Key Astronomers and their work

Question 1

What is Nicolaus Copernicus known for?

Answer 1

In 1543, Copernicus formulated the Heliocentric system, with the Sun at the centre rather than the Earth

Question 2

What is Tycho Brahe best known for?

Answer 2

In 1572, Brahe discovered a supernova in Cassiopeia

Question 3

What is Hans Lippershey known for?

Answer 3

In 1608, Lippershey invented the telescope`

Question 4

What is Galileo Galilei known for?

Answer 4

In 1609, Galileo discovered the 4 Jovian moons, the Moon’s craters and the Milky Way Galaxy

Question 5

What is Johannes Kepler known for?

Answer 5

In 1609, Kepler announced the first and second laws of planetary motion.
He announced the third law in 1619

Question 6

What is Kepler’s First Law (The Law Of Orbits)?

Answer 6

The first law states that planets move in elliptical orbits around the Sun at one focus of each ellipse (the other is empty)

Question 7

What is Kepler’s Second Law (The Law Of Areas)?

Answer 7

Kepler’s second law states that an imaginary line from the Sun to a planet sweeps out equal areas in equal intervals of time

Question 8

What is Kepler’s Third Law (The Law Of Periods)?

Answer 8

Kepler's third law states that the square of the orbital period (T) of a planet is proportional to the cube of its mean distance (r) from the Sun
T²
--- = A constant
r³
or t²=r³

Question 9

What is Giovanni Cassini known for?

Answer 9

In 1666, Cassini noticed the Martian Polar Ice Caps

Question 10

What is Isaac Newton known for?

Answer 10

In 1668, Newton built the first reflecting telescope. In 1687, he published The Theory Of Universal Gravitation

Question 11

What did Isaac Newton discover?

Answer 11

Newton discovered that the force of weight is directly proportional to the product of the masses of the two objects

Question 12

What is Newton’s inverse law?

Answer 12

Newton found that the strength of gravity follows an inverse square law, this means that the strength of gravity goes down by the increase of distance squared
F×d²=k
F = Force (Newtons) d= Distance (metres) K= a constant

Question 13

What is Edmond Halley known for?

Answer 13

In 1705, Halley computed the orbit of the eponymous Halley’s Comet using Newton’s laws

Question 14

What is Charles Messier known for?

Answer 14

In 1781, Charles Messier published an astronomical catalogue consisting of nebulae and star clusters that came to be known as 110 ‘Messier objects’

Question 15

What is Christian Doppler best known for?

Answer 15

In 1842, Doppler discovered the ‘Doppler effect’ of moving stars

Question 16

What is Albert Einstein known for?

Answer 16

In 1905, Albert Einstein came up with the Theory Of Relativity in ‘On The Electrodynamics Of Moving Bodies’.
In 1916, he introduced the General Theory of Relativity

Question 17

What are Hertzsprung and Russel known for?

Answer 17

During 1911-14, they introduced the H-R Diagram that shows how the characteristics of stars are related

Question 18

What is the main band running through the H-R Diagram called?

Answer 18

The main sequence band

Question 19

What is the Bayer System?

Answer 19

The Bayer system uses Greek letters to represent relative magnitudes

Question 20

What is a spectroscope?

Answer 20

A spectroscope is a device for producing and recording spectra for examination

Question 21

What are the different uses for a spectroscope?

Answer 21

Astronomers use spectroscopes to investigate the following properties of stars:

• Chemical composition
• Temperature
• Radial Velocity
• Stellar Classification (OBAFGKM)

Question 22

What did Edmond Halley do regarding astronomical units?

Answer 22

Edmond Halley devised a method of determining the size of an Astronomical Unit by observing transits of Venus

Question 23

What did transit observations determine?

Answer 23

A transit observations enabled the absolute size of the Solar system to be determined