An artist's illustration of an Earth-like planet. The search for planets that are similar to Earth is one of NASA's main goals. Many planets have already been discovered orbiting other stars, but so far only larger planets (the size of Jupiter or larger) have been found. New missions are being planned by NASA which will be able to detect smaller Earth-sized planets. Some of these missions will also try to detect signs of life on these planets by studying emissions in their atmospheres.


"We're Looking For A Second Earth"

European satellite project COROT will be launched Wednesday to seek out Earth-like planets beyond the solar system. DW-WORLD.DE spoke to Heike Rauer, German head of the project.

Scientists hope to get an insight into the planets of neighboring solar systems when the COROT satellite launches on Wednesday at 1423 GMT from Kazakhstan. A project of the French National Space Studies Center (CNES) in which the European Space Agency (ESA) is participating, COROT will send into orbit a telescope capable of detecting smaller, rocky planets that could support life. The mission is a milestone in the search for a second Earth, Heike Rauer said in an interview with DW-WORLD.DE.

DW-WORLD: The European Space Agency (ESA) has called COROT a unique astronomical mission. What is so special about this project?

Heike Rauer: For the first time, the COROT satellite will look from space for planets that don't orbit our sun, but instead circle other stars in other solar systems. We hope, with COROT, to find rocky planets close to a star. Until now, these planets have not been found, but we believe they exist. The research will hopefully discover a second Earth.

Can COROT find planets that are similar to Earth?

COROT finds planets by measuring changes in brightness. It observes a star from a certain point and if a planet passes within its orbit between the star and the satellite, the brightness changes and COROT measures that. One can think of it as similar to a lunar eclipse. Since COROT will only spend five months looking at a certain area, it is unlikely that it will see another Earth. An Earth-like planet would need an entire year to orbit around the star and then would come only one time in the year past the point that the satellite is watching. We will not likely find a second earth, but rather other planets, that are closer to the stars, where the orbiting period is shorter.

Could people live on these planets?

If the star these planets orbit around is as hot as our sun, it would be uninhabitable for humans, because the temperatures on the planet would be so high. But there are also so-called M Stars, which are not as hot. The planets that orbit around these stars are much cooler and could support life. When COROT finds such planets, it would naturally be extremely exciting. COROT cannot recognize whether there's life on these planets or whether life would be possible there. To find this out, one must examine the atmosphere and look for molecules such as water, ozone or oxygen.

Can COROT's findings be trusted or does it only provide a basis for information?

COROT measures the changes in the brightness of stars, which could have a variety of causes. Naturally, we hope that a change in brightness is produced by a planet. It could be that the star has spots or that it's not a star and a planet, but rather two stars crossing each other. To start out, the scientists must figure out what caused the crop in brightness. One cannot hope that COROT will immediately begin discovering terrestrial planets. The scientists will only announce they've found a planet if they're sure.

Interview by Christine Elsaeßer

To learn more about COROT


Habitable Planet Possible Around Nearby Star System

01 August 2006

Someday astronomers will likely create a long list of Sun-like stars with Earth-like planets around them. But technology has yet to reveal such worlds, instead allowing the detection only of much larger planets.

Most of the roughly 200 known extrasolar planets are larger than Jupiter. Many complete their orbital years in just a few days. This proximity to their stars creates noticeable wobbles in the stars that make the planets detectable.

But astronomers figure the giants probably formed farther out, in a disk of material swirling around a newborn star, and migrated inward. In doing so they would have destroyed any fledgling habitable worlds.

In recent years, with improving technology, researchers have found a handful of systems that could harbor life-bearing planets, in theory at least. A nearby star called 55 Cancri is one of the leading candidates.

The system

The 55 Cancri system involves three gas giant planets and another world that could be icy or rocky and is about the size of Neptune. The setup is 41 light-years from Earth and about 4.7 billion years old, comparable to our Sun.

Astronomers have said since 2002, when a planet was found at about the same orbital distance from 55 Cancri as Jupiter is from the Sun, that the star had the potential to harbor an Earth-sized world.

A new computer simulation shows that amid the giant worlds orbiting 55 Cancri, a small rocky world could indeed have formed--in theory--and attracted enough water to support life as we know it.

