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Basics of Our Solar System

How much do you know about our solar system, the galaxy it's found in, and the universe beyond? Get the quick facts on the solar system right here!

Our Solar System - What's In It?

If the Milky Way galaxy were shrunk down to the size of North America, our solar system would fit inside a coffee cup. Our solar system is made up of a star that we call the Sun , along with eight or nine planets (more on that later): Mercury, Venus, Earth, Mars, Jupiter, Saturn, Uranus, Neptune and the most controversial: Pluto. The solar system also includes the satellites of these planets, numerous comets, asteroids, and meteoroids.

Our Solar SystemOur Solar System

Our Solar System - How Many Planets?

It has long been taught that our solar system contains nine planets, but that number was cast into doubt in 2006 when the International Astronomical Union voted to reclassify Pluto as a dwaft planet. The reason for it's demotion has to do with Pluto not being "gravitationally dominant" in its orbital zone. What does that mean? For an object to be gravitationally dominant it must exert a gravitational pull on the objects surrounding it. For example, the earth has a stronger pull on the Moon than the Moon has on the earth. That means the earth is gravitationally dominant. There are two other dwarf planets in our solar system besides newly demoted Pluto: Ceres and Eris.

Planet NamesPlanet Names

Our Solar System - How Big is It?

In order to get a good visual of the relative sizes of our solar system, imagine a model that has been reduced by a factor of one billion. That means the Earth is now the size of an olive. The Moon is a pepper corn orbiting about a foot away. The Sun is now the height of a man and about a city block from Earth. Jupiter has just become the size of a large grapefruit and is five blocks away from the Sun. Saturn, the size of an apple, is ten blocks away, Uranus and Neptune, both lemons, are twenty and thirty blocks away. A human on this scale is the size of an atom and the nearest star is more than 24,850 miles (40,000 km) away.

Our Solar System - How Was It Created?

The question of how our solar system - and also our universe - were created is a seriously contentious issue! There is a chance that we might never know entirely, but there some well-researched theories as to how it was created. The most famous and believed by astronomers is the Big Bang theory. The theory goes that about 14 billion years ago, the entire universe was thousands of times smaller than a pinhead. It was incredably hot and dense. At some point the micor-universe exploded, the blast made all this debris in the universe. The planets, moons and asteroids today are the survivors from that explosion and our Sun is the central star and the universe is still expanding to this day.

  • Drop us a line if you know something cool about our solar system. It is a great subject for a science project at school.
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What's Your Favorite Heavenly Body?

  • Earth.
  • Mercury.
  • Jessica Alba.
  • Saturn.

Random In The Forums

jordand08 posted in New Users:
Welcome to KW! 
reply about 2 hours
Hi, Alex! I think I'm a little late, but still... hi :3 It's cool that you're one of the LGBTQ+. I feel I don't know many people who are :P Late welcome to KW!
reply about 2 hours
I'm in competition with no one , but I'm struggling just to be better than yesterday.....
reply about 3 hours
Here's my own forum for stories I write. I love writing, but I get kinda lazy sometimes. Expect a slow trickle :P It'll be a mish-mash of short stories I write. Some will be parts of an overall story, similar to chapters, and some will not. I'll try and note what page each part of a story is on and stuff. Now, the first one, that I wrote back in eighth grade. Very random and kind of odd. I didn't write it to be accurate, but to be silly and have fun.  Xp Starts out seeming very morbid, but trust me. It's not actual stuff. Note: It's not my best writing, though. I've improved. *** The dragon destroyed the entire village. Fires burned everywhere. Dead bodies laid on the ground to rot and appease the hunger of animals. Only one person--I mean two--were still standing; Khedra and Sammich. Trembling, Sammich stared at the horrendous beast. Khedra, brushing sand out of her bronzed face, spun, looking for it. "Sammich, where is it?! Tell me now or I'll slap you!" she shouted. "O-over there," Sammich said, pointing. "Where is there?! I CAN'T SEE IT, YOU DERANGED DONKEY!" Khedra yelled. "Open your eyes, woman!" She opened her eyes. Seeing the dragon, she grabbed her curved blades from the sand at her feet. "Don't just stand there, Sammich, fight it!" Khedra exclaimed, right in his ear. "But I don't have a weapon!" Sammich replied. "Because you're not scary!" "You said I'm not scary?!" Sammich bellowed. His English accent made Khedra's cheeks puff up with suppressed laughter. "Don't you laugh at me!" he continued, stomping over to the dragon, who was staring him down as a father does a disobedient son. Sammich grabbed one of the dragon's legs and started yanking on it, without effect. He looked like a savage, screaming his head off in a long battle cry. The dragon snorted, lifted its leg, shook Sammich off, and flew away as Sammich landed with a miniature mushroom cloud of sand and a loud POOF! The dragon clearly believed the young man wasn't worth his time. Chuckling, Khedra sheathed her curved blades while striding to Sammich, lying, frustrated, in the sand. She stuck out a hand, offering help to her friend. Sammich, scowling, with an adorable pout, took her hand and allowed her to pull him up. "We got rid of the dragon, everyone! You can stop hiding, now!" Khedra announced. The villagers disguised as rotting and torn bodies picked themselves up. The mage nearby let the illusion of fire fade from the houses, and stepped out from one of the buildings. "Bye, peoples!" Sammich called, shaking sand out of his tousled, chestnut hair. Khedra and Sammich ran off into the desert, towards the Oasis. *** I'm working on another one, now, so I'll at least post the fragment I have done tomorrow. This one I'm posting tomorrow will be better XD
reply about 4 hours
jordand08 posted in Debating:
"jordand08" wrote:Pink_Cool_ Girl, watch your language.​Anyway, no. Abortion shouldn't be about a choice. I believe in early abortions for those who are raped or molested. However, when you become pregnant, you know theres a CHANCE you COULD get pregnant, if you don't want to, use protection. People know the consequences with doing the "dirty", so if you think youre mature enough to do it, you can be mature enough to be a mom. And if you don't think you want to be a mom, theres adoption. Theres too many people who cant have babies for unknown reasons, I think that if you abort a baby, youre just throwing a smack in the face to those who cant have children.
reply about 9 hours