20 Space Facts for Kids That Are Out of This World

No list of fun facts about space is complete without some information about the planets. It's only natural for Earth's inhabitants to wonder about what the other planets are like!

• There used to be nine planets in Earth's solar system, but now there are only eight. Don't fear, though, none of the planets got destroyed. Instead, one of the original planets (Pluto) was demoted from planet status and reclassified as a dwarf planet.
• The eight planets in the solar system are Mercury, Venus, Earth, Mars, Jupiter, Saturn, Uranus, and Neptune. For an easy way to remember them, memorize a sentence like "My very effective memory just soaks up names." The first letter of each word starts with the same first letter of one of the planets.
• Mercury has the greatest same-day difference between high and low temperatures. Daytime temperatures can climb as high as 800 degrees Fahrenheit, while nighttime temperatures can plunge to 330 degrees below zero (-330 Fahrenheit) on the same day.
• You might think it gets hot on Earth during the summer, but Earth's temperatures are nothing compared to some other planets. Venus is the hottest planet in the solar system. Its surface temperatures fluctuate between 820 and 900 degrees Fahrenheit. How's that for extreme heat?
• Neptune is considered the coldest planet in the solar system. The average temperature there is 373 degrees below zero (-373 Fahrenheit). The temperature doesn't fluctuate much at all between daytime and nighttime.
• Saturn is actually not the only planet that has rings around it. Uranus, Jupiter and Neptune also have rings. Their rings just aren't visible from Earth.
  
• Mars has a nickname. It's often called the Red Planet because of the red hue of its atmosphere and surface. It might be more accurate to call it the Rusty Planet. Why? Its red color is caused by rust that forms as a result of iron minerals in the planet's soil.
• Earth also has a nickname. Some call Earth the Blue Planet. That's because Earth appears blue when you look at it from space, due to the fact that approximately 70 percent of the planet's surface is made up of water.
• Jupiter spins faster than any other planet in the solar system. This means it also has the shortest day of all the planets. Jupiter makes a complete rotation on its axis in just 10 hours, so that's how long a day is on that planet.

Of course, there's way more to the Milky Way galaxy than just the planets in the Earth's solar system. The Milky Way offers a whole galaxy of fun space facts to explore!

• How huge is the Milky Way galaxy? It's so enormous it's measured in light-years. While scientists used to believe that it would take approximately 100,000 light-years to travel from one side to the other, recent data suggest that it's actually 200,000 light-years across.
  
• The Milky Way is in constant motion. It never sits still, but rather continuously moves in a rotating pattern. The sun and solar system, which are located within the Milky Way, are also in continual motion as they orbit the Milky Way.
  
• A galactic year is the amount of time it takes the sun to orbit around the Milky Way one time. One galactic year might not sound like a long time, but it is! How long is it? Approximately 226 million Earth (terrestrial) years.
• Wish you could count all of the stars in the galaxy? You'll need to get to know some really large numbers! It is believed that there are around 100 thousand million stars in the Milky Way, most of which can't be seen from Earth.
• In case you were wondering, the Milky Way is not named after a candy bar! The name is linked to Greek mythology. Some say that that the Milky Way was created after Hera, a Greek goddess, sprayed milk across the sky.
  
• Not everyone uses the name Milky Way to describe the galaxy. For example, in parts of Africa, it is referred to as the Backbone of Night. In China, people refer to it as the Silver River.
• The Milky Way, one of many galaxies in the universe, is almost as old as the Universe itself. The universe is believed to be approximately 13.7 billion years old. In 2004, the results of a research study indicated that the Milky Way is around 13.6 billion years old (with a potential 800,000-year margin of error).
• No one has ever seen the entire Milky Way, as space travel beyond the galaxy is not yet a reality. The next frontier to conquer will be traveling beyond the solar system. In 2012, NASA's Voyager 1 space probe became the first vessel to leave the solar system and enter interstellar space, with future exploration expected.

Your parents and most other adults in your life probably studied space when Pluto was still a planet and dwarf planets didn't exist. You'll be able to wow them with information that's new to them when you master a few facts about the dwarf planets.

• The former planet Pluto lost its planet status in 2006 when the definition of a planet was updated to only include larger celestial bodies. It didn't lose all status, though. Instead, the category of dwarf planet was developed to include sub-planetary objects.
  
• Dwarf planets are similar to planets, but they are smaller. Because of their diminutive dimensions, their gravitational pull is weaker than that of the actual planets. Size isn't everything, though. They're still cool!
• Pluto isn't all on its own in the dwarf planet category. There are five known dwarf planets. In addition to Pluto, the identified dwarf planets are Ceres, Eris, Haumea, and Makemake.

When you look up at the sky, it's natural to wonder exactly what is up there in the universe and beyond. These fun and fascinating space facts for kids provide a glimpse beyond the confines of Earth. From here, they can explore and expand what they know by discovering these cool space and astronomy vocabulary words for kids. Don't forget to focus on our own planet with some Earth facts too!