The rocky planets closer to the sun and the gaseous planets in the outer solar system are composed of different substances. Because billions of years ago, the "baby" solar system was split in two by a "keeper" of the universe, preventing the mixing of matter inside and outside the solar system. Previously, there was a theory that Jupiter played the role of "goalkeeper". But a new study suggests that Jupiter may not be up to the task. The goalkeeper, a ring of dust and gas, is currently in Jupiter's orbit, but is now almost empty.

       Twenty years ago, chemists realized that the composition of the basic unit of a planet (a star or a smaller "pebble") varies greatly depending on the distance between the planet and the sun. Compared with the pebbles that make up "land" planets (such as the earth), the pebbles of gas planets (such as Jupiter) are rich in more organic molecules, such as carbon and volatiles, or ice and gas.

       Stephen Moyes, a professor at the University of Colorado at Boulder, said scientists previously believed that Jupiter was the "gatekeeper" to prevent the mixing of materials inside and outside the new solar system, because Jupiter is so big and has strong gravity that it can swallow up some pebbles before they reach the inner solar system.

       To test this theory, moyce and ram Blaser of Tokyo University of technology in Japan used computer simulation to reproduce the evolution of early solar system and inner planets. The results show that Jupiter's growth rate is not enough to prevent all carbon rich pebbles from flowing into the inner solar system. Moyce said that Jupiter as a "gatekeeper" is incompetent, it is like a "big leak spoon", the material from the outer solar system flows into the inner solar system continuously, which means that the inner and outer solar system planets will have similar components.

       They therefore proposed a new theory: in the early solar system, there may be one or more rings of high and low pressure gas and dust around the sun. These rings can prevent pebbles from moving inward, possibly trapping dust and causing dust to gather into different clusters to form different planets. Moyce said the rings may be "gatekeepers" to stop pebbles from moving toward the sun from the outer solar system. Of course, the rings are not completely sealed, and carbon bearing pebbles can still flow into the inner solar system, creating seeds for life on earth.

       Source: Science and Technology Daily