Solar System Builder (144.0K)
This Interactive will allow students to build their own solar system by placing planets of different masses at different locations and watching these systems evolve. Choose from a Sun and Earth system; our solar system up to Saturn; or 2,000 randomly-selected systems. Watch how a Hot Jupiter interacts with a Mercury-sized planet, or how Saturn interacts with a Mars-sized planet. What will happen? Check out the Interactive and see for yourself.

1		Is it likely that 51 Pegasi has an Earth in an stable orbit like ours? Why or why not? Need a Hint?
			A)	Certainly; it is the star alone that determines a planet's orbit.
			B)	Probably not, for the fast moving massive hot Jupiter would preturb Earth out of a stable, circular orbit in time and into a more eccentric one.
			C)	No, only jovians can exist around other stars.
			D)	No, any terrestial bodies would long ago have been caputured as moons of these jovians.

As with our own solar system, some of these stars have more than one companion already identified. We suspect that over time, these planets have come to orbital stability with respect to each other, just as we find in our own solar system.

2		Resonsances are important in stable orbits; we find that at Nu Andromedae, two jovians are known with average distances of 2.0 A.U. and 4.0 A.U. from their star. What does this resemble in our solar system? Need a Hint?
			A)	The orbits of Earth and Venus.
			B)	The orbits of Uranus and Neptune.
			C)	JThe orbits of upiter and Saturn
			D)	The orbits of Neptune and Pluto

In 1995, the discovery of a jovian planet orbiting the sun-like star 51 Pegasi every 5 days made us realize our own solar system is not the only model for planets orbiting stars. A decade later, our inverntory has passed 150 other solar systems. In this interactive and these questions, we open our eyes to the vast range of possible planets out there.

3		The hot jovians were the first planets found. Why? Need a Hint?
			A)	Only planets very close to their stars can eclipse them.
			B)	Jupiter is so far away from our Sun that its effect on the Sun's motion is not detectable.
			C)	The closer the massive planet is to its home star, the more its gravity deflects the star's motion, and the faster these wobbles will appear in the spectra.
			D)	They are the only type of planet that exists beyond our own.

In 1995, the discovery of a jovian planet orbiting the sun-like star 51 Pegasi every 5 days made us realize our own solar system is not the only model for planets orbiting stars. A decade later, our inverntory has passed 100 other solar systems. In this interactive and these questions, we open our eyes to the vast range of possible planets out there.

4		Which of these statements sums up the inventory of 150 planetary systems found to date? Need a Hint?
			A)	Most have circular orbits, but closer to their star than Jupiters.
			B)	As with our own system, there are about equal numbers of terrestrial and jovian planets out there.
			C)	Most are Jupiters where Mercury should be, with even more eccentric orbits than Mercury's.
			D)	The large jovians will destroy most terrestrials around other stars.

The Kepler mission for about 2010 will act as a terrestrial planet finder. If the masses of bodies like Earth are not sufficient to deflect their star's motion in space, then how could we find them.

5		On June 8, 2004, Venus transited the Sun. How could similar observations let us find Venus like worlds around other Suns? Need a Hint?
			A)	With better spectroscopes, we can find even smaller doppler shifts than Jupiters would produce.
			B)	A dark terrestrial world will occasionally transit its star, causing the star's light to drop slightly and with a regular periodicity.
			C)	With an occulting disk, we could block out the light of the star, and see the feeble reflection of its light off a terrestrial near it.
			D)	With radar, we could bounce waves off the solid surface of a terrestrial, just as we did to map Venus.