If Jupiter and Saturn are gas giants, could you fly straight through them? Audio recording of Dr. Marc reading this page. Click play to hear me read this to you! Our friends at the W.A. Gayle Planetarium in Montgomery, Alabama, are curious to know, if Jupiter and Saturn are gas giants, could you fly straight through them? We think of a gas as something very . . . well, airy. After all, air is the gas we all know and love. We breathe it and fly planes right through it with no trouble. So it makes sense to think that a gas planet must be like a big, airy cloud floating out in space. But take another look at Jupiter and Saturn—or pictures of them. Notice how round they are. You will never see a cloud on Earth so nearly spherical. Why are Jupiter and Saturn so round if they are just gas? For that matter, why are any planets round? Well, the short answer is—gravity. Gravity causes all matter to be pulled toward all other matter. Let's think about this in more detail. When the planets were first forming, the solar system was a big, swirling disk of gas and dust, with the newborn Sun at the center.

Bits of dust and clouds of gas were attracted to each other because of gravity. As these bits and clouds clumped, they attracted still more matter in their neighborhood and grew larger and larger until there was no longer any stray material nearby for them to attract. The growing planets were like big solar system vacuum cleaners, sweeping up all the debris in their paths. And they became round because gravity pulls equally toward the center of large masses such as planets, so anything sticking out gets pulled back to make a ball. The bigger a planet becomes, the heavier is the material weighing down on its center. Think of how it feels to dive under water. If you are wearing a face mask, you notice that as you dive deeper, the mask presses harder and harder on your face. Also, your ears start feeling the pressure even at 2 or 3 meters (5 or 10 feet) below the surface. The pressure you feel on your body is due to the weight of the water above you. The deeper you go, the heavier the water above you and so the greater the pressure on your body. Even on Earth's surface, each square inch of your body experiences 14.7 pounds of pressure due to the weight of the atmosphere above you.

If you could dive down to the center of Earth, the pressure on your body would be about 3.5 million times as great! The center of Jupiter is more than 11 times deeper than Earth's center and the pressure may be 50 million to 100 million times that on Earth's surface! The tremendous pressure at the center of planets causes the temperatures there to be surprisingly high. At their cores, Jupiter and Saturn are much hotter than the surface of the Sun! Strange things happen to matter under these extraordinary temperatures and pressures. Hydrogen, along with helium, is the main ingredient of Jupiter's and Saturn's atmospheres. Deep in their atmospheres, the hydrogen turns into a liquid. Deeper still, the liquid hydrogen turns into a metal! But what's at the very center of these planets? The material becomes stranger and stranger the deeper you go. Scientists do not understand the properties of matter under the extreme environments inside Jupiter and Saturn. Many different forces and laws of nature are at work, and the conditions inside these planets are very difficult to create in a laboratory here on Earth. But you can be sure that you wouldn't be able to fly through these bizarre materials!

As we now know, the gas giants are much more than just gas. Your Weight on Other Worlds | Exploratorium YOUR WEIGHT ON OTHER WORLDS Ever wonder what you might weigh on Mars or The Moon? Here's your chance to find out. TO DO & NOTICE: Fill in your weight below in the space indicated. You can enter your weight in any unit you wish. Click on the "Calculate" button. Notice that the weights on other worlds will automatically fill in. Notice that your weight is different on the different worlds. You can click on the images of the planets to get more information about them from Bill Arnett's incredible Nine Planets web site. ENTER YOUR WEIGHT HERE → A Few Different Types of Stars (better land at night to avoid burning your feet!) THE SUN WHAT'S GOING ON? Mass and Weight Before we get into the subject of gravity and how it acts, it's important to understand the difference between weight and mass. We often use the terms "mass" and "weight" interchangeably in our daily speech, but to an astronomer or a physicist they are completely different things. The mass of a body is a measure of how much matter it contains. An object with mass has a quality called inertia.

If you shake an object like a stone in your hand, you would notice that it takes a push to get it moving, and another push to stop it again. If the stone is at rest, it wants to remain at rest. Once you've got it moving, it wants to stay moving. This quality or "sluggishness" of matter is its inertia. Mass is a measure of how much inertia an object displays. Weight is an entirely different thing. Every object in the universe with mass attracts every other object with mass. The amount of attraction depends on the size of the masses and how far apart they are. For everyday-sized objects, this gravitational pull is vanishingly small, but the pull between a very large object, like the Earth, and another object, like you, can be easily measured. How? All you have to do is stand on a scale! Scales measure the force of attraction between you and the Earth. This force of attraction between you and the Earth (or any other planet) is called your weight. If you are in a spaceship far between the stars and you put a scale underneath you, the scale would read zero. Your weight is zero. You are weightless. There is an anvil floating next to you.

