Astronomy Test #1

Front 1

An imaginary sphere of arbitrarily large radius, concentric with the Earth and rotating upon the same axis. Projected upward from Earth's equator and poles are the celestial equator and the celestial poles.

Back 1

Celestial Sphere

Front 2

The apparent path that the Sun follows through the sky over the course of the year, relative to the stars, as seen from the vantage point of the Earth. It is traced on the imaginary celestial sphere

Back 2

Ecliptic

Front 3

Equivalent of geographic longitude. Measured in hours, minutes and seconds from the point where the ecliptic meets the celestial equator and moving towards the east. Each hour corresponds to 15 degrees of arc and 24 hours corresponds to 360 degrees.

Back 3

Right Ascension

Front 4

Comparable to geographic latitude. Measured in degrees north and south of the celestial equator.

Back 4

Declination

Front 5

Two imaginary points in the sky where the Earth's axis of rotation, indefinitely extended, intersects the celestial sphere.

Back 5

Celestial Poles

Front 6

An imaginary point directly "above" a particular location, on the imaginary celestial sphere.

Back 6

Zenith

Front 7

The angle of the object around the horizon, usually measured from the north increasing towards the east.

Back 7

Azimuth

Front 8

Sometimes referred to as elevation, is the angle between the object and the observer's local horizon. It is expressed as an angle between 0 degrees to 90 degrees

Back 8

Altitude

Front 9

A circle of twelve 30° divisions of celestial longitude that are centered upon the ecliptic. Historically, these twelve divisions are called signs.

Back 9

Zodiac

Front 10

An internationally defined area of the celestial sphere grouped around patternsformed by prominent stars within apparent proximity to one another on Earth's night sky.

Back 10

Constellations

Front 11

What causes the seasons?

Back 11

The Axial Tilt/Obliquity

Front 12

Precession changes ____ ____ and ______ ____

Back 12

North Star; Zodiac dates

Front 13

What are three factors of long term climate change?

Back 13

-Precession

-Change in elliptical orbit

-change in obliquity

Front 14

The Sidereal day is ______ than the Solar day

Back 14

shorter

Front 15

_____ and ______ represent points in the _____ (path of the Sun)

Back 15

Equinoxes; Solstices

ecliptic

Front 16

When the moon rotates in 27.3 days around the earth and in relation to the Stars

Back 16

Sidereal Month

Front 17

When the moon rotates in 29.5 days in relation to the Sun and complete phase change

Back 17

Synodic Month

Front 18

The phases of the moon change every:

Back 18

29.5 days

Front 19

What are the phases of the moon in order? (8 total)

Back 19

1) New

2) Waxing Crescent

3) First Quarter

4) Waxing Gibbous

5) Full Moon

6) Waning Gibbous

7) Third Quarter

8) Waning Crescent

Front 20

The moon is tilted in relation to place of Ecliptic by __ degrees

Back 20

5 degrees

Front 21

The idea that Earth as the center of the Universe. Main Explanation by Ptolemy with his epicycles.

Back 21

Geocentrism

Front 22

Ptolemy is famous for:

Back 22

geocentrism and epicycles

Front 23

The idea that the Sun as the center of the Universe. Main proponent was Copernicus. Theory proven by Galileo

Back 23

Heliocentrism

Front 24

Revived Heliocentric theory; he believed that the Earth rotating on its axis caused the visual effect of celestial bodies revolving around the Earth.

Back 24

Copernicus (Polish, 15-16th Centuries)

Front 25

Galileo (Italian, 16th century) is famous for:

Back 25

- First astronomical use of the telescope

- Discovered 4 moons of Jupiter

- Discovered geographic features of the moon

- Discovered Sun spots and rotation of the Sun

-Discovered phases of Venus, proving Heliocentric theory

Front 26

Planets orbit the Sun on elliptical paths. The Sun occupies one of the two foci

Back 26

Kepler's First Law of Planetary Motion (Law of Elliptic Orbits)

Front 27

An imaginary line connecting the Sun to a planet sweeps out equal areas in equal intervals of time. This means that given elliptical orbits where a planet will have a closest approach to the Sun, will travel fastest in its orbit at that time.

Back 27

Kepler's Second Law of Planetary Motion (Law of Areas)

Front 28

The square of a planet's period is proportional to the cube of its mean distance from the Sun.

Back 28

Kepler's Third Law of Planetary Motion (The Harmonic Law)

Front 29

Unless acted on by an external force, a body at rest will remain at rest. Unless acted on by an external force, a body in motion will continue to do so in a straight line at constant speed.

Back 29

Newton's First Law of Motion

Front 30

A body acted on by an external force will accelerate in the direction of the applied force. The greater the force, or the smaller the mass, the greater the acceleration will be.

Back 30

Newton's Second Law of Motion

Front 31

For every force, there is an equal magnitude, but oppositely directed, force.

Back 31

Newton's Third Law of Motion

Front 32

The rate of change of position. Both magnitude and direction must bespecified.

