Astronomers Find First Earth-like Planet in Habitable Zone

[C1ay]

Astronomers have discovered the most Earth-like planet outside our Solar System to date, an exoplanet with a radius only 50% larger than the Earth and capable of having liquid water. Using the ESO 3.6-m telescope, a team of Swiss, French and Portuguese scientists discovered a super-Earth about 5 times the mass of the Earth that orbits a red dwarf, already known to harbour a Neptune-mass planet. The astronomers have also strong evidence for the presence of a third planet with a mass about 8 Earth masses.

 

lefthttp://hypography.com/gallery/files/9/9/8/gliese581_thumb.jpg[/img]This exoplanet - as astronomers call planets around a star other than the Sun - is the smallest ever found up to now and it completes a full orbit in 13 days. It is 14 times closer to its star than the Earth is from the Sun. However, given that its host star, the red dwarf Gliese 581, is smaller and colder than the Sun - and thus less luminous - the planet nevertheless lies in the habitable zone, the region around a star where water could be liquid! The planet's name is Gliese 581 c.

 

"We have estimated that the mean temperature of this super-Earth lies between 0 and 40 degrees Celsius, and water would thus be liquid," explains Stéphane Udry, from the Geneva Observatory (Switzerland) and lead-author of the paper reporting the result. "Moreover, its radius should be only 1.5 times the Earth's radius, and models predict that the planet should be either rocky - like our Earth - or fully covered with oceans," he adds.

 

"Liquid water is critical to life as we know it," avows Xavier Delfosse, a member of the team from Grenoble University (France). "Because of its temperature and relative proximity, this planet will most probably be a very important target of the future space missions dedicated to the search for extra-terrestrial life. On the treasure map of the Universe, one would be tempted to mark this planet with an X."

 

The host star, Gliese 581, is among the 100 closest stars to us, located only 20.5 light-years away in the constellation Libra ("the Scales"). It has a mass of only one third the mass of the Sun. Such red dwarfs are intrinsically at least 50 times fainter than the Sun and are the most common stars in our Galaxy: among the 100 closest stars to the Sun, 80 belong to this class.

 

"Red dwarfs are ideal targets for the search for low-mass planets where water could be liquid. Because such dwarfs emit less light, the habitable zone is much closer to them than it is around the Sun," emphasizes Xavier Bonfils, a co-worker from Lisbon University. Planets lying in this zone are then more easily detected with the radial-velocity method, the most successful in detecting exoplanets.

 

Two years ago, the same team of astronomers already found a planet around Gliese 581. With a mass of 15 Earth-masses, i.e. similar to that of Neptune, it orbits its host star in 5.4 days. At the time, the astronomers had already seen hints of another planet. They therefore obtained a new set of measurements and found the new super-Earth, but also clear indications for another one, an 8 Earth-mass planet completing an orbit in 84 days. The planetary system surrounding Gliese 581 contains thus no fewer than 3 planets of 15 Earth masses or less, and as such is a quite remarkable system.

 

The discovery was made thanks to HARPS (High Accuracy Radial Velocity for Planetary Searcher), perhaps the most precise spectrograph in the world. Located on the ESO 3.6-m telescope at La Silla, Chile, HARPS is able to measure velocities with a precision better than one metre per second (or 3.6 km/h)! HARPS is one of the most successful instruments for detecting exoplanets and holds already several recent records, including the discovery of another 'Trio of Neptunes'.

 

The detected velocity variations are between 2 and 3 metres per second, corresponding to about 9 km/h! That's the speed of a person walking briskly. Such tiny signals could not have been distinguished from 'simple noise' by most of today's available spectrographs.

 

"HARPS is a unique planet hunting machine," says Michel Mayor, from Geneva Observatory, and HARPS Principal Investigator. "Given the incredible precision of HARPS, we have focused our effort on low-mass planets. And we can say without doubt that HARPS has been very successful: out of the 13 known planets with a mass below 20 Earth masses, 11 were discovered with HARPS!"

