Our Family Solar System (In Full Detail)
- 3 days ago
- 17 min read
Updated: 2 days ago
How well do we know our planet's family, the Solar System? Who are our neighbors, and what kind of system are we a part of? As a galaxy explorer, introducing you to our Solar System is my top priority. Let's learn more about our place in this universe!
Contents
What is the Solar System?
The solar system is a system consisting of an average-sized star at its center, 8 planets, 5 dwarf planets, and 290 natural satellites. Half of these 8 planets are terrestrial, and the other half are gas planets. All planets and other celestial bodies orbit the Sun, which is at the center and subject to its gravitational pull.
The solar system also contains an asteroid belt composed of rock and metal that separates the terrestrial and gaseous planets, and the Kuiper Belt, a ring of depressions mostly made of ice, in the outer layers of the system. Beyond this belt lies the hypothetical Oort cloud. The Oort cloud is a massive layer of ice and other small celestial bodies that encircles the solar system as a sphere.
How did the solar system form?
The solar system formed within a structure composed of gas, dust, and plasma known as the interstellar cloud. The solar system formed in one of these cloud types: a large-scale molecular cloud rich in hydrogen and containing helium and other heavy elements. This cloud is thought to be the remnant of a primordial supernova, formed approximately 4.6 billion years before the solar system. The hydrogen richness of the cloud stimulated star formation . Materials that had begun to collapse towards the center due to gravity before the sun formed gradually began to rotate faster, forming a disk around it.
This stage, where the foundations of the solar system are laid, is called the "presolar nebula." As time passes, a proto-star, or baby star, forms at the center. During this time, due to gravity , the material in the nebula is drawn into the proto-star's orbit, and the molecular cloud begins to flatten. When the hydrogen atoms in the core of the Sun, which is in the proto-star stage, become sufficiently hot, nuclear fusion begins. As a result of fusion, the star produces helium and energy. Millions of years later, when the central mass of the baby Sun reaches a sufficient level, it creates a bidirectional jet stream and completes its formation. The material around the Sun is no longer drawn in, and the proto-planetary disk moves away from the star.
While the Sun was still a protostar, gas giants formed in its protoplanetary disk. Jupiter and Saturn were the first to form from these gas giants, followed by Neptune and Uranus. Because these early planets gained their own gravity, they began to devour and grow, even though Neptune and Uranus are thought to remain relatively small. As Jupiter grew larger over time, it began to move away from the center, but Saturn was drawn towards it, entering into a 3:2 resonance with Jupiter. This orbital resonance caused the two planets to exert mutual gravitational influence three times in every two complete orbits when they were closest to each other.
The result of the orbital resonance of Jupiter and Saturn. Mercury, Venus, Earth, and Mars formed in Jupiter's inner orbit (red circle). (BYA = billions of years ago) Source
As Jupiter moved away from the center, it swallowed most of the gas in its path and carried rock fragments away from the Sun. This initiated the formation of terrestrial planets, including the Moon. However , Jupiter's descent disrupted Saturn's orbit, and Neptune shifted into Uranus's outer orbit. This orbital migration caused the scattering of rock and ice fragments surrounding the system at the time, and led to countless collisions in the inner core where the terrestrial planets formed. We call this event the Late Heavy Bombardment. After the bombardment, which lasted between 20 and 200 million years, the solar system stabilized and completed its formation.
How old is the solar system?
Scientists have measured the age of the Solar System to be 4.568 billion years .
Who deciphered the logic of the solar system?
The Greek philosopher Philolaus was the first to argue that the Sun was the center of the universe, around 400 BC. Another person who championed this view in more recent times was the Greek astronomer Aristarchus of Samos. However, there is one well-known figure who generally holds this view: Nicolaus Copernicus.
In the 1500s, mathematician and astronomer Nicolaus Copernicus revived the model of the solar system. Compared to the present day, geocentrism was prevalent in medieval Europe. In short, it was believed that the Earth was at the center of the universe. However, in the 16th century , Copernicus reintroduced the forgotten heliocentric model, arguing that the other planets revolved around the Sun. In fact, in his book De Revolutionibus Orbium Coelestium (On the Revolutions of the Celestial Spheres), published in 1543, he states, "The planets revolve around the Sun in a perfect circular motion," and "The Earth is not larger than the Sun."
