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This is information about the atmosphere in space.

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(Image credit: Terry Virts/NASA)

Earth's atmosphere is a thin band of air made up of numerous layers based on temperature.

Without this protective blanket, life on Earth would not exist as it protects us from heat and radiation emitted from the sun and contains the air we breathe.

Though oxygen is crucial for life on Earth, it is not the primary component of our atmosphere. According to education site Vision Learning Earth's atmosphere is composed of approximately 78 percent nitrogen, 21 percent oxygen, 0.93 percent Argon, 0.04 percent carbon dioxide as well as trace amounts of neon, helium, methane, krypton, ozone and hydrogen, as well as water vapor.

But just how high does Earth's atmosphere extend? Well, that depends on who you ask! According to NASA the upper layer of Earth's atmosphere - the exosphere - extends up to 6,200 miles (10,000 km), above which the atmosphere and space blend. Though not everyone agrees where space actually begins, most scientists agree that the Kármán line, situated 62 miles (100 km) above sea level, marks the transition point between Earth and space. Since 99.99997 percent of Earth's atmosphere is located below this point, it's considered a reasonable height to draw the boundary between Earth and space.
Related: Earth's layers: Exploring our planet inside and out
Earth atmosphere layers

(Image credit: Future)

Earth's atmosphere consists of five main layers from lowest to highest: troposphere, stratosphere, mesosphere, thermosphere and exosphere.

The layers are separated based on temperature according to the National Institute of Water and Atmospheric Research (NIWA).The atmosphere thins out in each higher layer until the gases dissipate in space. Air pressure decreases with altitude. At sea level, air pressure is about 14.7 pounds per square inch (1 kilogram per square centimeter), and the atmosphere is relatively dense. At 10,000 feet (3 km), the air pressure is 10 pounds per square inch (0.7 kg per square cm), which means molecules of gas that make up the atmosphere are less dense. That makes it harder for a person to breathe and get enough oxygen to live, although there is evidence for microbial life high up in the clouds.

Troposphere

The troposphere is the lowest and densest layer of the atmosphere and according to NIWA, approximately 75% of all the air in the atmosphere is found in this layer. The troposphere extends from Earth's surface to approximately 5 to 9 miles (8 to 14.5 km) high.

According to NASA, "Tropos" means change, and this atmospheric layer lives up to its name. Gases are constantly mixing in the troposphere and most of Earth's weather is found here. According to educational website CK-12, turbulence in the troposphere is created when the sun warms the Earth's surface, warming the air above. The warm air rises and then expands (due to the lower air pressure) and cools. The cool air sinks forming high pressure systems. According to WorldAtlas most helicopters and light airplanes fly in the troposphere.

Stratosphere

The stratosphere is the second layer of Earth's atmosphere. The stratosphere begins above the troposphere and extends approximately 31 miles (50 km) high. According to NIWA, most of the ozone found in Earth's atmosphere is in the stratosphere. Ozone protects us by absorbing harmful UV rays from the sun. The absorption of UV radiation heats up the stratosphere and temperatures in this layer actually increase with height. According to Weather.gov temperatures in the stratosphere range from approximately -60 degrees Fahrenheit (-51 degrees Celsius) at the bottom to 5 degrees F (-15 degrees C) at the top. Commercial airplanes tend to fly in the lower stratosphere so as to avoid the weather systems in the troposphere, according to aviation education site Aero Corner.

Mesosphere

The mesosphere is the third layer of Earth's atmosphere. According to NASA the mesosphere begins just above the stratosphere and extends to approximately 53 miles (85 km) high.

The top of the mesosphere, called the mesopause, is the coldest part of Earth's atmosphere, with temperatures averaging about minus 130 degrees F (minus 90 degrees C) according to the National Center for Atmospheric Research. The mesosphere is tricky to analyze as jets and balloons don't go high enough but satellites fly too high to directly study the layer. We do however know that most meteors burn up in this layer, and high-clouds known as noctilucent clouds (also known as polar mesospheric clouds) occasionally form in the mesosphere.

Thermosphere

The fourth layer of Earth's atmosphere is the thermosphere. It begins just above the mesosphere and extends to approximately 372 miles (600 km) high, according to NASA. The thermosphere is another atmospheric layer where temperatures rise with altitude, according to NIWA. The warming is caused by the absorption of ultraviolet light and X-rays emitted from the sun.

The thermosphere is considered part of Earth's atmosphere, but air density is so low that most of this layer is what is normally thought of as outer space. In fact, this is where the space shuttles flew and where the International Space Station orbits Earth.

Exosphere

The exosphere is the highest layer of Earth's atmosphere and extends from the top of the thermosphere approximately 6,200 miles (10,000 km) above Earth's surface according to NASA. The exosphere is composed of particles of hydrogen and helium, that are so widely dispersed they rarely collide.