 

HARPS is also very efficient in finding planetary systems, where tiny signals have to be uncovered. The two systems known to have three low mass planets - HD 69830 and Gl 581 - were discovered by HARPS.

 

"And we are confident that, given the results obtained so far, finding a planet with the mass of the Earth around a red dwarf is within reach," affirms Mayor.

 

Source: ESO

[HappytheStripper]

Nice Article.. I was seeing this on the news last night.. and it got me thinking.. no suprises there though.. unlike this beauty in the heavens..

 

In the beginning God created the heavens and the earth (Genisis 1.1) .. could he have created two..??

 

Scientific evidence supports.. that life on earth did not come into existence by accident.. Scientific evidence supports.. a series of sychronistic events occuring to create that which we know now.. and if you look closely enough.. you can see these events occuring on a daily basis..

 

There are so many conditions enabling life on earth to exist.. for example.. we have the right kind of sun.. emitting middle of the range radiation.. not too hot.. not too cold.. Our planet is the right distance from the sun.. if we were any closer the seas would boil.. and unlike other planets.. earths' orbit around the sun.. is very nearly circular.. unlike oher planets which have an elliptical (oval) orbit..

 

Our planet is just the right size.. It is big enough to retain an atomosphere.. and it seems the force of gravity is just right.. movement is with ease.. well for most people or animals.. and earth rotates at just the right speed.. creating that which we observe as time..

 

Nights do not get too cold.. because of a slow rotation.. also rotation is not too fast.. so as to creat cyclonic weather conditions..

 

It is with this knowledge and some theory.. the chances of these conditions appearing are unique.. this is why religions attribute these designs of creation to a creator..

 

Just a thought.. Ashley

[sciencegirl94]

Really interesting article. if you think about it, this could mean a lot in the future,

 

And I agree life is not just an accident, it's too complex and amazing just to be an accident.

 

But sometimes I do wonder... Why? Why is their life? Why here? Why like this? There is no advantage of life... No benefits if you look in a broad scale.

 

If you look up at the stars, you realize how small we are. If you get beyond how beautiful they are, you know they couldn't be reached in a lifetime. In many lifetimes... And that really makes me think what a real miracle that there is life. How amazing chemicals, substances can be. It is not just an accident that there is life. And that is why probably many people think that some kind of a creator created life. It's just too amazing.

 

this is just a though too...

[CraigD]

Nice Article.. I was seeing this on the news last night.. and it got me thinking…

Good synopsis of the “Goldilocks zone” points, Ashley. :)

 

A minor factual correction:

... and unlike other planets.. earths' orbit around the sun.. is very nearly circular.. unlike oher planets which have an elliptical (oval) orbit..

Nearly circular orbits are the norm, not the exception, in the Solar System. With an orbital eccentricity of .01671022, Earth has neither the most nor the least circular orbit in the Solar System – Venus (.00677323) and Neptune (.00858587) have more circular orbits, while the others have more elliptical ones.

 

At a nearly-zero .00005°, Earth does have the least inclined orbit of any planet, with Uranus (.76986°) a distant second, though none of the planets are inclined enough that one would much notice looking at a scale model.

 

The wikipedia article “Table of planets and dwarf planets in the Solar System” has this and other solar orbital data in a convenient form, with links to explanations of all its terms.

[HappytheStripper]

Good synopsis of the “Goldilocks zone” points, Ashley. :)

 

A minor factual correction

 

Lmao.. Thanks Craig.. I never knew about the Goldilocks Zone.. however.. it made for excellent Saturday Morning.. reading..

 

I won't tell you where my head was at.. when I wrote this.. needless to say.. thanks for the minor correction.. its days like these.. when I appreciate those.. whom have more information than I.. :naughty:

 

Ashley

[Buffy]

To good to pass up: The Onion: Earth-like Planet Discovered: What do you think?

 

The truth is out there,

Buffy

[Janus]

 

At a nearly-zero .00005°, Earth does have the least inclined orbit of any planet,

 

Not surprising, considering that it is the plane of the Earth's orbit by which orbital inclination is measured in reference to.