguish life on any of the planets. The relative proximity and high mass of the Earth's moon (or shall we say: sister planet) makes it likely that the planet will be subject to tidal disturbances and might imply a history of extreme geological instability.

Water covers a large part of the Earth's surface, but generally is only present in the form of very shallow oceans tainted with poisonous chloride salts in high concentrations. It's unclear if unchlorinated water exists on the surface and in any case it's doubtful that there's enough water to form a stable cycle able to support any but the most primitive extremophiles.

jerf2• 12 years ago

The "planet much harsher than Earth that develops an extremely aggressive, warlike lifeform far stronger than us" is an old science fiction trope. One of the most popular examples are the Klingons.

But what if Earth is that planet? Obviously it can support intelligent life, but while there's lots of ways it could be harsher, there's also lots of ways it could be friendlier. For instance, it would be nice if this ice age that we're in the middle of wasn't happening. (Incidentally, you can add that to your list of reasons why Earth can't possibly support advanced life... it's spent an awful lot of time nearly entirely frosted over lately. http://xkcd.com/1225/ )

kijin3• 12 years ago

Kepler 186 is an M1V red dwarf [1]. We don't know how old it is, but red dwarves tend to last tens of billions to trillions of years. (No red dwarf is known to have died of natural causes since the beginning of the Universe.) So this star could be much older than our Sun. The low metallicity of the star also supports the hypothesis that it is older than our Sun.

Which means that if there is life on Kepler 186f, it could be billions of years ahead of us. Would that have been a long enough time scale for an intelligent species to emerge, civilize, and develop a way to traverse the 500 light years between us and them? Or did the dim light (less UV ~ less mutation) and lower availability of heavy elements (less iron) in the star system hemper the evolution of life and/or civilization?

Will there ever be an answer to questions like this, perhaps in a thousand years, a million years, or even a billion years?

[1] https://en.wikipedia.org/wiki/Kepler-186

wellboy• 12 years ago

< red dwarves tend to last tens of billions to trillions of years.

The universe will be dead in 10 billion years tho ;)

sanxiyn• 12 years ago

Citation needed.

lutusp• 12 years ago

The universe will be dead in 10 billion years tho ...

Not so. There's no basis for this claim. The universe will continue to expand, and will eventually become much colder and darker than it is now, but there's no mechanism that ends the universe in our current models.

More here: http://arachnoid.com/dark_energy

kijin3• 12 years ago

You're confusing the universe with our solar system. The Sun is expected to have a lifespan of approx. 10 billion years, of which 4.6 billion have already elapsed.

As for the universe, see various conjectures at https://en.wikipedia.org/wiki/Ultimate_fate_of_the_universe

KhalilK• 12 years ago

We'll let Ω be the judge of that.

https://upload.wikimedia.org/wikipedia/commons/d/dc/Friedman...

danieltillett• 12 years ago

We don't know how old it is, but red dwarves tend to last tens of billions to trillions of years.

I am not sure if it is logical to argue that since red dwarfs can live a long time that any particular red dwarf is older than the sun. It is like arguing that since bristlecone pine can live for thousands of years that a particular individual tree you chance across is thousands of years old - it could be a young sapling.

I do agree that the low metallicity supports it being old, but there are young stars with lower metal levels. Really we just don't know at this stage, but it is an exciting discovery.

jotm3• 12 years ago

Well, from the looks of it, Mars was suited for life a long time ago. We still don't know if it had any intelligent life...

atmosx2• 12 years ago

I like the idea of evolved civilizations using prime numbers[1] to contact us.

[1] http://en.wikipedia.org/wiki/Contact_(1997_US_film)

hcarvalhoalves• 12 years ago

While it's fun to speculate, that's a lot of assumptions: intelligent species, civilization, travel, DNA mutation via UV...

Considering we don't know anything besides Earth, we may not be even in a position to recognize life (let alone intelligent life), since we have such a biased definition of it.

Just as until the microscope invention a whole universe of lifeforms was unknown, we could be looking at things at the wrong space/time scale and missing the obvious. I find this more exciting than the possibility of ever finding carbon-based, spaceship-building creatures.

jamesfranco• 12 years ago

OMG they find one of these all the time.

chjj• 12 years ago

I'm surprised this article didn't bother mentioning Gliese 581g: https://en.wikipedia.org/wiki/Gliese_581g

kijin3• 12 years ago

Gliese 581g is huge. Its mass is 3-4 times that of Earth. The newly discovered planet is much closer to the size of Earth, which is what the headline is all about. (Of course, mass and radius variations in this range have little to do with habitability, since both planets probably have enough gravity to hold onto an atmosphere.)

fragsworth• 12 years ago

Gliese 581g has a surface gravity estimated to be between 1.1 and 1.7 times Earth's gravity.

