Astronomy Report Astronomy Report
Recent News |  Archives |  Tags |  Space Weather |  Space Weather Email Alerts (New!) |  About |  Newsletter |  Submit News |  Links |  Subscribe to AstronomyReport.com RSS Feed Subscribe


More Articles
Has the puzzle of rapid climate change in the last ice age been solved?Has the puzzle of rapid climate change in the last ice age been solved?

Scientists enhance synthesis of chromium dioxide (100) epitaxial thin film growthScientists enhance synthesis of chromium dioxide (100) epitaxial thin film growth

Inside the cell, an ocean of buffeting wavesInside the cell, an ocean of buffeting waves

Blood cells are a new and unexpected source of neurons in crayfishBlood cells are a new and unexpected source of neurons in crayfish

Common household chemicals decrease reproduction in mice, study findsCommon household chemicals decrease reproduction in mice, study finds

Program earns kudos for improving grades, retaining studentsProgram earns kudos for improving grades, retaining students

Lithium-based neutron detector named among Top 100 technologies of the yearLithium-based neutron detector named among Top 100 technologies of the year

Geckos use toe hairs to turn stickiness on/offGeckos use toe hairs to turn stickiness on/off

Is empathy in humans and apes actually different?Is empathy in humans and apes actually different?

Scared of crime? Good.Scared of crime? Good.

A self-organizing thousand-robot swarmA self-organizing thousand-robot swarm

Genetically engineered fruit flies could save cropsGenetically engineered fruit flies could save crops

Eco-friendly 'pre-fab nanoparticles' could revolutionize nano manufacturingEco-friendly 'pre-fab nanoparticles' could revolutionize nano manufacturing

Diamonds are a quantum computer's best friendDiamonds are a quantum computer's best friend

Mercury in the global oceanMercury in the global ocean

Our ancestor's 'leaky' membrane answers big questions in biologyOur ancestor's 'leaky' membrane answers big questions in biology

Scientists discover the miracle of how geckos move, cling to ceilingsScientists discover the miracle of how geckos move, cling to ceilings

Crash-testing rivetsCrash-testing rivets

Photo editing algorithm changes weather, seasons automaticallyPhoto editing algorithm changes weather, seasons automatically

Seamless gene correction of beta-thalassemia mutations in patient-specific cellsSeamless gene correction of beta-thalassemia mutations in patient-specific cells

Geography matters: Model predicts how local 'shocks' influence U.S. economyGeography matters: Model predicts how local 'shocks' influence U.S. economy

Shrinking dinosaurs evolved into flying birdsShrinking dinosaurs evolved into flying birds

Running for life: How speed restricts evolutionary change of the vertebral columnRunning for life: How speed restricts evolutionary change of the vertebral column

Protein's 'hands' enable bacteria to establish infection, research findsProtein's 'hands' enable bacteria to establish infection, research finds

A healthy lifestyle adds years to lifeA healthy lifestyle adds years to life

Do probiotics help kids with stomach bugs?Do probiotics help kids with stomach bugs?

Strict diet suspends development, doubles lifespan of wormsStrict diet suspends development, doubles lifespan of worms

Identified for the first time what kind of explosive has been used after the detonationIdentified for the first time what kind of explosive has been used after the detonation

Copied from nature: Detecting software errors via genetic algorithmsCopied from nature: Detecting software errors via genetic algorithms

A wealth of habitable planets in the Milky Way (1/21/2012)

Tags:
planets, exoplanets, gravitational microlensing
Every starry night 100 million stars are observed using telescopes in Chile and New Zealand. If the search identifies a stellar location with a possible microlensing effect, it is automatically registered. Then the best 'lenses' are observed more closely at high resolution and their light curves are analyzed. One of the places this is done is at the Danish 1.5 meter telescope at ESO's La Silla Observatory in Chile. -  ESO/Z. Bardon
Every starry night 100 million stars are observed using telescopes in Chile and New Zealand. If the search identifies a stellar location with a possible microlensing effect, it is automatically registered. Then the best 'lenses' are observed more closely at high resolution and their light curves are analyzed. One of the places this is done is at the Danish 1.5 meter telescope at ESO's La Silla Observatory in Chile. - ESO/Z. Bardon

Six years of observations of millions of stars now show how common it is for stars to have planets in orbits around them. Using a method that is highly sensitive to planets that lie in a habitable zone around the host stars, astronomers, including members from the Niels Bohr Institute, have discovered that most of the Milky Way's 100 billion stars have planets that are very similar to the Earth-like planets in our own solar system - Mercury, Venus, Earth and Mars, while planets like Jupiter and Saturn are more rare. The results are published in the prestigious scientific journal, Nature.

