This article is taken from the journal Les Indispensables de Sciences et Avenir n°209 dated April/June 2022.
In every cubic centimeter of vacuum, there is a certain amount of energy specific to space, just by the fact it exists. At least that’s what the current Standard Model of cosmology suggests. An energy, of course, very, very little: not enough to boil a drop of rain in a cubic kilometer of empty space… Galactic Traveler’s Guide, “Space Is Big”, So great that this energy, equally present throughout its vast volume, is slightly more than twice the energy contained in matter, whether black or ordinary. The effect of this so-called “dark” energy – the only reason we don’t know its nature – is to accelerate cosmic expansion.
This strange idea took hold in 1998, when two teams led by Australian Brian Schmidt and American Saul Perlmutter announced that a supernova that exploded about 8 billion years ago appeared less bright and therefore farther away than expected. Until then, astronomers believed that the expansion of the universe had slowed steadily since the Big Bang, due to the gravitational attraction exerted on each other by galaxies – as well as decreasing the speed of the thrown object as it moved away from Earth. She goes.
gravitational attraction vs repulsive gravity
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