because the gravity keeps the giants planets' gases from escaping.
because the gravity keeps the giants planets' gases from escaping.
Jovian planets have a much stronger gravitational force due to their larger mass.
the planets have very strong gravitational pulls.
Because the mass of the planet holds it down.
Thermal energy causes some of the molecules at the outer edge of the Earth's atmosphere have their velocity increased to the point where they can escape from the planets gravity. T;)
The atmosphere is held in place by gravity. Other things being equal, the more massive the planet, the harder it is for a gas molecule to escape into space.
The terrestrial planets are less massive and therefore have less gravity. As a result, much of the lighter gases could escape, in the process of planet formation.
The Jovian planets have much higher escape velocities.
First, dust, debris and gases, left over from the formation of the sun and the planets. Second, gases and radiation produced by the sun (eg. solar wind). Third, various spacecraft and other technological artifacts, shot into space by humans (eg. the Pioneers and Voyagers launched by NASA).
Jupiter gases do not escape because Jupiter has enough gravity to hold the gases in place.
While terrestrial planets are made of rock and have gases in the atmosphere, jovian planets are made almost entirly of gases. If an atmosphere is made of gases in a planet, then the atmosphere of the planets with more gases will be thicker.