We often hear news about planets, especially Mars. But how many planets are there in our solar system? What are the names of these planets? What is its arrangement?
We will try to explain the topic in a simple way, we are in the universe, which is the largest known space and includes everything we know. The Big Bang theory tells us that the universe formed about 13.8 billion years ago. There are about 100 billion galaxies in it, and each galaxy has billions of stars.
One of these galaxies is our large habitat, it is called the Milky Way . When we look at the sky in the evening, and notice all of these stars, most of these stars are in the Milky Way.
Within the Milky Way, as in other galaxies, there are many stars and planets, with potentially many solar systems similar to our own. In fact, what we see in the sky that we call stars, could be like our sun and planets around it like ours.
The Solar System was formed about 4.56 billion years ago, formed from the Sun, which is at the center of the system.
The planets of the solar system, in order of their distance from the sun
Starting from the planet closest to the sun towards the dark boundaries of the solar system, the order of the planets of the solar system is as follows:
As you can see, there are eight planets in the solar system. But, weren’t there nine planets? What happened to the last planet?
That’s right, I’m talking about Pluto. Why was it not included within these planets? In fact, Pluto is a very special story. Once discovered in 1930, it was named Planet Nine. Unfortunately for him, in 2006, that is, several years ago, astronomers discovered that Pluto did not have the typical characteristics of a planet, so it was renamed a “dwarf planet”, and the number of planets in the solar system returned to eight, and so far, many sympathizers wish Pluto is joining the planets again, but that is not possible.
With Pluto removed from the list, let’s return to the eight planets. Did you notice the image above and how the dimensions of these planets differ? You sure knew right away which one was the largest. It is Jupiter. Then we have Saturn, Uranus and Neptune in order. While the smaller planets, which come after the previous giants, are our Earth, then Venus, then Mars, and then Mercury. This is the arrangement of planets according to their size.
The planets of the solar system, in order of size
The planets in the solar system are ranked from largest to smallest (kilometers in diameter):
- Jupiter (142.984 km)
- Saturn (120,536 km)
- Uranus (51,118 km)
- Neptune (49,528 km)
- Earth (12.756 km)
- Venus (12.104 km)
- Mars (6,780 km)
- MERCURY (4,875 km)
The sun has a diameter of 1,400,000 km. That is, we need to line up 10 planets like Jupiter to reach the diameter of the Sun.
We did not mention Pluto. As mentioned above, Pluto is no longer a planet, but a “dwarf planet”. Pluto has a diameter of 2,304 km, which is less than the radius of Mercury, the smallest planet in the solar system.
The diameter of planet Earth is approximately equal to the diameter of Venus (a difference of a few kilometers). Earth is the fifth planet in the solar system according to its size after the four giants.
Saturn is ten times the diameter of the Earth, twice the diameter of Mars, and three times the diameter of Mercury.
But what is the order of the planets according to the temperature? Let’s try to find out.
Planetary temperatures in the solar system
What are the average temperatures recorded on the planets? Here is a ranking from the hottest to the coldest:
- Venus (-180 to 475 ° C)
- Mercury (-173 to 427 ° C)
- Earth (-70 to 55 ° C)
- Mars (-120 to 25 ° C)
- Jupiter (-110 ° C)
- Saturn (-140 ° C)
- Uranus and Neptune (-200 ° C)
Pluto (knowing that it is not a planet) has a temperature of about -230 ° C.
But Mercury is closest to the sun, so how is Venus hotter? Why?
This is caused by the greenhouse effect caused by the atmosphere of Venus, as the atmosphere is rich in carbon dioxide, as the sun’s heat is trapped. On the other hand, Mercury, being smaller in size and thus having little gravitational force, is unable to retain gases and thus does not have a true atmosphere, which is why it is not able to trap the sun’s heat like Venus. This is the reason why Mercury is less hot than Venus.
The temperature in some regions of Mars reaches 25 degrees Celsius, which is excellent for living things. For this reason, we often talk about Mars as a possible place to live in the future. But that is not possible at the moment, given the lack of oxygen.
Now we can move to another feature of the planets, which differs from one planet to another. They are, in fact, two characteristics, the rotation of the planets around themselves and the rotation of the planets around the sun.
Duration of rotation of planets in the solar system
Each planet in the solar system has two revolutions, one around itself and one around the sun.
As we know, it takes about 24 hours for the Earth to orbit itself, and about 365 days (one year) to orbit the sun.
But how do other planets move? How long do they take? Here is an explanation.
Let’s start with the rotation of the planets around themselves (meaning the duration of the day on each planet). Here is the order from slowest to fastest:
- Venus: 5,832 hours (243 earth days)
- Mercury: 1,406.4 hours (58.6 Earth days)
- Mars: 24.62 hours
- Earth: 23.93 hours
- Uranus: 17.24 hours
- Neptune: 16.11 hours
- Saturn: 10.65 hours
- Buyer: 9.93 hours
The excluded Pluto orbits itself every 153.12 hours (6.38 Earth days).
Note that the larger planets in the solar system rotate faster than the smaller planets. Jupiter is the fastest, it lasts less than ten hours on this giant planet today.
Today on Venus is very long, lasting 8 months on Earth. That is, from morning to evening it takes 243 days.
On the other hand, Mars is very similar to our planet, with a day of 24.62 hours.
Now, let’s turn to how long the planets revolve around the sun. How long does it take for the planets to fully orbit the sun?
Here is the ranking from fastest to slowest:
- Mercury (88 days)
- Venus (year 224.7 days)
- Earth (365.26 days)
- Mars (687 days)
- Jupiter (11.86 years)
- Saturn (29.37 years)
- Uranus (84.1 years)
- Neptune (164.9 years)
As for the excluded Pluto, it takes 248.6 years to orbit the sun one complete revolution.
Note that the period of rotation of the planets around the sun depends on the distance from the sun. The farther away the planet is, the longer it will have to travel to form a full circle, and so it will take longer.
Venus has a peculiarity between planets, as the time it takes to orbit the sun (224.7 days) is less than the time it needs to revolve around itself (243 days), this means that a day on Venus is longer than a year.
On Mars, it lasts roughly a year on Earth. And on Neptune, the year lasts 164.9 years.