You, Earth, Local Group, Local Supercluster, solar system, Milky Way

The “celestial sphere” is just another name for our universe.

Which of the following statements about the celestial equator is true at all latitudes?

It represents an extension of Earth's equator onto the celestial sphere.

What is the ecliptic?

The Sun's apparent path along the celestial sphere.

Which scientists played a major role in overturning the ancient idea of an Earth-centered universe and about when?

Copernicus, Kepler, and Galileo; about 400 years ago.

Which of the following correctly describes the meridian in your sky?

A half-circle extending from your horizon due north, through your zenith. To your horizon due south.

How many archminutes are in 1 degree?

3,600

What is a circumpolar star?

A star that always remains about your horizon.

Which of the following is not a phase of the Moon?

Half Moon

If the moon is setting at 6AM, the phase of the Moon must be:

Full

What is an astronomical unit?

The average distance from the Earth to the Sun.

How did Eratosthenes estimate the size of Earth in 240BC?

By comparing the maximum altitude of the Sun in two cities at different latitudes.

Where was the Sun in Ptolemy's model of the universe?

Between the orbits of Venus and Mars

The controversial book of this famous person, published in 1543 (the year of his death), suggested that Earth and the other planets orbit the Sun.

Copernicus

He discovered that the orbits of planet are ellipses.

Kepler

He discovered that Jupiter has moons.

Galileo

If your mass is 60kg on Earth, what would your mass be on the Moon?

60kg

What would happen if the Space Shuttle were launched with a speed greater than Earth's escape velocity?

It would travel away from Earth into the solar system.

The force of gravity is an inverse square law. This means that, if you double the distance between two large masses, the gravitational force between them will:

Weaken by a factor of 4.

According to the universal law of gravitation, if you double the masses of both attracting objects, then the gravitational force between them will:

Increase by a factor of 4.

An atom in a excited state contains more of what type of energy than the same atom in the ground state?

Electric potential energy.

The wavelength of a wave is:

The distance between two adjacent peaks of the wave.

How are wavelength, frequency, and energy related for photons of light?

Longer wavelength means lower frequency and lower energy.

From lowest energy to highest energy, which of the following correctly orders the different categories of electromagnetic radiation?

Radio, infrared, visible light, ultraviolet, X rays, gamma rays

When an electron in an atom goes from a higher energy state to a lower energy state, the atom:

Emits a photon of a specific frequency.

The spectra of most galaxies show redshifts. This means that their spectral lines:

Have wavelengths that are longer than normal.

From laboratory measurements, we know that a particular spectral line formed by hydrogen appears at a wavelength of 121.6 nanometers (nm). The spectrum of a particular star shows the same hydrogen line appearing at a wavelength of 121.8 nm. What can we conclude?

The star is moving away from us.

How does the Sun's mass compare with that of the planets?

It's a 1000 times more massive than all the planets combined.

Which planet has the highest average surface temperature, and why?

Venus, because of its dense carbon dioxide atmosphere.

Which planet, other than Earth, has visible water ice on it?

Mars

Which of the following is furthest from the Sun?

A comet in the Oort cloud.

Which is the densest planet in the solar system?

Earth

The planet closest in size to Earth is:

Venus

Which of the following is not a characteristic of the inner planets?

They all have substantial atmospheres.

Which of the following is not a characteristic of the outer planets?

They have very few, if any, satellites.

Why did the solar nebula heat up as it collapsed?

As the cloud shrank, its gravitational potential energy was converted to kinetic energy and then into thermal energy.

What kind of material in the solar nebula could remain solid at temperatures as high as 1500K, such as existed in the inner regions of the nebula?

Metals.

What was the frost line of the solar system?

The distance from the Sun where temperatures were low enough for hydrogen compounds to condense into ices, between the present-day orbits of Mars and Jupiter.

According to the nebular theory, what are asteroids and comets?

The are leftover planetesimal's that never accreted into planets.

Rank the five terrestrial worlds in order of size from smallest to largest:

Moon, Mercury, Mars, Venus, Earth

Which of the terrestrial worlds has the strongest magnetic field?

