Bobby Ktxrliner, age 12 of Vancouver,. Canads for his question:

How do they measure the distance to the sun?

The distance between the earth and the sun is called the astronomical unit. This unit is used to calculate the scale of the Solar System. It is very important to astronomers to have a very accurate figure for this heavenly measuring rod, but the job of getting it is not an easy one. The distance of a star is measured with a vast, heavenly triangle and an angle called a parallax, However, the suns parallax cannot be measured directly with any accuracy, Instead it must be calculated from the parallax of another planet or asteroid.

The asteroid Eros sometimes comes very close to the earth where it can be calculated with accuracy. From these figures, the sun's parallax is calculated. The latest estimates set the suns average distance from the earth at 92,900,000 miles. The force of gravity and the speed of light have also been used to estimate the, distance of the sun.