The Sun is so far away that it would take the
Space Shuttle seven months to fly there. That's why the Sun, which
is a hundred times the diameter of the Earth, looks so small!
Three hundred years ago, astronomer Edmund Halley found a way to measure
the distance to the Sun and to the planet Venus. Knowing these distances
helped find the true scale of the entire Solar System for the first time.
Halley knew that every 121
years the planet Venus passes in front of the Sun. Venus’ position,
relative to the Sun behind it, appears very different when viewed
from two different places on Earth. How different depends on
how far away Venus and the Sun are from the Earth.
1761. Using observations
of the "transit
of Venus" made by astronomers around the world, the distance
to the Sun is determined to be 93 million miles. This photograph
is from the 1882 transit of Venus.
ABOVE: Our Sun is the nearest star. At 93 million
miles, the Sun provides the warmth that has allowed life to evolve
on Earth. Has life evolved elsewhere?