Populate tour edition with solar system data

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editions/tour/tiddlers/Solar System/Asteroid (253) Mathilde Image.png.meta

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+title: Asteroid (253) Mathilde Image
+type: image/png
+tags: Image

editions/tour/tiddlers/Solar System/Asteroid.tid

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+created: 20230720112554020
+modified: 20230720112827830
+title: Asteroid
+type: text/vnd.tiddlywiki
+tags: [[Solar System]]
+
+[img class=hero-image [Asteroid (253) Mathilde Image]]
+
+An asteroid is a space rock. It is a small object in the [[Solar System]] that travels around the [[Sun]]. It is like a [[planet|Planet]] but smaller. They range from very small (smaller than a car) to 600 miles (1000 km) across. A few asteroids have asteroid moons.
+
+The name "asteroid" means "like a star" in the ancient Greek language. Asteroids may look like small stars in the sky, but they really do move around the [[Sun]], while stars only seem to move because the [[Earth]] spins. Like [[planets|Planet]], asteroids do not make their own light. Because of this, some people think "asteroids" is not a good name, and think that the name "planetoid" ("like a planet") would be a better name.
+
+Giuseppe Piazzi found the first asteroid, in 1801. He called it Ceres, and it is the biggest object in the asteroid belt. Others, like Juno, Pallas, and Vesta were found later. In the 1850s so many had been found, that they were numbered by a Minor planet designation starting with 1 Ceres. Today, astronomers using computerized telescopes find thousands of asteroids every month. Asteroid impact prediction is one of the purposes.
+
+Asteroids are the leftover rock and other material from the formation of the [[Solar System]]. These rocks were too small to come together to make a [[planet|Planet]]. Some are made of carbon or metal. Depending on what's on the surface, they are classified into various asteroid spectral types including Type M (metal), Type S (stone), and Type C (carbon).
+
+Most asteroids in our [[Solar System]] are in the asteroid belt between [[Mars]] and [[Jupiter]]. Many are not in the main asteroid belt. The ones that come close to [[Earth]] are called Near-Earth asteroids. Many scientists think asteroids striking the [[Earth]] killed off all the dinosaurs and caused some of the other extinction events.

editions/tour/tiddlers/Solar System/Comet Image.png.meta

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+title: Comet Image
+type: image/png
+tags: Image

editions/tour/tiddlers/Solar System/Comet.tid

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+created: 20230720113501352
+modified: 20230720113633994
+title: Comet
+type: text/vnd.tiddlywiki
+tags: [[Solar System]]
+
+[img class=hero-image [Comet Image]]
+
+A comet is a ball of mostly ice that moves around in outer space. Comets are often described as "dirty snowballs". They are very different from [[asteroids|Asteroid]]. The orbital inclinations of comets are usually high and not near the ecliptic where most [[solar system|Solar System]] objects are found. Most of them are long-period comets and come from the [[Kuiper belt]]. That is very far away from the [[Sun]], but some of them also come near enough to [[Earth]] for us to see at night.
+
+They have long "tails", because the [[Sun]] melts the ice. A comet's tail does not trail behind it, but points directly away from the [[Sun]], because it is blown by the solar wind. The hard centre of the comet is the nucleus. It is one of the blackest things (lowest albedo) in the [[solar system|Solar System]]. When light shone on the nucleus of Halley's Comet, the comet reflected only 4% of the light back to us.
+
+Periodic comets visit again and again. Non-periodic or single-apparition comets visit only once.
+
+Comets sometimes break up, as Comet Biela did in the 19th century. Comet Shoemaker-Levy 9 broke up, and the pieces hit [[Jupiter]] in 1994. Some comets orbit (go around) together in groups. Astronomers think these comets are broken pieces that used to be one object.