Ionosphere

The ionosphere is a very active layer of Earth's atmosphere that spans the mesosphere, thermosphere and exosphere, according to NASA. It is not a distinct layer and actually grows and shrinks depending on how much energy it is absorbing from the sun.

We have the ionosphere to thank for the beautiful aurora displays that dance across the night sky. Here, the ions from solar wind collide with atmospheric oxygen and hydrogen molecules, exciting them into higher states of energy. The atoms shed this excess energy by emitting photons of light, which we see as the colorful aurora borealis and aurora australis.

(Image credit: NASA's MODIS instrument (Moderate Resolution Imaging Spectroradiometer).)

What's the difference between weather and climate?

Broadly speaking weather refers to short-term changes in atmospheric conditions whereas climate refers to the average weather conditions of a specific location over an extended period of time according to the United States Geological Survey. The National Oceanic and Atmospheric Administration (NOAA) further describes the difference simply as "climate is what you expect, weather is what you get".

Regional climate is defined by the University Corporation for Atmospheric Research as the average weather in a place over more than 30 years. A region's climate is often described, for example, as sunny, windy, dry, or humid. These can also describe the weather in a certain place, but while the weather can change in just a few hours, climate changes over a longer span of time.
Related: 7 solar system worlds where the weather is crazy
Earth's global climate is an average of regional climates. The global climate has cooled and warmed throughout history. Today, we are seeing unusually rapid warming. The scientific consensus, as stated by the Intergovernmental Panel on Climate Change (IPCC), is that greenhouse gases, which are increasing because of human activities, are trapping heat in the atmosphere.

Earth's atmosphere FAQs answered by an expert

What is Earth's atmosphere made of?

How high does Earth's atmosphere go?

(Image credit: NASA)

Are there different layers in Earth's atmosphere?

What would happen if Earth's atmosphere disappeared?

We asked Fangqun Yu a few frequently asked questions about Earth's atmosphere.

Atmospheric difference: Earth, Venus and Mars

To better understand the formation and composition of Earth, scientists sometimes compare our planet with Venus and Mars. All three of these planets are rocky in nature and are part of the inner solar system, meaning that they are in between the sun and the asteroid belt.

Venus' atmosphere is almost entirely composed of carbon dioxide. The entire planet is shrouded in thick toxic sulfuric acid clouds that trap heat, resulting in what is known as a runaway greenhouse effect. As such, Venus is the hottest planet in the solar system despite being the second closest planet to the sun.e. Spacecraft have to be heavily reinforced to survive the crushing pressure (90 times heavier than Earth), and the oven-like surface temperatures (900 Fahrenheit or 475 Celsius) hot enough to melt lead, according to NASA . s that Venus has no significant seasonal temperature changes.

Mars' atmosphere is also mostly composed of carbon dioxide, with traces of nitrogen, argon, oxygen, carbon monoxide and some other gases. The Red Planet's atmosphere is about 100 times thinner than Earth's - a very different situation from the ancient past, when geological evidence shows that Mars used to be much wetter and warmer billions of years ago, according to NASA. S. If you were to stand on Mars and look to the sky, you'd be greeted with a red hue caused by dust particles suspended in the air, rather than the blue skies we see here on Earth. Due to Mars' thin atmosphere, heat from the sun quickly escapes the planet. According to NASA, if you stood on the Martian equator at noon, your feet would experience a toasty 75 degrees Fahrenheit (24 degrees Celsius) though temperatures at your head would be rather chilly at around 32 degrees Fahrenheit (0 degrees Celsius).

Scientists routinely compare small, rocky exoplanets to Earth, Venus and Mars to get a better sense of their habitability. The routinely accepted definition of "habitability" is that a planet is close enough to the star for liquid water to exist on its surface. Too far, and the water turns icy; too close, and the water evaporates. However, habitability not only depends on the star-planet distance, but also the planet's atmosphere, the star's variability, and other factors.

Additional resources

You can explore the ionosphere in more detail with the National Weather Service and learn more about the historic increase in atmospheric carbon dioxide from Climate.gov. If you fancy reading about the fascinating world of the atmospheric microbiome then check out this interesting article in Scientific American.

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Earth's atmosphere: Facts about our planet's protective blanket

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Earth's atmosphere protects the planet in more ways than one. This thin band of air is unique to Earth, and we wouldn't exist without it.

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This is information about the sun.

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Our Sun is a normal main-sequence G2 star, one of more than 100 billion stars in our galaxy.

The Sun Profile

diameter: 1,390,000 km.
mass: 1.989e30 kg
temperature: 5800 K (surface) 15,600,000 K (core)

History of The Sun

The Sun is by far the largest object in the solar system. It contains more than 99.8% of the total mass of the Solar System (Jupiter contains most of the rest).

It is often said that the Sun is an "ordinary" star. That's true in the sense that there are many others similar to it. But there are many more smaller stars than larger ones; the Sun is in the top 10% by mass. The median size of stars in our galaxy is probably less than half the mass of the Sun.

