How many planets are there in the solar system? It’s a silly question, huh. There total of 8 planets in the solar system nowadays. Today, you are going to know about those 8 planets of the solar system.
There were not 8 planets always, before 2006, Pluto was also in the league. During the 26th General Assembly of IAU (International Astronomical Union), they defined the term Planet.
According to this new definition, Pluto was abdicated from being a planet and redefined as a dwarf planet.
With the exclusion of Pluto, currently there are only 8 planets in the solar system.
All these 8 planets of the solar system are orbiting around the sun with different spin cycle.
If this image is not clearly visible you can get it’s high resolution image from here
Each planet of the solar system has its own importance in the solar family. They all have different and specific characteristics. Whether we talk about their tilt, their seasons, their revolution time, their rotation, or their structure we will find a huge diversity there.
So, today we are targeting the compilation of general information of each and every planet of the solar system. It is not a detailed article about the planet, for that you may refer to the links in this article.
So let’s start the topic!
Mercury: The 1st of the 8 planets of the Solar System
It is the smallest planet of the solar system and also nearest planet to the sun.
Standing on the surface of this planet, we could observe the sun 3 times larger than viewed from the Earth. And seven times brighter.
It would amaze you to know that Mercury is not the hottest planet although it is the nearest. The hottest planet title is carried by the twin sister of the Earth, Venus.
It is the swiftest planet and completes its orbit in 88 earth days. Its swiftness is the reason it is named after the swiftest Roman God, Mercury.
Size and the Distance
It has a radius of 2440 kilometres which 1/3 of the Earth.
If we talk about its distance from the sun, it is only 58 million miles. In the term of the astronomical unit, it 0.4 AU ( Astronomical Unit) away from the sun.
Orbit & Rotation
Its orbit is highly eccentric. Its weird-shaped orbit takes the planet closest as 47 million kilometers and farthest as 70 million kilometers from the sun.
It orbits the sun every 88 days, with the swiftest speed of 47 kilometers per second through space which is faster than any other planet of the solar system.
As far as its rotation concerns, it rotates slowly on its axis and completes one rotation in every 59 earth days.
There is an amazing fact about its day-night cycle. Not each rotation of this planet provides a full day and night cycle.
Here on it, the sun keeps arisen for an entire year ( Mercurian Year) when closest to the sun. This period of time is considered as a day time on it.
Then after one year, the sun sets on mercury when farthest to the sun. So, calculating this, a day and night cycle on mercury completes in 88+88=176 earth days. It is really amazing, a day longer than a year, twice of it.
It has a tilt of 2 degrees on its axis, which means it rotates perfectly upright. Due to this position, it does not experience any seasonal change.
Its surface is very much similar to that of the earth’s moon. Scarred by many impact craters due to the collision of asteroids and meteorites.
Most of the its surface would appear grayish-brown to the human eye.
The temperature on it is extremely hot and cold too. When it is closest to the sun, i.e. daytime, its surface temperature can rise up to 430 degrees Celsius. And the minimum temperature is -180 degrees Celsius, it happens during the night time.
Moons & Rings
It does not have a single moon. Neither it has rings.
Venus: The 2nd of the 8 planets of the Solar System
This planet is also known as the twin sister of the earth is the 2nd planet from the sun. It is the closest planetary neighbor of earth.
There is a twist in its rotation, it rotates very slowly. Oh, no no no, it’s not the twist. The twist is, it rotates in the opposite direction to that of the other planets of the solar system.
Well, it is renowned as the hottest planet of the solar system and the reason is its thick atmosphere. It is so thick that not even heat can surpass it and get trapped in the thickest atmosphere.
It is the brightest planet of the solar system and it looks beautiful. Due to its beauty and brightness, it is named after the ancient Roman Goddess of love, Venus who is also known as Aphrodite.
Size and The Distance
This planet is 6,052 kilometers in radius which is just 326 kilometers less than that of the Earth.
It is 108 million kilometers away from the sun. In the terms of AU, it is 0.7 AU away.
It takes 6 minutes for sunlight to reach this planet from the Sun. In other words, we can say, venus is 6 light minutes away from the sun.
Orbit & Rotation
its rotation and orbit is unusual in many ways. The most unusual thing is its opposite rotation. It rotates opposite to the direction of most of the planets.
One more unusual thing, like Mercury, Venus has a day longer than a year. Even it has the longest day in all the planets of the solar system.
