Found: one Earth-like planet - Astronomers use gravity lensing to spot homely planets.

news@nature.com ^ | 25 January 2006 | Mark Peplow

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Published online: 25 January 2006; | doi:10.1038/news060123-5

Found: one Earth-like planet

Astronomers use gravity lensing to spot homely planets.

Mark Peplow

How to spot a planet: watch for wiggles in the light coming from a far distant star as it curves around another sun.© ESO

Astronomers say they have found the most Earth-like planet yet outside our Solar System. At just 5.5 times the mass of Earth it is one of the smallest extrasolar planets ever found, and orbits its star at a distance comparable to that of habitable worlds.

Similarly sized extrasolar planets have been found before. But the method used to detect them meant we could see smallish planets only when they were very close to their suns, and such bodies are battered by scorching radiation.

Planet OGLE-2005-BLG-390Lb looks much more like home. It lies about 390 million kilometres from its star: if it were inside our Solar System, the planet would sit between Mars and Jupiter.

It takes ten years for the planet to orbit its parent star, a common-or-garden red dwarf that lies about 28,000 light years from Earth, close to the centre of our Galaxy.

The search for a second Earth is the driving force behind our research.   Daniel Kubas at the European Southern Observatory in Santiago de Chile, Chile.

But sadly this Earth-like body probably isn't crawling with life. Its dwarf star is so dim that the surface temperature of this planet is thought to be about - 220 °C.

"The search for a second Earth is the driving force behind our research," says Daniel Kubas at the European Southern Observatory in Santiago de Chile, Chile, part of the team that made the discovery. They are optimistic that the clever method they used to spot the planet could soon uncover an alien twin to our own world.

Wobbly stars

More than 170 planets have been discovered outside our Solar System. Astronomers usually detect them by watching how they make their parent star wiggle, a technique known as the Doppler method. This is ideal if you are looking for massive planets orbiting very close to their star, which induce a lot of wobble.

But there is no way this can be used to find small, blue-green planets approximately 150 million kilometres from a yellow sun. It is simply not sensitive enough, says Didier Queloz, an astronomer from Geneva Observatory in Switzerland who was part of the team that found the first extrasolar planet, just 11 years ago¹.

The new sighting relies on an effect called gravitational lensing, where a massive object such as a star warps space so that it behaves like a lens. This means that it bends and slightly magnifies light from a more distant star before it reaches our telescopes. Adding a planet to the mix modifies the lensing effect by a tiny amount, just enough to work out its mass and orbit.

"Microlensing is the fastest way to find small, cool planets, down to the mass of the Earth," says Keith Horne, one of the planet's discoverers and an astronomer from the University of St Andrews, UK.

Spot the difference

The planet was found by a consortium of 73 astronomers from 12 different countries. Its star was first spotted by scientists working on the Optical Gravitational Lensing Experiment (OGLE), before the planet itself was noticed by astronomer Pascal Fouqué.

OGLE-2005-BLG-390Lb is only the third planet found using the microlensing technique so far, but astronomers expect to spot many more. "The other two microlensing planets have masses of a few times that of Jupiter, but the discovery of a five-Earth-mass planet is a strong hint that these objects are very common," says Jean-Philippe Beaulieu of the Astrophysics Institute of Paris. Beaulieu is lead author of the paper describing the find in this week's Nature².

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References

1. Mayor M.&

   Queloz D. . Nature, 378. 355 - 359 (1995). | Article | ISI | ChemPort |

2. Beaulieu J.P., et al. Nature, 439. 437 - 440 (2006). | Article |

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[SunkenCiv]

Note: this topic is from 2006.

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[SunkenCiv]

Artist's conception:

[TMSuchman]

It falls in to the third portion or so of it. Just because that there maybe a planet that may support life, there has to be life on there & then there has to be intelligent life smart enough, then smart enough to communicate out into space , ect....

But let’s also think that not all of life may be carbon based. There is a strong possibility there maybe a silicon based as well out there in the great beyond.

[AntiKev]

And hopefully figure out a way to get there and conquer them.

Let's get Mars and the Moon under our control first. But I'm right with you on your sentiment.

[timer]

It’s referred to as the Drake Equation, the probability of intelligent beings in UFOs visiting us. Actually the little grays are polysilane lifeforms. Polysilanes are easily photovolatized, that’s why they come at night. Their worlds have very thick cloud covers = always dark. Note the almond shaped eyes set at 90 degrees from each other = polarization at infrared wavelengths.

Google Louis DeBroglie and matter waves, his U = c^2/v equation for the speed of a matter wave crest; is c^2 a momentum-line(for fermions)or mass-area? At c^2 LINE you go(as a globality)at 1 light year in 105 sec. We’ve had the einstein c-limit hang up for too long already. See how they do it?

Finally, in the Roswell crash a metallurgical guy got a look at 3 dead aliens lying on 2 card tables : very badly sunburned from the harsh NM sunlight...polysilanes...

[timer]

Ah, but first you have to get nagin’s approval...

[I see my hands]

Yes, but it may take him two years to reply.

[timer]

Ah yes, but the sun won’t bloat into a red giant for another 5 billion years, that should be enough time for even a brain dead nagin to get the school buses rolling.