"Our results show that planets orbiting around stars are more the rule than the exception. In a typical solar system approximately four planets have their orbits in the terrestrial zone, which is the distance from the star where you can find solid planets. On average, there are 1.6 planets in the area around the stars that corresponds to the area between Venus and Saturn" explains astronomer Uffe Gråe Jørgensen, head of the research group Astrophysics and Planetary Science at the Niels Bohr Institute at the University of Copenhagen.

Searching for exoplanets

Over 1000 exoplanets have been found in our galaxy, the Milky Way, and most have been found using either the radial velocity method or the transit method, both of which are best suited to be able to find planets that are large and relatively close to their host star. With the radial velocity method you can measure that a star rocks in small circular motions due to a revolving planet's gravitational force. With the transit method you measure periodic changes in the brightness of a star. When a planet moves in front of the star, there is a little dip in the star's brightness and if this little dip occurs regularly, further observations can reveal whether there it is a planet. With both methods you most often find large planets in such small orbits around their stars, that they have no equivalents in our own solar system.

Habitable exoplanets

In order to find planets similar to the planets we know from our own solar system, researchers must use a third method - gravitational microlensing observations. But the gravitational microlensing method requires very special conditions concerning the stars location in the galaxy.

Uffe Gråe Jørgensen explains that you need to have two stars that lie on a straight line in relation to us here on Earth. Then the light from the background star is amplified by the gravity of the foreground star, which thus acts as a magnifying glass. When the stars pass close by each other in the sky, astronomers can observe the light from the background star first increase and then decrease again. If there is a planet around the foreground star, there might be a little extra bump on the light curve. But if the planet is very close to the star, the bump 'drowns' on the light curve, and if the planet is very far from star, you do not see it. "Therefore the method is most sensitive to planets that lie at an Earth-like distance from a star," explains Uffe Gråe Jørgensen.

It is rare that two planets pass by each other closely enough to create a microlens. We have therefore implemented a strategic search on two levels. Every starry night the research group scans 100 million stars using telescopes in Chile and New Zealand. If the scanning identifies a stellar location with a possible microlensing effect, it is automatically registered and all researchers are notified. Then the best 'lenses' are observed more closely at high resolution and their light curves are analyzed. One of the places this is done is at the Danish 1.5 meter telescope at ESO's La Silla Observatory in Chile.

"In a six year period from 2002 to 2007, we observed 500 stars at high resolution. In 10 of the stars we directly see the lens effect of a planet, and for the others we could use statistical arguments to determine how many planets the stars had on average. To be exact, we found that the zone that corresponds to the area between Venus and Saturn in our solar system had and average of 1.6 planets the size of five Earth masses or more," explains Uffe Gråe Jørgensen.

Billions of habitable planets

The microlensing results complement the best existing transit and radial velocity measurements. Using transit measurements, the American Kepler satellite has identified a very large number of relatively small planets in orbits smaller than even the innermost planet in our own solar system, Mercury, while many years of radial velocity measurements have revealed a large number of very large planets in both very small orbits and slightly larger orbits.

"Our microlensing data complements the other two methods by identifying small and large planets in the area midway between the transit and radial velocity measurements. Together, the three methods are, for the first time, able to say something about how common our own solar system is, as well as how many stars appear to have Earth-size planets in the orbital area where liquid what could, in principle, exist as lakes, rivers and oceans - that is to say, where life as we know it from Earth could exist in principle," says Uffe Gråe Jørgensen.

He explains that a statistical analysis of all three methods combined shows that out of the Milky Way's 100 billion stars, there are about 10 billion stars with planets in the habitable zone. This means that there may be billions of habitable planets in the Milky Way. For thousands of years people have been guessing how many planets there might be out there among the stars, where we could, in principle at least, live. Today we know this.

Are we alone in the universe?

But it is one thing, that the planets have the right temperature to be habitable in principle, but quite another thing, whether they are inhabited - whether there is life and perhaps even intelligent life on the planets.

