The solar system was formed 4.6 billion years ago. Our solar system consists of eight planets which all orbit around the Sun. These eight planets are
Mercury is the closest planet to the Sun and Neptune is the farthest from the Sun.
It is the closest planet to the Sun and is about as wide as the Atlantic Ocean. The distance from the Sun to Mercury is over 9 million. It is the smallest planet in the solar system. The planet was named after the Roman messenger to the gods.
Mercury is one of the four “terrestrial” planets in the solar system. It can be seen from Earth without a telescope. 18 Mercury would fit into the Earth.
Mercury has no atmosphere which means there is no wind or weather to speak of. Mercury has no water or air on the surface. Mercury has no Moons and does not have any rings.
Mercury has a very low surface gravity.
Mercury’s orbit around the Sun is the fastest orbit of all the solar system planets. It is the fastest planet and speed through space with 50km per second (or 31 miles per second). Mercury orbits the sun in 88 days, which means 59 Earth days equal 1 day on Mercury.
It is the second hottest planet in the solar system, reaching up to 4000 ° C degrees during the day, and at night, however, without an atmosphere to hold heat in, the temperatures plummet, dropping to -180 degrees Celsius.
Venus is the second closest planet to the Sun in the solar system. The distance from the Sun to Venus is over 67 million miles. It is the third smallest planet in the solar system. Being a rocky planet, Venus is also one of the four “terrestrial” planets in the solar system. It can be seen from Earth without a telescope.
Venus is named after the Roman goddess of beauty. It is also known as the morning star because at sunrise it appears in the east. It is also known as evening star as it appears at sunset when it is in the west. It cannot be seen in the middle of the night. The yellow clouds made of sulfur and sulfuric acid cover the entire planet and they reflect the light from the planet’s surface. This makes the planet the second brightest object in the night sky after the Moon.
Venus and Earth are close together in space and similar in size, which is the reason Venus is called Earth's sister planet.
Venus is very similar to Earth in terms of size and material. It is the hottest planet in the solar system with temperatures reaching 460°C/480°F.
Venus’s orbit around the sun is the second fastest orbit of all the solar system planets. Venus is the slowest rotating planet and rotates backward. 243 Earth days equals 1 day on Venus. It has no moons.
The surface of Venus hosts thousands of volcanoes, craters, and super-high mountain ranges.
The atmosphere on Venus is composed of carbon dioxide. The surface is heated by radiation from the sun, but the heat cannot escape through the clouds and layer of carbon dioxide. (This is a “greenhouse effect”).
Earth is the fifth largest planet of our solar system and is the third closest planet to the Sun. It has one natural satellite, the Moon. It is believed to the only planet where life exists. Earth is 70% water. Earth doesn’t have any rings. It is the densest planet in the solar system.
All planets were named after Roman and Greek gods and goddesses, except the Earth. However, the name Earth is more than 1000 years old and means ‘ground’.
Earth’s orbit around the Sun is the third fastest orbit in the solar system. Earth orbits the Sun in 365 days, which means that 1 year on Earth is 365 days.
Its temperature changes rapidly in different areas with the average temperature as 57 ° C.
Earth is very special because of the life that it supports. Earth tilts on an axis of 23.5 degrees. It has a powerful magnetic field that protects the planet from harmful elements from space.
Mars is the fourth closest planet to the Sun and is the second smallest planet in the solar system. It is one of the four “terrestrial” planets in the Solar System, along with Mercury, Venus, and Earth. It can also be seen from Earth without a telescope.
Mars has no rings. Mars would fit into the Earth.
The Sun looks half the size on Mars as it looks on Earth.
Mars was named after the Roman god of war. It is also described as the “Red Planet” because it is covered with rust-like dust.
Mars looks a lot like our home, though instead of blue oceans and green land, Mars is home to an ever-present red tint. This is due to a mineral called iron oxide that is very common on the planet’s surface.
Mars orbits the sun in 687 days, which means 687 Earth days is one year on Mars.
Mars is very cold and dry but water exists in the form of ice at the North and South poles. Mars has seasons like Earth too. These seasons are much longer than Earth seasons because Mars is so much farther from the sun.