The Sun is personified in many mythologies: the Greeks called it Helios and the Romans called it Sol.

The Sun is, at present, about 70% hydrogen and 28% helium by mass everything else ("metals") amounts to less than 2%. This changes slowly over time as the Sun converts hydrogen to helium in its core.

The outer layers of the Sun exhibit differential rotation: at the equator the surface rotates once every 25.4 days; near the poles it's as much as 36 days. This odd behavior is due to the fact that the Sun is not a solid body like the Earth. Similar effects are seen in the gas planets. The differential rotation extends considerably down into the interior of the Sun but the core of the Sun rotates as a solid body.

Conditions at the Sun's core (approximately the inner 25% of its radius) are extreme. The temperature is 15.6 million Kelvin and the pressure is 250 billion atmospheres. At the center of the core the Sun's density is more than 150 times that of water.

The Sun's power (about 386 billion billion mega Watts) is produced by nuclear fusion reactions. Each second about 700,000,000 tons of hydrogen are converted to about 695,000,000 tons of helium and 5,000,000 tons (=3.86e33 ergs) of energy in the form of gamma rays. As it travels out toward the surface, the energy is continuously absorbed and re-emitted at lower and lower temperatures so that by the time it reaches the surface, it is primarily visible light. For the last 20% of the way to the surface the energy is carried more by convection than by radiation.

The surface of the Sun, called the photosphere, is at a temperature of about 5800 K. Sunspots are "cool" regions, only 3800 K (they look dark only by comparison with the surrounding regions). Sunspots can be very large, as much as 50,000 km in diameter. Sunspots are caused by complicated and not very well understood interactions with the Sun's magnetic field.

A small region known as the chromosphere lies above the photosphere.

The highly rarefied region above the chromosphere, called the corona, extends millions of kilometers into space but is visible only during a total solar eclipse (left). Temperatures in the corona are over 1,000,000 K.

It just happens that the Moon and the Sun appear the same size in the sky as viewed from the Earth. And since the Moon orbits the Earth in approximately the same plane as the Earth's orbit around the Sun sometimes the Moon comes directly between the Earth and the Sun. This is called a solar eclipse; if the alignment is slighly imperfect then the Moon covers only part of the Sun's disk and the event is called a partial eclipse. When it lines up perfectly the entire solar disk is blocked and it is called a total eclipse of the Sun. Partial eclipses are visible over a wide area of the Earth but the region from which a total eclipse is visible, called the path of totality, is very narrow, just a few kilometers (though it is usually thousands of kilometers long). Eclipses of the Sun happen once or twice a year. If you stay home, you're likely to see a partial eclipse several times per decade. But since the path of totality is so small it is very unlikely that it will cross you home. So people often travel half way around the world just to see a total solar eclipse. To stand in the shadow of the Moon is an awesome experience. For a few precious minutes it gets dark in the middle of the day. The stars come out. The animals and birds think it's time to sleep. And you can see the solar corona. It is well worth a major journey.

The Sun's magnetic field is very strong (by terrestrial standards) and very complicated. Its magnetosphere (also known as the heliosphere) extends well beyond Pluto.

In addition to heat and light, the Sun also emits a low density stream of charged particles (mostly electrons and protons) known as the solar wind which propagates throughout the solar system at about 450 km/sec. The solar wind and the much higher energy particles ejected by solar flares can have dramatic effects on the Earth ranging from power line surges to radio interference to the beautiful aurora borealis.

Recent data from the spacecraft Ulysses show that during the minimum of the solar cycle the solar wind emanating from the polar regions flows at nearly double the rate, 750 kilometers per second, than it does at lower latitudes. The composition of the solar wind also appears to differ in the polar regions. During the solar maximum, however, the solar wind moves at an intermediate speed.

Further study of the solar wind will be done by Wind, ACE and SOHO spacecraft from the dynamically stable vantage point directly between the Earth and the Sun about 1.6 million km from Earth.

The solar wind has large effects on the tails of comets and even has measurable effects on the trajectories of spacecraft.

Spectacular loops and prominences are often visible on the Sun's limb (left).

The Sun's output is not entirely constant. Nor is the amount of sunspot activity. There was a period of very low sunspot activity in the latter half of the 17th century called the Maunder Minimum. It coincides with an abnormally cold period in northern Europe sometimes known as the Little Ice Age. Since the formation of the solar system the Sun's output has increased by about 40%.

The Sun is about 4.5 billion years old. Since its birth it has used up about half of the hydrogen in its core. It will continue to radiate "peacefully" for another 5 billion years or so (although its luminosity will approximately double in that time). But eventually it will run out of hydrogen fuel. It will then be forced into radical changes which, though commonplace by stellar standards, will result in the total destruction of the Earth (and probably the creation of a planetary nebula).

The Sun's satellites

There are eight planets and a large number of smaller objects orbiting the Sun. (Exactly which bodies should be classified as planets and which as "smaller objects" has been the source of some controversy, but in the end it is really only a matter of definition. Pluto is no longer officially a planet but we'll keep it here for history's sake.)