Who discovered the Solar System?
During the Renaissance, the famous astronomer Galileo Galilei discovered the Solar System with a telescope he built himself. In 1608, the appearance of a "binoculars" in the Netherlands that showed objects more closely piqued Galileo's interest, and he quickly figured out how it worked and built his own improved version. In 1609, Galileo became the first person to record celestial observations using the first version of the telescope. His observations of Venus, the brightest celestial object in the sky, revealed that Venus, like the Moon, has phases. As a result, he proved that Earth and other planets revolve around the Sun, thus discovering the Solar System.
Galileo's observations of the Moon, the moons around Jupiter, sunspots, and his reports of the countless individual stars that make up the Milky Way Galaxy also ignited the birth of modern astronomy.
In which galaxy is the Solar System located?
Now, let's address the question, "Where is the Solar System?" The Solar System is part of the Milky Way Galaxy, which belongs to the barred spiral galaxy class. Located in one of the spiral arms, the Solar System is approximately 27,000 light-years from the center of the galaxy.
How was it discovered that the Solar System is in the Milky Way Galaxy?
Galileo published his observations from 1609 in a small book called "Sidereus Nuncius" in March 1610. In the book, he wrote, "This telescope has enabled me to discover a great number of fixed stars never before seen, more than ten times the number of those naturally visible." This proved that the Solar System is part of a larger structure.
The first diagram of the Milky Way was made by William Herschel. Herschel was the court astronomer of King George III. The king commissioned him to build telescopes, including a 12-meter-long telescope with a 121 cm mirror. In the 1780s, Herschel used this telescope to create the first systematic map of the Milky Way. And yes, he counted the stars individually while creating the diagram.
In 1918, young astronomer Harlow Shapley discovered that clusters were centered around the constellation Sagittarius and formed a halo around the Milky Way. Using this data, Shapley not only located the center of our galaxy but also demonstrated that the Milky Way is very large. His observations also placed our Solar System far from the center of the galaxy . Given the size of our galaxy, Shapley emphasized that spiral nebulae, like globular clusters, are also part of the Milky Way.
In the 1920s, while using the 30-meter Hooker telescope at the Mount Wilson Observatory in California, Edwin Hubble proved that the Milky Way was not the entire universe , but part of a vast sea of island universes.
The birth of radio astronomy in the 1930s revealed that the galaxy is filled not only with dust, but also with an enormous amount of cold, neutral hydrogen gas. Most of the time, a hydrogen atom's proton and electron spin in the same direction. But sometimes the electrons spin in the opposite direction. For any given hydrogen atom, this happens only once every 100 million years. When this happens, energy is emitted at a wavelength of 21 cm⁻¹. These waves pass through dust clouds that obscure visible light, which has a much shorter wavelength. When astronomers first detected the 21 cm⁻¹ radiation in 1951, they began looking through these clouds to create a more comprehensive picture of the Milky Way.
Over the past 70 years, a picture of a massive galaxy with four main spiral arms has emerged. It was discovered that our solar system lies along the Orion Spur, a smaller arm situated between the Perseus and Sagittarius arms. In recent years, astronomers have discovered that the central bulge of our galaxy has a bar-like structure.
How many planets are there in the Solar System?
Although most of us think there are nine planets in our system, there are officially eight planets in the Solar System: Mercury, Venus, Earth, Mars, Jupiter, Saturn, Uranus, and Neptune. All of these planets orbit the Sun in specific paths and are all important parts of the system.
Dwarf Planets in the Solar System
The International Astronomical Union (IAU) states that there are five dwarf planets in the Solar System: Pluto, Ceres, Eris, Haumea, and Makemake.
Planets in the Solar System and Their Characteristics
The order of the Solar System is briefly as follows:
Mercury
Venus
Earth
Anthem
Jupiter
Saturn
Uranus
Neptune
Pluto (Dwarf planet)
Now that we've learned about our neighbors with whom we share the same star, let's give some brief information about the characteristics of the planets in our Solar System.
Mercury
Mercury, the planet closest to the Sun, is a terrestrial planet with a very hot silicate layer. Due to its proximity to the Sun, it also completes a full orbit the fastest in the system. It has a relatively weak exosphere and a rather eccentric orbit compared to other planets in the system. It is relatively small. The large difference in temperature between day and night is due to its very slow rotation on its axis and the absence of an atmosphere.