Back 32

Velocity

Front 33

The rate of change of velocity. Both magnitude and direction must be specified.

a=F/m

Back 33

Acceleration

Front 34

All objects in the universe attract all other objects with a force dependent upon the mass of the two objects and the distance between them.

Back 34

Newton's Law of Universal Gravitation

Front 35

There are ___ standard constellations recognized by the International Astronomical Union (IAU) since 1922. The majority of these go back to the __ constellations defined by Ptolemy in his Almagest (2nd century).

Back 35

88; 48

Front 36

Points north of the celestial equator have _____ declinations, while those to the south have ____ declinations.

Back 36

Positive; negative

Front 37

The study of all matter and energy in the universe

Back 37

Astronomy

Front 38

A great ring stones in the Salisbury plain in Southern England. Each significant stone lines up with another to point to some extreme position of the Sun and Moon. A set of holes around the perimeter probably was used to predict eclipses

Back 38

Stonehenge (2800-1075 BC)

Front 39

They knew (also Babylonians, Assyrians, and Egyptians) 1 year = 365.25 days

Determined the Moon's orbital period

Recorded Halley's Comet (467BC)

Recorded "Crab Nebula" supernova in 1054 AD

Back 39

The Chinese (1000 BC)

Front 40

The _____ and ____ ____ _____ had calendars and "medicine wheels" showing extreme annual positions of key celestial objects.

Back 40

Mayan; Native American Indians

Front 41

Was the first to believe in a heliocentric universe.

Thought the stars were at a great distance from the Earth and we couldn't detect their annual motion.

Back 41

Aristarchus (Greek, 3rd century BC)

Front 42

Was the first to measure the Earth's circumference.

Back 42

Eratosthenes (Greek, 3rd century BC)

Front 43

Two scientists who extolled the geocentric universe

Back 43

Hipparchus and Ptolemy (Greek, 2nd century BC)

Front 44

Made extensive and accurate observations of the positions of the planets, particularly Mars (w/o a telescope), which led to Kepler's formation of his laws of orbital motion

Back 44

Tycho Brahe (Danish, 16th Century)

Front 45

Discovered that the planets' orbit around the Sun were ellipses

Back 45

Johannes Kepler (German, 16th century)

Front 46

-Believed in immense universe with no particular center.

-He thought the Earth orbited the Sun.

-Believed in the possibility of life elsewhere

Back 46

Bruno (Italian, 16th century)

Front 47

Formulated integral calculus; the laws of mechanics and gravitation; invented the first reflecting telescope.

Back 47

Isaac Newton (English, 17th century)

Front 48

Studied comet orbit records, which suggested to him that the comets of 1531, 1607, and 1682 were the same comet returning. Predicted it would return in 1758.

Financed the publishing of Newton's the Prinicipia

Back 48

Edmund Halley (English, 17th century)

Front 49

The spinning of a celestial body about its (internal) rotational axis

Back 49

Rotation

Front 50

Proofs of the Earth's rotation:

Back 50

Foucault pendulum

Coriolis Force

Aritificial Satellite

Front 51

The orbiting of a body around a more massive "parent" body, that is, motion around an external axis.

Back 51

Revolution

Front 52

The closest approach of a planet to the Sun in its orbit around the Sun.

Back 52

Perihelion

Front 53

The farthest distance of a planet from the Sun in its orbit around the Sun.

Back 53

Aphelion

Front 54

Proofs of the Earth's Revolution:

Back 54

Parallactic motion of the stars

Variation in the radial velocity of a star

Aberration of starlight

Front 55

The slow, Westward wobbling of the Earth's rotational axis due to the gravitational pull of the Sun and the Moon on the Earth's equatorial bulge.

Back 55

Precession

Front 56

Current pole star is:

Back 56

Polaris

Front 57

The time it takes for one (360 degree) rotation of a planet with respect to the fixed stars.

23h 56 min

Back 57

Sidereal Day

Front 58

The time it rakes for one (360 degree) rotation of a planet with respect to the Sun as a reference. Avg: 24h 0min

Back 58

Solar Day

Front 59

The position of the Sun at the same time of the day to map out a figure 8 in the sky over 1 year

Back 59

analemma

Front 60

The moon has a "locked" or _____ rotation, keeping the same face toward the Earth all the time.

Back 60

Synchronous

Front 61

The closest approach of a satellite to the Earth in its orbit around the Earth

Back 61

Perigee

Front 62

The furthest distance of a satellite from the Earth in its orbit around the Earth.

Back 62

Apogee

Front 63

The shadow zone where sunlight is completely cut off

Back 63

Umbra

Front 64

The shadow zone where sunlight is partially cut off

Back 64

Penumbra

Front 65

When the moon is too far away from the Earth and/or the Earth is too close to the Sun for the Moon to cover the face of the Sun completely despite being properly centered.

Back 65

Annular eclipses

Front 66

When a celestial body with a large angular size in our sky passes b/w the Earth and a celestial body with a smaller apparent size in the sky.

Back 66

Occultations