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Chemical Fingerprints: What The Planets Reveal About Alien Life Forms

In their search for extra-terrestrial life, scientists are zeroing in on so-called exoplanets. To narrow the field down even more, they use powerful telescopes to draw conclusions about the chemical makeup of those planets’ atmospheres.

Anybody out there? (Patrick Hoesly)
Anybody out there? (Patrick Hoesly)
Norbert Lossau

BERLIN - Twenty-two year ago sensors on the spacecraft Galileo picked up the existence of life on planet Earth. No big surprise. But what was salient about the experiment was that the space probe's analysis system reached an accurate conclusion.

When it comes to the discovery of life on planets outside the solar system – the so-called extra solar or exoplanets – researchers depend on the sort of information Galileo provided. So far, 770 exoplanets have been discovered, and some of them are similar to Earth in certain respects. Yet even if an exoplanet had an atmosphere and a life-friendly surface, there's still no guarantee that it hosts forms of life.

So how can the existence of life on these planets be established? Bio-astronomers begin with the premise that, as is true for Earth, the existence of life depends on the make-up of a planet's atmosphere. To analyze the chemical composition of the atmospheres of exoplanets, scientists use spectroscopic methods.

The principle underlying such methods is this: you choose a time when the exoplanet, as seen from Earth, is opposite its central star. If the planet has an atmosphere, some of that light will pass through it. Substances in the atmosphere will absorb certain wavelengths in a characteristic way. The result is that certain wavelength absorption lines can be seen through a suitable space telescope. These lines are the equivalent of chemical finger prints from which you can deduce whether the atmosphere of the planet contains oxygen, water, methane, or carbon dioxide.

From that information, in turn, various conclusions can be drawn. One indication of life, for example, is if a planet's atmosphere contains simultaneous concentrations of both oxygen and methane. That's because the interaction of the gases normally results in their mutual elimination – unless there are life forms to balance the concentration by regularly producing the gases anew.

Lisa Kaltenegger, 35, a scientist working at Germany's Max Planck Institute, has developed atmospheric models for exoplanets to be used as a basis for the interpretation of spectroscopic data gathered from space telescopes like the planned NASA James Webb space telescope. The space agency plans to launch James Webb in 2018.

Even if the presence of life on exoplanets can only be established indirectly, the news when it comes – "Extra Terrestrial Life Discovered!" – is going to be sensational.

For her scientific contribution, Kaltenegger was awarded the German research institute's 2012 Heinz Maier Leibnitz Prize which rewards work already accomplished and incentivizes further research with a 16,000-euro grant.

Read the original article in German

Photo - PatrickHoesly

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Geopolitics

How Russia And China Are Trying To Drive France Out Of Africa

Fueled by the Kremlin, anti-French sentiment in Africa has been spreading for years. Meanwhile, China is also increasing its influence on the continent as Africa's focus shifts from west to east.

Photo of a helicopter landing, guided a member of France's ​Operation Barkhane in the Sahel region

Maneuver by members of France's Operation Barkhane in the Sahel region

Maria Oleksa Yeschenko

France is losing influence in its former colonies in Africa. After French President Emmanuel Macron decided last year to withdraw the military from the Sahel and the Central African Republic, a line was drawn under the "old French policy" on the continent. But the decision to withdraw was not solely a Parisian initiative.

October 23-24, 2019, Sochi. Russia holds the first large-scale Russia-Africa summit with the participation of four dozen African heads of state. At the time, French soldiers are still helping Mali, Burkina Faso, Mauritania, Chad, and Niger fight terrorism as part of Operation Barkhane.

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Few people have heard of the Wagner group. The government of Mali is led by Paris-friendly Ibrahim Boubacar Keita, although the country has already seen several pro-Russian demonstrations. At that time, Moscow was preparing a big return to the African continent, similar to what happened in the 1960s during the Soviet Union.

So what did France miss, and where did it all go wrong?

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