Before the 17th century, the universe was thought to have how many bodies? five eight eleven three

Eight.

Explanation:

Before 17th century the universe was thought to have only the following bodies:

The reason for this is that before the 17th century, all the stars were thought to lie on one big spherical shell called the Celestial sphere ( this counts as one body), and the planets Uranus and Neptune were discovered in 1781 and 1846 respectively. We had no inking of the existence of Pluto until 1930 when Clyde Tombaugh discovered it; The 4 moons of Jupiter were discovered by Galileo in 1610.

It is only later that it was realized that the stars are individual bodies, and that the planets had moons orbiting around them.

So before the 17th century we have only five planets,  a Celestial sphere, the sun, and the moon.

photocells convert light energy to electricity

neither accurate nor precise.