Scientists discover Earth-like planet
{{date|January 25, 2006}}
{{Correction|date=August 22, 2006|explanation=The source titled ''Discovery of OGLE 2005-BLG-390Lb, the first cool rocky/icy exoplanet'' is indicated below as published by the Institut d'astrophysique de Paris. However, the publisher is in fact, the Probing Lensing Anomalies NETwork (PLANET) Collaboration. The error is regretted.}}
[[Image:NewPlanet.jpg|right|200px|thumb|Artist's impression.]]
An international group of 73 scientists using 4 projects ([[w:Probing Lensing Anomalies Network|PLANET]] led by Jean-Philippe Beaulieu and Martin Dominik, RoboNet led by Michael
Bode and Keith Horne, [[w:OGLE|OGLE]] led by Andrzej Udalski, and [[w:MOA|MOA]] led by Phil Yock) from 32 institutions in 12 countries have discovered the smallest Earth-like planet yet.

The new planet is about 25,000 light years away and is close to the center of the [[w:Milky Way|Milky Way]].

The discovery was announced in the journal '''''[[w:Nature (journal)|Nature]]'''''. The journal also states the planet was found using a method called [[w:Gravitational microlensing|gravitational microlensing]], which detects small planets with a mass like that of [[w:Earth|Earth]].

[[w:Gravitational microlensing|Gravitational microlensing]] is where a light from a distant star is bent and magnified by the gravitational field of a foreground star. The presence of a planet around the foreground star causes light from the distant star to become momentarily brighter.

However, scientists say that the cold temperatures on the planet make the chance of finding any life on it "unlikely."

"We may predict with reasonable probability that microlensing will discover planets with masses like that of Earth at a similar distance from their stars and with comparable surface temperature," said study co-author [[w:Bohdan Paczynski|Bohdan Paczynski]] from [[w:Princeton University|Princeton University]].

So far the planet only goes by [[w:OGLE-2005-BLG-390Lb|OGLE-2005-BLG-390Lb]], and takes about ten years to orbit its parent star, a [[w:red dwarf|red dwarf]], a star that is smaller and much cooler than our own [[w:sun|Sun]].

Scientists say the new planet, which is about five and a half times the mass of [[w:Earth|Earth]], could either have a rocky core and a thin atmosphere, or be a small ice/gas world like [[w:Neptune (planet)|Neptune ]], but in either case, its "very large orbit and cooler parent star, makes it a very cold world."

The predicted surface temperature is -220&deg; Celsius (-364&deg; F), which means that should it have a rocky core, the planet may more closely resemble a massive version of [[w:Pluto|Pluto]] with a surface of frozen liquids and gas. Otherwise the planet would be a liquid mass, wrapped in clouds of ice crystals and gas, much like [[w:Neptune (planet)|Neptune]].

"This is very exciting and important," said Professor Michael Bode from [[w:Liverpool John Moores University|Liverpool John Moores University]], a principal investigator for the RoboNet project which helped to collaborate on the research. "This is the most Earth-like planet we have discovered to date, in terms of its mass and the distance from its parent star. Most of the other planets that have been discovered are either much more massive, much hotter or both."

This is the third planet in two years that scientists have found using gravitational microlensing.

In the past, more than 150 planets outside our solar system were found using a technique known as the [[w:radial velocity|radial velocity]] method. This method observes a wobble in stars caused by the planet's gravitational effects.