editions/tour/tiddlers/Solar System/Earth Image.png.meta

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+title: Earth Image
+type: image/png
+tags: Image

editions/tour/tiddlers/Solar System/Earth's Moon Image.png.meta

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+title: Earth's Moon Image
+type: image/png
+tags: Image

editions/tour/tiddlers/Solar System/Earth's Moon.tid

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+created: 20230720105302348
+modified: 20230720105451528
+title: Earth's Moon
+type: text/vnd.tiddlywiki
+
+[img class=hero-image [Earth's Moon Image]]
+
+The Moon is [[Earth]]'s only natural satellite. We usually see it in the night sky and also during the day. Some other planets also have moons or natural satellites.
+
+Our moon is about one-fourth of the width of the [[Earth]]. Because it is far away it looks small, about half a degree wide. The gravity on the moon is one-sixth of the [[Earth]]'s gravity. It means that something will be one-sixth as heavy on the Moon than on [[Earth]]. The Moon is a rocky and dusty place. It moves slowly away from the [[Earth]] at a rate of 3.8 cm per year, due to the effect of tidal dissipation.

editions/tour/tiddlers/Solar System/Earth.tid

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+created: 20230720102439731
+modified: 20230720105223869
+title: Earth
+type: text/vnd.tiddlywiki
+tags: Planet [[Rocky]]
+
+[img class=hero-image [Earth Image]]
+
+Earth is the third planet from the [[Sun]] in the [[Solar System]]. It is the only planet known to have life on it. The Earth formed about 4.5 billion years ago. It is one of four rocky planets on the inner side of the [[Solar System]]. The other three are [[Mercury]], [[Venus]], and [[Mars]].
+
+The large mass of the [[Sun]] keeps the Earth in orbit through the force of gravity. Earth also turns around in space, so that different parts face the Sun at different times. Earth goes around the [[Sun]] once (one year) for every 365​1⁄4 times it turns around (one day).
+
+Earth is the only planet in the [[Solar System]] that has a large amount of liquid water on its surface. About 74% of the surface of Earth is covered by liquid or frozen water. Because of this, people sometimes call it the blue planet.
+
+Because of its water, Earth is home to millions of species of plants and animals which need water to survive. The things that live on Earth have changed its surface greatly. For example, early cyanobacteria changed the air and gave it oxygen. The living part of Earth's surface is called the "biosphere".
+
+Earth is one of the eight planets in the [[Solar System]]. There are also thousands of small bodies which move around the [[Sun]]. The [[Solar System]] is moving through the Orion Arm of the [[Milky Way]] galaxy, and will be for about the next 10,000 years.
+
+Earth is about 150,000,000 kilometres or 93,000,000 miles away from the [[Sun]] (this distance is called an "Astronomical Unit"). It moves on its orbit at an average speed of about 30 km/s (19 mi/s). Earth turns all the way around about 365​1⁄4 times in the time it takes for Earth to go all the way around the [[Sun]]. To make up this extra bit of a day every year, an additional day is used every four years. This is named a "leap year".
+
+The [[Moon|Earth's Moon]] goes around Earth at an average distance of 400,000 kilometres or 250,000 miles. It is locked to Earth, so that it always has the same half facing Earth; the other half is called the "dark side of the moon". It takes about 27​1⁄3 days for the [[Moon|Earth's Moon]]  to go all the way around Earth, but because Earth is moving around the [[Sun]] at the same time, it takes about 29​1⁄2 days for the [[Moon|Earth's Moon]]  to go from dark to bright to dark again. This is where the word "month" came from, even though most months now have 30 or 31 days.