Characteristics of Mercury:
Diameter: 4,879.4 km
Volume: 0.056 Earth
Mass: 0.055 Earth
Average Temperature: 167°C
Daytime Temperature: Maximum 427°C
Nighttime Temperature: Maximum -180°C
Gravitational force: 3.7 m/s²
Aphelion: 69.82 million km
Perihelion: 46 million km
Rotation Speed around its own axis: 10.83 km/s
Complete Rotation Time Around Its Own Axis: 58 days 16 hours
Orbital Speed: 47.87 km/s
Full Orbit Period: 87.97 days
Axial Tilt: 0°
Number of satellites: 0
Year of Discovery: 3000 BC
Venus
Venus, the second planet in the solar system, is also the hottest. This is due to its atmosphere, which consists of 96.5% carbon dioxide, 3.5% nitrogen, sulfur dioxide, and other gases. Furthermore, with approximately 1,500 active volcanoes, the greenhouse effect on Venus doesn't seem likely to decrease anytime soon.
Characteristics of Venus:
Diameter: 12,103.6 km
Volume: 0.857 Earth
Mass: 0.815 Earth
Average Temperature: 464°C
Gravitational force: 8.87 m/s²
Aphelion: 108.94 million km
Perihelion: 107.48 million km
Rotation speed around its own axis: 6.52 km/h
Complete Rotation Time Around Its Own Axis: 243 days 26 minutes
Orbital Speed: 35.02 km/s
Full Orbit Period: 224.7 days
Axial Tilt: 177°
Number of satellites: 0
Year of Discovery: 1610
Earth
Now let's talk about this wonderful terrestrial planet we live on, the third in our solar system. Earth is the only planet in this vast universe that has proven – at least to us – the existence of life. Its atmosphere, composed of 78% nitrogen, 21% oxygen, 0.9% argon, and 0.1% other gases, protects the planet and us. It also has a strong magnetic field that can easily shield it from radiation from the Sun, unlike the other terrestrial planets, Mercury, Venus, and Mars.
Characteristics of the Earth:
Diameter: 12,742 km
Volume: 1.083 × 10^12 km3
Mass: 5.9721 × 10^24 kg
Average Temperature: 15°C
Gravitational force: 9.807 m/s²
Aphelion: 152,097,701 km
Perihelion: 147,098,450 km
Rotation speed around its own axis: 1,574 km/h
Complete Rotation Time Around Its Own Axis: 23 hours 56 minutes
Orbital Speed: 29.78 km/s
Full Orbit Period: 365.256365 days
Axial Tilt: 23°
Number of satellites: 1
Year of Discovery: 300 BC (as a planet)
Which planet is closest to Earth?
Mercury is the closest planet to Earth in terms of average distance. How is that possible? How can Venus, which is orbiting very close to Earth, be further away than Mercury, which is in a subset of the planet's orbit? The answer is actually simple: the reason Mercury is closer to Earth is... This is due to its orbit being shorter compared to Venus. On the other hand, when Venus and Earth are closest to each other, the distance between them is approximately 77.3 million km, and Venus temporarily regains the title of the closest planet to Earth.
Planets visible from Earth
The brightest planets visible in the sky are located in the southeast, south, and southwest directions.
Today, in a place with less light pollution , you can see Mercury, Venus, Mars, Jupiter, and Saturn—the brightest planets in our solar system—with the naked eye from Earth.
Anthem
Mars, also known as the Red Planet, is the fourth planet in the Solar System. Mars' atmosphere consists of 95% carbon dioxide, 3% nitrogen, 1.6% argon, and a high percentage of dust along with oxygen, carbon monoxide, water, methane, and other gases. We call Mars the "Red Planet" because of the iron oxide, or rust, in its soil. The high percentage of iron in Mars' soil and rocks explains how Mars became rusty. It turns out that 3.5 billion years ago, Mars had an ocean. Over time, its magnetic field weakened, and it was exposed to ultraviolet light, causing Mars to dry out and superoxidize with the iron on its surface. This transformed it into a rusty red planet.