==Sources==
{{wikipediapar|OGLE-2005-BLG-390Lb}}
*{{source|url=http://www.nature.com|title=Discovery of a cool planet of 5.5 Earth masses through gravitational microlensing|author=J.-P. Beaulieu, D. P. Bennett, P. Fouqué, A. Williams, M. Dominik, U. G. Jørgensen, D. Kubas et al.|pub=Nature|date=January 26, 2006}}
*{{source|url=http://planet.iap.fr/OB05390.news.html|title= Discovery of OGLE 2005-BLG-390Lb, the first cool rocky/icy exoplanet
|author=|pub=Institut d'astrophysique de Paris|date=January 25, 2006}}
*{{source|url=http://www.eso.org/outreach/press-rel/pr-2006/pr-03-06.html|title= It's Far, It's Small, It's Cool: It's an Icy Exoplanet!|author=|pub=ESO|date=January 25, 2006, 19:00 CET}}
*{{source|url=http://www.princeton.edu/main/news/archive/S13/82/11A86/index.xml?section=topstories|title=Researchers discover smallest planet outside solar system|author=Eric Quiñones|pub=Princeton University|date=January 25, 2006}}
*{{source|url=http://msnbc.msn.com/id/11013519/|title=Scientists spot a new Earthlike planet|author=Ker Than|pub=MSNBC|date=January 25, 2006}}
*{{source|url=http://news.bbc.co.uk/1/hi/sci/tech/4647142.stm|title=Smallest Earth-like planet found|author=Rebecca Morelle|pub=BBC News|date=January 25, 2006}}
*{{source|url=http://www.nature.com/news/2006/060123/full/060123-5.html|title=Found: one Earth-like planet|author=Mark Peplow|pub=news@nature.com|date=January 25, 2006}}
*{{source|url=http://skyandtelescope.com/news/article_1667_1.asp|title=Low-Mass Exoplanet|author=Robert Naeye|pub=Sky & Telescope|date=January 25, 2006}}

{{publish}}
{{archived}}

[[category:Science and technology]]
[[category:Space]]
[[Category:Astronomy]]
[[Category:Physics]]
[[Category:Exoplanets]]
[[Category:Princeton University]]

[[ca:Descobrixen un nou planeta en la constel·lació de Sagitari]]
[[de:Wissenschaftler entdecken erdähnlichen Planeten]]
[[es:Descubren un nuevo planeta en la constelación de Sagitario]]
[[fr:Découverte de la première exoplanète tellurique]]
[[it:Astronomia: scoperto il primo pianeta simile alla Terra]]
Artist's impression.
An international group of 73 scientists using 4 projects (PLANET led by Jean-Philippe Beaulieu and Martin Dominik, RoboNet led by Michael
Bode and Keith Horne, OGLE led by Andrzej Udalski, and MOA led by Phil Yock) from 32 institutions in 12 countries have discovered the smallest Earth-like planet yet.

The new planet is about 25,000 light years away and is close to the center of the Milky Way.

The discovery was announced in the journal 'Nature'. The journal also states the planet was found using a method called gravitational microlensing, which detects small planets with a mass like that of Earth.

Gravitational microlensing is where a light from a distant star is bent and magnified by the gravitational field of a foreground star. The presence of a planet around the foreground star causes light from the distant star to become momentarily brighter.

However, scientists say that the cold temperatures on the planet make the chance of finding any life on it "unlikely."

"We may predict with reasonable probability that microlensing will discover planets with masses like that of Earth at a similar distance from their stars and with comparable surface temperature," said study co-author Bohdan Paczynski from Princeton University.

So far the planet only goes by OGLE-2005-BLG-390Lb, and takes about ten years to orbit its parent star, a red dwarf, a star that is smaller and much cooler than our own Sun.

Scientists say the new planet, which is about five and a half times the mass of Earth, could either have a rocky core and a thin atmosphere, or be a small ice/gas world like Neptune , but in either case, its "very large orbit and cooler parent star, makes it a very cold world."

The predicted surface temperature is -220° Celsius (-364° F), which means that should it have a rocky core, the planet may more closely resemble a massive version of Pluto with a surface of frozen liquids and gas. Otherwise the planet would be a liquid mass, wrapped in clouds of ice crystals and gas, much like Neptune.

"This is very exciting and important," said Professor Michael Bode from Liverpool John Moores University, a principal investigator for the RoboNet project which helped to collaborate on the research. "This is the most Earth-like planet we have discovered to date, in terms of its mass and the distance from its parent star. Most of the other planets that have been discovered are either much more massive, much hotter or both."

This is the third planet in two years that scientists have found using gravitational microlensing.

In the past, more than 150 planets outside our solar system were found using a technique known as the radial velocity method. This method observes a wobble in stars caused by the planet's gravitational effects.


category:Science and technology
category:Space

ca:Descobrixen un nou planeta en la constel·lació de Sagitari
de:Wissenschaftler entdecken erdähnlichen Planeten
es:Descubren un nuevo planeta en la constelación de Sagitario
fr:Découverte de la première exoplanète tellurique
it:Astronomia: scoperto il primo pianeta simile alla Terra
Astronomy Physics Exoplanets Princeton University