Have they found any Earth-like planets in other solar systems yet?

Answer 1

New information is now to hand as a result of new methods of detection, Smaller extra-solar planets have been found orbiting red dwarf stars, previously considered an unlikely place to find them, As 85% of stars in the Milky Way are red dwarfs this significantly increases the chances of life being found elsewhere in the universe.

THE THREE SMALLEST KNOWN EXTRA-SOLAR PLANETS

In August 2004, a planet orbiting Mu Arae with a mass of approximately 14 times that of the Earth was discovered with the ESO HARPS spectrograph. It is the third lightest extrasolar planet orbiting a main sequence star to be discovered to date.

In June 2005 a third planet orbiting the red dwarf star Gliese 876 in Aquarius was announced. With a mass estimated at 7.5 times that of Earth, Gliese 876 d is currently the second-lightest known exoplanet that orbits an ordinary main-sequence star. It orbits at 0.021 AU with a period of 1.94 days.

(Gliese 876 d is the planet the contrubutor immediately before me is referring to)

On January 25, 2006 the discovery of OGLE-2005-BLG-390Lb was announced. This is the most distant and probably the coldest exoplanet yet found. It is believed to orbit a red dwarf star around 21,500 light years away, towards the centre of our galaxy. It was discovered using gravitational microlensing and is estimated to have a mass of 5.5 times that of Earth, making it the least massive known exoplanet to orbit an ordinary main-sequence star.

Prior to this discovery, the few known exoplanets with comparably low masses had only been discovered on orbits very close to their parent stars, but this planet is estimated to have a relatively wide separation of 2.6 AU from its parent star.

NAMING CONVENTION

According to astronomical naming conventions, the official designation for a body orbiting a star is the star's catalogue number followed by a letter. The star itself is designated with the letter 'a', and orbiting bodies by 'b', 'c', etc.

HOW MANY DO WE NOW KNOW ABOUT?

We now know of 205:

"Of the 205 extrasolar planets (those outside our solar system) discovered to date most have masses which are about the same or larger than Jupiter's.

Exceptions include a number of planets discovered orbiting burned-out star remnants called pulsars, such as PSR B1257+12, the planets orbiting the stars Mu Arae, 55 Cancri and GJ 436 which are approximately Neptune-sized, and a planet orbiting Gliese 876 that is estimated to be about 6 to 8 times as massive as the Earth and is probably rocky in composition."

(Gliese 876 is about 38 light years away from us.)

"It is far from clear if the newly discovered large planets would resemble the gas giants in our solar system or if they are of an entirely different type as yet unknown, like ammonia giants or carbon planets.

In particular, some of the newly discovered planets, known as hot Jupiters, orbit extremely close to their parent stars, in nearly circular orbits. They therefore receive much more stellar radiation than the gas giants in our solar system, which makes it questionable whether they are the same type of planet at all."

There is also a class of hot Jupiters that orbit so close to their star that their atmospheres are slowly blown away in a comet-like tail: the Chthonian planets.

NASA has a program underway to develop a Terrestrial Planet Finder artificial satellite, which would be capable of detecting the planets with masses comparable to terrestrial planets.

The frequency of occurrence of these planets is one of the variables in the Drake equation which estimates the number of intelligent, communicating civilizations that exist in our galaxy.

The first system to have more than one planet detected was Upsilon Andromedae. Twenty such multiple-planet systems are now known.

As regards main sequence stars, there are currently 48 known planets in 20 multiple planet systems and 150 known planets in single-planet systems.

Plus there are currently four known planets orbiting two different pulsars, one known planet orbiting a brown dwarf and two suspected free-floating planets, i.e. they don't appear to orbit a star.

