Exo-Planet confirmed to meet criteria for life

Conor108 · 17-05-2011 01:30PM #1

A super-Earth exoplanet, Gliese 581d, a rocky world orbiting a red dwarf star called Gliese 581, located around 20 light years from Earth, which makes it one of our closest neighbors, has been confirmed as the first planet outside our solar system to meet key requirements for sustaining life. Astronomers' modelling of planet shows it has the potential to be warm and wet enough to nurture Earth-like life, they said.

Gliese 581d orbits on the outer fringes of the star's "Goldilocks zone," where it is not so hot that water boils away, nor so cold that water is perpetually frozen. Instead, the temperature is just right for water to exist in liquid form.

"With a dense carbon dioxide atmosphere -- a likely scenario on such a large planet -- the climate of Gliese 581d is not only stable against collapse but warm enough to have oceans, clouds and rainfall," said France's National Centre for Scientific Research (CNRS).

Jaysus, the Gliese 581 solar system pops up a lot doesn't it. Planet Zarmina or Gliese 581g was the one in the news awhile back they suspected was in the habitable zone.

Full Story

Tenger · 17-05-2011 08:35PM

"Until now, the big interest in Gliese 581's roster of planets focussed on Gliese 581g. It leapt into the headlines last year as "Zarmina's World," after its observers announced it had roughly the same mass as Earth's and was also close to the Goldilocks zone, which has since been discounted by many experts. Some experts suspect that the Gliese 581g may not even exist but was simply a hiccup in starlight.

Its big brother, Gliese 581d, has a mass at least seven times that of Earth and is about twice our planet's size, according to the new study, which appears in a British publication, The Astrophysical Journal Letters.

The planet, spotted in 2007, had initially been dismissed as a candidate in the hunt for life.
It receives less than a third of the solar radiation Earth gets, and may be "tidally locked," meaning that one side of it always faces the sun, which would give it permanent dayside and nightside.

But the new model, devised by CNRS climate scientists Robin Wordsworth, Francois Forget and colleagues, showed surprising potential. Its atmosphere would store heat, thanks to its dense CO2, a greenhouse gas, warmed by the red light from the star.

"In all cases, the temperatures allow for the presence of liquid water on the surface," say the researchers. For visting space explorers, though, Gliese 581d would "still be a pretty strange place to visit," the CNRS said. "The denser air and thick clouds would keep the surface in a perpetual murky red twilight, and its large mass means that surface gravity would be around double that on Earth."

A spaceship traveling close to light speed would take more than 20 years to get there, while our present rocket technology would take 300,000 years."

BULLER · 17-05-2011 08:43PM

Maybe the proximity of Gliese makes it much easier to detect planets?

In any case this picture of the system compared with our own solar system is cool for scale
gliese-581-exoplanet-100929-02.jpg?1294512168

gliese-581-exoplanet-100929-02.jpg?1294512168

Plug · 17-05-2011 09:54PM

Are they any photos of these Exo planets? I mean they are like dusts particles from so far away. Do we even have the telescope technology to view them?

BULLER · 17-05-2011 11:12PM

Plug wrote: »

Are they any photos of these Exo planets? I mean they are like dusts particles from so far away. Do we even have the telescope technology to view them?

Good question. Directly imaging the light coming from these planets would require a mirror diameter of roughly 100 meters, depending on numerous factors. (for the Gliese planets it may be a lot smaller as its only 20light yrs away)

To put that in perspective, our current generation of "very large telescopes" have around 8 meter diameter mirrors.

Using new technology (adaptive mirrors + powerful computers) we can make much bigger mirrors and also account for atmospheric blur. These are called Extremely Large Telescopes ELT's (And no, I've dont have a clue who comes up with these names but they should have been sacked a long time ago)

Two are in developement: The aptly named 30 Meter Telescope and the European ELT which will be 42m. The latter is expected to be able to characterise exo-planet atmospheres which will be very exciting. Traces of life can possibly be detected that way.

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

Hope this helps.

Cú Giobach · 18-05-2011 07:51AM

Plug wrote: »

Are they any photos of these Exo planets? I mean they are like dusts particles from so far away. Do we even have the telescope technology to view them?

Read about it here.

There are a few more but are all only a couple of pixels in size (for now).

rccaulfield · 18-05-2011 09:26PM

Wow, With 7 times the mass of earth the gravity would destroy us though, 20 light years makes it tantalising for engine designers!

Raging_Ninja · 18-05-2011 09:42PM

rccaulfield wrote: »

Wow, With 7 times the mass of earth the gravity would destroy us though, 20 light years makes it tantalising for engine designers!

I believe its 2Gs, which I think should be survivable for most people.

Conor108 · 18-05-2011 11:08PM

https://www.youtube.com/watch?v=0iDyhg0BPZA

Brian Cox going through what gravity would be like on other planets. At around 3 mins he's experience 2.5 G so stronger than Gliese 581d.

clln · 19-05-2011 02:06AM

Very interesting reading here, i am just wondering what you all think is the best way to search for Exoplanets?
My impression is that it is the ongoing Kepler mission which does not look for planets directly but takes note of an intermittent dimming around a Sun that could indicate a planet(s) is orbiting it.
this is its homepage;

http://kepler.nasa.gov/

any good links to other ways Exoplanets are being researched?

rccaulfield · 19-05-2011 10:40PM

Tenger wrote: »

".

Its big brother, Gliese 581d, has a mass at least seven times that of Earth and is about twice our planet's size,
A spaceship traveling close to light speed would take more than 20 years to get there, while our present rocket technology would take 300,000 years."

