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How Many Planets Are in the Solar System?

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In this short explainer video, Universe Today publisher Fraser Cain explains just how many planets there are in the Solar System. How did we go from 9 to 8, and what does this mean for Pluto? --------------- How Many Planets are in the Solar System? I'm just going to warn you, this is a controversial topic. Some people get pretty grumpy when you ask: how many planets are in the Solar System? Is it eight, ten, or more? I promise you this, though, we're never going back to nine planets... ever. When many of us grew up, there were nine planets in the Solar System. It was like a fixed point in our brains. As kids, memorizing this list was an early right of passage of nerd pride: Mercury, Venus, Earth, Mars, Jupiter, Saturn, Uranus, Neptune and Pluto. But then in two-thousand-five, Mike Brown discovered Eris, an icy object thought to be about the same size as Pluto, out beyond its orbit. That would bring the total number of planets to ten. Right? There's no turning back, textbooks would need to be changed. In order to settle the dispute, the International Astronomical Union met in two-thousand-six, and argued for, and against Pluto's planethood. Some astronomers advocated widening the number of planets to twelve, including Pluto, its moon Charon, the Asteroid Ceres, and the newly discovered Eris. In the end, they changed the definition of what makes a planet, and sadly, Pluto doesn't make the cut: Here are the new requirements of planethood status: 1. A planet has to orbit the Sun. Okay fine, Pluto does that. 2. A planet needs enough gravity to pull itself into a sphere. Okay, spherical. Pluto's fine there too. 3. A planet needs to have cleared out its orbit of other objects. Uh oh, Pluto hasn't done that. For example, planet Earth accounts for a million times the rest of the material in its orbit, while Pluto is just a fraction of the icy objects in its realm. The final decision was to demote Pluto from planet to dwarf planet. But don't despair, Pluto is in good company. There's Ceres, the first asteroid ever discovered, and the smallest of the dwarf planets. The surface of Ceres is made of ice and rock, and it might even have a liquid ocean under its surface. NASA's Dawn mission is flying there right now to give us close up pictures for the first time. Haumea, named after the Hawaiian goddess of fertility, is about a third the mass of Pluto, and has just enough gravity to pull itself into an ellipsoid, or egg shape. Even though it's smaller, it's got moons of its own. Makemake, a much larger Kuiper belt object, has a diameter about two-thirds the size of Pluto. It was discovered in two-thousand-five by Mike Brown and his team. So far, Makemake doesn't seem to have any moons. Eris is the most massive known dwarf planet, and the one that helped turn our definition of a planet upside-down. It's twenty-seven-percent more massive than Pluto and the ninth most massive body that orbits the Sun. It even has a moon: Dysnomia. And of course, Pluto. The founding member of the dwarf family. Want an easy way to remember the eight planets, in order? Just remember this mnemonic: my very excellent mother just served us noodles. For all you currently writing angry tweets to Mike Brown, hold on a sec. Changing Pluto's categorization is an important step that really needed to happen. The more we discover about our Universe, the more we realize just how strange and wonderful it is. When Pluto was discovered eighty years ago, we never could have expected the variety of objects in the Solar System. Categorizing Pluto as a dwarf planet helps us better describe our celestial home. So, our Solar System now has eight planets, and five dwarf planets. Thanks for watching!
How many planets do you think are in the solar system? Get ready to have your misconceptions created in this Horizon special 'Bye Bye Planet Pluto'.
An Infographic trip through the wonders of the solar system. The solar system - well known from countless documentaries. 3D animation on black background. This infographic videos tries something different. Animated infographics and a focus on minimalistic design puts the information up front. We take the viewer on a trip through the solar system, visiting planets, asteroids and the sun. Short videos, explaining things. For example Evolution, the Universe, the Stock Market or controversial topics like Fracking. Because we love science. We would love to interact more with you, our viewers to figure out what topics you want to see. If you have a suggestion for future videos or feedback, drop us a line! :) We're a bunch of Information designers from munich, visit us on facebook or behance to say hi! The Solar System -- our home in space Help us caption & translate this video!
It’s long been theorized that there is a planet in our solar system that is beyond Neptune and Pluto. Amy is here to discuss new evidence that might back up this theory. Follow Amy on Twitter: Read More: New Dwarf Planet Found at Solar System’s Edge, Hints at Possible Faraway ‘Planet X’ “Astronomers have found a new dwarf planet far beyond Pluto's orbit, suggesting that this distant realm contains millions of undiscovered objects — including, perhaps, a world larger than Earth.” A distant planet may lurk far beyond Neptune “If Planet X exists, it may be anywhere from 250 to 1,000 times as far from the sun as Earth.” ____________________ DNews is dedicated to satisfying your curiosity and to bringing you mind-bending stories & perspectives you won't find anywhere else! New videos twice daily. Watch More DNews on TestTube Subscribe now! DNews on Twitter Trace Dominguez on Twitter Tara Long on Twitter DNews on Facebook DNews on Google+ Discovery News Download the TestTube App:
Astronomers have a massive breakthrough as they discover a weird and very bright extraordinary object in the far reaches of our solar system. Is it a planet? Is it a block of ice? Whatever it is, it's bigger than Pluto. Fascinating science video from BBC Horizon show 'Bye Bye Planet Pluto.'