It has nearly a perfectly circular orbit around the sun and tilted on its axis by just 3 degrees. Due to this, Venus never experiences a seasonal change.
Standing in the space and looking towards the Venus, from that point it looks bright white. This is because of the clouds that covers it and reflect and scatter the sunlight.
At the surface of it, the rocks are different shades of grey similar to that of the Earth.
The thick atmosphere filters the sunlight so that everything would look orange if you were standing on it.
The highest mountain on it, Maxwell Montes, is 20,000 feet high (8.8 kilometers), similar to the highest mountain on Earth, Mount Everest.
The landscape is dusty, and surface temperatures reach a scolding 880 degrees Fahrenheit (471 degrees Celsius).
Moons and Rings
Like Mercury, Venus has neither have a single or a rings.
Earth: The 3rd of the 8 planets of the Solar System
Our home planet is the third planet of the 8 planets of the solar system. It is the only place we know of so far that’s inhabited by living things.
Earth is the fifth-largest planet and the only world in our solar system with liquid water on the surface.
It is slightly larger (around 328 km) than nearby Venus, Earth is the biggest of the four planets closest to the Sun, all of which are made of rock and metal.
The name Earth is not less than 1,000 years old. All of the planets ere named after Greek and Roman gods and goddesses, except for Earth. The name Earth is a Germanic word, which means “the ground.”
Size & Distance
Earth is the biggest of the terrestrial planets, with a radius of 3,959 miles (6,371 kilometers), and the fifth-largest planet overall.
From an average distance of 93 million miles (150 million kilometers), Earth is exactly one astronomical unit away from the Sun because of one astronomical unit (abbreviated as AU), as AU is defined in the terms distance from the Sun to Earth.
This unit makes it easy to quickly compare planets’ distances from the Sun. It is about eight light minutes away from the sun.
So, sun light takes approx eight minutes to travel light from the Sun to our planet.
Orbit & Rotation
On it’s orbit, Earth completes one rotation every 23.9 hours.
It takes around 365.25 days to complete one revolution around the Sun.
That extra 0.25 day presents a challenge to our calendar system, which makes one year in 365 days.
To keep our yearly calendars consistent with our orbit around the Sun, every four years we add one day, that is the 29th day of Feb.
So, 29th day of Feb is called a leap day, and the year it’s added to is called a leap year.
Earth’s axis of rotation is tilted by 23.4 degrees with respect to the plane of Earth’s orbital path around the Sun.
This tilt causes our yearly cyclic seasons and weather.
When the northern hemisphere is tilted toward the Sun then the southern hemisphere is tilted away.
With the Sun higher in the sky, solar heating is much greater in the north producing summer there. Less direct solar heating makes the south cool.
After six months, the situation reversed and When spring and fall begin, both hemispheres receive roughly equal amounts of heat from the Sun.
Moons & Rings
Earth has a moon which we all know. It is the only natural satellite Earth has. As far as the rings concern, the Earth doesn’t have any.
Mars: The 4th of the 8 planets of the Solar System
Our Solar system is full of amazing things. There is a planet which is red hence it is called the red planet. This is Mars the red planet.
Do you know which is the most explored planet in our solar system after earth? Any guesses? No? let me tell you. Mars, yes it’s Mars. You got it right.
Mars is the most explored planet in the solar system after the earth and today we are going to discuss the same planet which is also known as the Red Planet.
This planet has a very important role in Indian astronomy.
Mars was named by the traditional Romans for his or her god of war because its reddish color was like blood.
Other civilizations also named the earth for this attribute; for instance, the Egyptians called it “Her Desher,” meaning “the red one.”
Even today, it’s frequently called the “Red Planet” because iron minerals within the Martian dirt oxidize, or rust, causing the surface to seem red.
Size & Distance
With a radius of two,106 miles (3,390 kilometers), Mars is about half the dimensions of Earth.
From a mean distance of 142 million miles (228 million kilometers), Mars is 1.5 astronomical units far away from the Sun. One Astronomical Unit (abbreviated as AU), is that the distance from the Sun to Earth.
From this distance, it takes sunlight 13 minutes to travel from the Sun to Mars.
Orbit & Rotation
Mars’ axis of rotation is tilted 25 degrees with reference to the plane of its orbit around the Sun. This is another similarity with Earth, which has an axial tilt of 23.4 degrees.