editions/tour/tiddlers/Solar System/Jupiter Image.png.meta

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+title: Jupiter Image
+type: image/png
+tags: Image

editions/tour/tiddlers/Solar System/Jupiter.tid

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+created: 20230720103949854
+modified: 20230720104126047
+title: Jupiter
+type: text/vnd.tiddlywiki
+tags: Planet [[Gas Giant]]
+
+[img class=hero-image [Jupiter Image]]
+
+Jupiter is the largest planet in the [[Solar System]]. It is the fifth planet from the [[Sun]]. Jupiter is a gas giant because it is so large, and made mostly of gas. The other gas giants in the Solar System are [[Saturn]], [[Uranus]], and [[Neptune]].
+
+Jupiter's mass is about 318 times the mass of [[Earth]]. This is more than twice the mass of all the other planets in the [[Solar System]] put together.
+
+Jupiter can be seen even without using a telescope. It is the third brightest object in the night sky. Only the [[Earth's Moon]] and [[Venus]] are brighter. The ancient Romans named the planet after their King of the Gods, Jupiter (Latin: Iuppiter).
+
+Jupiter has 95 known moons. About 75 of them are very small—less than five kilometres wide. The four largest moons of Jupiter are Io, Europa, Ganymede, and Callisto. They are called the Galilean moons because Galileo Galilei discovered them. Ganymede is the largest moon in the Solar System. Its diameter is larger than that of the planet [[Mercury]].

editions/tour/tiddlers/Solar System/Kuiper belt.tid

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+created: 20230720113703253
+modified: 20230720113733279
+title: Kuiper belt
+type: text/vnd.tiddlywiki
+
+The Kuiper belt is an area of the [[Solar System]] beyond the orbit of [[Neptune]] (at 30 astronomical units) to 50 AU from the [[Sun]].
+
+The objects within the Kuiper Belt together with the members of the scattered disk beyond, are together called trans-Neptunian.
+
+Many objects such as dwarf planets in the Kuiper belt are much bigger than the ones in the asteroid belt and are round. At least some Kuiper belt objects are icebound.
+
+The first objects in the Kuiper belt to be found were [[Pluto]] and Charon (moon) but the belt was only identified and named in 1992 when more Kuiper belt objects (KBOs) were found. A few thousand have since been discovered and more than 70,000 KBOs over 100 km (62 mi) in diameter are thought to exist.

editions/tour/tiddlers/Solar System/Mars Image.png.meta

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+created: 20230720103818354
+modified: 20230720103822277
+title: Mars Image
+type: image/png
+tags: Image

editions/tour/tiddlers/Solar System/Mars.tid

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+created: 20230720103800905
+modified: 20230720103915592
+title: Mars
+type: text/vnd.tiddlywiki
+tags: Planet [[Rocky]]
+
+[img class=hero-image [Mars Image]]
+
+Mars is the fourth planet from the [[Sun]] in the [[Solar System]] and the second-smallest planet. Mars is a terrestrial planet with polar ice caps of frozen water and carbon dioxide. It has the largest volcano in the [[Solar System]], and some very large impact craters. Mars is named after the mythological Roman god of war because it appears of red color.
+
+Space probes such as the Viking program landers are the main tools for the exploration of Mars.

editions/tour/tiddlers/Solar System/Mercury Image.png.meta

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+title: Mercury Image
+type: image/png
+tags: Image

editions/tour/tiddlers/Solar System/Mercury.tid

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+created: 20230720101415532
+modified: 20230720101809366
+title: Mercury
+type: text/vnd.tiddlywiki
+tags: Planet [[Rocky]]
+
+[img class=hero-image [Mercury Image]]
+
+Mercury is the smallest planet in the [[Solar System]]. It is the closest planet to the [[Sun]]. It makes one trip around the Sun once every 87.969 days.
+
+Mercury is bright when we can see it from [[Earth]]. It has an apparent magnitude ranging from −2.0 to 5.5. It cannot be seen easily because it is usually too close to the [[Sun]]. Because of this, Mercury can only be seen in the morning or evening twilight or when there is a solar eclipse.
+
+Less is known about Mercury than about other planets of our [[Solar System]]. Even with telescopes only a small, bright crescent can be seen. It is also hard to put a satellite in orbit around it. Two spacecraft have visited Mercury. The first one was Mariner 10. It only made a map of about 45% of the Mercury's surface from 1974 to 1975. The second is the MESSENGER spacecraft, which finished mapping Mercury in March 2013.
+
+Mercury looks like [[Earth's Moon]]. It has many craters and smooth plains. It has no moons and little atmosphere as we know it. However, Mercury does have an extremely thin atmosphere, known as an exosphere. Mercury has a large iron core. Because of this Mercury has a magnetic field about 1% as strong as that of the Earth. It is a very dense planet because its core is large.
+
+Temperature at the surface can be anywhere from about 90 to 700 K (−183 °C to 427 °C, −297 °F to 801 °F), with the subsolar point being the hottest and the bottoms of craters near the poles being the coldest.
+
+Known sightings of Mercury date back to at least the first millennium BC. Before the 4th century BC, Greek astronomers thought that Mercury was two different objects: The one that they were only able at sunrise, they called Apollo; the other one that they were only able to see at sunset, they called Hermes. The English name for the planet is from the Romans, who named it after the Roman god Mercury. The symbol for Mercury is based on Hermes' staff.
+
+Even though Mercury is the closest planet to the [[Sun]], it is not the hottest. This is because it has no greenhouse effect. The heat that the [[Sun]] gives it, quickly escapes into space. The hottest planet is [[Venus]].

