Neutron Stars Interactive (125.0K)

1			Jocelyn Bell of Cambridge initially discovered pulsars while looking for possible signs of ET. Why did she mislabel the first she found LGM-1 (for little green men)? Need a Hint?
			A)	Pulsars are powerful beams pointed just at us.
			B)	Pulsars carried encoded messages.
			C)	Pulsar signals repeated with seemingly artificial precision.
			D)	Pulsar signs are in the form of laser light, not a natural phenomena.

In this interactive, we can change both the spin axis relative to us, and the magnetic fields tilt to this spin axis. The results were very dramatic.

2			In what special situation did the pulses cease? Was this realistic? Need a Hint?
			A)	If the magnetic tilt was 90 degrees, the pulses would always miss us.
			B)	If the sum of the magnetic and spin axis tilts was close to 80 degrees; this will happen occasionally.
			C)	If the magnetic field exactly aligned with the spin axis; possible but not likely.
			D)	If the magnetic field were tilted at 45 degrees, and the spin axis was 45 degrees; very unlikely.

It was the speed of the faster pulsars which caused astronomers to understand their nature.

3			What sort of object produces pulsars, and how do we know this? Need a Hint?
			A)	They are a network of radio transponders set up by ET for space navigation; the accuracy of the signals can only be produced artificially.
			B)	They are radio transmissions from the surface of another Earth, with a very strong, recurrent transmitter.
			C)	They are the beams of a natural lighthouse, the product of a rapidly spinning neutron star and its tilted, intense magnetic field sweeping past us occassionally.
			D)	They are the bursts sent out of the poles of collapsing balck holes; only such events can be this intense.

Collapsing to city sized dimensions beyond the Chandrasekhar Limit, neutron stars are very exotic by our standards. Yet with their pulsar and magnetar stages, they can provide us with celestial violence and beauty that intrigue us. Let's study their properites with these questions

4			When it was realized that neutron stars must be no larger than cities, we had to take a close look at the nature of the atom. What change in atomic structure allowed for this incredible density? Need a Hint?
			A)	The electron shells of normal atoms have collapsed under gravitational pressure.
			B)	The protons and electrons have fused together, and their charges have cancelled out in this collapse.
			C)	The neutrons are decaying into protons that are trapped by the star's gravity, and beams of electrons that can escape because they are lighter.
			D)	In the collapse to a black hole, only quarks are left.

The lighthouse model of the interactive made us look closely at the ranges of inclinations of both rotation and magnetic field that are possible. Statistically, what does this tell us about how abundant neutron stars are in reality?

5			Can we observe all neutron stars? Why or why not? Need a Hint?
			A)	No, because over time, neutron stars will slow down to the point that the magnetic field will not produce an observable pulse.
			B)	No, because in many cases the spin axis is not properly aligned to have the signal pass Earth.
			C)	No, becuase even if the spin axis is right, the magnetic tilt might also be off enough for the signal to miss us.
			D)	All of the above factors are correct.