At 1.1x, it's possibly livable for humans, making it more interesting; 1.7x is probably too rough without some new technology or adaptations.

jswhitten• 12 years ago

Also, Gliese 581g is unconfirmed, and there is a lot of doubt about whether it exists.

wavesounds• 12 years ago

What is physically stopping us from actually seeing this planet with visible light? Is it that we can't build a big enough telescope?

Also would it be possible start broadcasting radio waves or maybe some kind of laser towards this planet incase there's something there that can respond to us a thousand years from now?

windsurfer• 12 years ago

Yes. We haven't build a large enough telescope to pick up the faint reflection of it's star's light on the surface.

dredmorbius• 12 years ago

Resolving power.

There are limits to the angular separation a telescope can detect. Even the very largest telescopes on Earth (or more often: arrays of several telescopes, effectively creating multi-thousand-kilometer baselines) can resolve the disks of even the largest stars. It turns out that Betelguese is roughly the same distance as Kepler 186f -- 643 light years (plus or minus 146), and its disk can be resolved, even to the point of detecting surface features. But Betleguese is roughly 1000 times the radius of our Sun, and 4x wider than Earth's own orbit: "If Betelgeuse were at the center of the Solar System, its surface would extend past the asteroid belt, possibly to the orbit of Jupiter and beyond, wholly engulfing Mercury, Venus, Earth and Mars." (Wikipedia)

http://en.wikipedia.org/wiki/Betelgeuse

http://www.space.com/7771-spots-sun-revealed-giant-star.html

For planets, we're limited to detecting brightness fluctuations in the parent star (how Kepler detects planets), and possibly spectral absorption lines.

That last would be hugely exciting, as it allows knowledge of the composition of the atmosphere of a planet. And there's one molecule whose presence would be an almost absolute certain tell-tale of life: oxygen.

Ordinarily, free oxygen reacts with other substances in its presence to create oxides. Only if new oxygen is being released will an atmosphere be high in oxygen. So a planet with an oxygen-rich atmosphere should almost certainly have light.

As for beaming radio signals, the challenge is in creating signals which would be strong enough to detect at 500 light years' distance. Signal strength for most broadcast sources would be undetectable even at the nearest star, 100x closer:

http://zidbits.com/2011/07/how-far-have-radio-signals-travel...

welterde• 12 years ago

There are limits to the angular separation a telescope can detect. Even the very largest telescopes on Earth (or more often: arrays of several telescopes, effectively creating multi-thousand-kilometer baselines) can resolve the disks of even the largest stars.

Just to clarify: In radio-bands we can easily achieve sub-mas angular resolution using VLBI (the mentioned multi-thousand-kilometer baselines) or large arrays (ALMA, VLA, etc.)

In the optical/NIR bands your baselines are typically limited to a few hundred meters, where you can go down to mas, but it's much more difficult than in the radio bands. And direct imaging of the disks of the largest stars is possible in the optical/NIR.

3rd3• 12 years ago

There is a very cool project for new space telescopes in the works. Here is a 6 minute TED talk about it, also explaining why it's difficult to detect planets directly within the visible spectrum: http://youtube.com/watch?v=XYNUpQrZISc

mentos• 12 years ago

I wonder where Earth lies on the spectrum between 'Rare Earth' and 'Principle of Mediocrity' [0]

Crazy to think that we may have awoken on this planet after an unfathomable amount of time and not appreciate how rare we are.

Does our situation get more or less beautiful if we discover no one else is out there?

[0] http://en.wikipedia.org/wiki/Rare_Earth_hypothesis

jotm3• 12 years ago

We've appreciated how unique we are for a pretty long time. Seeing quadrillions of other planets in the sky really makes you rethink that :-)

atmosx2• 12 years ago

Given the size of the universe[1], believing there's only one planet hosting biologically evolved organisms, falls a bit short IMHO.

That said, it won't change anything knowing there's no one else out there. Actually it would be a little bit frustrating because it would mean that there's nothing more to discover... Biologists might feel limited on this planet alone.

[1] http://en.wikipedia.org/wiki/Universe#Size.2C_age.2C_content...

unclebucknasty• 12 years ago

it won't change anything knowing there's no one else out there

But, we can never know that there's no one else out there, right? We can only discover that there is.

joe_the_user4• 12 years ago

Another possibility is that this is a "rare moment" in the history of Earth - we've have maybe 3.5 billion years of life while we've had 100K years of being language using animals and 10K years of civilization.

Still, perhaps every moment is rare in some way but we have the advantage of having a way to express that.

Scientists Find an ‘Earth Twin,’ or Perhaps a Cousin

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