The latest vertigo of cosmologists came at the turn of the 21st century: despite glasses and telescopes, observatories and supercomputers, it appeared that 68% of the content of the Universe just escaped them! Only 4.9% are indeed visible, the remaining 25% being the enigmatic dark matter. A new entity - majority and equally enigmatic - has burst into their discipline: dark energy. Before it, since the 1930s and thanks to the observations of the American Edwin Hubble, the astrophysicists had a fairly quiet mind: they had established that the space was expanding and that the matter, by its gravitational force attractive, ' opposed this expansion. The future of the universe depended only on the duel between expansion and gravitation. However, since dark energy has intruded into this duet, scientists are finding that space is swelling more and more quickly while the entity that causes this acceleration remains enigmatic. What is its nature ? Has she always existed? How much does it dilate the Universe? To answer this, cosmologists are counting on the European Space Agency's next mission, Euclid, which is scheduled to launch in 2022.
Some types of supernovae quickly attracted a lot of interest
It all started in 1998, with the precise observation campaigns of the supernovae, these stars which, exploding, see their luminosity suddenly increase up to 200 million times that of the Sun. Seen from Earth, they appear as a new star in the firmament and the archives report these periodic appearances. However, certain types of supernovae have very quickly attracted a lot of interest because their real brightness - that is to say intrinsic - is known, which makes it a valuable object. Indeed, it is very difficult for astronomers to know if a star shines a little in the sky because its brightness is low or because it is [...]