07:41 ... Science@ESA (Episode 7): Exploring our backyard, the Solar System (Part 1) In this seventh episode of the Science@ESA vodcast series Rebecca Barnes continues to journey through the wonders of modern astronomy bringing us closer to home as we begin to explore the Solar System. We'll discover the scale and structure of the Solar System, find out why we explore it and introduce the missions launched on a quest to further investigate our local celestial neighbourhood. --- Please SUBSCRIBE to Science & Reason: • --- The Solar System is made up of the Sun and all of the smaller objects that move around it. Apart from the Sun, the largest members of the Solar System are the eight major planets. Nearest the Sun are four fairly small, rocky planets - Mercury, Venus, Earth and Mars. Beyond Mars is the asteroid belt -- a region populated by millions of rocky objects. These are left-overs from the formation of the planets, 4.5 billion years ago. On the far side of the asteroid belt are the four gas giants - Jupiter, Saturn, Uranus and Neptune. These planets are much bigger than Earth, but very lightweight for their size. They are mostly made of hydrogen and helium. Until recently, the furthest known planet was an icy world called Pluto. However, Pluto is dwarfed by Earth's Moon and many astronomers think it is too small to be called a true planet. An object named Eris, which is at least as big as Pluto, was discovered very far from the Sun in 2005. More than 1,000 icy worlds such as Eris have been discovered beyond Pluto in recent years. These are called Kuiper Belt Objects. In 2006, the International Astronomical Union decided that Pluto and Eris must be classed as "dwarf planets". Even further out are the comets of the Oort Cloud. These are so far away that they are invisible in even the largest telescopes. Every so often one of these comets is disturbed and heads towards the Sun. It then becomes visible in the night sky. .
In this short video explainer, Universe Today publisher Fraser Cain helps you understand the full scale of the Solar System. Where does our Solar System end, and other star systems begin? In short, it's big, really big. ------------- For most of us, stuck here on Earth, we see very little of the rest of the Solar System. Just the bright Sun during the day, the Moon and the planets at night. But in fact, we're embedded in a huge Solar System that extends across a vast amount of space. Which begs the question, just how big is the Solar System? Before we can give a sense of scale, let's consider the units of measurement. Distances in space are so vast, regular meters and kilometers don't cut it. Astronomers use a much larger measurement, called the astronomical unit. This is the average distance from the Earth to the Sun, or approximately 150 million kilometers. Mercury is only 0.39 astronomical units from the Sun, while Jupiter orbits at a distance of 5.5 astronomical units. And Pluto is way out there at 39.2 astronomical units. That's the equivalent of 5.9 billion kilometers. If you could drive your car at highway speeds, from the Sun all the way out to Pluto, it would take you more than 6,000 years to complete the trip. But here's the real amazing part. Our solar system extends much, much farther than where the planets are. The furthest dwarf planet, Eris, orbits within just a fraction of the larger Solar System. The Kuiper Belt, where we find a Pluto, Eris, Makemake and Haumea, extends from 30 astronomical units all the way out to 50 AU, or 7.5 billion kilometers. And we're just getting started. Ever further out, at about 80-200 AU is the termination shock. This is the point where the Sun's solar wind, traveling outward at 400 kilometers per second collides with the interstellar medium - the background material of the galaxy. This material piles up into a comet-like tail that can extend 230 AU from the Sun. But the true size of the Solar System is defined by the reach of its gravity; how far away an object can still be said to orbit the Sun. In the furthest reaches of the Solar System is the Oort Cloud; a theorized cloud of icy objects that could orbit the Sun to a distance of 100,000 astronomical units, or 1.87 light-years away. Although we can't see the Oort Cloud directly, the long-period comets that drop into the inner Solar System from time to time are thought to originate from this region. The Sun's gravity dominates local space out to a distance of about 2 light-years, or almost half the distance from the Sun to the nearest star: Proxima Centauri. Believe it or not, any object within this region would probably be orbiting the Sun, and be thought to be a part of the Solar System. Back to our car analogy for a second. At those distances, it would take you 19 million years to complete the journey to the edge of the Solar System. Even NASA's New Horizons spacecraft, the fastest object ever launched from Earth would need 37,000 years to make the trip. So as you can see, our Solar System is a really really big place.