It's also weightless. Are you or the anvil mass-less? Absolutely not. If you grabbed the anvil and tried to shake it, you would have to push it to get it going and pull it to get it to stop. It still has inertia, and hence mass, yet it has no weight. See the difference? The Relationship Between Gravity and Mass and Distance As stated above, your weight is a measure of the pull of gravity between you and the body you are standing on. This force of gravity depends on a few things. First, it depends on your mass and the mass of the planet you are standing on. If you double your mass, gravity pulls on you twice as hard. If the planet you are standing on is twice as massive, gravity also pulls on you twice as hard. On the other hand, the farther you are from the center of the planet, the weaker the pull between the planet and your body. The force gets weaker quite rapidly. If you double your distance from the planet, the force is one-fourth. If you triple your separation, the force drops to one-ninth. Ten times the distance, one-hundredth the force. See the pattern? The force drops off with the square of the distance.

If we put this into an equation it would look like this: The two "M's" on top are your mass and the planet's mass. The "r" below is the distance from the center of the planet. The masses are in the numerator because the force gets bigger if they get bigger. The distance is in the denominator because the force gets smaller when the distance gets bigger. Note that the force never becomes zero no matter how far you travel. Perhaps this was the inspiration for the poem by Francis Thompson: All things That thou cans't not stir a flower without troubling a star. Isaac Newton This equation, first derived by Sir Isaac Newton, tells us a lot. For instance, you may suspect that because Jupiter is 318 times as massive as the Earth, you should weigh 318 times what you weigh at home. This would be true if Jupiter was the same size as the Earth. But, Jupiter is 11 times the radius of the Earth, so you are 11 times further from the center. This reduces the pull by a factor of 112 resulting in about 2.53 times the pull of Earth on you. Standing on a neutron star makes you unimaginably weighty.

Not only is the star very massive to start with (about the same as the Sun), but it is also incredibly small (about the size of San Francisco), so you are very close to the center and r is a very small number. Small numbers in the denominator of a fraction lead to very large results! The Earth Doesn't Actually Orbit The Sun? 5 You were taught that Earth and other planets in our solar system orbit the sun, and that our solar system orbits the center of the Milky Way. Is it possible that your science teacher had it wrong? Is everything you’ve learned about physics and gravity incorrect? Does The Earth Technically Orbit The Sun? Let us first start by saying that for all practical purposes, what you were taught isn’t entirely wrong. The Earth does in fact orbit the sun. In the strictest sense, however, it doesn’t. “But how can this be?”, you might ask. It’s been tested, verified and is common knowledge. It’s one of the first science lessons taught to kids in in grade school. How can our fundamental understanding of the solar system be wrong? Well, it’s actually due to a technicality. The Barycenter Of Our Solar System Everything that has mass has gravity.

The more massive something is, the more gravity it has. The sun and other planets all each have their own “gravity well” which interact and pull on one another. Because there are several different gravity wells interacting with each other, it means that everything in an orbital system (like our solar system) orbit the center of mass of the system. This center of mass is called the barycenter. The Earth, the sun and everything else in our solar system actually orbit this barycenter – not the sun. Where Is The Barycenter? In a single star system like ours, most of the time (but not always), the barycenter is located somewhere within the star itself. However, most barycenters continuously change as massive objects (like planets) orbit a star. If an unusual alignment happens where a large percentage of mass is on one side of the star, the barycenter can exist outside of the star’s radius. In cases of two star systems, the barycenter will be located between the two stars. If the stars aren’t of the same mass, it will be closer to the heavier, or more massive one. Bonus Fact: The Earth doesn’t even orbit where the barycenter currently is.

