Printable Space Quiz with Answers (Free PDF)

B. Sun

The Sun gives our planet light and heat. Daytime is when our part of Earth faces the Sun.

A. Rocket

A rocket is what launches people and spacecraft up into space.

C. Earth

Earth is our home planet. It is where we live.

B. Full Moon

When we can see the whole sunlit side of the Moon, it is called a full Moon.

True

The Sun is a star. It looks big and bright because it is much closer than other stars.

False

Moonlight is really sunlight bouncing off the Moon.

True

Earth spins. When our side faces away from the Sun, it is night.

The Sun gives Earth light and heat.

The Moon orbits Earth, which means it travels around us.

Astronauts wear space suits to stay safe when they work outside in space.

C. Jupiter

Jupiter is the largest planet. More than 1,000 Earths could fit inside it.

D. Mars

Rusty iron in the dirt and dust makes Mars look red.

A. Venus

Venus is hotter than Mercury, even though Mercury is closer to the Sun.

B. A constellation

People connect stars into pictures called constellations, like Orion or Ursa Major.

C. Saturn

Saturn has the biggest, brightest rings. They are made of ice and rock.

False

The Moon is less than a third as wide as Earth, so Earth is much bigger.

False

Earth spins. Day is on the side facing the Sun, and night is on the side facing away.

True

A space suit gives astronauts air to breathe and protects them from heat, cold and dust.

False

Gravity keeps you on the ground and makes things fall when you drop them.

year

One trip around the Sun takes Earth about 365 days, which we call a year.

day

Earth turns once about every 24 hours. That spin makes day and night.

Earth

The Moon orbits Earth. Earth orbits the Sun.

Mercury is the smallest planet and the nearest to the Sun.

Gravity is an invisible force that pulls objects toward each other.

Comets are made of dust and ice and are known for their long tails.

1. Mercury
2. Venus
3. Earth
4. Mars
5. Jupiter
6. Saturn
7. Uranus
8. Neptune

A. It is the closest star to Earth

The Sun is our closest star. Other stars are far, far away, so they look like tiny dots.

B. Around midday

At midday the Sun is highest in the sky, so shadows are shortest. A low Sun makes long shadows.

C. Jupiter and Saturn

Jupiter and Saturn are gas giants, with swirling gases above a core and no hard surface.

D. Earth's axis is tilted

Earth's tilted axis changes which part of Earth gets the Sun's most direct rays during the year.

A. Mars and Jupiter

Most asteroids orbit the Sun between Mars and Jupiter, in the main asteroid belt.

C. Distance

A light-year is the distance light travels in one year, about 9 trillion km (6 trillion miles).

True

Gravity is the force that draws objects toward the center of a planet or other body.

True

Earth takes about 365 days to orbit the Sun once. That is one year.

False

Half the Moon is always lit by the Sun. Phases come from how much of that half we see.

inner

The first four planets from the Sun are the inner planets, also called terrestrial planets.

dwarf

Pluto was reclassified as a dwarf planet. Ceres is also a dwarf planet.

revolves

Earth orbits (revolves around) the Sun in 365.25 days. Spinning on its axis is rotation.

A. New Moon

Solar eclipses happen only at new Moon, when the Moon is between Earth and the Sun.

B. Earth

In a lunar eclipse Earth is between the Sun and Moon, and Earth's shadow falls on the Moon.

C. The Moon's gravity

The Moon's gravity drives Earth's tides. The Sun's gravity also has a smaller effect.

D. That half of Earth tilts toward the Sun

Axial tilt, not distance, causes seasons. The Northern Hemisphere tilts toward the Sun in July.

A. Gas and dust

About 4.6 billion years ago a cloud of gas and dust collapsed under gravity, forming the Sun and planets.

B. 8 minutes

Sunlight takes about 8 minutes 20 seconds to travel the 150 million km (93 million miles) to Earth.

C. A spiral galaxy that contains our Sun

The Milky Way is a spiral galaxy, and our solar system lies along one of its spiral arms.

D. Hydrogen into helium

Main sequence stars fuse hydrogen into helium in their cores. This is the longest phase of a star's life.

A. Meteorite

A meteoroid that survives its trip through the atmosphere and hits the ground is a meteorite.

