Quark Dictionary of astronomy, letter Q It is one of the six particles that, it is believed, are the basic constituents of elementary particles called hadrons, such as the proton, the neutron or the pion. The quark concept was independently proposed in 1963 by American physicists Murray Gell-Mann and George Zweig.
Astrobiology Dictionary of astronomy, letter A Astrobiology is a branch of astronomy that investigates life in the Universe, in the broadest meaning of the term. Synonymous with astrobiology is "exobiology," that is, the biology of outer space. Astrobiology begins with the study of the appearance of life on our planet.
Jupiter is the fifth planet from the Sun, and the largest in the Solar System. It is the first of the so-called giants or exteriors. Jupiter is 1,400 times more bulky than Earth, but its mass is only 318 times that of our planet. The average density of Jupiter is a quarter of the density of the Earth, which indicates that it must be made up of gases rather than metals and rocks such as Earth and other inner planets.