Read more:


Many “Earths” out there, scientists say after new planet find

SOURCE: World Science
Jan. 25, 2006
Special to World Science

Astronomers say they have found the smallest planet ever detected around a normal star outside our solar system, and that the discovery suggests there are many Earth-like planets out there.

The planet weighs five times as much as Earth and orbits a relatively cool star, known as a red dwarf, every decade, astronomers said.

It would thus be the latest in a series of discoveries of increasingly Earth-like planets outside our solar system, since others found to date are even larger compared to Earth.

Also, with the finding, astronomers have now identified planets on both sides of the “habitable zones” of distant stars.

A habitable zone is a narrow region around a star whose temperature is such that liquid water can exist, so that presumably life can form.

Most planets found around stars other than the Sun, called extrasolar planets, to date have been in the hotter-than-habitable zone. The newfound world, by contrast, is too cold, astronomers said, suggesting the discovery of a planet lying in the lucky middle might not be far off.

“It’s encouraging that we now have examples of planets on both sides of the habitable zone,” said Scott Tremaine of Princeton University in Princeton, N.J., one of the astronomers who announced the finding.

The distance between the planet and its star is about three times that between the Earth and the Sun, the researchers found. That would put it somewhere between Mars and Jupiter in terms of distance from its host star.

Read more:

Scientists spot a new Earthlike planet

By Ker Than
Jan. 25, 2006

‘Microlensing’ detects faraway world just 5.5 times bigger than our own
Astronomers on Wednesday announced the discovery of what is possibly the smallest planet known outside our solar system orbiting a normal star.

Its orbit is farther from its host star than Earth is from the sun. Most known extrasolar planets reside inside the equivalent of Mercury’s orbit.

The planet is estimated to be about 5.5 times as massive as Earth and thought to be rocky. It orbits a red dwarf star about 28,000 light-years away. Red dwarfs are about one-fifth as massive as the sun and up to 50 times fainter. But they are among the most common stars in the universe.

So the finding suggests rocky worlds may be common.

"The team has discovered the most Earthlike planet yet,” said Michael Turner, assistant director for the mathematical and physical sciences directorate at the National Science Foundation, which supported the work.

The discovery is detailed in Thursday's issue of the journal Nature.

More to come
Prior to this discovery, the smallest extrasolar planet found around a normal star was about 7.5 Earth masses. Earth-sized planets have been detected, but only around dying neutron stars.

The newfound planet, named OGLE-2005-BLG-390Lb, is probably too cold to support life as we know it, astronomers said. With a surface temperature of 364 degrees below zero Fahrenheit (-220 degrees Celsius), it is nearly as >document.write(""); frigid as Pluto >document.write(''); .

It was discovered using a technique called “gravitational microlensing,” whereby 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.

Astronomers hailed the discovery as the first of a new class of small, rocky worlds located at far-out distances from their stars.

The planet and star are separated by about 2.5 astronomical units. One AU is equal to the distance between the Earth and the sun. Until now, no small planet had been found farther than 0.15 AU from its parent star.

The finding means planet hunters are one step closer to detecting their holy grail: a habitable Earthlike planet that can sustain liquid water and support life.

Read more:


Earth's "Bigger Cousin" Detected

13 June, 2005

The discovery of the smallest extrasolar planet (about seven-and-a-half times the mass of Earth) was announced today. An artist's conception of this world is pictured above. It’s the first rocky world found to be orbiting a star similar to our sun, and as such "it's like Earth's bigger cousin," declared astronomer Paul Butler.
Read more here. or here.

Many "Earths" Are Out There, Study Says

SOURCE: National Geographic News
Brian Handwerk
April 6, 2005

A new study of known planetary systems outside our solar system gives a theoretical boost to the search for extraterrestrial life. Researchers in England say that half of the systems could harbor habitable, Earthlike planets.

Barrie Jones, an astronomer at the Open University in Milton Keynes, England, co-authored the new study. He said, "We were particularly interested in the possible survival of 'Earths' in the habitable zone."