More detailed data and definitions of terms can be found on the data page.

More about the Sun

Open Issues

Is there a causal connection between the Maunder Minimum and the Little Ice Age or was it just a coincidence? How does the variability of the Sun affect the Earth's climate?

Since all the planets except Pluto orbit the Sun within a few degrees of the plane of the Sun's equator, we know very little about the interplanetary environment outside that plane. The Ulysses mission will provide information about the polar regions of the Sun.

The corona is much hotter than the photosphere. Why?

Interesting Facts about the Sun

The Sun is one of the millions of stars in the solar system. It is, however, larger than most (although not the biggest) and a very special star to us. Without the Sun there would be absolutely no life on Earth.

The Sun is 870,000 miles (1.4 million kilometers) across. This is so big it is hard to imagine, but it would take more than one million Earths to fill the size of the Sun!

The Sun is so big it takes up 99% of the matter in our solar system. The 1% left over is taken up by planets, asteroids, moons and other matter.

The Sun is about 4.5 billion years old. It is thought to be halfway through its lifetime. Stars get bigger as they get older.

As the Sun ages, it will get bigger. When this happens, it will consume some of the things close to it, and this includes Mercury, Venus and maybe even Earth and Mars. Luckily this is billions of years in the future.

The Sun is the centre of the solar system.

The Sun is 92.96 million miles (149.6 kilometers) away from Earth.

The Sun is made of a ball of burning gases. These gases are 92.1% hydrogen and 7.8% helium.

The sunlight we see on Earth left the Sun 8 minutes ago. This is the length of time it takes for the light to travel the distance between the Sun and the Earth.

When the moon goes around the Earth, it sometimes finds itself between the Earth and the Sun. This is called a solar eclipse and makes the Earth dark whilst the moon shuts out most of the Sun's light. This only lasts for a couple of hours while the moon continues its rotation and moves out of the way of the sun.

In ancient astronomy, it was thought that the Sun moved. People believed that the Earth stayed still and the Sun rotated around it.

About 2000 years ago some began to think it was the Sun that stays still whilst the planets make a path around it. This only became an accepted theory around the 1600s when Isaac Newton proposed the sun-centric solar system.

The Sun is almost a perfect sphere. It is the closest thing to a sphere found in nature with only a 6.2 mile (10 kilometres) difference between its vertical and horizontal measurements.

The Sun's core is extremely hot! An unthinkable 13,600,000 degrees Celcius!

The Sun has a very big magnetic field. It is the most powerful magnetic field in the whole solar system. This field is regenerating itself, but scientists are unsure how.

The Sun produces solar winds. These are a stream of particles from the Sun that stream out into space. This is why planets atmospheres are so important. They protect the planet from these solar winds.

The Sun rotates but not as Earth does. On Earth, the planet is rotating at the same speed no matter where you are. The Sun does not rotate like a solid object and is spinning faster at its equator than it is at its poles. It is complicated to say how fast the Sun is spinning but depending whereabouts on the Sun you are looking at it takes between 24 and 38 days to spin around.

The Sun has been both worshipped and feared throughout history by a variety of cultures.

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The Sun Facts | Information, History, Size, Formation & Definition

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Our Sun is a normal main-sequence G2 star, one of more than 100 billion stars in our galaxy. diameter: 1,390,000 km.mass: 1.989e30 kgtemperature: 5800 K (surface) 15,600,000 K (core) The Sun is by far the largest object in the solar system.

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This website tells what meteor showers are.

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A brief period of heightened meteor activity, often occurring regularly in a particular part of the sky at a particular time of year. Meteor showers are generally named after the constellation in which they appear to originate; thus the Perseids appear to originate in the constellation Perseus and the Leonids in the constellation Leo. The showers occur when the Earth passes through a region having a greater than usual concentration of interplanetary debris, such as particles left by a disintegrating comet, at certain points in its orbit. Although the meteors enter the Earth's atmosphere on parallel trajectories, perspective makes it appear as if they originate from the same point in the sky, known as the radiant.

A meteor shower is a celestial event in which a number of meteors are observed to radiate from one point in the night sky. These meteors are caused by streams of cosmic debris called meteoroids entering Earth's atmosphere at extremely high speeds on parallel trajectories. Most meteors are smaller than a grain of sand, so almost all of them disintegrate and never hit the Earth's surface. Intense or unusual meteor showers are known as meteor outbursts and meteor storms, which may produce greater than 1,000 meteors an hour.

Any other solar system body with a reasonably transparent atmosphere can also have meteor showers. For instance, Mars is known to have meteor showers, although these are different from the ones seen on Earth because the different orbits of Mars and Earth intersect orbits of comets in different ways.

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A brief period of heightened meteor activity, often occurring regularly in a particular part of the sky at a particular time of year. Meteor showers are generally named after the constellation in which they appear to originate; thus the Perseids appear to originate in the constellation Perseus and the Leonids in the constellation Leo.