Martian days are called sols—short for “solar day.” A year on Mars lasts 669.6 sols, which is that the same as 687 Earth days.
Like Earth, Mars has distinct seasons, but they last longer than seasons here on Earth since Mars takes longer to orbit the Sun (because it’s farther away).
And while here on Earth the seasons are evenly spread over the year, last 3 months (or one quarter of a year), on Mars the seasons vary in length because of Mars’ elliptical, egg-shaped orbit around the Sun.
The Red Planet is actually of many colors. At the surface we see colors like brown, gold and tan.
The reason Mars looks reddish is thanks to oxidization—or rusting—of iron within the rocks, regolith (Martian “soil”), and mud of Mars.
This dust gets kicked up into the atmosphere and from a distance makes the earth appear mostly red.
Interestingly, while Mars is about half the diameter of Earth, its surface has nearly an equivalent area as Earth’s land.
Mars is home to the most important volcano within the system, Olympus Mons. It’s three times taller than Earth‘s Mt. Everest with a base the dimensions of the state of the latest Mexico.
There is water on Mars today, but the Martian atmosphere is just too thin for liquid water to exist for long on the surface.
Today, water on Mars is found within the sort of water-ice slightly below the surface within the polar regions also as in briny (salty) water, which seasonally flows down some hillsides and crater walls.
Moons & Rings
Mars has two moons, Phobos and Deimos, that may have captured asteroids. They’re like Potato in Shape because they have very little mass for gravity to make them spherical.
As far as the rings concerns, it does not have any now. But, there is an expectation that in the next 50 million years when Phobos crashes into mars or torn apart, it could create a dusty ring around it.
Jupiter: The 5th of the 8 planets of the Solar System
As we all know, Jupiter is the fifth planet from our Sun. It is the largest planet in the solar system. More than twice as big as all the other planets combined together.
Jupiter has cold stripes and swirls, windy clouds of ammonia, and water. It is floating in an atmosphere of hydrogen and helium.
Jupiter’s very famous Great Red Spot is a giant storm far bigger than Earth that has raged for hundreds of years. Jupiter is surrounded by dozens of moons, it actually seems like another Jupiter System in itself.
Jupiter also has many rings, but unlike the famous rings of Saturn, Jupiter’s rings are very dull and made of dust, rather than ice.
Size and Distance
Jupiter has a radius which eleven times wider than that of Earth. It has a radius of 43,440.7 miles (69,911 kilometers).
From an average distance of 484 million miles (778 million kilometers), Jupiter is 5.2 astronomical units away from the Sun.
From this distance, it takes Sunlight 43 minutes to travel from the Sun to Jupiter.
Orbit & Rotation
Jupiter has the shortest day in the solar system. One day on Jupiter takes only about 10 hours (the time it takes for Jupiter to rotate or spin around once)
And it makes a complete orbit around the Sun (a year in Jovian time) in about 12 Earth years (4,333 Earth days).
Its equator is tilted with respect to its orbital path around the Sun by just 3 degrees. This means Jupiter spins nearly upright and does not have seasons as extreme as other planets do.
As a gas giant, Jupiter the largest planet doesn’t have a true surface. The planet is mostly swirling gases and liquids.
While a spacecraft would have nowhere to land on Jupiter, it wouldn’t be able to fly through unscathed either.
The extreme pressures and temperatures deep inside the planet crush, melt and vaporize spacecraft trying to fly into the planet.
Moons & Rings
With four large moons and many smaller moons, Jupiter forms a kind of miniature solar system in itself.
Jupiter has a total of 53 confirmed moons and 26 provisional moons awaiting confirmation of a discovery. Moons are named after they are confirmed.
Jupiter’s four largest moons—Io, Europa, Ganymede, and Callisto—were first observed by the astronomer Galileo Galilei in 1610 using an early version of the telescope.
These four moons are known today as the Galilean satellites, and they’re some of the most interesting destinations in our solar system.
Ganymede is the largest moon in the solar system (even bigger than the planet Mercury).
Discovered in 1979 by NASA’s Voyager 1 spacecraft, Jupiter’s rings were a surprise, as they are composed of small, dark particles and are difficult to see except when backlit by the Sun.
Data from the Galileo spacecraft indicate that Jupiter’s ring system may be formed by dust kicked up as interplanetary meteoroids smash into the giant planet’s small innermost moons.