It orbits where it was roughly eight minutes ago. If the sun suddenly vanished, we would continue to our orbit it for another 8 minutes before shooting off on some random tangent because gravity isn’t instantaneous – it propagates at roughly the speed of light. Fun Facts About Our Sun References: The Sun - Center of the Solar System The Sun - Center of the Solar System Downloadable Text- and Exercise Sheets available at our shop The sun is a star at the centre of our solar system . It is a huge spinning ball of hot gas that lights up the Earth and provides us with heat. Our sun is a medium-sized yellow star that is about 150 million km away from the Earth. Here are some important facts about our sun: The sun is one of more than 200 billion stars in our galaxy, the Milky Way . The Milky Way is one of billions of galaxies in our universe. There are as many galaxies, as there are stars in the Milky Way The sun is 30,000 light years away from the centre of the Milky Way. The sun is made up of over 70 % hydrogen, 27 % helium and other elements.

On the surface, the sun has a temperature of over 5,000 ° C and in its core a temperature of a few million degrees. Even though there are billions of stars, only about 6000 are visible to us. Even if the sun dies today, it can send light to Earth for years to come The sun was formed about 4.5 billion years ago. As a star of the second generation, it doesn't only burn hydrogen but also other elements, like helium and metals. They were formed when a big explosion took place, which formed our solar system. At the sun's centre, nuclear fusion produces great amounts of energy . This energy turns into heat and light , which warms up the solar system and makes it brighter. The sun has enough energy for about 5 billion years. Then it will explode and a cloud of gas will destroy all the planets of the solar system The sun's diameter is about 1.4 million km. It is 10 times larger than the planet Jupiter and over 100 times larger than the Earth. About 1.3 million Earths could fit into the sun. But it is not a big star compared to others in our universe.

The core is the inner part of the sun. It is the place where the star converts hydrogen to helium. The energy travels to the outer parts of the sun as radiation. The photosphere is the surface of the sun. The chromosphere is the lower atmosphere with temperatures of up to 7000° C. The corona is the upper atmosphere. You can only see it during an eclipse. It is one of the hottest parts of the sun with temperatures as high as a million degrees C. A solar flare happens when the sun's magnetic fields crash into each other. It causes gas to shoot out of the sun. Sometimes these flares shoot up as high as 100,000 km and can last for hours. Solar flares are not really dangerous to us but they can interfere with radio signals on Earth. The eclipse of the sun is one of nature's most spectacular special effects. It happens when the Earth passes through the moon's shadow. The moon always has a shadow and if the sun, the Earth and the moon are in the right line, the moon's shadow passes over the Earth. When this happens the sun is blocked from your view and it gets as dark as night, but only for a few minutes.

This shadow might only be a few hundred kilometres wide and people from all over the world come and see it. The sun gives us heat, light, our food and the air that we breathe. It powers the atmosphere to give us winds and rain. Even coal and oil come from plants and animals that lived millions of years ago and depended on the sun for life. The sun heats the land, the oceans and our air. Green plants use the sun's rays to turn carbon dioxide into the oxygen that we breathe.

block = here: you cannot see it carbon dioxide = the gas that is produced when animals or people breathe out cloud = a white or grey object in the sky that has very small drops of water in it compared = to see how two or more objects are like or not like each other convert = change degree = unit for measuring the temperature depend on = here : need diameter = the line from one side of a circle to the other eclipse = when the moon is between the Earth and the Sun even though = although, while fit = go into galaxy = there are millions of stars and planets that form a galaxy - the Milky Way is our galaxy helium = a gas that is lighter than air and is used to make balloons float huge = very, very big hydrogen = the lightest of all gases; It is colourless and forms water if you join it with oxygen interfere = mix up light year = the distance that light travels in one year = about 9,500,000,000,000 km nuclear fusion = the centre of hydrogen atoms join together and produce energy oxygen = gas that is in the air and that we need to breathe power = to give energy to provide = give radiation = the heat, light or other energy given out by

 something ray = line of light solar = everything that has to do with the sun solar flare = a large explosion of the sun's atmosphere that produces a lot of energy spin = rotate, go around surface = the hard top part of a planet visible = if you can see something Topics HubbleSite - Reference Desk - FAQs Reference Desk Frequently Asked Questions What is the solar system?

