Erdachen worlds in sight

Soon the first earth-toothing exoplanet in the network of planetary fishermen – Europe currently has the nose ahead thanks to Corot

Gemach, Gemach. In contrast to the message of the ESO of April last year, which fails many newspapers, in particular boulevard-blooded – any critical distance -, there is no the least notice for a "second earth" so far. Anyway, a "second earth" can not exist, but our planet – Nomen Est Omen – in the vastness of the ALLS is also a unique piece like all its planetary brother. At best in a parallel universe, a counterpart of the earth could drift .. . Nevertheless, either in the foreseeable future or at the latest in the next decade, the planetary anniversaries more than just an earth-tooth exoplaneous trail. It’s all just a matter of good technology and sufficient time – and both are the hard-working planet’s jags, though they needed more money for their creative and so important work urgently even more money and deserved.

Erdachen worlds in sight

Our home planet – on "outdoor" or. He will not miss a carer dirt planetard. Credit: NASA

Even before two decades, pessimism infected astronomers have negated the existence of planets outside of the solar system smoothway. There was drunken, so it was unexpected dogma, at best accomplish asteroids, stars and galaxies the room with "material" life. Of Lunaren, let alone planetary startrabants be noticeable any traces.

Credit: NASA

More planets as stars

In the meantime, in the annals of the history of science, a contrary knowledge of publishes has been found: in our dairy strain – and thus also in all the other 100 to 500 billion galaxies "of our" universe – planets have all the sparkling stars have expired the rank. They are stronger and more numerous represented with gross security than all stellar structures that flood all with light. While the notorious ignorant once more of a better, the optimists are intolessed in their forecasts, as Charles Lineweaver from National University in Canberra (Australia). He has been going on for several years that at least 30 billion ground planets alone in the galaxy reflect the light of their suns.

Erdachen worlds in sight

Lonely and lost – a galaxy in which billions of planets are located … Credit: NASA / Dietmar Hager

Certainly, which are officially confirmed extrasolar planets, from a few exceptions – once again – primarily highly highly successful planetary contemporaries who have little common with our home planet have little mean and allow biological life due to their peculiarities. Experience is presented as uberdimensioned heater gas giants, whose coarse amongwhars between Neptune and Jupiter, sometimes even several Jupiter masses has. Only a few turned out to be mass-bearer or as potential hoarding. A second earth, at least one earth-tooth planet, who really softened this attribute to honor, was not below it. Nevertheless, those around the globe with earth-bound observatories and space telescopes are set up 270 planets, which in 221 different planetary systems [stand: 5. February 2008] have become approached, only the top of the top of a huge cosmic iceberg, which is increasingly waking up. It is becoming more and more – and in the face of the always sensitive instruments, you will be getting smaller, masseimmer and thus always more earthy.

The coarse in the planetary Bound of the solar system is not alone. There are still numerous other colleagues Jupiters who move in his "weight class". Credit: ESA

Supposed "super earth"

Like ground arm, of which the public in April in April last had a picture when the European sadstierwarte ESO launched the message, scientists had the smallest and mass-rich extrasolar planet spurted. In fact, this was localized using a sophisticated observation stick and technology and a special apparatus with the 3,6-meter telescope of the ESO in the constellation Libra (Lat. Libra) An exoplanet with the only 5-fold ground ground, which has only the 1.5 fold Earthradius. 20.5 light-years removed from the earth, he surrounds his hometimes Gliese 581 once within 13 days. Although he circles his mother sun in a distance of only 10.7 million kilometers (this is 14 times lower than the distance earth sun), are to prevail on this distant world temperatures between 0 and 40 degrees Celsius. Flow water goods in this world theoretically conceivable, as the planet in a habitable zone position and therefore keep liquid water. So at least the statement of the ESO.