editions/tour/tiddlers/Solar System/Milky Way Image.png.meta

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+created: 20230720095228607
+modified: 20230720095237609
+title: Milky Way Image
+type: image/png
+tags: Image

editions/tour/tiddlers/Solar System/Milky Way.tid

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+created: 20230720095039202
+modified: 20230720095530636
+title: Milky Way
+type: text/vnd.tiddlywiki
+
+[img class=hero-image [Milky Way Image]]
+
+The Milky Way is our home galaxy. It contains around 400 billion stars, including our [[Sun]].
+
+The Milky Way has a diameter of about 170,000 or 200,000 light years, and is a barred spiral galaxy. The idea that the Milky Way is made of stars goes back to the Ancient Greek philosopher Democritus.
+
+The Milky Way has three main parts: a disk, where the [[Solar System]] is, a bulge at the core, and an outer halo all around it. Although the word "disk" suggests it is flat, the Milky Way is actually not quite flat. It is slightly warped and twisted.
+
+This galaxy belongs to the Local Group of three large galaxies and over 50 smaller galaxies. The Milky Way is one of the largest galaxies in the group, second to the Andromeda Galaxy. Its closest neighbour is the Canis Major Dwarf Galaxy, which is about 25,000 light years away from the Earth. The Andromeda Galaxy is moving towards the Milky Way Galaxy, and will collide with it in about 3.75 billion years. The Andromeda Galaxy moves with a speed of about 1,800 kilometres per minute.

editions/tour/tiddlers/Solar System/Moon.tid

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+created: 20230720113324534
+modified: 20230720113416564
+title: Moon
+type: text/vnd.tiddlywiki
+tags: [[Solar System]]
+
+Bodies which orbit [[planets|Planet]] are called moons. They vary in size. The [[Earth]] has only one moon. Some other planets have many moons, and some have none. When people write just "the moon", they are usually talking about the moon of the Earth. [[Earth's Moon]] is written with a capital letter, Moon. The Latin word for the moon is luna, which is why the adjective used to talk about the moon is "lunar". For example, lunar eclipse.
+
+Anything that goes around a planet is called a satellite. Moons are natural satellites. People also use rockets to send machines into orbit around the Earth. These machines are called artificial (man-made) satellites.

editions/tour/tiddlers/Solar System/Neptune Image.png.meta

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+title: Neptune Image
+type: image/png
+tags: Image

