Answer needed for a quiz?

Question

I have racked my brains for this one! Here is an example of one of the questions, 90 D in R A, which is 90 Degrees in a Right Angle. This answer I need is 2002 GJ.

I am thinking it's something to do with the year 2002, but cannot think what the GJ means!

Thank you in advance for any assistance.

Answer 1

The year 2002 was the year for the Golden Jubilee of Queen Elizabeth II.

Answer 2

The only thing I could find was:

Gigajoule, which is a measurement of energy.