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This is a website about The Milky Way.

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Tereza Pultarova and Daisy Dobrijevic and Nola Taylor Tillman and Elizabeth Howell

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Milky Way Galaxy: Facts About Our Galactic Home

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We are living in a golden age of Milky Way research and exploration.

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This is a website with information about the astroid belt.

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Within the main asteroid belt, scattered in orbits around the sun are bits and pieces of rock left over from the dawn of the solar system. Most of these objects, called planetoids or asteroids - meaning "star-like" - orbit between Mars and Jupiter in a grouping known as the main asteroid belt.

The main asteroid belt lies more than two-and-a-half times as far as does from and contains millions of asteroids. Most of these are relatively small, from the size of boulders to a few thousand feet in diameter. But some are significantly larger.

How did the asteroid belt form?

Early in the life of the solar system, dust and rock circling the sun were pulled together by into planets. But not all of the ingredients created new worlds. A region between Mars and Jupiter became the asteroid belt.

Occasionally people wonder whether the belt was made up of the remains of a destroyed planet, or a world that didn't quite get started. However, according to NASA, the total mass of the belt is less than , far too small to weigh in as a planet. Instead, the debris is shepherded by Jupiter, which kept it from coalescing onto other growing planets.

Observations of other planets are helping scientists to better understand the solar system. According to a developing theory known as, in the first 5 million years of the solar system, Jupiter and are thought to have moved inward toward the sun before changing direction and heading back to the outer solar system. Along the way, they would have scattered the original asteroid belt before them, then sent material flying back to refill it.

"In the Grand Tack model, the asteroid belt was purged at a very early stage and the surviving members sample a much larger region of the solar ," John Chambers of the Carnegie Institution for Science wrote in a "Perspectives" piece published online in the journal Science.

Our solar system isn't the only one to boast an asteroid belt. A cloud of dust around a star known as zeta Leporis looks a lot like a young belt. "Zeta Leporis is a relatively young star - approximately the age of our sun when the Earth was forming," Michael Jura said in a. "The system we observed around zeta Leporis is similar to what we think occurred in the early years of our own solar system when planets and asteroids were created." A professor at the University of California, Los Angeles, Jura has since passed away.

Other also contain signs of asteroid belts, suggesting that may be common.

At the same time, studies of white dwarfs, sun-like stars at the end of their lifetimes, show signatures of rocky material falling onto their surface that suggest such belts are common around dying systems.

(Image credit: ISAS/JAXA)

Belt composition

Most of the asteroids in the main belt are made of rock and stone, but a small portion of them contain iron and nickel metals. The remaining asteroids are made up of a mix of these, along with carbon-rich materials. Some of the more distant asteroids tend to contain more ices. Although they aren't large enough to maintain an atmosphere, but there is evidence that some asteroids contain water.

Some asteroids are large, solid bodies - there are more than 16 in the belt with a diameter greater than 150 miles (240 km). The largest asteroids, Vesta, Pallas and Hygiea, are 250 miles (400 km) long and bigger. The region also contains the dwarf planet Ceres. At 590 miles (950 km) in diameter, or about a quarter of the size of our moon, Ceres is round yet is considered too small to be a full-fledged planet. However, it makes up approximately a third of the mass of the asteroid belt.

Other asteroids are piles of rubble held together by gravity. Most asteroids aren't quite massive enough to have achieved a spherical shape and instead are irregular, often resembling a lumpy potato. The asteroid 216 Kleopatra resembles a dog bone.

Asteroids are classified into several types based on their chemical composition and their reflectivity, or albedo.

C-type asteroids make up more than 75 percent of known asteroids. The "C" stands for carbon, and the surfaces of these extremely dark asteroids are almost coal-black. Carbonaceous chondrite meteorites on Earth have a similar composition, and are thought to be pieces smashed off of the larger asteroids. While C-type asteroids dominate in the belt, according to the European Space Agency, they make up only about 40 percent of the asteroids closer to the sun. These include subgroups of B-type, F-type, and G-types.

S-type asteroids are the second most common type, making up about 17 percent of known asteroids. They dominate the inner asteroid belt, becoming rarer farther out. They are brighter and have metallic nickel-iron mixed with iron- and magnesium-silicates. The "S" stands for silicaceous.

M-type asteroids ("M" for metallic) are the last major type. These asteroids are fairly bright and most of them are composed of pure nickel-iron. They tend to be found in the middle region of the asteroid belt.

The remaining rare types of asteroids are A-type, D-type, E-type, P-type, Q-type, and R-type.

In 2007, launched a mission, Dawn, to visit Ceres and Vesta. Dawn reached Vesta in 2011 and remained there for over a year before traveling on to reach Ceres in 2015. It will remain in orbit around the dwarf planet until the end of its mission.