B. Away from the Sun

A comet's dust and gas tail stretches away from the Sun.

False

Earth lies along a spiral arm about halfway from the galaxy's center, and the Solar System orbits that center.

True

A light-year is the distance light travels in one Earth year.

False

The Moon rotates, but its rotation matches its orbit (tidal locking), so one side always faces Earth.

True

Lunar eclipses occur at full Moon, when Earth is between the Moon and the Sun.

True

Venus rotates once in 243 Earth days but orbits the Sun in 225 Earth days.

terrestrial

The four inner planets are known as terrestrial planets because they have solid surfaces.

supernova

Massive stars collapse when their fuel runs out and blow apart in a supernova, sometimes leaving a neutron star or black hole.

white

NASA says the Sun will last about 5 billion more years before it becomes a white dwarf.

orbit

Gravity keeps the planets in orbit around the Sun.

spiral

The Milky Way is a spiral galaxy with a disk of stars spanning more than 100,000 light-years.

Comets are cosmic snowballs of frozen gases, rock, and dust that orbit the Sun.

Asteroids are rocky, airless remnants of the solar system's formation, mostly between Mars and Jupiter.

Galaxies consist of stars, planets, and clouds of gas and dust bound together by gravity.

The Moon's orbit is tilted compared to Earth's orbit around the Sun, so the Moon usually passes above or below Earth's shadow.

The tilt of the Moon's orbit means eclipses happen only occasionally instead of every month.

Terrestrial planets are smaller with solid, rocky surfaces and are closer to the Sun. Gas giants are much larger, have no hard surface, and are farther out.

Inner planets have solid surfaces. The giant outer planets have swirling gases above a core.

A. Gravity

Fusion's outward pressure supports the star's mass against gravity, which keeps the star from collapsing.

C. On the main sequence

The Sun is a main sequence star, fusing hydrogen into helium in its core, as most stars do for most of their lives.

B. A white dwarf

A Sun-like star ejects its outer layers as a planetary nebula, leaving its hot core behind as a white dwarf.

D. The oldest light we can observe

The CMB is the oldest light we can observe, a glow left over from the early universe as the first atoms formed.

B. Space is expanding

As space expands, it stretches light traveling through it to longer, redder wavelengths. More distant galaxies show larger redshifts.

A. 8 Earth years

Period squared equals distance cubed (years and AU): 4 cubed is 64, and the square root of 64 is 8.

D. One quarter as strong

Gravity is inversely proportional to the square of the distance, so doubling the distance gives 1/4 the force.

C. 3.26 light-years

A parsec is the distance at which a star shows a parallax of one arcsecond: about 3.26 light-years.

C. Chemical elements

Each element absorbs light at specific wavelengths, so the pattern of dark lines reveals which elements are present.

D. A periodic dip in the star's brightness

When a planet crosses in front of its star, it blocks a small fraction of the light, repeating each orbit.

A. The core of a massive star collapses

When a massive star's core collapses, protons and electrons are crushed into neutrons, and neutrons can halt the collapse.

B. Earth's atmosphere blocks X-rays

Earth's atmosphere absorbs X-rays, so X-ray detectors must be positioned above it.

False

Massive stars use their fuel faster. The Sun gets about 10 billion years on the main sequence; massive stars only millions.

True

A planet's gravity tugs its star back and forth, shifting the starlight slightly bluer and redder.

False

Radio waves have the longest wavelengths in the electromagnetic spectrum, far longer than visible light.

True

Gravity just beneath the event horizon is strong enough that nothing, not even light, can escape.

One AU is the distance from the Sun to Earth's orbit, about 150 million km (93 million miles).

A light-year is the distance a photon travels in a year, about 9.5 trillion km (5.9 trillion miles).

Elements absorb light at characteristic wavelengths, leaving dark lines in a spectrum that identify them.

Stars on the main sequence of the H-R diagram burn hydrogen into helium.

Inside the event horizon, gravity is strong enough that nothing, not even light, can escape.

Nuclear fusion: hydrogen nuclei join to form helium, releasing energy as light and heat.

The Sun's core fuses hydrogen into helium, and the released energy is what the Sun radiates.

Any two: galaxies' light is redshifted, showing space is expanding; the cosmic microwave background is leftover light from the early universe.