The surface of Mars has many craters, deep valleys, and volcanoes. Mars experiences violent dust storms which continually change its surface.
Mars has many massive volcanoes. The largest peak on the red planet is a volcano called Olympus Mons, which is three times higher than Mount Everest, the highest mountain on Earth. Mons is the Latin word for mountain.
Mars has a very thin atmosphere with carbon dioxide over 95%. It is not thick enough to trap the sun's heat like Venus, so the planet is very cold. Temperatures range from -120 Degrees Celsius on winter nights to 25 Degrees Celsius in the summer.
Mars has two moons called Phobos and Deimos, both are probably asteroids which were caught up by Mars’ gravitational field.
Jupiter is the largest planet in the solar system. It is over twice the size of all the other planets in the solar system. It is so big that more than 1300 Earth could fit inside it
It is called after the ancient Roman sky-god, Jupiter, known to the Greeks as Zeus. Jupiter was the first Planet created in the Solar System
Jupiter is made up of layers and layers of gas, which is why it is a gas planet. Jupiter is the first of the “gas giants”, Jupiter, Saturn, Uranus, and Neptune. These gas planets are called Jovian Planets.
Jupiter has 4 rings.
Jupiter is the stormiest planet in the Solar System. The most famous feature on the surface of the planet is the ‘Great Red Spot’ which is actually a storm that has been blowing for about 350 years, if not longer.
Jupiter has 67 moons! The first 4 largest moons of Jupiter are called Galilean moons, as they were discovered by the famous Astronomer Galileo. One particular moon, Europa might be able to sustain life in an ocean below its icy surface.
It takes Jupiter 12 Earth years to orbit the sun, which is a very long time; however as Jupiter orbits very slow around the sun compared to Earth, it rotates very fast. 1 day on Jupiter lasts for about 10 hours, compared to Earths 24 hours.
There is one spacecraft currently orbiting Jupiter called Juno. Juno is trying to solve how the planet formed and finding out more about the winds that occur.
Saturn was named after the ancient Roman god of agriculture.
It is the sixth planet from the Sun.
Saturn is the second largest planet, after Jupiter.
Saturn is a gas giant like Jupiter, Neptune, and Uranus. Planets that do not have a proper solid surface as they are mainly made up of gases are known as gas giants. Gas giants have a small rocky core. The gas planets are also called ‘Jovian Planets’.
Saturn is very well known for its rings. Saturn has 7 layers of rings. These rings are made up of millions of ice crystals, some as big as houses and others as small as specks of dust. Although the other gas giants also possess these kinds of rings, only Saturn’s rings can be seen the clearest from Earth through a telescope. The rings were first seen by Galileo in 1610 through a telescope.
Saturn has 62 moons in total. Saturn’s moon Titan is bigger than the planet Mercury.
Saturn is the least dense planet in the solar system, as it is made up of more hydrogen than helium so it is less dense.
Saturn is the last planet that can be seen without using a telescope or binoculars and the planet was known in the ancient world before telescopes were invented. However, the rings of Saturn can only be seen using a telescope.
The temperature on Saturn is around -288 degrees on average. It takes Saturn 29 Earth years to orbit the sun, which is a very long time. However, as Saturn orbits very slow around the sun compared to Earth, it rotates very fast. 1 day on Saturn lasts for about 10 hours & 15 minutes, compared to Earths 24 hours.
Uranus is the seventh planet from the sun. It is one of the four gas planets. Uranus was the first planet discovered by telescope. It was discovered by astronomer William Herschel in the 18th century in 1781.
Uranus has 27 moons in total and 13 rings.
Uranus is also called the Ice Giant
It was named after the Greek god of the sky.
Uranus is the third largest planet in the solar system. It is the second coldest planet in the solar system with an average temperature of around -350 degrees.
It takes Uranus 84 Earth years to orbit the Sun. 1 day on Uranus lasts for about 17 hours, compared to Earth’s 24 hours. It rolls like a barrel rather than spinning like Earth and the other planets in our Solar System.