While most of the asteroid belt is made up of rocky objects, Ceres is an icy body. Hints of organic material spotted by Dawn suggest that it may have formed farther out in the solar system before landing in the belt. While the organics have only been seen on the surface, that doesn't mean more material might lie on the dwarf planet.

"We cannot exclude that there are other locations rich in organics not sampled by the survey, or below the detection limit," Maria Cristina De Sanctis, of the Institute for Space Astrophysics and Space Planetology in Rome, told Space.com by email.

(Image credit: NASA/JPL-Caltech )

Asteroid mining

Asteroids have more than enough gold, plus other precious metals, to provide a few lifetimes' worth of fortunes. But there are plenty of other reasons asteroids are valuable. But how do we get these metals from these faraway asteroids? Perhaps the best way is to bring the rocks to Earth. Most of the metals we use in our everyday lives are buried deep within the Earth. And we mean deep: when our young planet was still molten, almost all of the heavy metals sank to the core, which is pretty hard to get to. The accessible veins of gold, zinc, platinum and other valuable metals instead came from later asteroid impacts on Earth's surface.

Those asteroids are the fragmented remains of almost-planets, but they contain all the same mixtures of elements as their larger planetary cousins - and you don't have to dig down into their cores to get it. But the main problem with asteroids is that they are far away. To launch from Earth's surface and go into orbit, a rocket needs to change its velocity from zero to eight kilometres (five miles) per second.

To rendezvous with an average asteroid, the rocket has to change its velocity by another 5.5 kilometres (3.4 miles) per second. That requires almost as much fuel as the launch itself, which the rocket would have to carry as dead weight, adding to the already-high cost of trying to set up a remote mining operation in the first place. And once the asteroid was mined, asteroid prospectors would be faced with a difficult choice: They could try to refine the ore right there on the asteroid, which would entail setting up an entire refining facility, or ship the raw ore back to Earth, with all the waste that would involve.

Building a belt

The main belt lies between Mars and Jupiter, roughly two to four times the Earth-sun distance, and spans a region about 140 million miles across. Objects in the belt are divided into eight subgroups named after the main asteroids in each group. These groups are the Hungarias, Floras, Phocaea, Koronis, Eos, Themis, Cybeles and Hildas.

Although Hollywood often displays ships making close calls through asteroid belts, the trip is generally uneventful. A number of spacecraft have safely traveled through the asteroid belt without incident, including NASA's New Horizons mission to .

"Fortunately, the asteroid belt is so huge that, despite its large population of small bodies, the chance of running into one is almost vanishingly small - far less than one in a billion," wrote New Horizons principle investigator. "If you want to come close enough to an asteroid to make detailed studies of it, you have to aim for one."

Within the asteroid belt are relatively empty regions known as Kirkwood gaps. These gaps correspond to orbital resonances with Jupiter. The 's gravitational pull keeps these regions far emptier than the rest of the belt. In other resonances, the asteroids can be more concentrated.

(Image credit: Getty )

Discovery of the asteroid belt

Johann Titius, an 18th-century German astronomer, noted a mathematical pattern in the layout of the planets and used it to predict the existence of one between Mars and Jupiter. Astronomers scoured the heavens in search of this missing body. In 1800, 25 astronomers formed a group known as the Celestial Police, each searching 15 degrees of the for the missing planet. But the discovery of the first body in this region came from a nonmember, Italian astronomer Giuseppe Piazzi: he named it Ceres. A second body, Pallas, was found a little over a year later.

For some time, both of these objects were referred to as planets. But the discovery rate of these objects increased, and by the beginning of the 19th century, more than 100 had been found. Scientists quickly realized that these were too small to be considered planets, and they began to call them asteroids.

Additional resources

You can read more about asteroids and the updated current asteroid count at NASA's Solar System Exploration asteroid page. Additionally you can learn more about the formation of the main asteroid belt in this article by Cosmos Magazine.

Bibliography

" Asteroids". NASA Solar System Exploration (2021).

" The Grand Tack". Southwest Research Institute.

" Forming Terrestrial Planets". Science (2014).

" UCLA Astronomers Identify Evidence Of Asteroid Belt Around Nearby Star: Findings Indicate Potential For Planet Or Asteroid Formation". University of California (2001).

" Asteroids: Structure and composition of asteroids". European Space Agency (2022).

" SwRI Scientist Studies Geology of Ceres to Understand Origin of Organics". Southwest Research Institution (2017).

" New Horizons Crosses The Asteroid Belt". Space Daily (2006).

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The main asteroid belt, between Mars and Jupiter, is where most asteroids orbit.

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This is a website to tell what are dewarf planets.

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(Image: © ESO/L. Calçada)

Dwarf planets are worlds that are too small to be considered full-fledged planets, but too large to fall into smaller categories.

In recent years, there's been a lot of hubbub about Pluto losing its status as one of the planets of the solar system. Pluto is no longer considered the ninth planet in the series of major planetary objects, but instead is now just one of the many so-called "dwarf planets." The debate started anew after the New Horizons mission passed by Pluto in 2015, revealing a world of surprising geological complexity. As of 2017, delegates from the mission are trying to get Pluto's planethood status back.