editions/tour/tiddlers/Solar System/Neptune.tid

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+created: 20230720104752241
+modified: 20230720104941305
+title: Neptune
+type: text/vnd.tiddlywiki
+tags: Planet [[Gas Giant]]
+
+[img class=hero-image [Neptune Image]]
+
+Neptune is the eighth and farthest planet from the [[Sun]] in the [[Solar System]]. It is an ice giant. It is the fourth-largest planet in the system. Neptune has five rings. These rings are hard to see from the [[Earth]].
+
+Neptune's mass is 17 times [[Earth]]'s mass and a little bit more than [[Uranus]]' mass. Neptune is denser and smaller than [[Uranus]]. Its greater mass makes its gravity make its atmosphere smaller and denser.
+
+It was named after the Roman god of the sea, Neptune. Neptune's astronomical symbol is ♆, the trident of the god Neptune.
+
+Neptune's atmosphere is mostly hydrogen and helium. It also contains small amounts of methane which makes the planet appear blue. Neptune's blue color is much darker than the color of [[Uranus]]. Neptune also has the strongest winds of any planet in the [[Solar System]], as high as 2,100 km/h or 1,300 mph.
+
+Urbain Le Verrier and John Couch Adams were the astronomers who discovered Neptune. Neptune was not discovered using a telescope. It was the first planet to be discovered using mathematics. In 1821, astronomers saw that [[Uranus]]' orbit was different from what they expected. Another nearby planet's mass was changing [[Uranus]]' orbit. They found Neptune was the cause.
+
+Voyager 2 visited Neptune on 25 August 1989. It was the only spacecraft to visit the planet. Neptune used to have a huge storm known as the "Great Dark Spot". Voyager 2 discovered the spot in 1989. The dark spot was not seen in 1994, but new spots were found since then. It is not known why the dark spot disappeared. Visits by other space probes have been planned.

editions/tour/tiddlers/Solar System/Planet Image.png.meta

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+title: Planet Image
+type: image/png
+tags: Image

editions/tour/tiddlers/Solar System/Planet.tid

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+created: 20230720112945287
+modified: 20230720113139369
+title: Planet
+type: text/vnd.tiddlywiki
+tags: [[Solar System]]
+
+[img class=hero-image [Planet Image]]
+
+A planet is a large object such as [[Venus]] or [[Earth]] that orbits a star. Planets are smaller than stars, and they do not make light. [[Jupiter]] is the biggest planet in the [[Solar System]], while the smallest planet in the [[Solar System]] is [[Mercury]].
+
+Planets are shaped like a slightly squashed ball (called a spheroid). Objects that orbit planets are called satellites. A star and everything which orbits it are called a star system.
+
+There are eight planets in the [[Solar System]]. [[Pluto]] used to be called a planet, but in August 2006, the International Astronomical Union decided it was a dwarf planet instead. There are four more known dwarf planets in the [[Solar System]], Ceres, Makemake, Eris and Haumea.
+
+The name "planet" is from the Greek word πλανήτης (planetes), meaning "wanderers", or "things that move". Until the 1990s, people only knew the planets in the [[Solar System]].
+
+4,905 extrasolar planets (exoplanets) have been discovered in 3,629 planetary systems (January 2022 data). The count includes 808 multi-planetary systems. Known exoplanets range in size from gas giants about twice as large as Jupiter down to just over the size of the [[Moon|Earth's Moon]]. About 100 of these planets are roughly the size as [[Earth]]. Nine of these orbit in the habitable zone of their star.

editions/tour/tiddlers/Solar System/Pluto Image.png.meta

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+title: Pluto Image
+type: image/png
+tags: Image