The tilt of the planets axis is at a strange 98 degrees which is very different from all of the other planets in the solar system.
Uranus’ atmosphere is mostly hydrogen but it also contains large amounts of a gas called methane. Methane absorbs red light and scatters blue light so the planet appears as blue-green in color.
Neptune is the eighth planet from the Sun, which actually it the furthest planet from the Sun. The distance from the Sun to Neptune is over 2795 million miles. Neptune is also one of the four gas planets.
Neptune was discovered in 1846, and can only be seen through a telescope.
It is the fourth largest planet in the solar system. Neptune has 6 rings.
Neptune has 13 moons. One of its moons named Triton is the most unusual moon since it orbits Neptune in the opposite direction of Neptune’s own rotation on its axis. All the other major satellites (moons) in the Solar System follow their planets round as they turn.
Neptune is a large, water planet. Its upper atmosphere is made of the gas methane which gives the planet a bright blue color. It suffers the most violent weather in our Solar System.
The average temperature on Neptune is around -392 degrees, which makes the planet the coldest planet in the solar system. Storms have been spotted swirling around its surface and freezing winds that blow about 10 times faster than hurricanes on Earth making it the windiest planet in the Solar System.
It takes Neptune 165 Earth years to orbit the sun. 1 day on Neptune lasts for about 16 hours, compared to Earths 24 hours.
Dwarf Planets are small rocky bodies that orbit the sun in our solar system. They are similar to the other eight planets but are smaller. A dwarf planet is defined as a celestial object that is neither a true planet nor a natural satellite.
It is in direct orbit of a star.
It is massive enough for its gravity to compress it into a spheroid.
It has not cleared the neighborhood of other materials around its orbit.
As of 2008, there are five recognized dwarf planets starting from the closest one to the Sun and then outwards:
Ceres-Pluto-Haumea-Makemake-Eris
Ceres is the closest dwarf planet to the Sun and is located in the asteroid belt between Mars and Jupiter, making it the only dwarf planet in the inner solar system. It is the only planet that is not in the Kuiper belt. It is the smallest of the bodies currently classified as dwarf planets with a diameter of 950 km. Ceres was discovered by astronomer Giuseppe Piazza in 1801.
Pluto is the second closest dwarf planet to the Sun. It is located in the Kuiper belt. Pluto was once a planet and was the ninth planet in the solar system until it was found to be a dwarf planet instead. It is the largest of the dwarf planets but only the second most massive with Eris being the most massive. Pluto has 5 moons.
Haumea is the third closest dwarf planet to the Sun. It is located in the Kuiper belt. It is unique in its elongated shape making it the least spherical of the dwarf planets. It rotates so fast that it completely turns on its axis every 4 hours. In 2009 a dark red spot on Haumea was discovered which stands out from surrounding crystalline ice. It’s thought this spot could be an area of the dwarf planet that is with a higher concentration of minerals and carbon-rich compounds than the rest of the icy surface.
Makemake is the fourth closest dwarf planet to the sun and is located in the Kuiper belt. It is red in color, has 1 moon, is a perfect sphere and has no atmosphere.
Eris is the fifth closest dwarf planet to the sun and is located in the Kuiper belt. Eris has 1 moon, and is in a strange orbit around the sun. Eris at times in orbit around the sun leaves the Kuiper belt altogether and then come back in.
There are many more dwarf planets in the solar system waiting to be discovered.
The definition of a day is the amount of time it takes an astronomical object to complete one full spin on its axis.
Mercury = 58.6 Earth days
Venus = 243 Earth days
Earth = 23 hours, 56 minutes
Mars = 24 hours, 37 minutes
Jupiter = 9 hours, 55 minutes
Saturn = 10 hours, 33 minutes
Uranus = 17 hours, 14 minutes
Neptune = 15 hours, 57 minutes
Mercury = 87.97 days
Venus = 224.7 days
Earth = 365.26 days
Mars = 1.88 years
Jupiter = 11.86 years
Saturn = 29.46 years
Uranus = 84.01 days
Neptune = 164.79 days
