There is a very cool program called Universe Sandbox. It lets you mess around with the universe by adding planets, changing the size of stars, etc. You can even place silly things like bowling balls and dice. I downloaded the free demo, which includes the premium features for an hour, and basic simulation viewing as long as you want.
I must say, I’m very impressed. I opened up the Solar System simulation and placed the biggest star I could find just outside the Asteroid Belt . The gravity sucked everything into it within days(seconds in real-time). I was strangely… pleased. 😈 Anyway, It is a very cool program.
Some screen shots from Google Images:
This is Endor. Yes, it is in the game. The Death Star is even there. Geeks UNITE!
I divided by zero, and now a bunch of stars are in a row. Never. Divide. By. Zero!
I wonder if eggs would really orbit bowling balls in zero-gee...
I am extremely impressed and I plan to buy it when I have the money. Here is the link:
THE VERDICT:
Pros:
*Very cool
*Includes a Star Wars Easter egg
*Extensive tutorial
*Reasonably easy to use
* Graphics are simply stunning
Cons:
*A bit expensive, at an asking price of about $20, or $10 on Steam
*Not always accurate, especially on higher times per second in the Solar System simulation
*Planets just get a bright impact point when hit by a smaller object, but will occasionally get bigger when hit by another planet
SCORE : 8 out of 10
Nathan the Jedi Master 