"There are so many unique events in our solar system that have created the basis for the development of life on Earth. Comets brought water to our planet so that life could arise and a series of random events set in motion an evolution that lead to humans and intelligent life. It is very unlikely that the same circumstances would be present in other solar systems," believes Uffe Gråe Jørgensen, "but perhaps other coincidences in other solar systems have led to entirely different and exciting new forms of life. Recent research of planets around other stars has shown us that there is in any case billions of planets with orbits like Earth and of comparable size to the Earth."

Uffe Graae Jorgensen is an astrophysicist, associate professor, and head of the research group Astrophysics and Planetary Science at the Niels Bohr Institute, University of Copenhagen. Uffe Graae Jorgensen explains the new results about exoplanets. Planets orbiting around stars are more the rule than the exception and many of the planets are surprisingly similar to our own Earth. We now know that are as many as 10 billion such planets in the Milky Way. Uffe Gråe Jørgensen also explains about the method they have used called gravitational microlensing observations and he explains what a standard solar system looks like. - Niels Bohr Institute

Note: This story has been adapted from a news release issued by the University of Copenhagen

Post Comments:

Solar X-rays

Geomagnetic Field

Search
New Articles
Astrophysicists detect destruction of 3 stars by black holes

Follow the radio waves to exomoons, physicists sayFollow the radio waves to exomoons, physicists say

Taking astronomy to the next levelTaking astronomy to the next level

White dwarfs crashing into neutron stars explain loneliest supernovaeWhite dwarfs crashing into neutron stars explain loneliest supernovae

Violent solar system history uncovered by WA meteorite

Step closer to birth of the sun

NASA's Hubble finds supernova star system linked to potential 'zombie star'NASA's Hubble finds supernova star system linked to potential 'zombie star'

Triangulum galaxy snapped by VSTTriangulum galaxy snapped by VST

Planet-like object may have spent its youth as hot as a starPlanet-like object may have spent its youth as hot as a star

A hellacious two weeks on Jupiter's moon IoA hellacious two weeks on Jupiter's moon Io

Extreme volcanism: Image captures 1 of the brightest volcanoes in the solar systemExtreme volcanism: Image captures 1 of the brightest volcanoes in the solar system

Companion planets can increase old worlds' chance at life

Scientist underlines threat of inevitable 'solar super-storms'

Hubble shows farthest lensing galaxy yields clues to early universeHubble shows farthest lensing galaxy yields clues to early universe

NASA's Fermi space telescope reveals new source of gamma raysNASA's Fermi space telescope reveals new source of gamma rays



Archives
August 2014
July 2014
June 2014
May 2014
April 2014
March 2014
February 2014
January 2014
December 2013
November 2013
October 2013
September 2013
August 2013
July 2013
June 2013
May 2013
April 2013
March 2013
February 2013
January 2013
December 2012
November 2012
October 2012
September 2012
August 2012
July 2012
June 2012
May 2012
April 2012
March 2012
February 2012
January 2012
December 2011
November 2011
October 2011
September 2011
August 2011
July 2011
June 2011
May 2011
April 2011
March 2011
February 2011
January 2011
December 2010
November 2010
October 2010
September 2010
August 2010
July 2010
June 2010
May 2010
April 2010
March 2010
February 2010
January 2010
December 2009
November 2009
October 2009
September 2009
August 2009
July 2009
June 2009
May 2009
April 2009
March 2009
February 2009
January 2009
December 2008
November 2008
October 2008
September 2008
August 2008
July 2008
June 2008
May 2008
April 2008
March 2008
February 2008
January 2008
December 2007
November 2007
October 2007
September 2007
August 2007
July 2007
June 2007


Science Friends
Agricultural Science
Sports Tech
Biology News
Biomimicry Science
Cognitive Research
Chemistry News
Tissue Engineering
Cancer Research
Cybernetics Research
Electonics Research
Forensics Report
Fossil News
Genetic Archaeology
Genetics News
Geology News
Microbiology Research
Nanotech News
Parenting News
Physics News


  Archives |  Submit News |  Advertise With Us |  Contact Us |  Links
Use of this site constitutes acceptance of our Terms of Service and Privacy Policy. All contents © 2000 - 2015 Web Doodle, LLC. All rights reserved.