Saturn: The 6th of the 8 planets of the Solar System
The sixth planet from the Sun and the second-largest Saturn has got the title of the most beautiful planet of the solar system.
All the beauty which Saturn has is due to its dazzling system of icy rings which gives Saturn a uniqueness among the planets.
Saturn is not the single planet that has rings, but no other planets are as splendid or as complex as Saturn‘s.
Saturn is a massive ball composed mostly of the same atoms as our Sun is made, hydrogen and helium, just like its fellow gas giant and the planet of the great red spot, Jupiter.
Center of gravity for more than 60 known moons, Saturn is home to a few of the most fascinating landscapes in our entire solar system.
The Saturn system is a rich source of scientific exploration and still holds many mysteries, from the jets of water that rain from Enceladus to the methane lakes on smoggy Titan.
Known from ancient times, Saturn is the most distant planet from Earth found by the naked human eye without any aid of a telescope or other technologies.
The planet is named after the god of agriculture and wealth, a Roman god who was also the father of Jupiter.
Size & Distance
9 times wider than Earth, Saturn has a radius of 58,232 kilometers. If we assume Earth to be the size of a nickel, Saturn would be as big as a volleyball.
9.5 astronomical units far from the Sun, Saturn has an average distance of 1.4 billion kilometers.
One astronomical unit in short AU, equals the distance from the Earth to Sun.
Sunlight take 80 minutes to reach to the Saturn from the Sun.
Orbit & Rotation
After Jupiter, Saturn experiences the second-shortest day in the solar system.
Saturn has a day of only 10.7 hours (it is also the time taken by Saturn to rotate or spin around once).
Saturn completes its orbit around the Sun (a year in Saturnian time) in about 29.4 Earth years (10,756 Earth days).
Like Earth, Saturn is tilted by 26.73 degrees at axis with respect to its orbit around the Sun.
This makes clear that, like Earth, Saturn must have experiencing seasons.
Saturn has no actual surface, as being a gas giant.
The planet is nothing but mostly swirling gases and liquids deeper down.
Although a spacecraft would have no surface on Saturn to land, it could also not float unscathed.
Its extreme temperatures and pressures deep inside the planet, crush, melt and vaporize every spacecraft which try to fly into the planet.
Moons & Rings
Saturn is home to a vast array of intriguing and unique worlds.
From the smoggy surface of Titan to crater-riddled Phoebe, all the Saturn‘s moons tells another piece of the story orbiting the Saturn system.
Currently Saturn has 53 confirmed moons with 29 additional provisional moons awaiting confirmation.
Scientists are very fascinated about the rings of Saturn. By what materials the rings of Saturn are made of.
By astronomers speculation, Saturn‘s rings are made of pieces of comets, asteroids, or shattered moons that have been broken up before they reached the planet, torn apart by Saturn‘s powerful gravity.
They are made of billions of small pieces of ice and rock covered with another material such as dust.
The ring particles mostly range from tiny, dust-sized icy grains to chunks as big as a house. A few particles are as large as mountains.
The rings would look mostly white if you looked at them from the cloud tops of Saturn, and interestingly, each ring orbits at a different speed around the planet.
Its ring system extends up to 282,000 kilometers from the planet, yet the vertical height is typically about 10 meters in the main rings.
Uranus: The 7th of the 8 planets of the Solar System
The third-largest planet in our solar system and the seventh from the Sun, Uranus is windy and very cold.
The icy Gas giant is surrounded by 27 small moons and 13 faint rings as it rotates at a 98-degrees angle from the plane of its orbit.
This unique tilt makes Uranus appear to spin on its side, and orbiting the Sun like a rolling ball rather than a spinning like other planets.
Uranus is the first planet that has been found with the aid of a telescope. Uranus was discovered in 1781 by astronomer William Herschel, although he originally thought it was either a comet or a star.
It was two years later that the object was universally accepted as a new planet, in part because of observations by astronomer Johann Elert Bode.
William Herschel tried unsuccessfully to name his discovery Georgium Sidus after King George III. Instead, the planet was named for Uranus, the Greek god of the sky, as suggested by Johann Bode.
Size and Distance
With a radius of 15,759.2 miles (25,362 kilometers), Uranus is 4 times wider than Earth.
From an average distance of 1.8 billion miles (2.9 billion kilometers), Uranus is 19.8 astronomical units away from the Sun.
