The Astronomy Book

44

I NOTICED

A NEW AND

UNUSUAL

STAR

HE TYCHONIC MODELT

I

n the 16th century, the exact

orbits of the planets were a

mystery. Danish nobleman

Tycho Brahe realized that accurate

observations would need to be

taken over an extended period

of time if this problem were to be

solved. The need for better data

was underlined by the fact that a

conjunction of Jupiter and Saturn in

1562, when Tycho was 17, occurred

days away from the time predicted

by the best available astronomical

tables. Tycho undertook to take

measurements along the entirety

of the planets’ visible paths.

The astronomy of Tycho’s

time still followed the teachings

that Aristotle had laid down nearly

IN CONTEXT

KEY ASTRONOMER

Tycho Brahe (15 46 –1601)

BEFORE

1503 The most accurate

star positions to date are

recorded by Bernhard

Walther at Nuremberg.

1543 Copernicus introduces

the idea of a sun-centered

cosmos, improving the

prediction of planetary

positions. These, however,

are still inaccurate.

AFTER

1610 Galileo’s use of the

telescope starts a revolution

that eventually supersedes

naked-eye astronomy.

1620 Johannes Kepler

completes his laws of

planetary motion.

1670s Major observatories

are established in all the

capitals of Europe.