Historical development of astronomy Flashcards
who were the 5 main people who influenced astronomy and describe their lives
1 - Claudius Ptolemy 2 - Nicolaus Copernicus 3 - Galileo Galilei 4 - Johannes Kepler 5 - Isaac Newton
1
lived from 85 - 165 AD. made his observations in Egypt between 127 - 142 AD. he believed that Earth was in the centre of the universe and that everything revolved / orbited around it. his model was called the geocentrism (geo = Earth meaning earth at the centre)
His ideas revolutionary for their time and those beliefs held for 1400 years before Copernicus came up with another theory.
2
lived from 1473 - 1543. in 1514 he suggested that Earth wasn’t in the centre but that all planets revolved around Sun. this idea called heliocentrism (helios = Sun meaning Sun in the centre)
he made following assumptions:
- bodies in space don’t all revolve around a particular point.
- all planets revolve around the Sun. (he thought Sun was near centre of universe).
- stars don’t move - their movement is actually rotation of the Earth.
- sun doesn’t move across our skies, instead, what we see is result of Earth moving around the Sun.
his beliefs weren’t well receive by those of his day. but, many of his ideas are correct as we know it today.
3
first man to point telescope at sky and use it to observe the bodies in space with it.
lived from 1564 - 1642. his greatest contribution was that his theories built on observation of space. in 1610, he observed 4 bodies that moved around Jupiter in way that was different to stars. these later on discovered to be 4 of Jupiter’s moons.
he believed in Copernicus’s heliocentric model his work helped him to build onto his theory. his support of this model wasn’t approved by many and he even spent final years of his life under house arrest.
4
lived from 1571 - 1630. he bought more scientific approach to astronomy, in world were difference between astronomy and astrology wasn’t so clearly distinguished.
Galileo and Kepler achieved most of their work at same time and though they often disagreed on many points, together they built on the theories we now use. Kepler believed that Moon responsible for tides while Galileo believed the tide were caused by rotation of the Earth.
5
lived from 1642 - 1726. his major contribution to astronomy was in his development of the Law of Universal Gravitation, which describes how two bodies, like Earth and the Moon, can be drawn to Each other by gravity. it also described how all of the objects on the Earth’s surface are drawn towards it centre, in same way all over its surface.
meaning - astronomy and astrology
astronomy - a science that studies the objects outside of the Earth’s atmosphere (planets, stars, asteroids, galaxies) and the relationships between these objects.
astrology - the belief that the positioning of the stars and planets relate to and affect events that occur in the human world.
what did our ancestors identify celestial objects as
gods and spirits
also related these objects and their movements to natural phenomena, like rain, drought, the season and the tides.
what is the ecliptic
one of the earliest observations of predictable patterns from Earth. this is the path across the sky in which the Sun appears to travel of course of a year. reality Earth orbit Sun, for early observers appeared that Sun moved on this ecliptical belt. the paths of the Moon, star and visible planets also appeared to remain close to the ecliptic.
what is the zodiac
a circle of 12 constellation that can only be seen at certain times of the year. they always seem to follow path taken by the Sun and Moon on the ecliptic. this circle of twelve 30 degree divisions of celestial longitude was used by early people as a star map or calender to measure direction at the time.
name 3 ancient civilisations that used the sky as a calender
Babylonians, Greeks and Egyptians
what did the San use to tell the time, seasons and the months and for how long
20 000 years
Sun = tell time
Moon = count months
Star sightings = for start and end of seasons.
describe a year
calender year = time between two dates with the same name in a calendar.
time period of year usually includes 4 seasons and it is commonly based on the Solar year, which is the orbital period of Earth revolving around the Sun.
for early observers on Earth this corresponded to the period it takes the Sun to complete on course through the zodiac along the ecliptic. most common modern calendar is based on Roman calendar of 365 1/4 days. It divides year into twelve months alternating with 30 and 31 days each. there are other calendars years in use like the lunar year of about 354,37 days. it consists of twelve full cycles of the of the phases of the Moon, a seasonal year is the time between successive recurrences of a seasonal event, like flooding of a river or the migration of a species of bird.
what are the names of each of the zodiac constellations
Aries, Taurus, Gemini, Cancer, Leo, Virgo, Libra, Scorpio, Sagittarius, Capricorn, Aquarius, and Pisces.