Astronomers estimate that there could be as many as 200 dwarf planets in the solar system and the Kuiper Belt. But the differences between planets and dwarf planets may not be obvious at first.

Dwarf planets of the solar system

The International Astronomical Union defines a planet as being in orbit around the sun, has enough gravity to pull its mass into a rounded shape (hydrostatic equilibrium), and has cleared its orbit of other, smaller objects. This last criterion is the point at which planets and dwarf planets differ. A planet's gravity either attracts or pushes away the smaller bodies that would otherwise intersect its orbit; the gravity of a dwarf planet is not sufficient to make this happen. [ Meet the Dwarf Planets of the Solar System]

(Image credit: Karl Tate, SPACE.com contributor)

As of 2014, the IAU recognizes five named dwarf planets: Ceres, Pluto, Eris, Haumea, and Makemake. But those aren't the only ones. Other solar system bodies that are possibly dwarf planets include Sedna and Quaoar, small worlds far beyond Pluto's orbit, and 2012 VP113, an object that is thought to have one of the most distant orbits found beyond the known edge of our solar system. The object DeeDee could also be a dwarf planet, according to observations made in 2017. According to NASA, scientists think that there may be more than a hundred dwarf planets awaiting discovery.

However, the debate over the status of dwarf planets, particularly Pluto, remains a hot topic. The primary concern stems from the requirement for a planet to clear out its local neighborhood.

"In no other branch of science am I familiar with something that absurd," New Horizons principle investigator Alan Stern told Space.com in 2011. "A river is a river, independent of whether there are other rivers nearby. In science, we call things what they are based on their attributes, not what they're next to."

Is a dwarf planet a separate entity from a planet, or simply another classification? The question may not be settled in the near future.

(Image credit: NASA, ESA, J. Parker (Southwest Research Institute), L. McFadden (University of Maryland))

Ceres

Ceres is the earliest known and smallest of the current category of dwarf planets. Sicilian astronomer Giuseppe Piazzi discovered Ceres in 1801 based on the prediction that the gap between Mars and Jupiter contained a missing planet. It is only 590 miles (950 km) in diameter and has a mass of just 0.015 percent that of Earth.

In fact, Ceres is so small that it is classified as both a dwarf planet and an asteroid, and is often named in scientific literature as one of the largest asteroids in the solar system. Although it makes up approximately a fourth of the mass of the asteroid belt, it is still 14 less massive than Pluto.

Unlike its asteroid neighbors, Ceres has a nearly round body. The rocky dwarf planet may have water ice beneath its crust. In 2014, the European Space Agency's Herschel Space Observatory detected water vapor spewing from two regions on Ceres.

NASA's robotic Dawn mission arrived at Ceres in 2015. The mission has shown many interesting features on its surface, ranging from various bright spots to a 4-mile-high (6.5-kilometer-high) mountain. (Another mission, the European Space Agency's Herschel Space Observatory, spotted evidence of water vapor in 2014.)

Pluto

Pluto is the most well known of the dwarf planets. Since its discovery in 1930 and until 2006, it had been classified as the ninth planet from the sun. Pluto's orbit was so erratic, however, that at times it was closer to the sun than the eighth planet, Neptune. In 2006, with the discovery of several other rocky bodies similar in size or larger than Pluto, the IAU decided to re-classify Pluto as a dwarf planet.

(Image credit: NASA, ESA, and M. Buie (Southwest Research Institute))

Despite its small size - 0.2 percent the mass of Earth and only 10 percent the mass of Earth's moon - Pluto's gravity is enough to capture five moons of its own. The pairing between Pluto and its largest moon, Charon, is known as a binary system, because both objects are orbiting around a central point that is not within the mass of Pluto.

NASA's New Horizons mission flew by Pluto in 2015 and revealed a wealth of surprises. This included zones that are bereft of craters (indicating the surface is relatively young), mountains that are likely as high as 11,000 feet (3,500 meters), and even haze above the dwarf planet's surface.

Eris

When it was first discovered, Eris was thought to be the largest of the dwarf planets, with a mass 27 percent larger than that of Pluto and a diameter of approximately 1,400 to 1,500 miles (2,300 to 2,400 km). It was the discovery of Eris that prompted the IAU to reconsider the definition of a planet. Further observation went on to suggest that the dwarf planet is slightly smaller than Pluto.

The orbit of Eris is very erratic, crossing that of Pluto and nearly intersecting the orbit of Neptune, but is still more than three times larger than Pluto's orbit. It takes 557 years for Eris to orbit the sun. At its farthest point from the sun, a point that is also called its aphelion, Eris and its satellite Dysmonia travel far beyond the Kuiper Belt. The surface of Eris is likely nitrogen and methane-rich, but in a thin (1 millimeter) layer across the surface. Some scientists suggest the surface is the condensed atmosphere of Eris, which expands into gas when the dwarf planet is closer to the sun.

