The kind of numeric simulation you describe almost certainly is not conserving energy due to the failure to appropriately handle close perigees with tiny time increments in the numeric approximation. That's the main reason why these things produce high speed "projectiles".
On Thu, Dec 19, 2013 at 3:48 PM, David Roberson <[email protected]> wrote: > I have been enjoying the* Planets* simulation on my Linux system and > noticed something that gave me a bit of concern. Perhaps some of my > fellow vorts have information concerning the issue that I am about to > mention which sheds light upon the real danger. > > When I play with a system that contains a large multitude of planet like > objects generated randomly within a small region of space I see that in > every case many of the objects are ejected from the region at a high rate > of speed into open space. I am not too confident that the program does a > great simulation of the real process since it operates in 2 dimensions only > while the real systems use 3. > > My concern is that this process would typically send a large number of > dangerous mass objects into the region between stars and as a consequence > some in our direction. The ones that cross our orbit could lead to a > catastrophe if they were to collide with the earth. The objects that do > not collide would likely continue on their paths through space and out the > other side of our solar system. > > Is there reason to consider this situation as dangerous and is there > evidence that this has happened before? Today, most of the comets and > asteroids are considered in orbit around our sun, but is that the only > condition? > > How close to earth would an asteroid need to pass before it is detected by > our systems? And, if the size were large enough to cause an extinction > level event, would we see it before it was too late? > > It is fairly well established that the history of earth has included many > extinction events and they have generally been assumed to be from objects > in orbit around the sun. Does anyone know of any proof that none from way > out there has impacted us? > > I recall reading about a period of earth's history where a large quantity > of collisions came after the earth was similar to today. This happened > when the earth was millions if not a billion years old and since the sun > was formed along with numerous brothers, perhaps some of the ejections from > it's twins caused the event. The delay would have give them enough time to > reach us from adjacent star systems if traveling at a high velocity. > > Do we have reason to worry? > > Dave >
