Earth's Abrupt Edge: 4B Year Old Star Encounter Revealed

[meteor]

"Computer simulations show a close encounter with a passing star about 4 billion years ago may have given our solar system its abrupt edge and put small, alien worlds into distant orbits around our sun."

http://www.astrobio.net/news/modules.php?op=modload&name=News&file=article&sid=1330

That's interesting. I've heard of people that exchage marbles, but exchanging planets seems more serious stuff

 

[tony873004]

"Computer simulations show a close encounter with a passing star about 4 billion years ago may have given our solar system its abrupt edge and put small, alien worlds into distant orbits around our sun."

http://www.astrobio.net/news/modules.php?op=modload&name=News&file=article&sid=1330

That's interesting. I've heard of people that exchage marbles, but exchanging planets seems more serious stuff

Actually, you don't need a supercomputer to do these kinds of simulations. I used a program I wrote called Gravity Simulator (www.gravitysimulator.com) to reproduce an experiment done by astronomers using a supercomputer to explore the orgin of Sedna's orbit. I got the exact same results they did.

Astronomers Alessandro Morbidelli and Harold F. Levison investigated Sedna's origins by performing numerical integrations using the Swift_rmvs3 orbit integrator to explore the idea that Sedna may have once been gravitationally bound to another star or brown dwarf, and stripped away by the Sun, where it entered a highly eccentric solar orbit.

Using Gravity Simulator, I reproduced their experiment. Morbidelli and Levison set up the following starting conditions: The visiting brown dwarf has a mass of 0.05 solar masses. It is has a velocity of 1 km/s relative to the Sun at infinity. Its approach distance to the Sun is 200 AU. The brown dwarf has a disk of test particles orbiting it in the plane of the encounter at random distances between 20-100 AU.


In Morbidelli and Levison's experiment, 44% of the Brown Dwarf's objects were captured into Solar orbit. In Gravity Simulator, consistent with Morbidelli and Levison's experiment, 8 of 20 objects were captured into Solar orbit.

As the simulation begins, the Brown Dwarf system is closing in on the Solar System
from a distance of just under 1 trillion kilometers.
http://orbitsimulator.com/gsimyabb/1.GIF

The Brown Dwarf system closes its distance to the Sun.
The green planet around the Sun is Neptune.
http://orbitsimulator.com/gsimyabb/2.GIF

As the Brown Dwarf system gets even closer,
the Sun's gravity starts distorting the system.
http://orbitsimulator.com/gsimyabb/3.GIF

The Sun sends a strong gravitational tidal force through the Brown Dwarf system.
Objects outside the Brown Dwarf's Hill sphere are stripped away.
Some enter a Solar orbit.
http://orbitsimulator.com/gsimyabb/4.GIF

After all the dust has settled, 8 objects which originally orbited the Brown Dwarf
are now orbiting the Sun, some in Sedna-like orbits.
http://orbitsimulator.com/gsimyabb/5.GIF