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Mysteries of the Universe

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Astronomy for children
leap second The leap second, which is added at the same time worldwide at 23:59:59 UT, 23:59:60 is counted, the next second is counted 0:00:00 ...
   
Global Cloud Cover The sky on Earth is strangely dominated by clouds, but in some places, the shape of the landscape favors the deserts, the desert of the Tibetan plateau...
   
Passage of the inert to the living Passage of the inert to the living : our chemistry, one that constitutes us, started with a small molecular edifice built on a carbon skeleton...
   
structure of the Earth Earth in an aquarium : the materials are stacked in the order of their density, iron and nickel in the deepest and iron sulfide, silicates, water, nitrogen...
   
Neutrinos Neutrino beta emission: The beta decay (β) concerns neutrinos. This will happen during the decay of a nucleus...
   
Geological time and mass extinctions Geological time and mass extinctions : the volcanic succession ones after the others would they had an impact on the evolution of biodiversity...
   
Size of the universe What is the size of the universe?
Behind this simple question hides extremely complex concepts, and perhaps even...
   
2015 International Year of Light 2015, the International Year of the Light. 2015 will reveal our history, still mysterious, but more and more luminous because ...
   
Primitive or primordial soup The primitive soup made of inert organic molecules has led to the emergence of life on Earth. The first chemist to try this cuisine is Stanley Miller ...
 
recombination in cosmology.html Recombination, in cosmology marks the time where the universe became transparent to radiation. This is the time when electron ...
   
Adaptive optics and laser guide star Adaptive optics, laser star allows no longer be dependent on a real star, close to the observed object, so one reduces ...
   
seafloor relief The topography of the seafloor creates ripples on the surface of the sea that correspond to a mini background topology ...
   
magnetization Magnetism and magnetic moment: how works this invisible force, is the rotation of the electrons around the nucleus that creates the magnetic field in matter ...
   
diable de poussière sur Mars Unusual images of astronomy. Rosette Nebula, tattoos on Mars, double eclipse.
"It's better to see once than hear a hundred times."
   
Modern cathedrals and large telescopes Modern cathedrals: the largest telescope is to come, E-ELT will be located in the Atacama Desert in Chile, its first light are planned ...
   
Hadean Hell of the Hadean: the Hadean is in the first million years of Earth history, at that time the primitive nebula, ie the solar system formation is hell ...
   
simulator planets orbit Online simulator.
Mercury, Venus, Earth, Mars, Jupiter, Saturn, Uranus and Saturn from all angles with the Astronoo simulator.
 

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.

 
 

World population...

Disaster of great eruptionImage of pure gold atom seen by Scanning Tunneling Microscope
Super eruption or
global catastrophe...
Closer to the matter
image of the atom...
  
entropy effects, the passage of TimeSouth Atlantic Anomaly (SAA)
The passage of Time...
South Atlantic
Anomaly (SAA)...
  
Impact craters on EarthSpectroscopy, emission lines, absorption lines
Impact craters
on Earth
Spectroscopy inexhaustible
source of information...
12 particles of matter and bosonsThe problem of the rotation curve of a galaxy
12 particles of matter...MOND theory
and its contradiction...
atomic orbitals or electronic orbitalsEclipses, the orbital plane of the Moon
The atomic orbital
or image atom...
Eclipses explained by
plan lunar orbit...
 
  
Atomic clock fountain of cesium atomsChimborazo volcano in Ecuador, the highest mountain of the world
The incredible precision
of the second...
Chimborazo, highest
mountain of the world...
  
Bioluminescence of living organismsAberration of light
Bioluminescence of
living organisms
Effects of aberration
of light...
  
Merope nebula IC 349 and stellar windsPluton and its satellites
Stellar winds of
the Merope nebula...
Pluto system...
bullet cluster and dark matterPrinciple of absorption and emission of a photon
Bullet cluster,
evidence of dark matter...
Principle of atomic
absorption and emission...
Cycle de Saros et ExeligmosSensitivity to initial conditions, lorenz attractor
Saros cycle
and Exeligmos...
Chaos and sensitivity
to initial conditions...
 

Thème de la semaine

Exoplanets

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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L'astronomie pour les enfants
Astronomy for children...
 
Simulator, rotation and position of the planets (dynamic graphic)
Simulator, the
revolution of the planets...
 
Simulator revolution and orbits of asteroids
Simulator the round
of asteroids...
 
Definition of astronomical terms in SMS format
Astronomical terms
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