The solar system consists of a central star, the Sun, and all of the smaller celestial bodies that continuously travel around it. The smaller bodies include eight planets: Mercury, Venus, Earth, Mars, Jupiter, Saturn, Uranus, and Neptune, which are themselves orbited by more than 140 moons. (Only Mercury and Venus have no moons.) In addition, the solar system contains millions of rocky asteroids and billions of icy comets. All of these objects are held together in a group by the Sun's gravity. How did the solar system form? The planets, asteroids and comets in the solar system are loose objects left over from the formation of the Sun. Originally the gas and dust that would become the Sun was the core of a cloud much larger than the solar system, probably several light-years across. (One light-year is equal to approximately 6,000,000,000,000 miles.) The core was slowly rotating at first, but as it collapsed it spun faster, like a spinning ice-skater pulling in his arms. The rotation prevented the material at the core's equator from collapsing as fast as material at the poles, so the core became a spinning disk.

Gas and dust in the disc spiraled gradually in to the center, where it accumulated to form the Sun. But because dust is denser than gas, some of the dust settled to the mid-plane of the disc. These dust particles stuck together to make clumps, then clumps stuck together to make rocks, then rocks collided to make planets. In the case of the "gas giant" planets, Jupiter, Saturn, Uranus and Neptune, the rocky cores were massive enough to also attract some of the gas. The outer layers of these planets are made up of hydrogen and other gases. So the Sun is the collapsed core of an interstellar gas cloud, and the planets, asteroids and comets are small lumps of dust or ice chunks which stayed in orbit instead of spiraling into the Sun. The planets all formed within a very short period, probably a few million years, about five billion years ago. How old is the solar system? The solar system is about 4.6 billion years old. How big is the solar system? There are no physical boundaries in space. The solar system consists of eight planets orbiting around one star: the Sun.

Neptune, the farthest planet from the Sun, orbits approximately 30astronomical units from the Sun. An astronomical unit is a unit of length used by astronomers. One astronomical unit equals the distance from Earth to the Sun: 93 million miles (149 million km). Some of the comets associated with the solar system travel on orbits that take them much farther from the Sun than Neptune. How many planets are there in our solar system? Our solar system officially has eight planets and one star: the Sun. In order from the Sun out, the planets are: Mercury, Venus, Earth, Mars, Jupiter, Saturn, Uranus, and Neptune. The discovery of an object larger than Pluto in 2005 rekindled the debate over whether such objects, belonging to the "Kuiper Belt" – a collection of icy bodies located beyond Neptune – should be called planets. Pluto and other large members of the Kuiper Belt are now considered "dwarf planets." Can you see any planets with the "naked eye?" Mercury, Venus, Mars, Jupiter and Saturn can be seen with the unaided eye. That is how they were discovered by ancient civilizations. Uranus and Neptune were discovered using telescopes.

Are there differences among the planets in our solar system? Planets come in different sizes, compositions and colors. The four planets closer to the Sun are called "rocky" planets. They are small in size and similar to Earth in composition. They have no rings and only two of them (Earth and Mars) have moons. The four outer planets, also called "gas giants," are much larger than the rocky planets. They all have rings and have many moons. The gas giants are made up mostly of hydrogen, helium, frozen water, ammonia, methane and carbon monoxide. Which planets are called the "rocky" or "terrestrial" planets? Mercury, Venus, Earth and Mars are called "rocky" or "terrestrial" planets. They are similar to Earth in composition. Heat from the Sun evaporated lightweight elements like hydrogen and helium into interplanetary space. Mostly rock and metal was left in this zone and clumped together to form the inner rocky planets. Which planets are called the "gaseous" planets? Jupiter, Saturn, Uranus and Neptune are called the "gaseous" planets.

Jupiter and Saturn contain the largest percentages of hydrogen and helium, while Uranus and Neptune contain the largest shares of ices – frozen water, ammonia, methane and carbon monoxide. Which planets have rings? The four gas giants, Jupiter, Saturn, Uranus and Neptune, have rings. How thick are Saturn's rings? The Hubble telescope has captured snapshots of Saturn with its rings nearly edge-on to our view. Read more about it . Saturn's rings are incredibly thin. The main rings are generally only about 30 feet (10 meters) thick, though parts of the main and other rings can be several kilometers thick. The rings are made of dusty ice, in the form of boulder-sized and smaller chunks that gently collide with each other as they orbit around Saturn. Saturn's gravitational field constantly disrupts these ice chunks, keeping them spread out and preventing them from combining to form a moon. The rings have a slight pale reddish color due to the presence of organic material mixed with the water ice. Find out more from HubbleSite: Hubble discoveries about Saturn in NewsCenter . How close do Earth and Mars get? Mars and Earth are like two cars on a racetrack as they journey around the Sun.

