Our universe

As far away as we are able to observe, our Universe reveals a very strange reality.  It is mostly made up of … emptiness.

Matter is found only within galaxies.

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Because they shine and emit light, the stars are the visible part of this matter.  (…)

They are, however,  so bright that they prevent us seeing dark masses, much smaller, that we call planets.

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The Sun is one of the very numerous stars in our galaxy, which is called the “Milky Way”  (…)

Its size and brightness are  rather modest (…) but it's an exceptional star because it is ours.

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Our planet, Earth, is the third planet among 8 in our solar system.

In addition to 8 planets, we find large numbers of smaller bodies like asteroids (…), comets (…) and dwarf planets like Pluto.

We regularly discover new stellar systems in the Universe, but the solar system seems to be unique because one planet, our planet, Earth, satisfied all of the conditions necessary for the appearance of life. (…)

For this reason alone, the solar system, which would otherwise be a stellar system like so many others,  is quite exceptional.