Redshift shows the universe is expanding, and the CMB is the oldest light we can observe.

Transit: the star dims slightly each time a planet crosses in front. Radial velocity: the planet's pull makes the star wobble, shifting its light by the Doppler effect.

Transits show a repeating dip in brightness; radial velocity shows a repeating Doppler shift from the star's wobble.

It speeds up. Kepler's second law: a line from the Sun to the planet sweeps equal areas in equal times.

Kepler's second law means a planet moves fastest at perihelion, its closest point, and slowest at aphelion.

B. Venus

Venus spins once in about 243 Earth days but circles the Sun in about 225.

D. Saturn

Saturn is the only planet in our solar system with an average density less than water.

A. 99.8%

The Sun holds 99.8% of the solar system's mass. Everything else combined is a rounding error.

C. Mars

Olympus Mons on Mars is the tallest volcano known in the solar system, far taller than Mount Everest.

D. Uranus

Uranus appears to spin sideways, rolling along its orbit instead of spinning upright like most planets.

B. 8 minutes

The Sun is about 8 light-minutes from Earth, so sunlight takes about 8 minutes to arrive.

A. Titan

Titan has a thick atmosphere, plus rivers, lakes and seas of liquid methane and ethane.

C. Jupiter

Jupiter has the shortest day in the solar system, about 9.9 hours.

C. Storm

The Great Red Spot is a long-lived storm in Jupiter's atmosphere.

A. Rotates once per orbit

The Moon is tidally locked: it spins exactly once per orbit, so one side always faces Earth.

C. Proxima Centauri

Proxima Centauri, about 4.25 light-years away, is part of the Alpha Centauri system but slightly closer than stars A and B.

D. Sirius

Sirius, also called the Dog Star, is the brightest star in our nighttime sky.

A. Andromeda

Andromeda is the closest large spiral galaxy, about 2.5 million light-years away. The nearer Magellanic Clouds are dwarf galaxies.

C. Barred spiral

The Milky Way is a large barred spiral galaxy, with a long bar of stars across its center.

A. 1 billion tons

Neutron star material is so dense that a sugar cube of it would weigh about 1 billion tons on Earth.

B. Event horizon

Past the event horizon, gravity is so strong that nothing, not even light, can escape.

D. Pulsar

Pulsars are spinning, highly magnetized neutron stars. Their beams sweep past us like a lighthouse.

C. 5%

Ordinary matter is about 5% of the mass-energy. Dark matter is about 27% and dark energy about 68%.

B. 13.8 billion years

Cosmologists date the Big Bang to about 13.8 billion years ago. Earth is only 4.5 billion years old.

B. Earth's atmosphere bending starlight

Moving pockets of air bend starlight on its way down to us. Above the atmosphere, stars do not twinkle.

B. Soviet Union

The Soviet Union launched Sputnik 1 on Oct. 4, 1957, beginning the space age.

D. Yuri Gagarin

Soviet cosmonaut Yuri Gagarin orbited Earth in Vostok 1 in 1961, on a flight lasting 108 minutes.

B. Valentina Tereshkova

Valentina Tereshkova flew Vostok 6 on June 16, 1963, becoming the first woman in space.

C. Apollo 11

Apollo 11 carried Neil Armstrong, Buzz Aldrin and Michael Collins on the first crewed lunar landing, in July 1969.

A. Michael Collins

Michael Collins stayed in the command module Columbia while Armstrong and Aldrin descended in the lunar module Eagle.

C. A dog

Laika, a dog, rode Sputnik 2 and became the first animal to orbit Earth.

A. Apollo 13

An explosion on Apollo 13 cost power and oxygen, but the crew looped around the Moon and splashed down safely.

D. Sally Ride

Sally Ride flew on space shuttle Challenger's STS-7 mission on June 18, 1983.

B. Its primary mirror had the wrong shape

Hubble's primary mirror had an aberration that blurred early images. A 1993 servicing mission installed corrective optics.

D. Phonograph record

Each Voyager carries a gold-plated phonograph record of sounds and images selected to portray life on Earth.

About 384,400 km (238,855 miles)

The Moon is an average of 384,400 km (238,855 miles) from Earth.