Although GLIES 581C still pays to the smallest or marginest exoplanets, but from a "second earth", a "super earth" (here the question arises, what a "super earth is supposed to be overhead), as many newspapers still before one half year, can no longer be in the least speech, not least because gleade 581c circles a so-called red dwarf star of type m. Solar stars are exposed durable (depending on the ground they become up to 50 trillion years old), very light and mass-arms stars, which are estimated more than 70 percent of all stellar formars in the milk strain. On average, this star class is far small, cold and lights average 50 times more weak than about stars of the type of our sun. Meanwhile, there is unity that the supposed earthly planet around Gliese 581 is at best at the inner edge of the habitable zone and is too close to his sun, which is why it was extremely warmed to him, to heave for the training of biological life forms, as we You know and skate.

Erdachen worlds in sight

The earth is the only planet of our solar system exactly in a habitable zone. Nevertheless, biological life forms could also have found a niche outside of this region. Credit: NASA

Gleade 581D – by no means obvious

During the gleade 581C thus fully booked his status as an earth-tooth planet, the attention of the astronomers was irrelevant to his planetary brother, which was discovered at the same time. Gleade 581D, so the name of the planet with the eight-fold ground mass, surrounds his sun within 84 days once. Already in July 2007, it crystallized that Gliese 581d could be a cheeky candidate for life.

Credit: ESO

Gleade 581D is – just like our moon around our earth – during an orbit exactly once again around its own axis and always shows his mother’s star the same side, which results in that on one side of the planet always night and thus clinking cold, on the otherwise continued day and ergo permanent heat the climate Prague. In other words, only in those transition zones between "day" and "night" could have been trained. Notwithstanding his eight terrestrial masses, Gleade 581d could be an earth-toothing and more life-friendly conditions than the supposed "super earth", which – as well as generally accepted – not the status earthly deserves, although gleade 581c could certainly be a habitable world.

Credit: NASA / David A. Aguilar (CFA)

The first of its kind

If it is reserved for a telescope, if it has ever earned a probe to discover the first real earth-tooth planet, then this is Corot (convection, rotation and planetary transits). The space telescope has been attracting since 27. December 2006 in a polar orbit in 826 kilometers of its circles and copied his service officially on the 3. February 2007 on. The high-tech saving room starters the first of its kind to target and systematically rigorous to extrasolar planets, which are a bit massive than the earth.

On the 27th.12.2006 at 8:23 am local time or. 15:23 o’clock mez started Corot into the all. Image: CNES / AAS / STARSEM

The 4,20 meter high and 670 kilograms of heavy ESA satellite with a 27-centimeter mirror is so sensitive and effective that it could even track an exoplanet from the double mass of the earth. The precision of the four CCD detectors (spectral range of 370 to 950 nm) from Corot is currently unrivaled according to the Osterreich astrophysicist Werner Wolfgang Weiss: "A MUCKE could fly past a floodlight plant, and Corot was measure the occurring brightness fluctuation from over 800 kilometers away."In order to find a sky corper with a few earths, Corot nevertheless needs a lot of gluck, but the space operates on the basis of the transit method, in which researchers measure the brightness fluctuations of a star, which are caused by passing planets.

The transit of the first extrasolar planet discovered by Corot . This planet was discovered because he passes past his star and darkened him at short notice. The decrease in star brightness is clearly visible. Image: cnes

Unfortunately, transits, so passed through planets in front of the bright slice of their mother star, are rare statistically, so that successes can only be achieved on the virtue patience and perseverance. And as already mentioned, the planetard must have the unknown factor Happiness repeatedly. For justifies planets via transit can only be trailing if the perspective of the observer of the startrabant is between telescope and extrasolar sun and the planetary car is almost perpendicular to the sky level. Only then can the slightly fused stellar light be measured and the invisible planet are made indirectly "visible", whereby the extremely low fluctuations are difficult to calculate. Nevertheless, the scientists can conclude from the intensity and duration of these fluctuations on the rough and orbit of the planet.