Characteristics of Mars:
Diameter: 6,779 km
Volume: 0.151 Earth
Mass: 0.107 Earth
Average Temperature: -65°C
Daytime Temperature: 22°C
Night Temperature: -99°C
Gravitational force: 3,720.76 m/s²
Aphelion: 249,261,000 km
Perihelion: 206,650,000 km
Rotation speed around its own axis: 866 km/h
Complete Rotation Time Around Its Own Axis: 24 hours 36 minutes
Orbital Speed: 24,077 km/s
Full Orbit Period: 686.93 days
Axial Tilt: 25°
Number of satellites: 2
Year of Discovery: 1610
Jupiter
Jupiter, the fifth planet in the Solar System and a gas giant that played a major role in the formation of terrestrial planets, is the largest planet in our system. Composed of gas, liquid, and metallic hydrogen and helium from its outer layers inwards, with its outermost atmosphere being 90% hydrogen and 10% helium, this enormous gas giant is the largest planet in our system. Because it is composed of the same elements as the Sun and its mass is not large enough to initiate thermonuclear fusion, some sources label Jupiter as a "failed star." Also, although not widely known, Jupiter, like Saturn, has rings, but they are not very impressive.
Characteristics of Jupiter:
Diameter: 139,820 km
Volume: 1321.33 Earth
Mass: 317.83 kg Earth
Average Temperature: -110°C
Gravitational force: 25.92 m/s²
Aphelion: 817 million km
Perihelion: 741 million km
Rotation Speed around its own axis: 45,558 km/h
Complete Rotation Time Around Its Own Axis: 9 hours 55 minutes
Orbital Speed: 13.07 km/s
Full Orbit Period: 11.86 years
Axial Tilt: 3°
Number of satellites: 95
Year of Discovery: January 7, 1610
Saturn
Saturn, the sixth planet in the Solar System, is the second largest. We recognize Saturn by its enormous rings. These rings, approximately 282,000 km long and about 1 km thick, consist of layers D, C, B, A, F, G, and E from the inside out. They contain billions of pieces of ice, dust, and rock. After Jupiter, Saturn is the oldest planet in the Solar System.
Characteristics of Saturn:
Diameter: 116,464 km
Volume: 763.59 Earth
Mass: 95.16 Earth
Average Temperature: -140°C
Day Temperature: -170°C
Night Temperature: -280°C
Gravitational force: 11.19 m/s²
Aphelion: 1,514.50 million km
Perihelion: 1,352.55 million km
Rotation Speed around its own axis: 36,840 km/h
Complete Rotation Time Around Its Own Axis: 10 hours 33 minutes
Orbital Speed: 9.69 km/s
Full Orbit Period: 29.42 years
Axial Tilt: 27°
Number of satellites: 146
Year of Discovery: 1610
Uranus
Uranus, the seventh planet in our solar system, is an ice giant. Its crust, above its core, consists of liquids of water, methane, and ammonia. Its atmosphere is composed of 83% hydrogen, 15% helium, 2% methane, and other elements. Uranus is the coldest planet in the solar system. It is also the only planet to orbit the Sun sideways with a 98-degree axial tilt. This tilt is thought to be caused by a collision between an Earth-sized protoplanet and Uranus. It also has 13 rings.
Characteristics of Saturn:
Diameter: 50,724 km
Volume: 63.08 Earth
Mass: 14.54 Earth
Average Temperature: -195°C
Day Temperature: -197°C
Night Temperature: -224°C
Gravitational force: 9.01 m/s²
Aphelion: 3 trillion km
Perihelion: 2.7 trillion km
Rotation Speed around its own axis: 14,794 km/h
Complete Rotation Time Around Its Own Axis: 17 hours 14 minutes
Orbital Speed: 6.81 km/s
Full Orbital Period: 83.75 years
Axial Tilt: 98°
Number of satellites: 27
Year of Discovery: March 13 1781
Neptune
Neptune, the second ice giant in the solar system, is in the outermost orbit. A layer of ice, methane, and ammonia surrounds its core. Its atmosphere consists of 80% hydrogen, 19% helium, and methane, and it has five main rings.
