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Mysteries of the Universe


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The Seven Wonders of the World The Seven Wonders of the World, our world has grown, it is now spreading to the outer solar...
heliosphere The heliopause is the last frontier of the solar system, it is at ≈130 AU (20 billion km)...
vacuum state The vacuum has a considerable energy this vacuum energy would be greater...
leap second The leap second, which is added at the same time worldwide at 23:59:59...
Passage of the inert to the living Passage of the inert to the living: our chemistry, one that constitutes us, started...
structure of the Earth Earth in an aquarium: the materials are stacked in the order of their density, the iron to the center...
Geological time and mass extinctions Geological time and mass extinctions : the volcanic succession ones after...
Size of the universe What is the size of the universe? Behind this simple question hides extremely complex concepts...
recombination in cosmology.html Recombination, in cosmology marks the time where the universe became transparent...
seafloor relief The topography of the seafloor creates ripples on the surface of the sea that correspond...
magnetization Magnetism and magnetic moment: how works this invisible force, is the rotation of the electrons...
Modern cathedrals and large telescopes Modern cathedrals: the largest telescope is to come, E-ELT will be located in the Atacama Desert...
Hadean Hell of the Hadean: the Hadean is in the first million years of Earth history, at that time...
Primitive or primordial soup The primitive soup made of inert organic molecules has led to the emergence of life on Earth...
2015 International Year of Light 2015, the International Year of the Light. 2015 will reveal our history, still mysterious...
Theme of the week


Exoplanets are by definition located outside our solar system. The search for extrasolar planets is a real challenge for humanity, the underlying question that scientists are trying to answer is "are we alone in the Universe?".
Since the first discovery of extrasolar planets in 1995 (51 Pegasi b), a large number of space projects such as HARPS (2003), CoRoT (2006), Kepler (2009), JWST (2018) to Darwin (2020) have obtained funding.
Until 2020, the methods used to find exoplanets, are indirect methods (effect of transit effect on the radial velocity, microlens effect ...), that is to say that exoplanets are detected only by the effects that it induces on their star. But from 2020, with the DARWIN space project, all humanity will see an extrasolar planet directly and perhaps a exoterre.
How to detect exoplanets?
Transit (periodic micro-eclipse) occurs every time the planet passes between the star and the observer. At that time, the planet obscures some of the light from the star, producing a detectable periodic dimming. This remarkable idea is used to detect the planet and directly determine its size and its orbit. The diameter of Jupiter is 10 times smaller than the Sun, Jupiter mask so 1% of the luminosity of the Sun as it passes in front of a distant observer. Earth it is 100 times smaller than the Sun, so do mask 1/10000th of its brightness.
How to see exoplanets?
With Darwin, we'll see the planet or rather its atmosphere that reflects light from its star. Any light that is perfectly aligned with the telescopes (that of the star) will be extinguished and so the planet can be seen without being dazzled by the nearby star.
What are the biosignatures that will reveal the presence of life on distant exoplanets?
By analyzing the spectrum of light from the atmosphere of a planet, it is possible to detect the presence of chemical compounds such as carbon dioxide (CO2), water (H2O), ozone (O3), oxygen (O2) or other ionic assembly, and therefore no organic compounds based on a carbon skeleton. CO2 in large quantities and the water would be the signature of photosynthetic activity. Oxygen has a specific feature. This aggressive atom may not remain in a gaseous envelope around a planet because it binds very easily with metals and rocks, to make oxides. If there is oxygen in quantity around a planet that means biotic phenomena exist.

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Astronomy - The curiosity that characterizes humanity, has enabled man to understand the major astronomical phenomena and it now gives a dramatic sense stronger what is happening before our eyes.

« It is entirely possible that behind the perception of our senses, worlds are hidden of which we are unaware. »
Albert Einstein (1879-1955), Nobel Prize in Physics in 1921 for his interpretation of the photoelectric effect.

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