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

Scientists Believe that Uranus Took Two Massive Impacts

There is little debate that Uranus is a strange place. It is the only planet in the solar system to be 90º off axis and quite literally rolls around the sun. This odd sideways polar position for Uranus may have been caused from not one but two giant impacts. This comes from simulations that were run by two astronomers at the Observatory of Côte d'Azur in Nice, France. To get such a huge tilt, Uranus would have to have been smashed into by another planet the size of Uranus which would have totally disrupted Uranus' system of moons. Since that is not the case, the two astronomers suggest that Uranus could have been hit by two Earth sized planets several billion years ago. Scientists also suspect that Neptune may have been impacted very much like Uranus, leading many astronomers to reconsider their models of how the outer Solar System formed.........

Check out the Dvice article here

Gas Giant - Grow fast or die!

Now here is a discovery that must blow a big hole in planet formation theories. If you have been noticing lately, Jupiter class extra-solar planets have been found with surprising ease over the past few years. But according to observations done with NASA's Spitzer Space Telescope, the jovian gas giants are under the gun when it comes to formation.

Smithsonian astronomers examined the 5 million-year-old star cluster NGC 2362 and found the infra-red tell-tale of planetary formation...but with a twist.

According to the Science Daily blog:

• They found that all stars with the mass of the Sun or greater have lost their proto-planetary disks. Only a few stars less massive than the Sun retain their proto-planetary disks. These disks provide the raw material for forming gas giants like Jupiter. Therefore, gas giants have to form in less than 5 million years or they probably won't form at all.

The forces that play into gas giant formation are not yet clearly understood, however it is clear that these mechanisms are both fast and extremely efficient.


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