Earth is on the inside track and travels faster than Mars, which is on the outside. When Earth laps Mars about every two years, it comes as close as 35 million miles (56 million km) or as far away as 63 million miles (101 million km) because of Mars’ highly elongated orbit. What is a comet? Comets are small, fragile, irregularly shaped bodies composed mostly of a mixture of water ice (ice composed of H20), dust, and carbon- and silicon-based compounds. They have highly elliptical orbits that repeatedly bring them very close to the Sun and then swing them into space. Comets have three distinct parts: a nucleus, a coma and a tail. The solid core is called the nucleus, which develops a coma with one or more tails when a comet sweeps close to the Sun. The coma is the dusty, fuzzy cloud around the nucleus of a comet, and the tail extends from the comet and points away from the Sun. The coma and tails of a comet appear only when the comet is near the Sun. Find out more from HubbleSite: Hubble discoveries about comets from NewsCenter . How did comets form?

Comets are some of the material left over from the formation of the planets. Our entire solar system, including comets, was created by the collapse of a giant, diffuse cloud of gas and dust about 4.6 billion years ago. Much of the matter merged into planets, but some remained to form small lumps of frozen gas and dust in the outer region of the solar system, where temperatures were cold enough to produce ice. Find out more from HubbleSite: Hubble discoveries about comets from NewsCenter . Why do comets have tails? Comets are lumps of frozen water ice, gas and dust. As a comet approaches the Sun, it starts to heat up. The ice transforms directly from a solid to a vapor, releasing the dust particles embedded inside. Sunlight and the stream of charged particles flowing from the Sun – the solar wind – sweeps the evaporated material and dust back in a long tail. The comet's ingredients determine the types and number of tails. What are the types of comet tails? There are two types of comet tails: dust and gas ion. A dust tail contains small, solid particles that are about the same size found in cigarette smoke.

This tail forms because sunlight pushes on these small particles, gently shoving them away from the comet’s nucleus. Because the pressure from sunlight is relatively weak, the dust particles end up forming a diffuse, curved tail. A gas ion tail forms when ultraviolet sunlight rips one or more electrons from gas atoms in the coma, making them into ions (a process called ionization). The solar wind then carries these ions straight outward away from the Sun. The resulting tail is straighter and narrower. Both types of tails may extend millions of kilometers into space. As a comet heads away from the Sun, its tail dissipates, its coma disappears, and the matter contained in its nucleus freezes into a rock-like material. Where do comets come from? Comets are found in two main regions of the solar system: the Kuiper Belt and the Oort Cloud. There are two types of comets: short-period comets and long-period comets. Short-period comets – comets that frequently return to the inner solar system – probably come from the Kuiper Belt beyond the orbit of Neptune.

Astronomers estimate that this belt contains at least 200 million objects, which are thought to have remained essentially unchanged since the birth of the solar system 4.6 billion years ago. Long-period comets, which can take thousands of years to complete their orbits, are thought to emanate from the Oort Cloud, a vast group of frozen bodies in the outer part of the solar system. The Oort Cloud is thought to extend 50,000 times the distance from the Earth to the Sun. Oort Cloud comets, like their Kuiper Belt brothers, probably originated in the region of the solar system between Jupiter and Neptune, but were ejected from to the Oort Cloud by close encounters with the gravity of the giant planets. Comets are kicked out of the Oort Cloud and the Kuiper Belt by the pull of the gravity of another object – a planet, a star, or another small body. They then begin their journey toward the inner solar system and the Sun. What path do comets follow through the solar system? Planets have nearly circular orbits, but comets have elongated paths around the Sun. A comet is at "aphelion" when its orbit is farthest from the Sun.

It is at "perihelion" when it is closest to the Sun. Due to angular momentum, a comet will travel fastest at perihelion and will slow down as it approaches aphelion. Comets can be classified by their orbital period: that is, the time it takes them to make one complete trip around the Sun. Comets with short and intermediate orbital periods of less than 200 years – like Comet Halley, whose orbital period is 76 years – spend most of their time between Pluto and the Sun. These comets originally formed in the Kuiper Belt, but a gravitational "push" from the planets, especially Jupiter, swung them closer to the Sun. A long-period comet will have an orbital period of more than 200 years. Comet Hale-Bopp, for example, completes an orbit about every 4,000 years. Scientists think that this type of comet spends most of its time way out in the Oort Cloud at the farthest edge of our solar system. What is the difference between a meteor, a meteoroid, a meteorite, an asteroid and a comet? Most of us probably have seen meteors or shooting stars.

