Astronomy Basics
The Planets
Earth's Motions
Moon, Tides and Eclipses
Space Exploration and Gravity
100
What is astronomy?
The study of space and celestial objects.
100
What are the eight planets in order from the Sun?
Mercury, Venus, Earth, Mars, Jupiter, Saturn, Uranus, Neptune.
100
What causes day and night on Earth?
Earth's rotation on its axis.
100
What causes the phases of the Moon?
The relative positions of the Moon, Earth, and Sun.
100
Who was the first person to walk on the Moon?
Neil Armstrong.
200
What is meant by a solar system?
A group of planets orbiting a star.
200
What is an astronomical unit (AU)?
The average distance from Earth to the Sun (~150 million km).
200
What causes the seasons?
Earth's tilt on its axis and its orbit around the Sun.
200
What causes tides on Earth?
The gravitational pull of the Moon and Sun.
200
When did this happen, and what was the spacecraft?
1969, Apollo 11.
300
Which model places the Sun at the center of our solar system?
The heliocentric model.
300
Which planet is the hottest?
Venus.
300
Why do day lengths vary at different times of the year?
Because Earth is tilted relative to its orbit around the Sun.
300
What is the difference between spring and neap tides?
Spring tides are higher; neap tides are lower.
300
What is gravity?
The force of attraction between masses.
400
What do we call the line at 0° longitude that divides Earth into east and west hemispheres? (Hint: this line is found in London, UK).
The Greenwich Meridian.
400
What is the tallest mountain in the solar system, and on which planet?
Olympus Mons on Mars.
400
When is summer in the Southern Hemisphere?
December to February.
400
What causes a solar eclipse?
The Moon blocks the Sun’s light
400
Why do we weigh less on the Moon?
Because the Moon has less mass and weaker gravity.
500
Name the imaginary line opposite at about 180° longitude. (Hint: this line is found in the Pacific Ocean).
The International Date Line.
500
Which planet has the longest orbit around the Sun?
Neptune.
500
What are a solstice and an equinox?
Solstice is the longest or shortest day of the year; equinox is when day and night are equal length.
500
What causes a lunar eclipse?
Earth blocks sunlight from reaching the Moon.
500
Would it be harder to leave a larger planet by rocket? Why?
Yes, due to stronger gravity requiring more energy to escape.