Erdachen worlds in sight

To ensure that the satellite that can hold the vibrations at the start, Corot was already pushed through in advance. Credit: CNES

Two is Better

No wonder so that Corot’s success rate with so far two confirmed exoplanets is at first glance. In truth, however, the probe is in a perfect condition and operates without errors and very successful. Meanwhile, the Corot scientists have launched only two discoveries so far has a scientifically sound background. For, in contrast to the NASA, which operates an offensive press work and quickly attracted with sensational messages, the ESA, the CNES (French Space Agency) and the DLR, with intent in elegant accessibility, to avoid misunderstandings and unnecessary mistakes.

Corots First light took place in the night of the 17th. On the 18th. January 2007 Credit: ESA

The worldwide scattered planetary community has consistently learned from errors of earlier days. Passing the times, since many of the pronounced researchers could rely on the rapid rediscovery of an exoplanet, without his earnings previously multiple mapping or by an independent resp. Alternatively check the alternative measurement method. In this regard, the specifications are very strict at the Corot research team. If the European satellite registers about a transit, a second source, better said a telescope operating on the principle of the radial speed method, confirm the status of the supposed planet.

In this technique, the Planetenjager focuses its attention primarily on the gravitational power of the suspected planet and the resulting small movement of its central star. If the observed star begins to eggs, its rhythmic shifts can be determined by changing the radial speed. Only after such a MEng’s new planet creates the leap into the "European" encyclopadia of the extrasolar planets, which catalogs and manages Jean Schneider.

Erdachen worlds in sight

Corot is looking for Massearmen Exoplanets, but also explores the interior of stars with the help of astroseismological measurement methods. Credit: CNES 2006 – D. Ducros

Carrying the fact that transits are rather a rare phanomena, Corot therefore scans many stars simultaneously. For about five months each, the satellite 27-centimeter telescope is a total of five sky fields and at the same time monitor about 12.000 stars whose light is disassembled with a prism in multiple colors to better distinguish coverages through planets from other brightness fluctuations. Whether Corot ever discovered an earth-tooth planet, depends on many factors that are not predictable; Nevertheless, the Swedish astrophysicist and ESA project scientist of the Corot Mission of Malcolm Fridlund is choosing optimism. "Corot will deliver the first image of an earth-tooth planet, which circles a different home star."

Corot has a star field for five months with more than 12.000 stars in view. After the planned mission duration of three years, Corot is therefore a total of 60.000 stars with apparent brightness between 11. and 16. Have observed the order. Image: cnes

Currently three transits upgrade

The fact that the scientists of the Corot team can not be published every discovery of an exoplaneet immediately, is in the nature of the transit method. If Corot became a hitherto unknown planet, which is the blobe just before his homternattern and whose light is slightly fused, this unique transit was far from being done to initiate follow-up observations. "To pay as ‘planetary candidate’, a possible transit must always take place at least three times. So you have to wait a long time for further distant planets, "explores Prof. Dr. Heike rough, project manager of the Corot participation of the DLR and scientist at the DLR Institute for Planeto Research in Berlin-Adlershof. "It will depend on the models of telescopes on the ground, whether we can also go to examine candidates after one or two transits on radial speed variations."The factor" Time "also wins a special weight by the Current Current Current, as the probe can only explore planets with a maximum of 50 days of circulation period as a result of the polar Erdorbit. In other words. To register a total of three events, so Summa Summarum to record three transits, the researchers have to invest half a year. And time costs money … also in exoplaneto research. Only then will the earthbound telescopes be called on the plan, such as the 3.6-meter ESO observatory in La Silla (Chile) or the best telescope at Observatoire de Haute-Provence (OHP) in France. For this purpose, Heike rough opposes Telepolis:

This type of successive monitoring is about providing the signal of planetary candidates photometrically. First of all, we would first see if it really is the star, which shows a transit in the light curves, and not a double star standing in the sky. This helps to save time and effort to save the radial speed quantities.