A meteor is the flash of light that we see in the night sky when a small chunk of interplanetary debris burns up as it passes through our atmosphere. "Meteor" refers to the flash of light caused by the debris, not the debris itself. The debris is called a meteoroid. A meteoroid is a piece of interplanetary matter that is smaller than a kilometer and frequently only millimeters in size. Most meteoroids that enter the Earth's atmosphere are so small that they vaporize completely and never reach the planet's surface. If any part of a meteoroid survives the fall through the atmosphere and lands on Earth, it is called a meteorite. Although the vast majority of meteorites are very small, their size can range from about a fraction of a gram (the size of a pebble) to 100 kilograms (220 lbs) or more (the size of a huge, life-destroying boulder). Asteroids are generally larger chunks of rock that come from the asteroid belt located between the orbits of Mars and Jupiter.

Comets are asteroid-like objects covered with ice, methane, ammonia, and other compounds that develop a fuzzy, cloud-like shell called a coma and sometimes a visible tail whenever they orbit close to the Sun. Find out more from HubbleSite: Hubble discoveries about asteroids , comets , and Kuiper Belt objects from NewsCenter . What is the asteroid belt? The asteroid belt is a zone between the orbits of Mars and Jupiter. Scientists believe that the asteroids in the asteroid belt never formed a planet because the gravity of nearby Jupiter kept pulling them apart. Today, millions of asteroids probably inhabit the asteroid belt, with many more scattered throughout the solar system. Find out more from HubbleSite: Hubble discoveries about asteroids from NewsCenter . What is Planet X? When astronomer Percival Lowell decided to search for a planet beyond Neptune in the 1930s, he called the object of his search "Planet X." This search led to the discovery of Pluto, but for many years some astronomers believed that another world larger than Pluto must exist undiscovered beyond Neptune. They thought this because Neptune's orbit seemed to be influenced by the gravity of an unseen planet.

More recent studies indicate that Neptune's orbit is not influenced by undiscovered bodies, and that a large "Planet X" most likely does not exist. Some of the myths and misconceptions about Planet X are debunked on Phil Plait's Bad Astronomy website: The prospects for new planet discoveries in our solar system are small. However, astronomers are now finding hundreds of planets orbiting other stars. Has Hubble looked for Planet X? Astronomers are always on the lookout for new members of the solar system. The most active programs involve searches for new comets, asteroids and satellites of the outer planets, but a few scientists have undertaken an on-again, off-again search for planets beyond Neptune. Astronomers can rule out an object as big as Jupiter orbiting a little further out than Neptune, since its gravitational effect on Neptuneï¿½s orbit would be pretty obvious. It would also be easily visible because of its brightness. To go undetected, a planet similar in size and composition to the other outer planets would have to be very far from the Sun.

We do know of many other objects orbiting the Sun that are similar to Pluto, which belongs to the Kuiper Belt – a field of icy, comet-like bodies located beyond Neptune. In 2005, an object likely larger than Pluto, named Eris, was located in the Kuiper Belt. Find out more on HubbleSite: Evidence suggests huge ninth planet exists past Pluto at solar system's edge | Science | The Guardian Space Evidence suggests huge ninth planet exists past Pluto at solar system's edge Astronomers investigating the odd alignment of rocks beyond Pluto have concluded that an undetected icy planet four times the size of Earth must exist Wednesday 20 January 2016 14.17 EST Last modified on Thursday 15 December 2016 11.28 EST Close This article is 1 year old As science often does, it began with a “huh?” Some distant objects far beyond Pluto were behaving very oddly. The orbits of a handful of space rocks had aligned for no apparent reason. Though stumped at first, astronomers now have an explanation: a huge ninth planet at the edge of the solar system.

If the researchers have their sums right, the mysterious new world is 10 times more massive than Earth and up to four times the size. Nicknamed Planet Nine, it moves on an extremely elongated orbit, and takes a staggering 10,000 to 20,000 years to swing once around the sun. The icy world, if it exists, has evaded detection because it is so far away. Scientists at the California Institute of Technology (Caltech) calculate that the closest it comes to the sun is 15 times the distance to Pluto. It then heads into uncharted territory, 75 times further out than Pluto, or about 93 billion miles from the sun. A ray of light would take a week to get there. “We saw a strange signal in the data that meant something odd was going on in the outer solar system,” Mike Brown, an astronomer at Caltech, told the Guardian. “All of these distant objects were lined up in a weird way and that shouldn’t happen. We worked through the mundane explanations, but none of them worked out.” Pinterest At 0:00 we see the six aligned objects, all falling within the same plane.