editions/tour/tiddlers/Solar System/Pluto.tid

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+created: 20230720113803689
+modified: 20230720114100139
+title: Pluto
+type: text/vnd.tiddlywiki
+
+[img class=hero-image [Pluto Image]]
+
+Pluto is a dwarf [[planet|Planet]] in the [[Solar System]]. Its formal name is 134340 Pluto, and its planetary symbol ⯓ or ♇. Pluto is the ninth largest body that moves around the [[Sun]]. Upon first being discovered, Pluto was considered a planet but was reclassified to a dwarf planet in 2006. It is the largest body in the [[Kuiper belt]].
+
+Like other members of the [[Kuiper belt]], Pluto is mainly made of rock and ice. It is quite small. It is about a fifth (⅕) of the weight of the [[Earth's Moon]]. It is only a third (⅓) of its volume. Pluto is very far from the [[Sun]], so its temperature is very low. The average temperature on Pluto is -226 to -240 degrees Celsius. It has an odd orbit and this orbit is very sloped. It takes Pluto to 30 to 49 AU (4.4–7.4 billion km) from the [[Sun]]. This causes Pluto to sometimes go closer to the Sun than [[Neptune]].
+
+Since it was discovered in 1930, Pluto was thought to be the [[Solar System]]'s ninth planet. In the late 1970s, the minor planet 2060 Chiron was found and people learned that Pluto had a small size. Later, in the early 21st century, the scattered disc object Eris and other objects like Pluto were discovered. Eris was initially believed to be 27% larger than Pluto, but was later found to be slightly smaller. On August 24, 2006, the International Astronomical Union (IAU) gave a definition to the word "planet" for the first time. By this definition, Pluto was not a planet anymore. It became a "dwarf planet" along with Eris and Ceres. After this, Pluto was put on the list of minor planets and was downgraded in 2006 by astronomer Michael E Brown. It was given the number 134340. Some scientists still think that Pluto should be classified as a planet.

editions/tour/tiddlers/Solar System/Saturn Image.png.meta

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+title: Saturn Image
+type: image/png
+tags: Image

editions/tour/tiddlers/Solar System/Saturn.tid

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+created: 20230720104344173
+modified: 20230720104515376
+title: Saturn
+type: text/vnd.tiddlywiki
+tags: Planet [[Gas Giant]]
+
+[img class=hero-image [Saturn Image]]
+
+Saturn is the sixth planet from the [[Sun]] in the [[Solar System]].
+
+Saturn is one of the four gas giant planets in the [[Solar System]], together with [[Jupiter]], [[Uranus]], and [[Neptune]]. It is the second largest planet in the [[Solar System]] ([[Jupiter]] is larger).
+
+Saturn was named after the Roman god Saturnus. He was considered to be the same as the Greek god Kronos. Saturn's symbol is ♄ which is the symbol of Saturnus' sickle.
+
+Inside Saturn is probably a core of iron, nickel, silicon and oxygen compounds, surrounded by a deep layer of metallic hydrogen, then a layer of liquid hydrogen and liquid helium and finally, an outer gaseous layer.
+
+Saturn has 145 known moons orbiting the planet.  The largest moon is Titan. Titan is larger in volume than the planet [[Mercury]]. Titan is the second-largest moon in the [[Solar System]]. The largest moon is a moon of [[Jupiter]], Ganymede. There are also many rings around Saturn. These rings are made of ice with some rocks and dust. Some people think that that the rings were made by a moon impact or other event. Saturn is about 1,433,000,000 km (870,000,000 mi) on average from the [[Sun]]. Saturn takes 29.6 Earth years to move around the [[Sun]].

editions/tour/tiddlers/Solar System/Solar System Image.png.meta

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+title: Solar System Image
+type: image/png
+tags: Image

