1. Asteroid
   Star
2. Planet
   Nebula

Our sun is a big beautiful star and the center of the entire solar system! The sun keeps our planet from turning into one big ball of ice out there in space, so we give it mad respect.

1. Venus
   Mars
2. Mercury
   Earth

When it comes to planets, Venus really knows how to heat things up as its greenhouse gas effect keeps this planet so sizzling all year round. Talk about being way too hot to handle!

1. Quantum Game Theory
   String Theory
2. The Theory of Relativity
   The Big Bang Theory

In addition to being a hit television show, The Big Bang Theory is the most popular theory that explains the creation of the universe. It essentially states that the universe exploded into existence.

1. The debris field
   The tail
2. The head
   The spray

Comet tails are created when the comet passes too close to the sun. They usually consist of gas and dust, and either follow or precede the comet depending on where it is in relation to the sun.

1. Io
   Orion
2. Pluto
   Jasper

Jupiter has 79 known moons! Io is just one of the more famous moons that orbit around this massive planet. We just know about the 79 moons, but there could certainly be more than that!

1. Rock
   Gas
2. Water
   Fluorescent light

The sun is a giant ball of gas which is comprised mostly of hydrogen and partially of helium. The gas is extraordinarily hot and you couldn't get anywhere near the sun without burning to a crisp.

1. Planet
   Asteroid
2. Star
   Blackhole

Millions of these huge asteroids litter the vast expanse of space. Although they are giant, they are not considered planets, although the larger ones are sometimes called "planetoids."

1. 5.5 thousand years old
   2 million years old
2. 100 years old
   4.5 billion years old

Our amazing sun is 4.5 billion years old, give or take a year. This massive star has been around for a long time, and we would be completely lost (and dead) without its warming light.

1. North
   South
2. East
   West

If you want to catch an amazing sunrise, you will have to look to the east! The sun rises in the east and makes its way across our sky over the course of the day, finally setting in the west.

1. Neptune
   Mars
2. Earth
   Venus

The chilly Neptune is the planet that is furthest away from the sun. This giant has 17 times more mass than our Earth and is known for being dark, icy and totally mysterious.

1. A lunar eclipse
   A solar eclipse
2. A blackout
   A supernova

When the sun, moon and Earth are aligned in a specific way, the sun can temporarily be blocked out by the shadow of the moon. We call this a solar eclipse, and it's a highly anticipated celestial affair.

1. Sirius
   Io
2. Sol
   Orion

Like many celestial bodies in our galaxy, the sun is named after a Roman god. Sol is the Roman counterpart of the Greek god Helios, who is fittingly the god of the sun. Sol is also "sun" in Spanish!

1. Sally Ride
   Buzz Aldrin
2. Yuri Gagarin
   Neil Armstrong

It was simply one small step for Neil Armstrong, but one giant leap for all of mankind when this pioneering American astronaut became the very first person to set foot on the moon.

1. Supernova
   Aurora Borealis
2. Milky Way
   Pleiades

Visit Alaska during the winter, and you might get treated to one of the most amazing light shows that you will ever see. The Aurora Borealis is a burst of beautiful color in the sky, caused partially by the solar wind.

1. Earth
   Mars
2. Pluto
   Jupiter

Jupiter is an absolutely enormous planet. It is twice the size of all other planets in our solar system combined and has 318 more mass than Earth. This giant is the fifth planet from the sun.

1. They are inside a giant black hole.
   They are really comets.
2. Light takes time to travel.
   All of the stars we see exist currently.

This might be a tough one for some people to wrap their minds around, but many of the stars that we gaze up at no longer exist. This is because light takes time to travel, and the stars are so far away.

1. Mars
   Earth
2. Jupiter
   Neptune

Mars is nicknamed "The Red Planet" because the iron oxide that dusts its surface gives it the unmistakable red hue that makes it stand out in the sky. There is also a blockbuster movie called "The Red Planet."

1. Astrology
   Physics
2. Astronomy
   Zodiacalogy

Astronomy mixes together some of the most important scientific practices like math, chemistry and physics to study what is going on in the outer space that surrounds our home planet.

1. Uranus
   Venus
2. Jupiter
   Neptune

Venus is known as "The Morning Star" because it rises just a few hours ahead of the sun and fades away as the day begins. Ancient seafarers used Venus as a way to navigate their ships.

1. Archimedes
   Francis Bacon
2. Galileo Galilei
   René Descartes

Galileo Galilei is one of the most important people when it comes to the study of astronomy. He pioneered the idea that the Earth revolved around the sun, a radical notion at the time.

1. Supernova
   Event Horizon
2. Nebula
   Solar flare

The Event Horizon is the absolute last place that you can turn back before getting sucked into a black hole with no escape, but we would advise that you not even get that close to one!

