Presentation on theme: " The outer planets are called Jovian or Jupiter- like. These planets are made of gas and are several times more massive than the Earth. The Jovian."— Presentation transcript:
The outer planets are called Jovian or Jupiter- like. These planets are made of gas and are several times more massive than the Earth. The Jovian planets grew to present size in about 10 million years. When studying outer planets you must take into account their size and position.
Jovian planets grew mainly from the gas in the solar nebula. The rotating gas and dust of the solar nebula may have become unstable and formed the outer planets by direct gravitational collapse. This means the outer planets were able to form from the gas without first forming a dense core by accretion.
The Jovian planets formed in the outer solar nebula, where the lower temperatures allowed the gas to form large amounts of ices. (Three times more ices than silicates for inner planets) The Jovian planets then grew rapidly and became massive. They had enough gravity to attract vast amounts of nebular gas and grew rich in helium and hydrogen the light gasses.
The four Jovian planets may have formed closer to the sun in the region of Jupiter and Saturn. Gravitational interactions shift Jupiter slightly inward and Saturn slightly outward. That forces Uranus and Neptune to migrate rapidly outward to their present orbits.
Migration would have happened over many millions of yrs. It effected smaller objects dramatically. 1. pushed the Kuiper belt objects to larger orbits. 2. flung many planetesimals into highly elliptical orbits, and they hit planets.
Jupiter grew massive and because of its position, it was able to gravitationally disturb the motion of near by planetesimals. The bodies that should have formed a planet was thrown into the sun or out of the solar system. The asteroids we see today are the last remains of the rocky planetesimals.
Comets are the last of the icy planetesimals. Some comets formed in the outer solar nebula beyond Neptune. Many comets were ejected far into the outer solar system by the massive Jovian planets
Large satellite systems of the Jovian planets contain two kinds of moons. 1. Moons formed in orbit around the forming planet. 2. Moons may be captured planetesimals and asteroids.
A large mass makes it easier for a planet to hold onto orbiting ring particles. Being farther from the sun, the particles are not as easily swept away by the pressure of sunlight and the solar wind. This is why no rings are around inner planets and are found around outer planets.