editions/tour/tiddlers/Solar System/Solar System.tid

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+created: 20230720093645837
+modified: 20230720112852404
+title: Solar System
+type: text/vnd.tiddlywiki
+
+[img class=hero-image [Solar System Image]]
+
+The Solar System is the [[Sun]] and all the objects that orbit around it. The Sun is orbited by [[planets|Planet]], [[asteroids|Asteroid]], [[comets|Comet]] and other things.
+
+The Solar System is about 4.568 billion years old. The Sun formed by gravity in a large molecular cloud. It is mainly hydrogen, which it converts into helium through nuclear fusion. The planets are in a flattened orbiting disk. This disk was left over from the cloud that formed the Sun. Eventually, the gas and dust of the disk came together into planets. It is thought that almost all stars and their planets form this way.
+
+The Sun is a star. It makes up 99.9% of the Solar System's mass. This means that it has strong gravity. The other objects are pulled into orbit around the Sun. The Sun is mostly made out of hydrogen, and some helium and higher elements. All heavier elements, called metals in astronomy, account for less than 2% of the Sun's mass. Oxygen is about 1% of the Sun's mass. Iron (0.2%) is the most plentiful of the other elements.
+
+There are eight planets in the Solar System. From closest to farthest from the Sun, they are: [[Mercury]], [[Venus]], [[Earth]], [[Mars]], [[Jupiter]], [[Saturn]], [[Uranus]] and [[Neptune]]. The first four planets are called terrestrial planets. They are mostly made of rock and metal, and they are mostly solid. The last four planets are called gas giants. This is because they are much larger than other planets and are mostly made of gas.
+
+Six of the planets, and the six largest dwarf planets, are orbited by [[moons|Moon]]. There are more than 200 moons in the Solar System. [[Mercury]] and [[Venus]] have no moons, and [[Jupiter]] and [[Saturn]] have the largest number of moons. The largest moon is [[Ganymede]] which is a moon of [[Jupiter]]. [[Titan]] is one of [[Saturn]]’s moons. It is the only moon in the Solar System to have an atmosphere, which is mainly composed of nitrogen.
+
+The Solar System also contains other things. There are [[asteroid belts|Asteroid]], mostly between [[Mars]] and [[Jupiter]]. Further out than [[Neptune]], there is the [[Kuiper belt]] and the scattered disc. These areas have dwarf planets, including [[Pluto]], Makemake, Haumea, Ceres and Eris. There are thousands of very small objects in these areas. There are also [[comets|Comet]], centaurs, and interplanetary dust.

editions/tour/tiddlers/Solar System/Sun Image.png.meta

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+created: 20230720095341229
+modified: 20230720095343728
+type: image/png
+title: Sun Image
+tags: Image

editions/tour/tiddlers/Solar System/Sun.tid

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+created: 20230720094834001
+modified: 20230720095518349
+title: Sun
+type: text/vnd.tiddlywiki
+tags: [[Solar System]]
+
+[img class=hero-image [Sun Image]]
+
+The Sun, also known as Sol, is a star at the center of our [[solar system|Solar System]]. It is a yellow star that gives off different types of energy such as infrared energy (heat), ultraviolet light, radio waves and light. It also gives off a stream of particles, which reaches [[Earth]] as "solar wind". The source of all this energy is nuclear fusion. Nuclear fusion is the reaction in the star which turns hydrogen into helium and makes huge amounts of energy. It is a nearly perfect ball of hot plasma.
+
+The Sun is a star like many others in our [[Milky Way]] galaxy. The Sun is a type of star called a G-type main-sequence star based on its spectral class.
+
+The Sun has existed for a little over 4.5 billion years. It is going to continue for at least as long again.
+
+The Sun is about a hundred times as wide as the Earth. It has a mass of 1.9891×1030 kg. This is 333,000 times the mass of the [[Earth]]. 1.3 million [[Earths|Earth]] can fit inside the Sun. The Sun fuses about 600 million tons of hydrogen into helium every second.
+
+The Sun is the main source of energy for the [[Earth]]. This energy is made deep inside the Sun in a process called nuclear fusion. Four hydrogen atoms are fused together to make one helium atom. Some of the leftover matter turns into energy. This is the same way energy is released in a hydrogen bomb.

