Astronomers found the first exoplanet having the same mass as Earth, named KOI-314c. It is the lightest exoplanet ever found, whose the second lightest is Kepler-78b, with 1.7 times Earth's mass.

Located at 200 light-years from the Sun, KOI-314c has a surface temperature of 100°C orbits around its star in only 23 days. Its host star is less massive and cooler than the Sun. The planet has the same mass as Earth's, but is 1.6 times bigger than our planet.

The fact that the orbital period is only 23 days shows that the planet is close to the host star, and so it couldn't contain liquid water, and life. However, according to David Kipping from Harvard-Smithsonian Center for Astrophysics who is the main author of the discover, the exoplanet would have a very thick atmosphere containing hydrogen and helium. The beginning of its life could be the same as Neptune's, then the planet would have lost some of its atmospheric gases over time.

However, Kipping's team of astronomers who participated at HEK Project (Hunt for Exomoons with Kepler) thought that KOI-314c was in the beginning an exomoon orbiting around KOI-314b, an exoplanet having same size as KOI-314c but with 4 times Earth's mass, and orbiting around its host star in only 13 days. The team of astronomers saw then that KOI-314c was finally a planet and not an exomoon.

Sources : Sciences et Avenir (french) and Slate.com

Read also : Exomoon research could start at 1800 light-years from the Sun...

From 1989 to 1995, astronomers discovered the first exoplanets. 1056 exoplanets later, they probably discovered the first exomoon, located at 1800 light-years from the Sun. Pandora could have finally a cousin ...

To see exommons (in the fiction), you just have to search "space wallpaper" or "planets wallpaper" on Google. Or, re-watch the films Avatar (Pandora) and Return of the Jedi (Endor).

But here, we are approaching reality. David Bennett (of the University of Notre Dame, Indiana) and his colleagues report on 13 December that they spotted a microlensing event in 2011, named  MOA-2011-BLG-262, using several telescopes in the world. First, they saw the star's light amplified to 70 times its normal brightness. And an hour later, a second came, smaller increase in brightness. So that would mean that a great object passed in front of the star, followed by a smaller object.

The first scenario that fits in the microlensing data is the following : it's an exoplanet followed by its moon, and both are at a distance of 1800 light-years from the Sun. The exoplanet's mass is about 4 times the mass of Jupiter, while the mass of its moon is half Earth's mass, that is to say 3 x 10^24 kg, so 20 times the mass of Ganymede (which is the heaviest moon of the solar system).
Even weirder : according to this model, the exomoon would be orbiting at about 20 million km from its host planet, while Ganymede orbits at 1,070,000 km from Jupiter. If the scenario is correct, we would have to explain why it is possible that there's a great distance between the planet and its moon.

The second scenario which could work is that the two detected objects are much further away and consists of a very small star or a failed star known as a brown dwarf, orbited by a Neptune-mass planet.

Today we can't confirm any of the 2 scenarios. However, exomoon research interest astronomers because exomoons in more normal planetary systems might even support life. If it is true, we could find then "cousins" of Pandora (whose Jake Sully could explore the oceans in Avatar 2).

Sources : NewScientist and International Science Times...

It is a new step for exoplanets discovery. Thanks to Hubble Space Telescope, astronomers managed first to determine the color of a planet outside the solar system. Its name ? HD 189733 b. And the little surprise : this exoplanet is deep blue. You said blue, like Earth ? Yes. But a bit different of blue you can see on a picture of our planet.

Discovered in september 2005 by a team of astronomers from France and Switzerland, HD 189733 b, located at 63 light-years from the Sun, is a gas giant which is 1.26 times Jupiter's size and which orbits around its star (HD 189733, an orange dwarf) in only 2.2 days at a distance of 4.7 million kilometers.

The atmosphere of this planet says a lot : more than 1,000°C (because of its proximity with its star), 7,000 km/h winds. Its composition : water vapor, methane and carbon dioxide. A bit similar to our atmosphere's, but being a gas planet with extreme conditions, HD 189733 b couldn't welcome life.

But the most important is its color. Deep blue. How to find the color of this planet (like any other planet actually) ? Astronomers have observed the exoplanet before, during and after its passage in front of, then behind its star and evaluated each time the quantity and nature of light received, by noting the differences depending on the position. A graph is obtained. 
"We saw the light of the whole system falling in the blue part of the spectrum when the planet passed behind the star. From there, we can understand that the planet is blue, because its signal is constant for the other colors measured", said Tom Evans from Oxford University. (Source : maxisciences.com, french article)
An other question : why is Hd 189733 b blue ? For the moment, the blue of the planet could be because of silicate particles in the atmosphere. Thanks to this method, astronomers hope find the color of other exoplanets (whose more than one thousand are officialy cataloged). With beautiful planet wallpapers that we can find on Google Images, yes, we could find blue, red, yellow, orange, green, purple planets. The thing which will be even more important, will be the first real photos of an exoplanet. Patience !...

