Hipparchus
 Believed in an Earth-centred universe.
 Completed the first known star catalogue.
 Developed a system for comparing star
brightness which is still used today.
Claudius Ptolemy
 Believed in an Earth-centred universe.
 For more than a thousand years no one
seriously questioned his theory.
 Later European astronomers learned about
his work from Greek and Arab ones.
Nicolas Copernicus
 Did not believe the theories of Ptolemy
and Hipparchus.
 Developed the first Sun-centred model
with five planets orbiting around the sun
in crystalline spheres.
 Was very secretive about his theory but
published a book about it just before he
died.
Tycho Brahe
 Made the most accurate measurements of
the position of the stars and planets so far.
 All his observations done without
telescopes – they had not been invented.
 Accepted many of Copernicus’s ideas but
thought that the planets revolved around
the Sun, which revolved around the Earth.
Johannes Kepler
 Became assistant to the famous
astronomer Tycho Brahe.
 Believed in the theories of Copernicus.
 Used Tycho Brahe’s data to develop his
own theories about the movements of the
planets.
Galileo Galilei
 One of the first people to use a telescope.
 Revived the theories of Copernicus, and
got into trouble with the Church.
 Was put under house arrest for the rest of
his life and died blind from staring at the
Sun through a telescope.
Sir Isaac Newton
 Developed Newton’s Law of Gravity when
home from university because of the
plague.
 Did not tell anyone about his ideas for
years.
 His friend Edmund Halley convinced him
to write a book, and he paid for it too.
Edmund Halley
 He used Newton’s Laws to calculate the
orbit of a comet.
 He realised it was the same comet
observed by other astronomers in 1607,
1531 and 1456.
 He predicted that it would reappear in
1758 - and it did. It is now called Halley’s
comet.
Sir William Herschel
 Discovered the first of the modern planets
– Uranus – which made him famous.
 Made over 400 telescopes, the largest 40
feet (12 metres) long.
 Studied the movement of the stars and
realised that the Solar System is moving
through space.
Caroline Herschel
 Lived when women didn’t do things like
astronomy.
 However her brother taught her
astronomy and mathematics, and gave her
a telescope.
 She found three new nebulae and eight
comets and was the first woman to be
made an honorary member of the Royal
Society.
Albert Einstein
 Was a clerk in an office studying part-time
when he developed some of the most
important scientific theories of the 20th
century.
 Then became one of the most famous
scientists ever.
 Showed scientists that things like black
holes existed.
Edwin Hubble
 Discovered that nebulae were galaxies out
in the universe which were moving away
from us.
 This showed that Einstein had made a
mistake in one of his theories!
 The space telescope named after him has
sent back some incredible pictures from
deepest space.