MULTI-PLANET SYSTEMS

Star Planet / Minimum Mass(× Jupiter) / Orbital Distance (× Earth) / Orbital Period (days)

47 Ursae Majoris b 2.63 2.13 1089.0
47 Ursae Majoris c 0.792 3.79 2594

55 Cancri A e 0.045 0.038 2.81
55 Cancri A b 0.784 0.115 14.67
55 Cancri A c 0.217 0.24 43.93
55 Cancri A d 3.92 5.257 4517.4

Gliese 777 A c 0.057 0.128 17.1
Gliese 777 A b 1.502 3.92 2891

Gliese 876 d 0.023 0.021 1.94
Gliese 876 c 0.56 0.13 30.1
Gliese 876 b 1.98 0.21 61.02

HD 12661 b 2.30 0.83 263.6
HD 12661 c 1.57 2.56 1444.5

HD 37124 b 0.61 0.53 152.46
HD 37124 c 0.6 1.64 843.6
HD 37124 d 0.66 3.19 2295

HD 38529 b 0.78 0.129 14.309
HD 38529 c 12.70 3.68 2174.3

HD 69830 b 0.033 0.0785 8.667
HD 69830 c 0.038 0.186 31.56
HD 69830 d 0.058 0.63 197

HD 73526 b 2.9 0.66 188.3
HD 73526 c 2.5 1.05 377.8

HD 74156 b 1.86 0.294 51.643
HD 74156 c > 6.17 3.40 2025

HD 82943 b 0.88 0.73 221.6
HD 82943 c 1.63 1.16 444.6

HD 108874 b 1.36 1.051 395.4
HD 108874 c 1.018 2.68 1605.8

HD 128311 b 2.58 1.02 420.514
HD 128311 c 3.21 1.76 919

HD 168443 b 7.7 0.29 58.116
HD 168443 c 16.9 2.85 1739.50

HD 169830 b 2.88 0.81 225.62
HD 169830 c 4.04 3.60 2102

HD 202206 b 17.4 0.83 255.87
HD 202206 c 2.44 2.55 1383.4

HD 217107 b 1.37 0.074 7.1269
HD 217107 c 2.1 4.3 3150

Mu Arae d 0.044 0.09 9.55
Mu Arae e 0.52 0.92 310
Mu Arae b 1.7 1.5 638
Mu Arae c 3.1 4.17 2986

Upsilon Andromedae A b 0.687 0.0595 4.617113
Upsilon Andromedae A c 1.98 0.832 241.23
Upsilon Andromedae A d 3.95 2.54 1290.1

Answer 2

No. Planets in other solar systems can only be detected by the gravitational effect that they have on the star they are orbitting. For the gravitational effect to be noticeable by scientists with telescopes a planet would have to be far more massive than earth. The ones discovered so far are the size of Jupiter or Saturn. It could well be some time before technology allows us to discover smaller planets in other solar systems.

Answer 3

The smallest planet discovered outside our solar system, so far, is between 5 and 7 times bigger than Earth.

Answer 4

The short answer is that there seem to be planets everywhere. They're unlikely to be very similar to Earth though.
(try typing "planets in other solar systems" into yahoo search...)

Answer 5

Eris, the biggest dwarf planet commonly used, became got here across in an ongoing survey at Palomar Observatory's Samuel Oschin telescope through astronomers Mike Brown (Caltech), Chad Trujillo (Gemini Observatory), and David Rabinowitz (Yale college). We formally said the call on 6 September 2006, and it became familiar and presented on 13 September 2006.

Answer 6

No,Earth like planets have not been found yet. If they were, you could be sure that it would create quite a furore on our Earth. The chances of finding one are pretty slim due to our backward technology in telescope sight. For an astronomy discussion visit astrowhiz on Yahoo Groups!

Answer 7

I think at this point there is no way of telling - I'm pretty sure planets are found by the gravitational effect they have on their parent star, which can only show the approximate mass of the planet(s).

Answer 8

I don't know of any outside of the solar system, but one of Jupiter's moons, Europa, is thought by many to be capable of sustaining life. I has a massive ocean encased in ice, protected from the ravages of space.

Answer 9

No. I believe telescopes aren't sensitive enough yet to detect anything smaller than a gas giant. Small, rocky planets like Earth don't make enough of a shadow against their sun when they orbit it for us to find them.

Answer 10

Yes !!

It happened the Week of June 18, 2005.
Here is the info ..

Answer 11

Yes, but they kept it a secret. It can house only a select few after they blow up the earth.