1. Atmosphere
   Sheen
2. Nebula
   Orbit

An orbit is a path that one celestial body makes around another celestial body because of gravitational pull. Our Earth orbits the sun, and our moon orbits us, making the journey in roughly one month.

1. Gravity
   Physics
2. Orbit
   Radiation

Gravity is essentially what keeps all objects where they are supposed to be in our universe. The gravity of our planet Earth keeps us from flying off into space, as the Earth attracts us to it.

1. Apollo 13 Initiative
   Space Exploration Initiative
2. Strategic Defense Initiative
   Bay of Pigs Initiative

Ronald Reagan's Strategic Defense Initiative, also known as "Star Wars" was a missile defense system launched up into space to protect the United States from Russian nuclear attack.

1. Venus
   Mars
2. Mercury
   Pluto

Venus is the second planet from the sun and is known for its steamy atmosphere and volcanic landscape. It is far too hot to live on and is named for the Roman goddess of beauty. In the real-color image show here, the surface is obscured by thick sulfuric acid clouds.

1. Io
   Orion
2. Scorpius
   Galileo

Orion's Belt is a constellation that is made up of three brilliant stars: Alnilam, Mintaka and Alnitak. It is easily visible in the sky and has been traditionally used for navigation.

1. Asteroid belts
   Supernovas
2. Event horizons
   Nebulas

Nebulas are brilliant clouds of gas and dust that drift around in the sky and act as the birthplace for new stars. They are often very far away from our planet and can only be faintly seen.

1. Uranus
   Jupiter
2. Neptune
   Mercury

The giant of our galaxy is also home to the "Great Red Spot." Jupiter's trademark spot is likely the case of an anticyclonic storm that wages on the planet due to very high pressure.

1. Mars
   Pluto
2. Venus
   Neptune

The ice giant Neptune is named after the Roman god of the sea. It is so far away from Earth, that it is the only other planet in our universe that can't be seen with the naked eye.

1. Astroflyers
   Spacenauts
2. Cosmonauts
   Galaxiers

The Russian term for "astronaut" is "cosmonaut." The most famous Russian cosmonaut is Yuri Alekseyevich Gagarin, the first person to go into space. There have been several notable cosmonauts since then. Shown here is Valentina Tereshkova, the first woman in space.

1. Mercury
   Mars
2. Venus
   Earth

Mercury is the smallest planet in our universe, and also the closest to the sun. Although Mercury is closest to the sun, it's not as hot as Venus because its atmosphere is different.

1. The Red Planet
   The Blue Planet
2. The Human Planet
   The Water Planet

Earth is known as "The Blue Planet" because, when seen from space, it appears to be greenish-blue. This is because Earth is mostly covered in water, which appears blue from outer space.

1. Supernova
   Asteroid belt
2. Nebula
   Blackhole

Black holes are famous traps for everything imaginable, including light. They are created when stars collapse and are surrounded by an Event Horizon, which you cross at your own risk.

1. Stephen Hawking
   Edwin Hubble
2. Carl Sagan
   Neil deGrasse Tyson

Stephen Hawking was a theoretical physicist who penned a number of brilliant books and theories about black holes. He was one of the most influential scientists the world has ever seen.

1. Jupiter
   Mercury
2. Saturn
   Neptune

Tiny Mercury does not have any rings. It also does not have a moon. It is theorized that any moon or rings would be pulled into the sun since Mercury is so close to that giant star. Shown here is an image of Saturn and its rings taken by NASA's Hubble Space Telescope.

1. Scorpius
   Gemini
2. Virgo
   Leo

Leo is one of the first constellations that was ever discovered and also represents the zodiac Leo sign, a fire sign that represents people born between July 23rd and August 22nd.

1. Yes
   No
2. Only stars in the Andromeda Galaxy
   Only stars close to the Earth's poles

Stars do not burn forever and all of them, including our own sun, will eventually run their course and burn out. When larger stars finally do die they can collapse and form black holes.

1. Andromeda Galaxy
   Orion Galaxy
2. Sol Galaxy
   Milky Way Galaxy

Our galaxy exists within the massive Milky Way Galaxy, a huge spiral-shaped galaxy that is one of many in the overall universe. Our whole galaxy has not been fully mapped because it's so massive.

1. Mercury
   Mars
2. Pluto
   Venus

Poor Pluto! This tiny planet used to be the ninth in the solar system, but it has since been demoted to a dwarf planet. It happened because the International Astronomical Union changed the qualifications for planethood.

1. 1969
   1942
2. 2001
   1899

It was just one small step for man, but one giant leap for mankind when Neil Armstrong took the first tentative steps on the moon. This game-changing event happened on July 20, 1969. Shown here is Buzz Aldrin in a photo taken by Neil Armstrong, who can be seen in the reflection in Aldrin's visor.