Did the Solar System Have Many More Gas Giants Early In It's History?

Back when the solar system was only 600 million years old the system looked and acted much much stranger than it does today. For instance it now appears that at this early stage in the formation of the solar system there may have been more than four giant planets initially, and some were ejected into inter-stellar space. This conclusion is borne out by the fairly common occurrence of free floating planets that already exist in interstellar space.

From the Daily Galaxy article:

Dr. David Nesvorny of the Southwest Research Institute states that these conclusions:

• come from the analysis of the trans-Neptunian population of small bodies known as the Kuiper Belt, and from the lunar cratering record.

However the problem that arises from this conclusion comes from the orbit of the gas giant Jupiter which would have imparted much more kinetic energy to the inner system possibly causing Mars or Venus to collide with Earth!

There is a solution it would seem. Computer simulations of Jupiter and the other gas giants during this period of great instability have shown that Jupiter did not stay in it's present orbit but "jumped" into orbits closer to the sun plus swapping orbits with Uranus or Neptune. One weird thing kept coming up when the simulations were run with the present plants in place. When Jupiter skipped in towards the sun, it would have destabilized Uranus or Neptune's orbit ejecting them from the solar system...since that DIDN'T happen then there must have been other planets of similar size and mass that were ejected. Since free floating planets have been observed, it isn't much of a stretch to consider our own system doing something similar.

Check out the Daily Galaxy article here