"This is often called the Goldilocks zone—where the temperature of an 'Earth' is just right for water to be liquid at its surface. If liquid water can exist, so could life as we know it."

The location of a system's habitable zone depends on how bright and hot the that system's star is. The zone can shift over the eons as the star ages and becomes brighter and hotter.

Jones collaborated with Open University colleagues Nick Sleep and David Underwood. The team used computer models to map the habitable zone in some 130 known exoplanetary systems—star-planet formations found outside our solar system.

Read more:

Diamond Planets: Rich Possibilities for Other Worlds

By Robert Roy Britt
Senior Science Writer
08 February 2005

The solid planets in our solar system are made mostly of silicates. Rock, basically. A new study shows that planets around some other stars might be made mostly of carbon instead. Deep inside such worlds, where pressures are intense, the carbon would make layers of diamonds that could be miles thick.

The rich-sounding worlds are modeled after a certain type of space rock, known as the carbonaceous chondrite, which are thought to be broken bits of asteroids. Many of them have been collected on Earth.

"These meteorites contain large quantities of carbon compounds such as carbides, organics, and graphite, and even the occasional tiny diamond," Marc Kuchner of Princeton University said in a teleconference with reporters Monday evening from an extrasolar planet conference in Aspen.

The idea builds on other reasonable theories.

The planets in our solar system formed from a disk of gas and dust left behind from the Sun's formation. In regions where there was extra carbon or a lack of oxygen, carbon compounds like graphite and carbides would condense out of the mix, instead of stone.

Carbides are a ceramic used to line the cylinders of engines. They can take the heat of being very close to a star.

Kuchner and his colleague, Sara Seager of the Carnegie Institute of Washington, figure that concept fits nicely with discoveries of planets around other stars, including some that are surprisingly close to their host stars -- much closer than Mercury is to the Sun. Carbon planets could survive at high temperatures near a star, they say.

Read more:


Worlds: A Mission of Discovery

Book Review: 'Worlds: A Mission of Discovery' by Alec Gillis

This is essentially a movie style picture book. This book is huge. The width is just shorter than my keyboard.

The story premise is on space exploration. It is told in a photo essay way with captions and quotes. The write up is pretty interesting.

Here's an excerpt:

"Toxicity analysis showed that a large portion of the creature's body was incompatible with my digestive system, so I carefully avoided those areas. Even so, after eating I became violently ill, suffering nausea and hallucinations for two days. I discovered the only edible tissue is the facia between the skin and muscle. Even that tastes like a shoe marinated in battery acid."

The pictures included in the book are amazing, and big. They look as if taken from a real camera, with details like depth of field. The creatures created are very realistic. I've absolutely no idea how they create those creatures. A quick look at the credits on the back suggest a combination of 3D and sculptures.

This is an interesting book that can be read as fast as a comic book.

Visit the link beside to read more reviews on Amazon. If you buy from the link, I get a little commission that helps me get more art books for review.

Country-specific Amazon links for this book: /

Product Description:

Worlds is more than just an absorbing and, ultimately, heart-wrenching work of fiction, it is a visual masterpiece. Not since Wayne Barlowe's Expedition has an artist conceived an alien biosphere in such baroque detail, while remaining true to nature's fundamental principles of adaptation, selection and ecological interdependence. These worlds are intricately conceived, their biomes scientifically plausible, while possessing a sufficient sense of the quirky and outrageous to mirror nature's own outlandish inventiveness.

Worlds is a visual depiction of humankind's first exploration of life-supporting planets, shown in a dynamic vérité photographic style and told in a firstperson narrative. Created by Academy Award-nominated visual effects artist Alec Gillis, Worlds leads the reader on a journey to undiscovered landscapes, populated by unknown life forms. Worlds is a mission of discovery that becomes a struggle for survival, and in the process celebrates humanity's spirit of exploration.

"...a visual masterpiece...."
- writer/director James Cameron


The Habitable Zone

For an alien planet to house life it must be:

Close enough to its sun to receive enough energy.

Not so close to its sun that it's too hot for liquid water to exist.

This region around a star is known as the 'habitable zone'.

