History of History of the the

AstronomyAstronomyStudents of 4ºA - ESO

Madrid - Spain

AstronomyAstronomyAstronomy, the law of the stars, is the science that treats the study of the celestial bodies, its movements and the phenomena related to them.

All the civilizations have had contact with them. It is the oldest science.

People have felt fascination for the sky. They have deified the Stars, The Sun and the Moon.

They have tried to measure the time and to have a calendar:DAY: Rotation of the Earth. MONTH: Cycle of the Moon.YEAR: Translation of the Earth around the Sun.

Stonehenge (Salisbury, UK, 3000 a.C.)

First European Astronomical observatory?

Egipcian Astronomy Egipcian Astronomy 4000 b.c.4000 b.c.

• The year lasted 365 The year lasted 365 days: 12 months of 30 days: 12 months of 30 days, and 5 more days days, and 5 more days called called epagomenos.epagomenos.• Calendar with 3 seasons Calendar with 3 seasons of 4 months each: of 4 months each: Flood, Flood, winter and summer.winter and summer.• Gyzeh Pyramid Gyzeh Pyramid aligned aligned with the Pole Star: its with the Pole Star: its shadow marks the shadow marks the beginning of the seasons.beginning of the seasons.

The Babylonians The Babylonians 3000-3000-600 600 b.cb.c

. ZIGURATS. Meteorological observatories.

. Name of the constellations: the Zodiac.

. Movement of the planets.

. Average length between two equal Moon’s phases: 29.53064 days

AristotelesAristoteles 384-322 b.C. 384-322 b.C.

. Greek philosopher and scientific.

. The Earth is not flat; it’s a sphere, that is why the stars seem to change its height in the horizon.

. The Earth is the centre of the Universe and the celestial bodies are fixed on a number of spheres moved by a “divine force”.

Aristarco of SamosAristarco of Samos 320 320

b.c.b.c.

He is the first one who upholds the “Heliocentric theory”: the Sun is the centre of The Universe. He anticipated Copernicus in 18 centuries.

He measured the distance Earth-Sun using the parallax method.

The Moon diameter is 20/57of the Earth’s. The distance from the Moon to the Earth is 79 times the radius of the Earth (actually it is 60).

ErastotenesErastotenes Cirene,276 aC-Alejandría, 194 b.C. Cirene,276 aC-Alejandría, 194 b.C.

. Father of the Geodesy. . Diameter of the Earth: distance Alejandría-Siena, (Asuán): 5000 stadiums (x 160mts)= 800Km Circunf: 800x360/7,2=40000 Km Radius=6362 Km

Claudius PtolomeoClaudius Ptolomeo 100- 100-160 a.d.160 a.d.

. Almagesto, 13 tomes: Summary of all astronomic knowledge of the Greek civilization.

. Geocentrism: The Earth, motionless (inmobile), is the centre of the Universe. Everything revolves around it. The moon and the planets have circular-epycycle orbits around a central point, that revolves around the Earth. (Theory of the circles above circles). This explains the different brightness of the celestial objects and the retrograde movement of the planets.

PtolomeoPtolomeo 100-160 a.d. 100-160 a.d.PTOLOMAICUS’ SYSTEM

Nicolas CopernicusNicolas CopernicusTorun, Poland, 1473-1543Torun, Poland, 1473-1543

. Founder of the modern astronomy for his heliocentric theory:- The Sun is the centre of the

Universe and, Mercury, Venus, Earth and The Moon, Mars, Jupiter and Saturn, revolve around it. - The stars stay fixed and they don’t orbit around the Sun.- The Earth has movements: daily rotation, annual translation and annual inclination of its axis. - The retrograde movement of the planets is due to the movement of the Earth.. His work De revolitionibus orbium coelestium

(1507-1532) was published when he died, in 1543.

Nicolas CopernicusNicolas CopernicusTorun, Poland, 1473-1543Torun, Poland, 1473-1543

COPERNICANUS’ SYSTEM

Johannes KEPLERJohannes KEPLERGermany, 1571-1630Germany, 1571-1630

. One of the main figures of the scientific and astronomic revolution.

. He formulated the three laws of the planetary movements:

3rd. Law: the relation of the squares of the

ellipses.

2nd. Law: the planets trail on

1st. Law: the planets move in

equal areas in equal times.

orbital periods and the cubes of the biggest semiaxis is constant.

Galileus Galileus GalileiGalilei (Pisa, (Pisa,

Italy,1564-1642)Italy,1564-1642)

. He discovered the sunspots.

. He pointed at the sky with the first telescope (refractor).

. He was the first one in watching the Saturn

rings.. He discovered the Jupiter satellites.. He discovered that Venus has got phases.. He watched the mountains on the Moon.

He was the first in using the scientific method.

ISAAC NEWTON ISAAC NEWTON England, 1643-1727England, 1643-1727

Physicist, philosopher, mathematician, inventor.

Gravitational Law:

3 laws of the dynamics: icF=ma

Optics: nature and spectrum of the light.

Newtonian telescope (reflector).

Integral and differential calculus.

XVIII and XIX XVIII and XIX centuries centuries The great boom The great boom

of the Astronomyof the Astronomy

The Discovery of Uranus (1789) and Neptune (1846).

Cosmology is born (study of the structure of the Universe).

Photography appears (1822) and the spectral analysis (Fraunhofer): Astrophysics is born.

Discovery of the Martian canals (false) by Schiaparelli in 1877.

Wilhelm Herschel’ telescope

XVIII and XI8X XVIII and XI8X centuries centuries Wilhelm Wilhelm

HERSCHEL’ telescope in MadridHERSCHEL’ telescope in Madrid

In 1800 Herschel built a large teles- cope, a bit smaller than the one he had in England, which is installed in the Royal Observatory of Madrid. Nowadays only the original lens (made of metal) is preserved.

Heber Doust Curtis Heber Doust Curtis Virginia, USA, 1872-1942Virginia, USA, 1872-1942

He was famous for his studies about the nebular spinals, that are regions of the interstellar space formed by gases.

He had a great debate with Shapley about the dimensions of our galaxy.

There are some other galaxies outside ours.

Trifida nebular (M20)

Edwin Powell Edwin Powell HubbleHubble Missouri, USA, 1889- Missouri, USA, 1889-

19531953He classified the galaxies.

He showed the expansion of the Universe measuring the displacement towards the red between distant galaxies.

The Milky Way is not the centre of the Universe.What had to happen for the galaxies began to move away? BIG BANG