The scientific study of the stars and other objects in
space is called astronomy. Astronomers observe the Universe using telescopes,
which focus light from distant objects and make them clearer. Different types
of telescope also reveal rays of light that are invisible to the human eye. On
the ground, radio telescopes capture radio waves. Telescopes in space study
rays that cannot pass through Earth’s atmosphere.
The Hale Telescope at Palomar Observatory in California, USA, was
completed in 1948, and was the first giant telescope. It has a light-gathering
mirror 508 cm (200 in) across. There are two types of telescope that study
light. Reflecting telescopes capture light with a mirror, and refracting
telescopes use a lens. All modern professional telescopes are reflectors.
BIOGRAPHY: GALILEO Italian, 1564-1642
Galileo was a physicist, mathematician, and an astronomer. In 1609
he built a telescope and became the first person to use one to look at the
heavens. He saw mountains on the Moon, spots on the Sun, observed the phases of
Venus, and discovered Jupiter’s four large moons. In later life, his
support for the view of Copernicus that Earth and the planets circle round the
Sun brought him into conflict with the Church.