To learn more about: Habitable Zone , here & click here.
Stellar Ecospheres - The Habitable Zone of Stars & click here.

How Many Habitable Planets & Moons...
How Many Habitable Earths Are Out There?
How Many Habitable Planets Could Be Out There?


Astronomers find possible rocky planet

SOURCE: San Francisco Ghronicle
Keay Davidson, Chronicle Science Writer
Thursday, August 26, 2004

Earth-like orb spins too close to its star to be habitable

What might be the first known "Earth-like" planet orbiting a star like our own sun has been reported by European astronomers.

The discovery, if verified by further observations, unveils "a new class of planets" and points to a fresh stage of astronomical research, one that is profoundly relevant to the quest for extraterrestrial life, said Alan Boss of Carnegie Institution in Washington, D.C.

That stage is one about which science-fiction buffs have long dreamed: the detection of faraway planets that, like Earth, are relatively small, rocky bodies where plants and creatures might evolve.

"It looks to me like the first discovery of an extrasolar terrestrial- type planet!!" said an excited e-mail message to The Chronicle from Boss, who was not involved in the discovery but is one of the world's leading authorities on planetary formation. An extrasolar planet orbits a star other than our sun.

The planet is too small to be seen directly. The discovery, made by Nuno C. Santos of Portugal and 15 colleagues from France, Switzerland and Chile, was hastened by the development of a sophisticated new telescope that detects slight shifts in the star's motions as it is nudged back and forth by the tiny planet's gravitational pull.

Their find is suspected of being a rocky body that, like Earth, has an iron core. Although perhaps up to 14 times as massive as Earth, it is by far the smallest known planet yet seen that orbits a yellow, "G"-type star similar to our sun.

Another leading expert, Timothy Brown of the National Center for Atmospheric Research in Boulder, Colo., called Wednesday's news "really exciting. The people that do this (research) are among the best anywhere. ... The evidence (for a rocky planet) looks persuasive."

Inevitably, laypeople ask astronomers whether new extrasolar planets supply evidence for the possibility of alien life, Brown noted with a chuckle. Astronomers have long assumed that life, if it exists elsewhere, almost certainly evolved on a rocky surface like Earth's.

Read more:

Mars Missions Offer Clues in Hunt for New Worlds

Is there another Mars out there?

Within the next decade, NASA plans to develop space telescopes with super-sharp vision that can detect planets like Mars or Earth around other stars. In the meantime, learning as much as we can about our terrestrial next-door neighbors will help us understand what to look for, according to scientists at NASA's Jet Propulsion Laboratory (JPL) in Pasadena, Calif.

This image shows the Spirit rover probing its first target rock on Mars, Adirondack. Each mission to the red planet teaches us more about our terrestrial neighbor.

More than 100 planets have been discovered outside our Solar System, but they all are gaseous giants like Jupiter and Saturn. NASA's search for life beyond our Solar System hinges on finding smaller, rocky planets. As far as we know, only this type of planet could harbor liquid water on the surface, a feature considered essential to life.

Read more:


The Search for More Earths

SOURCE: Universe Today
Written by Fraser Cain
 July 12th, 2004

Until a decade ago, astronomers weren't even sure there were any planets outside the Solar System. You'd be hard-pressed to find anyone who believed we had the only planets in the entire Universe, but we still didn't have any direct evidence they existed. That all changed in October 5, 1995 when Michel Mayor and Didier Queloz announced they had discovered a planet half the mass of Jupiter orbiting furiously around a star called 51 Pegasi. The discoveries came fast; at last count, there are 122 confirmed extrasolar planets.

But these extrasolar systems generally look nothing like our own Solar System. Many contain massive planets which orbit extremely close to their parent star; no chance for life there. Planets roughly the size and orbit of Jupiter have been uncovered, but it's impossible for the current technology to see anything the size of our own Earth.

Fortunately, there's a series of ground and space-based observatories in the works that should be capable of detecting Earth-sized planets around other stars. NASA and the ESA are working towards the goal of being able to directly photograph these planets and measure the composition of their atmospheres. Find large amounts of oxygen, and you've found life.