Originally considered to be a mission with eight telescopes, Darwin had to pay the financial closures of the ESA tribute. It starts all probability from 2015 with a total of four satellites. Credit: ESA

Stripped Darwin mission

Corots Mission must be seen in a rough connection. Last but not least, it should name as a scouting mission of powerful space telescopes the way to all. For to find planets from the rough of the earth in habitable zones, in the opinion of many researchers even more sensitive telescopes and more long-range observation times will be of notes. The NASA high performance telescope Kepler, which is intended to scan a certain sky cutting on an earth-tooth planet for several years with its 1.4-meter mirror for several years, fills these conditions.

Erdachen worlds in sight

Still under construction, but already in February, the NASA satellite Kepler should relate in the earth’s matroad position in order to find soothing and puncto mass even smaller planets. With very rough chance, this mission will start early in the end of 2009 … Credit: NASA

And six years later dared the ambitious ESA mission Darwin the next step. It should originate from eight satellites, but has existed for some time but on the paper only as a slackened version with a total of four elements.

Provided that Darwin aboard an Ariane-V or Soyuz-Fregat missile forced the Jump to the so-called Lagrange point L 2, which is 1.5 million kilometers away from the earth from an operating point where the gravitational force is the Keep Libra, so that spaceships are quasi quiet in the room, the four satellites will disconcerate a number of earthly planets. Finally, the interferometry super telescope can survey the captured radiation such that the image sharpness of a 50 meter coarse tension tube is generated, which in turn helped Darwin, not alone to take up earth-tooth planets, but also to search in their atmosphere for chemical traces of life.

Lagrange point L 2 Credit: ESA

Equipped with four individual spacecraft, three of which are each added with an infrared telescope with a main mirror diameter of three to four meters and the number four is to maintain the light of the trio bundling and at the same time as the central station the contact with the blue planet, the signals of the Three telescopes combined according to the principle of the NULLING interferometer.

Thanks to the resulting sensitence of the telescope, the astronomers can even study the chemical composition of the atmosphere of "earth-close" exoplanets. The jointly operating telescopic infrared spectrographs make it possible. But they only occur in action when Darwin has a promising candidate spurt.

Biosignatures indicate live

By means of a spectral analysis in which the light reflected light is disassembled into its various color components, the detectors in the infrared light evaluate the temperature and chemical composition of the respective planet atmosphere. Since each chemical element leaves a unmistakable fingerprint in the light spectrum, all biosignatures betray: so everything that indirectly suggests life.

Erdachen worlds in sight

What Auberrish Planetary Jam with us on biosignures "saw" … Credit: ESA

When the telescopic spectrographs of the Darwin fleet disassemble the light reflected by the planet in its color components and found gases such as oxygen, water vapor, carbon dioxide or methane, this was a strong indication of the presence of water and biological activity on the distant world. This can determine the temperature and chemical composition of the exoatmosphere.

Found the researchers on an earthy, in a habitable zone planet for about oxygen, which arises on earth as a by-product of photosynthesis, and detected them there also ozone, another form of responsive oxygen, would be a strong indication of life, But did not do absolute security because the researchers know many non-biological processes that can lead to an oxygen-containing atmosphere. Unnould the discovery of Ozone ever been a step in the right direction.

Venus. Hollish neighbor, on which a great likelihood no biological life exists. Some researchers still believe that in Venus atmosphere could live in a high of 50 kilometers of microbes. Credit: ESA

Nevertheless, the best indication was allowed to be the presence of oxygen together with methane or carbon dioxide because this combination is often found in the earth’s atmosphere. Liberty but only one index proof – not more, but also less. However, who liked it exactly, must already make the sample from examples and fly there.

Attractions (unfortunately in bad resolution) Video Ober Corot

How the ESA wants to prove living on exoplanets: an interesting ESA animation.

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