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damienpaul
2004-Jan-12, 01:27 AM
After reading many theories about the oddities in the solar system, namely for Venus, Uranus etc - I was wondering, just how many planets were there in the early solar system? and what was the cause of the sort of solar system billiards that knocked everything about?

Littlemews
2004-Jan-12, 02:11 AM
I was wondering, just how many planets were there in the early solar system?
If u count those Minor planet as a planet, then there is more than 9 planets in the solar system.


and what was the cause of the sort of solar system billiards that knocked everything about?
I am not sure what cause this, but refer to all those book saids, it's Meteorites that cause of sort of solar system billiards that knocked everything. Something when it gets hit, it will move when there is no air (Newton's 1st law), until it hits other boject... if the impact is too powerful, then it can blow up the entire object into pieces..

damienpaul
2004-Jan-12, 02:23 AM
actually, i was referring to the primitive solar system and about mercury-->mars sized objects as a minimum - the reason I ask, is because it looks like that venus, earth, uranus and possibly mercury have copped a massive hammering in the past.

jkmccrann
2005-Oct-30, 05:52 PM
After reading many theories about the oddities in the solar system, namely for Venus, Uranus etc - I was wondering, just how many planets were there in the early solar system? and what was the cause of the sort of solar system billiards that knocked everything about?

I would posit that that's a pretty much impossible question to pin down to an exact number, but I don't think it would be that high, I guess it comes back to how you define a planet again! hehehehe

The battering that the Terrestrial planets have taken, and the battering that we can see, particularly on places like Mercury & The Moon is by objects nowhere near approaching the size of the planets we have in the Inner Solar System, it is by objects much smaller, much like those we find in the Asteroid Belt and Kuiper Belt at the minute.

Before a relatively stable system can be reached, like we have now, it's going to be inevitable that the higher number of objects competing in the smaller space are going to be involved in a lot of collisions.

Have you heard the one about the Mars size object canoning into Earth and creating the Moon? Now there's something to consider in all this, and probably the major example we could refer to in terms of collisions with the Earth.

ngc3314
2005-Oct-30, 07:11 PM
After reading many theories about the oddities in the solar system, namely for Venus, Uranus etc - I was wondering, just how many planets were there in the early solar system? and what was the cause of the sort of solar system billiards that knocked everything about?

It is a law of solar-system dynamics that an object will stay in orbit until it hits something else. The planets we see today are the end (or more accurately "current") results of the system's whole history of acretion and fragmentation. For the major planets, this process effectively froze once there were a small number of big masses in well-separated orbits. Carl Sagan supervised several students in early simulations of how different random realizations of protoplanet distributions might end up, finding that it's not too unusual to have giant planets in the middle of the radial distribution and smaller ones on the inside and outside. They thought this supported the mediocrity of our solar system, something perhaps belied by the hot Jupiters and so forth which turn out to be numerous. The next chapter came with understanding of how iant planets and protoplanetary disks overlap - Doug Lin and company missed a smashing prediction over 20 years ago when their simulations suggested that lots of giant planets should migrate inward and perhaps all the way to the star.

Kaptain K
2005-Oct-31, 06:07 PM
It is a law of solar-system dynamics that an object will stay in orbit until it hits something else.
Actual collision isn't necessary. An object the size of Jupiter swinging through the inner system would send the inner planets flying. An object the size of Earth could eject Mercury and (probably) Mars.

Planetwatcher
2005-Nov-03, 09:42 AM
I know of a program on the National Geographic channel recently dealing with the birth of the Earth, which claimed there may have been 20 or more planets in the inner Solar System which formed the 4 we have today.

redshifter
2005-Nov-03, 08:31 PM
I saw that program, it was very interesting. Basically, that is what they were showing as well, that at one point there were many planets in the inner Solar System, but over time many collisions occured, resulting in the planets we have today. They did a very interesting simulation on the formation of the moon, that a very large object collided with Earth at a very shallow angle (more like a 'glancing blow') and the resulting debris formed the moon.