Raging_Ninja wrote: »

I believe its 2Gs, which I think should be survivable for most people.

I'm quoting Tenger here, that it has a mass 7 times that of the earth?

Kidchameleon · 19-05-2011 11:29PM

Slightly off topic but have a read:

http://www.nasa.gov/home/hqnews/2011/may/HQ_11-148_Free_Planets.html

Raging_Ninja · 19-05-2011 11:41PM

rccaulfield wrote: »

I'm quoting Tenger here, that it has a mass 7 times that of the earth?

It also has to do with radius. Newton's law of universal gravitation:

$0f36df929ac9d711a8ba8c5658c3bfee.png$

F is the force between the masses
G is the gravitational constant
m1 is the first mass
m2 is the second mass
r is the distance between the masses

Edit: looking back I'm going to have to withdraw the claim of 2Gs, I misread another article. Sorry about that.

Tenger · 20-05-2011 10:59PM

rccaulfield wrote: »

I'm quoting Tenger here, that it has a mass 7 times that of the earth?

I was just quoting the OP linked article:

"Its big brother, Gliese 581d, has a mass at least seven times that of Earth and is about twice our planet's size, according to the new study, which appears in a British publication...............................................
.....It receives less than a third of the solar radiation Earth gets...............
........Its atmosphere would store heat, thanks to its dense CO2, a greenhouse gas, warmed by the red light from the star............................
.................The denser air and thick clouds would keep the surface in a perpetual murky red twilight, and its large mass means that surface gravity would be around double that on Earth."

Plug · 21-05-2011 10:30AM

Whats the difference between size and mass? Is mass the weight? The more mass the stronger the gravitational pull?

Conor108 · 21-05-2011 03:23PM

The planet has 7 times Earth's mass, but the size of the planet is twice that of Earth. So the radius of the planet is twice Earth's radius.

$0f36df929ac9d711a8ba8c5658c3bfee.png$

So even though its 7 times Earth's mass, dividing by it's larger radius squared brings it down to ~2G yeah?

https://www.youtube.com/watch?v=391txUI76gM

Capt'n Midnight · 22-05-2011 12:04AM

Raging_Ninja wrote: »

I believe its 2Gs, which I think should be survivable for most people.

Make a great prison planet
because it's a one way trip to the surface

Escape velocity = root( 2GM/r) M =7 x earth r = 2 x earth

so escape velocity is 1.87 times ours
and it may have a thicker atmosphere as it would be able to hang on to more Hydrogen than we can, which won't help if you trying to lift off again

AlmightyCushion · 22-05-2011 12:13AM

Capt'n Midnight wrote: »

Make a great prison planet
because it's a one way trip to the surface

Escape velocity = root( 2GM/r) M =7 x earth r = 2 x earth

so escape velocity is 1.87 times ours
and it may have a thicker atmosphere as it would be able to hang on to more Hydrogen than we can, which won't help if you trying to lift off again

If we develop technologically to the stage where we could actually send a prisoner to that planet within their lifetime, I imagine leaving a planet like that would be doable to making it as much of a one way trip as most other planets.

Rubecula · 22-05-2011 02:17AM

Plug wrote: »

Whats the difference between size and mass? Is mass the weight? The more mass the stronger the gravitational pull?

Size is as it says the size ie something you measure in inches... or miles or whatever you use.

Mass in simple terms, is the amount of stuff there.

Weight is a characteristic of gravity. If you have no gravity there is no weight. In a way Weight is the force with which two objects attract each other using gravity.

Think of an extreme example.... Black hole has gravitationa attraction that is to all intents and purposes infinite inside it's event horizon, but the mass is not infinite. Even a super massive black hole has a estimatable mass, such as the one in our galaxy that may have a mass of a few million suns (Yeah a lot, but not infinite) The same black hole weighs nothing as you can not measure it against another body, but anything on it (impossible in itself) would weigh a lot more than on Earth.

Another example is anything on the moon weighs about a sixth of what it weighs on Earth, but it's mass is unchanged, and size is not altered either.

AlmightyCushion · 22-05-2011 02:22AM

Rubecula wrote: »

Size is as it says the size ie something you measure in inches... or miles or whatever you use.

Mass in simple terms, is the amount of stuff there.

Weight is a characteristic of gravity. If you have no gravity there is no weight. In a way Weight is the force with which two objects attract each other using gravity.

Think of an extreme example.... Black hole has gravitationa attraction that is to all intents and purposes infinite inside it's event horizon, but the mass is not infinite. Even a super massive black hole has a estimatable mass, such as the one in our galaxy that may have a mass of a few million suns (Yeah a lot, but not infinite) The same black hole weighs nothing as you can not measure it against another body, but anything on it (impossible in itself) would weigh a lot more than on Earth.

Another example is anything on the moon weighs about a sixth of what it weighs on Earth, but it's mass is unchanged, and size is not altered either.

So what you are saying is forget weightwatchers and move to the moon.

Capt'n Midnight · 22-05-2011 02:23AM

AlmightyCushion wrote: »

If we develop technologically to the stage where we could actually send a prisoner to that planet within their lifetime, I imagine leaving a planet like that would be doable to making it as much of a one way trip as most other planets.

Neptune , Uranus and Saturn are all 1.16G-1.19G with escape velocities twice earths (or nearly 3 times in the case of Saturn) and so would make ideal colonies. Ok you would have to use a warm baloon to keep them off the "surface"

Exo-Planet confirmed to meet criteria for life

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