Characteristics of Neptune:
Diameter: 49,244 km
Volume: 57.74 Earth
Mass: 17.15 Earth
Average Temperature: -200°C
Day Temperature: -201°C
Night Temperature: -223°C
Gravitational force: 11.27 m/s²
Aphelion: 4.55 trillion km
Perihelion: 4.47 trillion km
Rotation Speed around its own axis: 9,719 km/h
Full Rotation Time Around Its Own Axis: 16 hours
Orbital Speed: 5.43 km/s
Full Orbital Period: 163.72 years
Axial Tilt: 28°
Number of satellites: 14
Year of Discovery: September 23 1846
Pluto
I couldn't bring myself to ignore Pluto, the tiny planet in our solar system. Pluto was actually considered a planet from 1930 to 2006 , and our solar system had nine planets. However, in 2006, the International Astronomical Union (IAU) introduced three rules for a celestial body to be classified as a planet:
A planet must be round.
A planet must orbit a star.
A planet must have cleared the area around its orbit.
Pluto actually passes the first two tests; it's round and orbits the Sun. However , because Pluto is so small in mass, it's not gravitationally dominant in its orbit around the Sun. Pluto has only 0.007 times the mass of the other bodies in its orbit. In contrast, Earth has 1.7 million times the mass of the other bodies in its orbit. Therefore, Pluto is not a planet, but a dwarf planet.
On the other hand, Pluto's atmosphere is mostly composed of nitrogen, methane, and carbon monoxide. It consists of 70% rock and 30% icy water. Its orbit is eccentric compared to other planets. Pluto also has a moon called Charon, which is very close in mass to Pluto itself. Pluto and Charon are gravitationally locked, meaning they always see the same side of each other.
Characteristics of Pluto:
Diameter: 2,366.6 km
Volume: 0.0065 Earth
Mass: 0.0022 Earth
Average Temperature: -225°C
Day Temperature: -222°C
Night Temperature: -242°C
Gravitational force: 0.62 m/s²
Aphelion: 7.304 trillion km
Perihelion: 4.434 trillion km
Rotation Speed around its own axis: 4,666 km/h
Complete Rotation Time Around Its Own Axis: 153 hours
Orbital Speed: 4.74 km/s
Full Orbital Period: 247.92 years
Axial Tilt: 120°
Number of satellites: 5
Year of Discovery: February 18, 1930
Types of Planets in the Solar System
The planets in the Solar System are divided into two groups: terrestrial and gas planets. This division is due to the orbital resonance of Jupiter and Saturn.
Terrestrial Planets in the Solar System
The four planets closest to the Sun —Mercury, Venus, Earth, and Mars—are terrestrial planets. This group of four is also known as the inner planets because their orbits are close to the Sun. However, the reason these planets are terrestrial is due to Jupiter and Saturn. After these two gas giants began orbiting the Sun, they absorbed gas from their orbits and surrounding areas. As a result, rocky deposits remained, laying the foundation for planets that would form closer to the Sun. Earth is the largest terrestrial planet in the Solar System.
Gas Planets in the Solar System
The gas planets in the solar system are also known as the outer planets: Jupiter, Saturn, Uranus, and Neptune. They are also called outer planets because they are very far from the Sun and have wide orbits. The largest of the gas planets in the Solar System is Jupiter.
The Largest Planet in the Solar System
The largest planet in our system is Jupiter, with a diameter of 69,911 km. Jupiter is 1,120% larger than Earth; you could fit more than 1,300 Earths inside it. The second largest planet is Saturn, with a diameter of 58,232 km, 945% larger than Earth in diameter. You could fit 764 Earths inside Saturn.
Planets in the Solar System, Order of Size
The surface areas of the planets in the Solar System, from largest to smallest:
Jupiter (69,911 km)
Saturn (58,232 km)
Uranus (25,362 km)
Neptune (24,622 km)
Earth (6,371 km)
Venus (6,052 km)
Mars (3,390 km)
Mercury (2,440 km)
The Smallest Planet in the Solar System
Mercury, with a diameter of 4,879.4 km, is the smallest planet in the Solar System. Slightly more than a third the size of Earth, Mercury appears to be shrinking over time. A 2014 study showed that this small planet consists of a single continental plate on top of a cooling iron core, and as the core cools, it solidifies, reducing the planet's volume and causing it to shrink.
The Planets in the Solar System, from smallest to largest.
