DAMMER ASTRONOMY TEST #1

smaklin's desperate last attempt at learning the entire unit the night before the test

What happens to ships when they go over the horizon?

Ships disappear over the horizon bottom first.

What happens to constellations when you change latitude?

Constellations change with latitude.

What shape shadow does the Earth cast on the Moon during a lunar eclipse?

A round shadow.

Who calculated the circumference of the Earth in the 3rd century BCE?

Eratosthenes.

When was the first circumnavigation of the Earth completed?

1519-1522 CE.

Which objects did ancient astronomers call "wandering stars"?

Planets: Mercury, Venus, Mars, Jupiter, Saturn.

What is Ptolemy's Geocentric Model?

Earth-centered model.

Why did Ptolemy think the Earth was at the center?

No observed stellar parallax.

How did Ptolemy's Geocentric Model explain retrograde motion?

With epicycles.

What is Copernicus's Heliocentric Model?

Sun-centered model.

How did Copernicus's Heliocentric Model explain retrograde motion?

Retrograde motion explained naturally.

What were Galileo's two main pieces of evidence for heliocentrism?

Phases of Venus, moons of Jupiter.

What causes the seasons?

Earth's 23.4° tilt, not distance from the Sun.

What changes because of Earth's axial tilt?

Day length changes, Sun's path changes, opposite hemispheres have opposite seasons.

When do solstices occur?

June and December.

What happens at the solstices?

The Sun is tilted maximum toward or away from the Earth.

When do equinoxes occur?

March and September.

What happens at the equinoxes?

Day and night are equal in length.

Why does seasonal lag occur?

Oceans cause thermal inertia.

What direction does latitude run, and what does it measure?

Latitude runs east-west, measures north-south.

What is the latitude at the equator?

0°.

What is the latitude at the poles?

90°.

What direction does longitude run, and what does it measure?

Longitude runs north-south, measures east-west.

What is the longitude of the prime meridian?

0°.

What is the maximum longitude?

180°.

What is elevation in astronomy?

Angle above the horizon.

What is declination in astronomy?

Angle above or below the celestial equator.

What is the relationship between latitude and the celestial pole?

Latitude equals the elevation of the celestial pole.

Where does the Sun rise and set?

The Sun rises in the east and sets in the west.

Which constellation contains the Andromeda Galaxy?

Andromeda.

Which constellation contains Sirius, the brightest star?

Canis Major.

Which constellation is shaped like a "W"?

Cassiopeia.

What does Cassiopeia point to?

North Star and Andromeda.

Which constellation is easily identifiable and has a head that points north?

Orion.

What does Orion's left arm point to?

The Big Dipper.

Which constellation contains the Great Square?

Pegasus.

What does Pegasus connect to?

Andromeda.

Which constellation contains the Big Dipper?

Ursa Major.

What do the pointer stars in the Big Dipper point to?

Polaris.

Which constellation contains Polaris (the North Star)?

Ursa Minor.

Which constellation is also called the Southern Cross?

Crux.

What is the Southern Cross used for?

To find the South Celestial Pole.

Which constellation can also be used to find the South Celestial Pole with bright stars and a perpendicular line?

Centaurus.

Why does the same side of the Moon always face the Earth?

The Moon is tidally locked.

What does waxing mean?

The Moon's light is growing.

What does waning mean?

The Moon's light is shrinking.

How long does it take the Moon to orbit the Earth?

About 28 days.

What is the shape of the Moon's orbit?

Elliptical.

What does the elliptical orbit of the Moon cause?

Apparent size changes and libration.

Is the Moon moving closer or farther from the Earth?

The Moon is moving away from the Earth.

What is a solar eclipse?

The Moon's shadow on the Earth.

When does a solar eclipse occur?

New moon.

What is a lunar eclipse?

The Earth's shadow on the Moon.

When does a lunar eclipse occur?

Full moon.

What is the umbra in an eclipse?

The part that causes a total eclipse.

What is the penumbra in an eclipse?

The part that causes a partial eclipse.

Why don't eclipses happen every month?

The Moon's orbit is tilted, so eclipses only occur at the nodes.