00:38 shows Planet Nine is required to be anti-aligned to these objects, but shares the same plane. At 00:56 we see that the planet forces objects into orbits perpendicular to the plane of the solar system and oriented at right angles to Planet Nine. Brown and his colleague, Konstantin Batygin, had been investigating claims that 13 icy objects in the Kuiper belt, the region of space where Pluto lies, shared some unusual orbital features that could be explained by the presence of a small planet. They expected to prove the idea wrong, but then made their own curious discovery. The researchers found that six of the 13 Kuiper belt objects moved on orbits that headed in the same direction. “If you looked down on the solar system and had the sun in the centre, all of these objects would head out to the 9 o’clock position,” said Brown. Moreover, their orbits were all tilted at the same angle to the eight known planets in the solar system. In science, the banal must be ruled out before more exotic explanations can be considered. The astronomers wondered whether the Kuiper belt might hold enough rocky debris from the birth of the solar system to nudge the objects into the same orbits.

But simulations ruled this out: the Kuiper belt would need to be 100 times more massive than it is. They next considered a new planet. Their first computer models had a world circling around the Kuiper belt objects, but this did not work either. Another explanation came by accident, when they added a massive planet on its own elongated orbit, which swung out in the opposite direction to the Kuiper belt objects - towards 3 o’clock in a solar system viewed from above. Batygin was sceptical that they had hit on the right answer. According to his simulations, a large planet in such a bizarre orbit would send some Kuiper belt objects into orbits that ran perpendicular to the planets in the solar system. But the astronomers later found that four such objects had already been spotted. “When we found that, my jaw sort of hit the floor,” said Brown. “The only way to get the orbits lined up is to have a distant, more massive planet shepherding them around.” Details appear in the Astronomical Journal . Chris Lintott , the Oxford professor of astrophysics, and a presenter on The Sky at Night, said the finding was exciting.

“People have proposed the existence of an extra planet several times over the years, but this is the most detailed and most convincing analysis.” Pinterest Six of objects in the Kuiper belt (in magenta) line up in a single direction. When viewed in three dimensions, they are also all tilted away from the plane of the solar system. Such alignment can only be maintained by some outside force - Planet Nine. Photograph: Caltech/R. Hurt (IPAC) “One very interesting thing is that the planet is predicted to be between Earth and Neptune in mass. We see lots of planets this size in our surveys of planets elsewhere in the galaxy, and it’s been something of a mystery as to why our solar system doesn’t have its own version of this very common planet type,” he added. But some serious questions remain. “It’s not at all clear how you form such a large world and move it to the outer reaches of the solar system,” Lintott said. “We know the early history of the solar system was chaotic - and there’s evidence for a larger planet escaping all together - but the details are murky at best.” The planet is so large that with sensitive enough telescopes, astronomers should be able to see it crossing the night sky.

The search has already begun with the Subaru telescope in Hawaii. Brown said he would be surprised if the planet was not found in the next five years. Brown, who played a key role in demoting Pluto from planetary status to a more lowly dwarf planet, said the discovery of a ninth planet might be good news for those who are still upset about Pluto being kicked out of the planetary club. “All those people who are mad that Pluto is no longer a planet can be thrilled to know that there is a real planet out there still to be found. Now we can go and find this planet and make the solar system have nine planets once again.” “As a scientist, you should never believe your idea too much until someone else confirms it, but we’ve not been able to come up with any alternative,” he said. “Now we’ve publicly announced it, I’m sure many people will try their hand at coming up with other explanations.” Solar System Facts - Interesting Facts about the Solar System Eris Solar System Facts The Solar System was formed approximately 4.6 billion years ago and consists of the Sun, planets, dwarf planets and other astronomical objects bound in its orbit.