The planets in the Solar System, from smallest to largest in size, are:
Mercury (2,440 km)
Mars (3,390 km)
Venus (6,052 km)
Earth (6,371 km)
Neptune (24,622 km)
Uranus (25,362 km)
Saturn (58,232 km)
Jupiter (69,911 km)
The Coldest Planet in the Solar System
Uranus is the coldest planet in the solar system, with a temperature of -224°C. Although Neptune is the farthest planet from the Sun, the reason Uranus is so cold is theorized to be due to a massive collision in the past. It is thought that Uranus lost all the energy in its core as a result of this catastrophic collision.
The Planets in the Solar System from Coldest to Hottest
The order of the planets in the Solar System, from coldest to hottest, based on average temperature:
Neptune (-200°C)
Uranus (-195°C)
Saturn (-140°C)
Jupiter (-110°C)
Mars (-65°C)
Earth (15°C)
Mercury (167°C)
Venus (464°C)
The Hottest Planet in the Solar System
Venus is the hottest planet in the Solar System. Despite being second only to Mercury in terms of average temperature, Venus's exceptional heat is due to its atmosphere. Venus's atmosphere is so dense in hydrogen that it traps all the heat, creating a very strong greenhouse effect and reducing heat loss almost to zero day and night.
Why is Mercury colder than Venus?
The only reason Mercury doesn't surpass Venus in temperature is because it lacks an atmosphere. There are two reasons for this: its size and its proximity to the Sun. Mercury is the smallest planet in our solar system, and this disadvantage is that it doesn't have enough gravitational pull to hold gases around it. On the other hand, it's the closest planet to the Sun, meaning even if it had enough gravitational pull, the Sun would destroy its atmosphere.
The Planets in the Solar System from Hottest to Coldest
The planets in the Solar System, from hottest to coldest on average, are:
Venus (464°C)
Mercury (167°C)
Earth (15°C)
Mars (-65°C)
Jupiter (-110°C)
Saturn (-140°C)
Uranus (-195°C)
Neptune (-200°C)
The Oldest Planet in the Solar System
Jupiter is the oldest planet in the Solar System. Saturn formed after Jupiter. Uranus and Neptune are known to have formed later.
The Youngest Planet in the Solar System
The youngest planet in the Solar System is one of the terrestrial planets, but it's not known for certain which one. According to a 2013 article, the resonance between Jupiter and Saturn caused numerous proto-terrestrial planets to form in Jupiter's interior over time. The Late Heavy Bombardment is also thought to have played a significant role in this. The impact of these events and the formation and disappearance of proto-planets make it difficult to determine which terrestrial planet formed first.
The fastest orbiting planet around the Sun.
Mercury is the fastest-rotating planet around the Sun. There is only one reason for this: its proximity to the Sun. The closer a planet is to its central star, the more it is affected by gravity, and consequently, the faster it rotates around it. The distance between Mercury and the Sun is 68.761 million km. For comparison, the distance between Earth and the Sun is 148.56 million km.
The rotation order of the planets in the Solar System, from fastest to slowest.
The planets' orbits are listed in descending order of proximity to the Sun, along with their complete orbital periods:
Mercury: 47.87 km/h (87.97 days)
Venus: 35.02 km/h (224.7 days)
Earth: 29.78 km/s (365.256365 days)
Mars: 24.077 km/s (686.93 days)
Jupiter: 13.07 km/h (11.86 years)
Saturn: 9.69 km/h (29.42 years)
Uranus: 6.81 km/h (83.75 years)
Neptune: 5.43 km/h (163.72 years)
The slowest planet orbiting the Sun.
Neptune is the slowest-rotating planet around the Sun because it is 4.4727 billion kilometers away. Or, as a slightly more mind-boggling fact, let's say that the distance between Neptune and the Sun is approximately 352,647 Earths. I hope this has amazed you.
The rotation order of the planets in the Solar System, from slowest to fastest.
The planets' orbits are listed in descending order of proximity to the Sun, from slowest to fastest, along with their complete orbital periods:
Neptune: 5.43 km/h (163.72 years)
Uranus: 6.81 km/h (83.75 years)
Saturn: 9.69 km/h (29.42 years)
Jupiter: 13.07 km/h (11.86 years)
Mars: 24.077 km/s (686.93 days)
Earth: 29.78 km/s (365.256365 days)
Venus: 35.02 km/h (224.7 days)
Mercury: 47.87 km/h (87.97 days)
