Cool Space Facts


As long as human beings have been looking into the night sky, we have been wondering what is out there. Many cultures have created stories, myths, and songs about space, imagining creatures of all types from angry to friendly.

Cool Space Facts Introduction

In the last number of years we have learned more about space than at any other time in history. We began sending rockets into space in the 1960s and here we are, only sixty years later, watching images sent back from space missions to Mars, asteroids, and comets, and astronauts living in the space station that orbits our Earth.

Along the way, we have learned a lot about space that changed previous ideas and gave us entirely new ones. As we continue to explore we will find that space and the universe brings exciting concepts that astound the imagination.

Cool Space Facts for Kids:

  • Our sun is over 300,000 times bigger than the Earth.
  • Halley’s Comet only enters our inner solar system every 75 years. The last time it was visible from Earth was in 1986 and the next time will be in 2061.
  • Venus has temperatures over 450 degrees C and is listed as the hottest planet in our solar system.
  • Scientists believe that our solar system was formed over 4.6 billion years ago.
  • The Earth has constant activity in the way of weather, erosion, earthquakes, and volcanic flow that cover up the many impact craters that have occurred on the planet.
  • The moon seems like it has more scars and craters than Earth because it has less activity that affects its surface than Earth.
    We know about the rings of Saturn but there are other planets in our solar system that have rings, including Jupiter, Uranus, and Neptune. Their rings just aren’t as big and obvious.
  • The moon doesn’t have any wind to blow around and cover the footprints and rover tire tracks that were left by the astronauts. It’s believed that those prints will stay there for millions of years.
  • In 2006, the International Astronomical Union (IAU) downgraded Pluto from our ninth planet to a dwarf planet.
  • Mars has lower gravity than Earth. A person that weighs 200 pounds on Earth would only weigh 76 pounds if they stood on Mars.
  • Uranus is the only planet in our solar system that rotates on its side and Venus is the only planet in our solar system that spins backwards relative to the other planets.
  • Some of the meteoroids that are traveling through our solar system are speeding through it at around 26 mi per second/42 km per second.
  • The first human made object that was sent into space was the Russian satellite Sputnik, launched in 1957.
  • The gravity from our sun and moon give us the low and high tides of our oceans, seas, and water.
  • Our sun is thought to be an average-sized star and yet one million Earths could fit inside the sun.
  • For many years, scientists thought that the Earth might be the only planet in our solar system with liquid water. NASA findings show strong evidence that Mars might have liquid water.
  • Comets are made up of sand, ice, and carbon dioxide and are leftover materials from the formation of our solar system 4.5 billion years ago.
  • The gas giants in our solar system are Jupiter, Saturn, Uranus and Neptune. They are almost completely gas so you wouldn’t be able to walk on them.
  • Throughout the years of space travel humans have left a lot of trash in Earth’s orbit. This is called “space junk” and it’s believed that there are 500,000 pieces of space junk in orbit today.
  • Earth is hit by an asteroid around the size of a car around once per year. Thankfully, most of it burns up in the atmosphere before it hits land.
  • Scientists believe that there are more stars in the universe than there are grains of sand on all of Earth’s beaches.
  • When you are on Mars, the sunset looks like it’s blue.
  • There isn’t any atmosphere in space and that means that it doesn’t have a medium for sound to travel in. This makes space completely silent.
  • Radio waves can be sent and received in space, so astronauts use radio waves to communicate back to Earth.
  • The closest planet to the sun is Mercury, but it’s Venus that is the hottest planet in the solar system. Venus has an average temperature of around 450 degrees C.
  • Other than Earth, scientists believe that the only other planet in the solar system that could be hospitable to life is more than likely Mars. This is due to the 1986 discovery of a rock from Mars that is thought to contain microscopic fossils.
  • It’s thought that there are between 200-400 billion stars in the Milky Way galaxy.
  • Scientists believe that there are billions of galaxies in the universe.
  • The cost of a complete spacesuit from NASA is $12,000,000. 70% of this cost is for the control module and backpack.
  • Neutron stars are some of the smallest and densest stars that we know of in the universe. They may only have a radius of around 6 mi/10 km but they also have a density that is around two times that of the sun. Their fast rotation means that they can spin as fast as 600-712 times per second.
  • Neutron stars are created when the core of a star collapses after a supernova explosion.
  • Yale University scientists believe that they have found a rocky planet 40 light-years away called 55 Cancri e that has a radius that is twice that of our Earth’s and a mass that is eight times greater. They think the surface is made up of graphite and diamond.