From this distance, it takes sunlight 2 hours and 40 minutes to travel from the Sun to Uranus.
Orbit and Rotation
One day on Uranus takes about 17 hours (the time it takes for Uranus to rotate or spin once). And Uranus makes a complete orbit around the Sun (a year in Uranian time) in about 84 Earth years (30,687 Earth days).
Uranus is the only planet whose equator is nearly at a right angle to its orbit, with a tilt of 97.77 degrees—possibly the result of a collision with an Earth-sized object long ago.
This unique tilt causes the most extreme seasons in the solar system. For nearly a quarter of each Uranian year, the Sun shines directly over each pole, plunging the other half of the planet into a 21-year-long, dark winter.
Uranus is also one of just two planets that rotate in the opposite direction than most of the planets (Venus is the other one), from east to west.
As an ice giant, Uranus doesn’t have a true surface. The planet is mostly swirling fluids. While a spacecraft would have nowhere to land on it, it wouldn’t be able to fly through its atmosphere unscathed either.
The extreme pressures and temperatures would destroy a metal spacecraft.
Moons & Rings
It has 27 known moons. While most of the satellites orbiting other planets take their names from Greek or Roman mythology.
Its moons are unique in being named for characters from the works of William Shakespeare and Alexander Pope.
All of its inner moons appear to be roughly half water ice and half rock. The composition of the outer moons remains unknown, but they have likely captured asteroids.
Uranus has two sets of rings. The inner system of nine rings consists mostly of narrow, dark grey rings.
There are two outer rings: the innermost one is reddish like dusty rings elsewhere in the solar system, and the outer ring is blue like Saturn‘s E ring.
Neptune: The 8th of the 8 planets of the Solar System
The most distant planet of the solar system, Neptune is an Ice Giant that has Dark, Cold, whipped by supersonic winds.
Neptune is the only planet of the solar system that is not visible to a naked eye.
If we are to experience the sun’s high noon light on Neptune, it would feel as a dim twilight to us on the Earth. That far is the Neptune from the sun.
It is the first planet of the solar system located through mathematical calculations rather that physical observation.
Urbain Le Verrier predicted it by, Johann Galle discovered it in 1846.
Le Verrier suggested it’s name after the Roman god of the sea.
Size & Distance
Neptune has a radius of 24,622 kilometers. It is about four times wider than Earth.
From an average distance of 2.8 billion miles (4.5 billion kilometers), Neptune is 30 astronomical units away from the Sun.
Orbit and Rotation
Taking its rotation into consideration, Neptune completes its rotation in about 16 earth hours. And it takes around 165 earth years to complete one orbit around the sun.
At some events Neptune is even farther from the Sun than dwarf planet Pluto.
Neptune has 28 degrees of tilt on its axis with respect to the plane of its orbit around the sun. This is very much similar to that of Earth and the mars.
This means that Neptune experiences seasons just like we do on Earth; however, since its year is so long, each of the four seasons lasts for over 40 years.
Neptune does not have a solid surface.
Hydrogen, helium, and methane are the main compositions of Its atmosphere.
Extends to great depths, gradually merging into water and other melted ices over a heavier, solid core with about the same mass as Earth.
Moons & Rings
Neptune has 14 known moons.
William Lassell discovered Neptune’s largest moon Triton on October 10, 1846. That is too just 17 days after Johann Gottfried Galle discovered the planet.
Scientists gave the name of Neptune after the Roman god of the sea. So they renounced its moons for various lesser sea gods and nymphs in Greek mythology.
Triton is the only large moon in the solar system that circles its planet in a direction opposite to the planet’s rotation (a retrograde orbit), which suggests that it may once have been an independent object that Neptune captured.
Neptune at least five main rings and four prominent ring arcs that we know of so far.
Names of rings starting near the planet and moving outward are Galle, Leverrier, Lassell, Arago, and Adams.
The rings are Very new and of short age.
So this was all about the planets of the solar system. We are not alone in the solar system. May be there is no other planet with living organism but still, we are not alone.
There is someone protecting us from the outer world like Jupiter is protecting us from the collision of asteroids. Moon becomes the reason of seasonal changes.
There are a lot other things in the solar system that we can learn.
If you are an Indian you must know the importance of “NavGrah” in the Indian Astronomy.
This is not the end. There are a lot of things need to learn from the solar system itself. It has endless mysteries. So, Stay tune and subscribe Us fro such amazing knowledge.
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