Stonehedge to Hubble

Stonehenge

Prehistoric monument and ancient observatory, built 2500 BC

Hubble Space Telescope

Launched 1990 by Space Shuttle Discover

Astronomy

Science that studies the nature of stars and all celestial bodies in the Universe. Oldest scientific discipline. Provides perspective about our place in the Universe.

Prefixes to know

Kilo(3), mega(6), giga(9), tera(12)

Distances

Earth: km. Solar system: 1 AU= 1.5x10^8 km (distance from Earth to Sun). Milky Way: closest star is 4 light years (300,000 AU) away. Center is 26,000 ly, while entire Galaxy is 100,000 ly. The closest large galaxy is 2.5x10^6 ly away. The finite age of the (observable) Universe is 13.8x10^9 yr.

Cosmology

Discipline that deals with the nature of the Universe as a whole. Most cosmology doesn't relate to human beings.

Science

System of acquiring knowledge, using observation and experimentation to test theories of natural phenomena. Technology is the application of science to human purposes.

Scientific method

1. Observe. 2. Develop a theory. 3. Use the theory to make predictions. 4. Perform experiments to test predictions. Scientific Theory is a carefully constructed proposition that accounts for all known data and makes specific, quantitative predictions.

Pseudoscience

Claim presented as scientific but without adhering to the scientific method. Claims are often exaggerated or unprovable.

Archaeoastronomy

The study of how people in the ancient past have understood the phenomena in the sky, how they used them, and what role the sky played in their cultures.

Ancient Astronomy

Study of ancient people's understanding of the sky, including finding direction, keeping time, and ritualistic practices.

Goseck Circle

Discovered near Goseck, Germany. Built 5000 BC. Earliest known structure with a recognizable astronomical alignment (Winter Solstice).

Avebury Henge

Large megalithic monument built 2800 to 2400 BC.

Newgrange

Tomb in Ireland, thin slit illuminates central tomb during sunrise on winter solstice. Built 3200 BC.

Ancient Chinese astronomers

Kept records of astronomical events. Made the first recorded observations of supernovae.

Greek Astronomy

Greeks were the first to look for rational explanations for astronomical phenomena in a systematic way.

Thales of Miletus

Advanced idea of an orderly Universe that could be understood.

Anaximander

determined length of the year and predict times of solstice and equinox

Pythagoras

One of the founders of geometry. Introduced concept of cosmos. Proposed that Earth was a sphere.

Plato

Thought that the universe must be understood in terms of circular motion.

Eudoxus

Developed a detailed mathematical theory for the motions of the planets.

Aristotle

Provided first detailed argument for a spherical Earth.

Phases of the Moon

Moon moves 12o East each day. Moon catches up and passes the sun, causing phases in a 29.5 day cycle, and eclipses when the conditions are right.

Aristarchus

First to make a serious attempt at measuring the distances to the Sun and the Moon.

Angular Diameter

Apparent size of an object in the sky

Parallax

Apparent shift in position of nearby stars

Hipparchus

Astronomer who improved instruments and discovered Earth's precession

Ptolemy

Astronomer who refined geocentric model with epicycles

Epicycle

Small circle in which a planet moves in Ptolemaic system

Deferent

Large circle along which epicycles move in Ptolemaic system

Eccentric

Point around which planets move in Ptolemaic system

Equant

Point around which deferent rotates in Ptolemaic system

Great Library of Alexandria

Ancient library with significant scientific works

Eratosthenes

Astronomer who calculated Earth's circumference and proved its roundness

Middle Ages

Historical period between Rome's fall and Constantinople's fall

Neo-Platonism

Philosophical idea of merging Pagan and Christian beliefs

Renaissance

Cultural rebirth period in Europe

Heliocentrism

Model with Sun at the center of the solar system

Gregorian Calendar

Calendar reform by Pope Gregory XIII in 1582

Tycho Brahe

Astronomer known for accurate pre-telescope observations

Ptolemaic system

A geocentric model of the universe where the Earth is at the center, with all celestial bodies orbiting around it.

Copernican system

A heliocentric model of the universe where the Sun is at the center, with the Earth and other planets orbiting around it.

Comet tail

The part of a comet that always points away from the sun due to the solar wind.

Kepler's First Law

Planetary orbits are ellipses with the Sun at one focus. The sum of the distance from two points to any point on the ellipse is fixed.

Kepler's Second Law

A line joining a planet and the Sun sweeps out equal areas during equal intervals of time.

Kepler's Third Law

The square of the period of an orbit is proportional to the cube of the semi-major axis. Expressed as P2 = kA3 or P = A3/2.

Perihelion

The point in an orbit that is closest to the Sun.

Aphelion

The point in an orbit that is farthest from the Sun.

Period (P)

The time required for a celestial body to complete one orbit.

Semi-major axis

Half of the longest diameter of an ellipse, defining the size of the orbit.

Galileo Galilei

introducing the telescope and pioneering experimental physics.

Law of Inertia

An object at rest remains at rest, and an object in motion will stay in motion until acted on by an unbalanced force.

Isaac Newton

Invented infinitesimal calculus and disciovered natural light

Copernicus supported the idea that the Sun was at the center of the solar system.

True

Where was Copernicus from?

Poland

How many km per second is the speed of light?

300,000

The Milky Way’s closest neighboring galaxy is the Andromeda Galaxy.

True

An eclipse is caused by the Moon going behind the Sun.

False

Annular Eclipse

When the Moon is not large enough to fully cover the Sun during an eclipse

What is it called when the Earth blocks the Sun’s light from shining on the Moon?

Lunar Eclipse

What is above the Earth's North Pole?

Polaris, the North Star

What word did Eratosthenes first coin?

Geography

Where is Stonehenge located?

British Isle

A solstice occurs when the Sun reaches either its most northern or southern point in its path across the sky.

True

During summer in the northern hemisphere, the Sun rises in the ___ and sets in the ____.

northeast, northwest*

The elevation of the Sun at noon is lower in the sky during the summer

False

Parallax is hard to see because the stars are so far away. 

True

According to Kepler, planetary orbits are circular

False

Aristotle was a student of which of the following?

Plato

How many constellations are there?

88

A constellation is a cluster of comets that make a pattern in the night sky.

False

What shape did Anaximander believe the Earth to be?

Cylinder

What did Aristotle believe the stars were composed of?

ether"

Which one of the following is in order of increasing amounts of illumination on the side of the Moon towards the Earth:

new moon, waxing crescent, waxing gibbous, first quarter

At what phase is the moon not visible?

New Moon

m

m

How many named phases of the moon are there?

8

What phase of the moon comes before the New Moon?

Waning Crescent

Johannes Kepler

Revolutionized cosmology with his laws of planetary motion

Full order of moon phases

NEW MOON, WAXING CRESCENT, QUARTER MOON, WANING GIBBOUS, FULL MOON, WAXING GIBBOUS, THIRD QUARTER MOON, WAINING CRECENT.