Haumea and Makemake

Haumea and Makemake are the most recently named dwarf planets in the solar system.

Haumea is unique because of its ellipsoid shape, only just meeting the hydrostatic equilibrium criteria for dwarf planet status. The elongated shape of the dwarf planet is due to its rapid rotational spin, not a lack of mass, which is about one-third that of Pluto. The cigar-shaped dwarf planet rotates on its axis every four hours, likely a result of a collision. The odd object also hosts a red spot and a layer of crystalline ice. Finally, Haumea is the only object in the Kuiper belt other than Pluto known to host more than one moon.

A moon was discovered around Makemake in 2016, more than a decade after the dwarf planet itself was found. Its diameter is known to be about two-thirds that of Pluto, and the newly found moon will allow for measurements of its mass. Makemake is also of value to the astronomical community, as it is another reason for the reconsideration of the definition of a planet. Its comparable mass and diameter to Pluto would grant it planet status if Pluto wasn't also stripped of that title.

Dwarf planets as 'plutoids'

Pluto, Eris, Haumea and Makemake are all known as " plutoids," unlike the asteroidal dwarf planetoid Ceres. A plutoid is a dwarf planet with an orbit outside that of Neptune. Plutoids are sometimes also referred to as " ice dwarfs" due to their diminutive size and cold surface temperatures.

The outer planets show evidence of interaction with plutoids. Triton, the largest moon of Neptune, is likely a captured plutoid, and it is even possible that the odd tilt of Uranus on its axis is due to a collision with a plutoid. Similarly to dwarf planets, there are potentially hundreds of plutoid objects in the solar system that have yet to be given official status.
Additional reporting by Elizabeth Howell and Nola Taylor Redd, Space.com contributors Additional resources

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Dwarf Planets: Science & Facts About the Solar System's Smaller Worlds

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(Image: © ESO/L. Calçada) Dwarf planets are worlds that are too small to be considered full-fledged planets, but too large to fall into smaller categories. In recent years, there's been a lot of hubbub about Pluto losing its status as one of the planets of the solar system.

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This is a cool website for kids that want to do fun activites and project dealing with the solar system.

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Introduction: How to Make 3D Solar System Project for Kids

I made this solar system 3d model for my kid. So, she can understand better and can remember all the planets name. It can be good for school science project also.It's a good 3d model for classroom or homeschool project It's easy and fun. Anyone can make it at home. In this tutorial, I will show you step by step prosses. Let's get started.

For this project what you need:

1) Foam balls (Different size for all the planets and the sun)

2) Black Foamboard

3) Acrylic paint

4) Hot glue

5) foam sheet

6) white chalk

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Make It Bridge

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Step 1: Making Planets

I choose different size of foam balls, the bigger one for the sun. For painting the sun I used acrylic color and painted with the paintbrush, for texture I used tissue paper. All the planets are hand painted. And for Saturn ring, I used foam sheet and colored it with acrylic paint and glue it to the Saturn.

Step 2: Finishing Solar System

Now I cut the foam board (11x20 inch) 1 piece, (3x11 inch) 2 pieces, (3x20 inch) 2 pieces. Then join together as shown in the video and make it like box Now paint with acrylic color using tissue paper so it will create a texture. Then take a toothbrush dip into white paint and sprinkle with your finger for more realistic look. Then using chalk draw the line of the orbit of the planets. And then stick all the Planets and the Sun using hot glue. Now your 3D Solar system is done.

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How to Make 3D Solar System Project for Kids

# data[].attributes.attachment_link.description
How to Make 3D Solar System Project for Kids: I made this solar system 3d model for my kid. So, she can understand better and can remember all the planets name. It can be good for school science project also.It's a good 3d model for classroom or homeschool project It's easy and fun.

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This is a great interactive website with alot of information, games, and videos on it

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This science worksheet will teach your third-grade students about the planets in the solar system. Your young astronomers will name each of the eight planets and their order by reading from a list of clues. After completing this solar system worksheet, they will have learned the two planets that have rings, that Mercury is the closest planet to the sun, and more interesting facts about Earth and space science!

Penmanship Practice: Cursive

This workbook focuses on penmanship practice. In the process, she'll also get a head start on composition by using her new handwriting skills to write short stories and paragraphs.

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Solar System | Worksheet | Education.com

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This science worksheet will teach your third-grade students about the planets in the solar system. Your young astronomers will name each of the eight planets and their order by reading from a list of clues.

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This is a video that will be very helpful to younger students when trying to learn about the solar system.

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This is a short video on what the solar system is and what it consist of.

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The Solar System is the gravitationally bound system of the planets and the Sun plus other objects that orbit it, either directly or indirectly. Of the objects that orbit the Sun directly, the largest eight are the planets, with the remainder being smaller objects, such as dwarf planets and small Solar System bodies