  • A single day on Venus is almost longer than a single Earth year. It takes 243 Earth days for Venus to complete one orbit that would be a day.
  • It takes Venus 18 Earth days (or less) to complete a single year rotation around the sun.
  • We have learned that galaxies in the universe are always moving. The closest galaxy to the Milky Way is the Andromeda galaxy and it’s believed that in 3.75 billion years, the two galaxies will collide and will form a giant elliptical galaxy.
  • If two pieces of the same type of metal touch each other in space they will experience what is called “cold welding” and permanently bond together. This is because unlike Earth, space doesn’t have air or water that separates the metal, and in space it doesn’t know that they are separate pieces.
  • Astronomers have been searching space and have located a huge water vapor cloud 10 billion light-years away that seems to hold around 140 trillion times the amount of water in our Earth’s oceans. This makes it the largest discovery of water ever found so far.
  • Scientists have a theory that the moon was once part of the Earth when it was a young planet. It’s thought that at one time there was a collision with a giant object that broke a piece of Earth away and as the material orbited the Earth due to gravitational pull, it eventually became the moon.
  • We know that our sun is huge, but the astounding part is that the mass of the sun takes up 99.86% of the mass of our entire solar system.
  • The sun is made up of three quarters hydrogen and helium.
  • Olympus Mons is a volcano on Mars that is three times the size of Mt. Everest. Scientists think that the volcano might still be active.
  • Scientists believe that the observed part of the universe is around 13.8 billion years old.
  • Since the universe was formed in the Big Bang, the universe continues to expand.
  • It’s estimated that in the observable universe there are 2 trillion galaxies.
  • Scientists always thought that the space in between the galaxies was empty. Recent discoveries have shown that there is actually one atom per cubic meter of space between the galaxies.
  • Our solar system is made up of the sun, planets, dwarf planets, moons, and other objects zooming around in space such as asteroids and comets.
  • For many years astronomers listed our solar system with nine planets. However, that changed when the International Astronomical Union (IAU) created the classification of a dwarf planet and downgraded Pluto from a planet to a dwarf planet.
  • Our solar system has eight planets: Mercury, Venus Earth, Mars, Jupiter, Saturn, Uranus, and Neptune.
  • If you added all of the planets together they would make up only 0.14% of the mass of the solar system. 99% of the mass would be from the gas giants of Jupiter, Saturn, Uranus, and Neptune.
  • Except for Earth, the planets are named after the mythological Greek and Roman gods.
  • If you added up the mass of all of the moons in our solar system it would be less than 0.1% of the mass of the Earth.
  • Scientists believe that a majority of the universe is made up of a mysterious element called “dark matter.” They don’t know much about dark matter and they can’t see it, but they have done mathematical calculations to show that it exists.
  • Another mysterious discovery that scientists have made is the fact that the universe is expanding at exponential rates. They have developed a theory that involves the existence of “dark energy” to explain why the universe is expanding as it is.
  • When we see Uranus in the solar system it is a lovely, featureless, blue ball that seems like it is floating in space.
  • Uranus is one of the gas giant planets and scientists don’t know why it’s rotating on its side. They have a theory that it might have experienced a collision in its ancient past that caused it tot tilt.
  • Io is one of the moons of Jupiter and it has hundreds of volcanos. Io is thought to be the most active moon in the solar system, spewing plumes as high as 250 miles into the atmosphere.
  • So far, our space explorations to other planets, moons, and asteroids have shown that Mars has the biggest volcano in the solar system. Olympus Mons is 374 mi/602 km across and 16 mi/23 km high.
  • Mars sets a few records in our solar system including the planet that has the longest valley. Valles Marineris is 2,500 mi/4,000 km long and over ten times longer than Earth’s Grand Canyon. The 1971 view taken from the Mariner 9 spacecraft show the canyon to be about as long as the United States.
  • We are very lucky on Earth to be able to see solar eclipses. We can see them because the sun is exactly 400 times the moon’s size and the moon is 400 times closer to the Earth.
  • If our sun was the size of an average front door, the Earth would be the size of a nickel.
  • Lightning storms on Jupiter and Saturn turn methane into carbon soot that falls and hardens into chunks of graphite and then diamonds. So it rains diamonds on Saturn and Jupiter and scientists think the largest of these are about one centimeter in diameter.
  • The Hubble Space Telescope spotted a planet in 2013 that was blue and seemed to look quite a bit like Earth. But the planet has a temperature of 1,832 degrees F and it rains glass sideways at around 4,300 mph.
  • Pan is one of Saturn’s moons and it is in the shape of a walnut because it’s absorbing some of the material that make up Saturn’s rings.
  • If you lined up all of the planets in our solar system they would fit in between the moon and the Earth.