editions/tour/tiddlers/Solar System/Uranus Image.png.meta

@@ -0,0 +1,3 @@
+title: Uranus Image
+type: image/png
+tags: Image

editions/tour/tiddlers/Solar System/Uranus.tid

@@ -0,0 +1,19 @@
+created: 20230720104606510
+modified: 20230720104721998
+title: Uranus
+type: text/vnd.tiddlywiki
+tags: Planet [[Gas Giant]]
+
+[img class=hero-image [Uranus Image]]
+
+Uranus is the seventh planet from the [[Sun]] in our [[Solar System]]. Like [[Neptune]], it is an ice giant. It is the third largest planet in the solar system.
+
+The planet is made of ice, gases and liquid metal. Its atmosphere contains hydrogen (1H), helium (2He) and methane. The temperature on Uranus is −197 °C (−322.6 °F; 76.1 K) near the top of its atmosphere, but its small solid core (about 55% the mass of [[Earth]]) is probably about 4,730 °C (8,540 °F; 5,000 K).
+
+The planet is tilted on its axis so much that it is sideways. It has five big moons, many small ones, and a small system of 13 planetary rings.
+
+The distance between Uranus and the [[Sun]] is about 2.8 billion km. Uranus completes its orbit around the [[Sun]] in 84 earth years. It completes a spin around its axis in 17 hours and 14 minutes. This means there are about 43,000 Uranian days in one Uranian year.
+
+Uranus was discovered in 1781. This planet can be seen with the naked eye under perfect conditions. John Flamsteed saw it decades earlier but mistook it for a star (34 Tauri).
+
+Uranus is named after Uranus, the Greek name of the Sumerian god Anu, who was a god of the sky.

editions/tour/tiddlers/Solar System/Venus Image.png.meta

@@ -0,0 +1,3 @@
+title: Venus Image
+type: image/png
+tags: Image

editions/tour/tiddlers/Solar System/Venus.tid

@@ -0,0 +1,16 @@
+created: 20230720101839792
+modified: 20230720104223481
+title: Venus
+type: text/vnd.tiddlywiki
+
+[img class=hero-image [Venus Image]]
+
+Venus is the second planet from the [[Sun]]. Venus is the only planet in the [[Solar System]] that has a day longer than a year. The year length of Venus is 225 [[Earth]] days. The day length of Venus is 243 [[Earth]] days.
+
+Venus is a terrestrial planet because it has a solid, rocky surface like other planets in the inner [[Solar System]]. Astronomers have known Venus for thousands of years. The ancient Romans named it after their goddess Venus, goddess of love and beauty.
+
+Venus is the brightest thing in the night sky except for the Moon. It is sometimes called the morning star or the evening star as at some elongations it is easily seen just before the sun comes up in the morning. At other times, it can be seen just after the sun goes down in the evening. Venus comes closer to the [[Earth]] than any other planet does.
+
+Venus is sometimes called the sister planet of L as they are quite similar in size and gravity. In other ways the planets are very different. Venus' atmosphere (air) is mostly carbon dioxide with clouds of sulphuric acid. Sulphuric acid is a chemical that is poisonous to life. For this it is sometimes known as the Earth's "evil twin".
+
+The thick atmosphere makes it hard to see the surface. Until the late twentieth century many thought there might be life there. The pressure on Venus' surface is 92 times that of [[Earth]]. Venus is one of only 2 planets in the [[Solar System]] (the other being [[Mercury]]) that has no moons. Venus spins very slowly on its axis and it spins in the opposite direction to the other planets.

editions/tour/tiddlers/System/$__themes_tiddlywiki_vanilla_options_sidebarlayout.tid

@@ -0,0 +1,4 @@
+title: $:/themes/tiddlywiki/vanilla/options/sidebarlayout
+type: text/vnd.tiddlywiki
+
+fluid-fixed

editions/tour/tiddlers/System/DefaultTiddlers.tid

@@ -1,3 +1,4 @@
 title: $:/DefaultTiddlers
 
+[[HelloThere]]
 [[Solar System]]

editions/tour/tiddlers/System/HelloThere.tid

@@ -0,0 +1,5 @@
+title: HelloThere
+
+Welcome to this TiddlyWiki about the [[Solar System]].
+
+With many thanks to the [[Simple English Wikipedia|https://simple.wikipedia.org/]], the original source of this material.

editions/tour/tiddlers/System/styles.tid

@@ -3,3 +3,7 @@ tags: [[$:/tags/Stylesheet]]
 
 \rules only filteredtranscludeinline transcludeinline macrodef macrocallinline
 
+.hero-image {
+max-width: 300px;
+max-height: 300px;
+}