After the passage of the asteroid 2012-DA14 near the Earth, Mars could know the same think, but with a comet, called C/2013 A1.

It's Robert H. McNaught, australian astronomer at Siding Spring Observatory, who has discovered this comet on January 3rd 2013. Just after this discover, the first calculations showed that C/2013 A1 would be near of Mars at more than 100,000 km.
But the last estimates showed a distance of 37,000 km, with a 190,000 km/h speed (according to the Daily Mail) and a diameter between 15 and 50 km. The date announced for this passage near Mars is October 19th 2014. Further, the comet will be near of the sun one week later (October 25th).

If C/2013 A1 crash on Mars, a crater of more than 500 km in diameter could be form and create a great cataclysm. Astronomers must wait march 2014 to have more accurate data about the comet, and check if, yes or no, the comet will crash on the red planet. It will be the duty of Curiosity and Opportunity rovers, with Mars Reconnaissance Orbiter (MRO) to give us next year more info about the comet.
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Notice to astronomers and amateurs : tonight asteroid 2012-DA14 pass near Earth at 7:26 P.M. (London time GMT+00). It will be possible to see with binoculars.

Here are some numbers: 2012-DA14, a near-Earth asteroid discovered a year ago, is 45 meters in diameter and has a mass of about 120 000 tonnes (120 million kilograms). We assure you: this big rock is closer to the earth at about 27,700 km above the ground.

After this passage, the asteroid will change its orbital period: from 368 to 317 days. We won't see him again until 16 February 2046 and will be about 1.5 million kilometers from Earth.
 
You can see this event in live thanks to NASA : they have given a link to see in live the passage of DA14. The live begins at 7:00 P.M. (London time). Watch it :
http://www.nasa.gov/multimedia/nasatv/index.html

Or see the passage from an other website, from the Canary Islands :
http://events.slooh.com/

We will show you after some photos taken, in this article, in about one hour. ...

If we want to find the double of the Earth, one of the first things to do is to find a telluric planet with a size similar to our planet. At least 17 billions in the Milky Way : it's the new estimate published by the American Astronomical Society on January 7th based on an analysis of data collected by the Kepler Space Telescope.

And a "sister" of the Earth must be in the habitable zone : it mustn't be neither too cold nor too hot to discover maybe, if the planet is telluric, life at least in the microscopic scale. It's one of the greatest dreams of an astronomer.

But among these 17 billion planets, is there one, two or more like our Earth ? Actually we know zero. But with Kepler Space Telescope, among 2 700 potential exoplanets, 4 planets have a size about 2 times Earth's and are in their own habitable zone.

The Milky Way is so big, too big for us. It's true that we'll don't find all the planets in our galaxy (only 850 found and cataloged), but find a planet with many similarities to the Earth would be a great discovery....

Observing stars and planets, everyone can do that. The birth of a star ? We don't know, but we know how they are born, and that 3-4 stars are born each year in our galaxy. But the birth of a planet ? Now, YES.

Thanks to ALMA radiotelescopes in Atacama desert, Chile, ESO astronomers, whose Simon Casassus, have obeserved the gas supply of a giant gas planet around HD 142527. This star, located at about 450 light-years away from the Earth, is surrounded by a gigantic disc of gas and cosmic dust in two parts, with a huge space between the two parts : the internal has a radius similar to the orbit of Saturn (about 750 M km) and the external 14 times farther.

Probably named HD 142527 b, this planet is one of the first exoplanets (extrasolar planet) discovered in 2013. It is powered by huge gas flows, and so it confirms the theory on the formation of giant planets.

"Astronomers had predicted the existence of these flows, but this is the first time we were able to observe them", said Simon Casassus in a statement from the ESO.

We know that it's very hard to observe directly planets in formation because they are very deep in these gas flows, almost completely opaque. But these flows are studied and so the astronomers will learn more about them.

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Source : eso.org...

One of the wonders of the universe is the picture for these Christmas holidays by Hubble Space Telescope : here is the Spiral Planetary Nebula, NGC 5189 (Gum 47, ID 4272).

We know a little bit things about it : discovered in 1826, the symmetrical nebula NGC 5189 is located in the southern small constellation of Musca. At the beginning seen as bright emission, Henize has seen and verified that NGC 5189 is a quasi-planetary nebula. His structure in the picture looks like a giant and bright blue-oranged ribbon.

A few years ago, NASA has estimated it to be 1 780 light-years away from Earth. It has a neighbor, the Hourglass nebula (MyCn18) located at 8,000 years away for Earth and which looks like a hourglass (see MyCn18's picture by HST).

And now, the question is : for Christmas, will we find a nebula which looks like a Christmas ball, a tree, a snowman ? No idea, but space still reserves us many surprises ......