Earth

Which of the following most likely explains why Venus does not have a strong magnetic field?

Its rotation is too slow.

Which two properties are most important in determining the surface temperature of a planet?

Distance from the Sun and atmosphere.

How large is an impact crater compared to the size of the impactor?

10 times larger.

The relatively few craters that we see within the lunar maria:

Were formed by impacts that occurred after those that formed most of the craters in the lunar highlands.

The Caloris Basin on Mercury covers a large region of the planet, but few smaller craters have formed on top of it. From the we conclude that:

The Caloris Basin formed toward the end of the solar system's period of heavy bombardment.

Olympus Mons is a:

Shield volcano on Mars

Why does Venus have such a great difference in temperature between its “no atmosphere” temperature and its actual temperature?

It has a large amount of greenhouse gases in its atmosphere.

Which of the following worlds has the most substantial atmosphere?

Venus

Why doesn't Venus have seasons like Mars and Earth do?

Its rotation axis is not tilted.

Where is most of the water on Mars?

Frozen on the peaks of its tall volcanoes.

How does Jupiter's core compare to Earth's?

It is about the same size but is 10 times more massive.

If we know the size of an asteroid, we can determine its density by:

Determining its mass from its gravitational pull on a spacecraft, satellite, or planet.

What is Jupiter's Great Red Spot?

A long-lived, high pressure storm.

The four Galilean moons around Jupiter are:

A mixture of rock and ice, with the ice fraction increasing with distance from Jupiter.

Why are there no impact craters on the surface of Io?

Io did have impact craters but they have all be buried in lava flows.

Which moon has the most substantial atmosphere?

Titan

How thick are Saturn's rings from top to bottom?

A few tens of meters.

Which is closest tot he average distance between asteroids in the asteroid belt?

1 million km

Why isn't there a planet where the asteroid belt is located?

Gravitational tugs from Jupiter prevented materials from collecting together to form a planet.

What do we call a small piece of solar system debris found on Earth?

Meteorite

Halley's comet is named after the English scientist Edmund Halley because he:

Calculated its orbit and predicted that it would return in 1758.

What part of a comet points directly away from the Sun?

The plasma tail

Most of the planets discovered around other stars:

Are more massive than Earth and orbit very close to the star.

The core of the Sun is:

Hotter and denser than the surface.

What two forces are balanced in what we call gravitational equilibrium?

Outward pressure and gravity.

What is the average temperature of the surface of the Sun?

6,000K

Which layer of the Sun do we normally see?

Photosphere

At the center of the Sun, fusion converts hydrogen into:

Helium, energy, and neutrinos.

What is granulation in the Sun?

The bubbling pattern on the photosphere produced by the underlying convection.

Double Cluster

Perseus

2 Open Clusters
('H' & Chi) @
7000-8000 Light Years

Horsehead Nebula

Orion

Emission & Dark Nebulae
Stellar Birthplace

Crab Nebula

Taurus

Supernova Remnant
Endpoint of Stellar Evolution

Lagoon Nebula

Sagittarius

Stellar Nursery
Emission Nebula

Hercules Cluster

Hercules

Globular Star Cluster
Population II Stars

Eagle Nebula

Serpens

Emission Nebula
Stellar Birthplace

Trifid Nebula

Sagittarius

Dark, Reflection, and
Emission Nebulae

Dumbbell Nebula

Vulpecula

Planetary Nebula
After Giant Stage in Sun

Andromeda Galaxy

Andromeda

Spiral Galaxy
Visible to Unaided Eye @
2 Million Light Years

Orion Nebula

Orion

Stellar Nursery
Emission Nebula

Beehive Cluster

Cancer

Open Star Cluster
Population I Stars

Pleiades Cluster
(7 Sisters)

Taurus

Open Star Cluster
Young Population I Stars

Whirlpool Galaxy

Canes Venatici

Spiral Type Galaxy

Virgo A

Virgo

Giant Elliptical Galaxy
in Virgo Cluster @
60 Million Light Years

Sombrero Galaxy

Virgo

Edge View of
Spiral Galaxy