Corot – 2006
The European Space Agency will be the first off the mark in the hunt for rocky planets with the launch of Corot in 2006. It'll carefully monitor the brightness of stars, watching for a slight dimming that happens in regular intervals. These dimmings are called "transits", and happen when a planet passes in between the Earth and a distant star. The concept of a "transit" should be fresh in your mind – Venus performed one recently on June 8, 2004. Corot will be sensitive enough to detect rocky planets as small as 10 times the size of the Earth.

A follow on mission, Eddington, was originally scheduled for launch in 2007, would have been able to spot planets half the size of the Earth. But it was recently canceled, unfortunately.

Kepler – 2007
The first space observatory designed to find Earth-sized planets in orbit around other stars will be Kepler, named after the German astronomer who devised the laws of planetary motion. It's scheduled to launch in 2007, and will also use the transit method to detect planets.

Kepler has an extremely sensitive photometer hooked up to its one-metre telescope. It'll monitor the brightness of hundreds of thousands of stars in a chunk of sky about the same size as your outstretched hand, and watch for that telltale periodic "dimming".

Over the course of its four year mission, Kepler should discover plenty of objects orbiting other stars, and its photometer is just sensitive enough that it should notice an Earth-sized planet as it crosses in front of a star for a few hours.

Space Interferometry Mission – 2009
Next up will be the Space Interferometry Mission, due for launch in 2009. Once in space, the SIM will take up a position in orbit that trails the Earth as it goes around the Sun, slowly drifting further and further away – this'll give it a good, stable view of the heavens, without having the Earth around to block the view.

The observatory is designed to measure the distance to stars with incredible precision. It's so precise, that it should be able to spot a star being moved through the gravitational interaction with its planets. For example, if you looked at the position of our own Sun from a distant point, it would look like it's wobbling around thanks to the gravity of Jupiter, Saturn, and even the Earth. SIM will be able to detect a star's interactions with planets down to the size of a few times the mass of the Earth. That's precise.

Terrestrial Planet Finder – 2012-2015
Unlike the previous missions, which will detect Earth-sized planets indirectly, the Terrestrial Planet Finder (TPF) will "see" them. It's scheduled for launch in 2012 and will nullify the light from distant stars by a factor of 100,000 times, revealing their planets. The final design is still in the works, but it could end up being a group of spacecraft flying in close formation, merging their light together to form a much larger virtual space telescope.

The TPF will pick up where SIM leaves off, surveying the habitable zone of stars 50 light years away from the Earth. Not only will it be able to see Earth-sized planets in these zones, it'll be able to analyze the composition of their atmospheres. Here's the key: the TPF will be able to spot the presence of oxygen, water vapour, methane and carbon dioxide in Earth-sized planets in the habitable zone of other stars. If could find the fingerprint for life in the atmospheres of these planets.

Find life on other planets, and you can assume that it's probably common throughout our Milky Way galaxy, and maybe even the entire Universe.

 Darwin – 2014
Shortly after the TPF gets to work, the European Space Agency is planning to launch Darwin; a flotilla of 8 spacecraft working together to find Earth-sized planets and search for the chemical signatures of life. Darwin will be the most powerful space-based observatory, providing images 10-times more detailed than even the James Webb Space Telescope (due for launch 2009).

Stars are billions of times brighter than the planets that orbit them, so Darwin will solve this problem by observing in the infrared spectrum, where this difference is much smaller. It'll also be capable of canceling out starlight to reveal the much dimmer planets.

Darwin is similar enough to the Terrestrial Planet Finder, that the two agencies are considering combining their designs into a single mission funded by both groups.

Maybe we aren't alone after all.
In just a decade, and less than 20 years after the discovery of the first planets orbiting other stars, astronomers should be able to supply us with an answer to one of the most fundamental questions humans have asked themselves… are we alone? If the Terrestrial Planet Finder hasn't turned up evidence of life yet, then the answer will still be, "not yet". But there's a chance that in 10 years, you'll be reading news that that life has been discovered orbiting another star.

But that won't be the end of it. The scientists will press on, with new equipment, observatories and techniques to search even deeper into space. And the philosophers and theologians will get to work considering our place in a very crowded Universe.