The formation was cause by the collapse of a giant molecular cloud, the mass at the centre collecting to form the Sun and a flat disk of dust around it which the planets and other bodies would eventually be formed from. 99.86% of the system’s mass is found in the Sun and the majority of the remaining 0.14% is contained within the solar system’s eight planets. The four smaller inner planets , also known as the “terrestrial planets” (Mercury, Venus, Earth and Mars), are primarily composed of rock and metal. The four outer planets , also known as the “gas giants” (Jupiter, Saturn, Uranus and Neptune), are substantially larger and more massive than the inner planets. The two innermost gas giants, Jupiter and Saturn, are the larger of the four and are composed mainly of hydrogen and helium. The two outermost gas giants, Uranus and Neptune, are composed largely of ices, (water, ammonia and methane) and are sometimes also referred to as the “ ice giants “.

Other objects of note in the Solar System are the dwarf planets (Ceres, Pluto, Haumea, Makemake & Eris), moons , asteroids, the asteroid belt, comets and the Kuiper belt. Facts about the Solar System See the planets and the dwarf planets pages for more information or click an image below to find out more about the solar system. NASA’s New Horizons spacecraft is on a ... Random Image At what speed does the Earth move around the Sun? (Beginner) - Curious About Astronomy? Ask an Astronomer At what speed does the Earth move around the Sun? (Beginner) Short version: Earth's average orbital speed is about 30 kilometers per second. In other units, that's about 19 miles per second, or 67,000 miles per hour, or 110,000 kilometers per hour (110 million meters per hour). In more detail: Let's calculate that. First of all we know that in general, the distance you travel equals the speed at which you travel multiplied by the time (duration) of travel. If we reverse that, we get that the average speed is equal to the distance traveled over the time taken.

We also know that the time it takes for the Earth to go once around the Sun is one year. So, in order to know the speed, we just have to figure out the distance traveled by the Earth when it goes once around the Sun. To do that we will assume that the orbit of the Earth is circular (which is not exactly right, it is more like an ellipse , but for our purpose a circle is close enough). So the distance traveled in one year is just the circumference of the circle. (Remember, the circumference of a circle is equal to 2×π×radius.) The average distance from the Earth to the Sun is about 149,600,000 km. (Astronomers call this an astronomical unit, or AU for short.) Therefore, in one year, the Earth travels a distance of 2×π×(149,600,000 km).

This means that the speed is about: speed = 2×π×(149,600,000 km)/(1 year) and if we convert that to more meaningful units (knowing that there are, on average, about 365.25 days in a year, and 24 hours per day) we get: speed = 107,000 km/h (or, if you prefer, 67,000 miles per hour) So the Earth moves at about 110,000 km/h around the Sun (which is about one thousand times faster than the typical speed of a car on a highway!) Thanks for your explanation, but I was hoping for an explanation a little more precise, since I already knew the one you gave. In the case of your question about the speed of the Earth around the Sun, there isn't really a more 'precise' answer. The only approximation I did in the calculation I sent you is assuming that the orbit of the Earth is circular. This is in fact a very good approximation. One of Kepler's laws describing planetary motions states that all orbits are ellipses. This is the case for Earth's orbit.

But not all ellipses come in the same shape. They are described by their 'eccentricity', which tells us how flattened they are. The eccentricity of an ellipse is a number that varies between 0 and 1, 0 being a perfect circle, and close to 1 being a very flattened ellipse. It turns out that the orbit of the Earth right now has an eccentricity of about 0.017. This means it is almost a circle, making our approximation valid. So under the one approximation that was made, the calculation couldn't really be more 'precise'. And as for the average Earth-Sun distance, the true value changes slightly over time due to gravitational perturbations from the other planets, so there really isn't much point in using a more precise value than the one given above. Now if you want to calculate the speed of the Earth on its orbit without assuming it is a circle, it is another ball game! First of all, I cannot give you a precise answer, because the speed of the Earth changes all the time as the Earth moves around the Sun. This is because Kepler's second law says that on its orbit, a planet will sweep equal areas in equal amounts of time.

This means that when the Earth is closer to the Sun (which happens in early January, about two weeks after the northern winter solstice) it's moving faster than when it is farther away. (For more information on how the Earth's orbital speed varies over the course of a year, please see this answer .) Unless you specified a certain date, this means I cannot give you a precise value for the speed of the Earth assuming its orbit is an ellipse. We are better off to stick with the first number we got - the average speed. I hope this answers your question now! This page was last updated on February 28, 2016.

Question: What would you find if you travelled to the centre of the solar system?
Answer: The Sun