- Distance from the Sun: 57.9 million km - Diameter: 4,879 km - Average Temperature: -173°C to 427°C - Interesting Fact: It is the closest planet to the Sun and has a thin atmosphere. Mercury has a diameter of about 4,879 kilometers (3,032 miles), making it the smallest planet in our solar system. It is approximately 0.38 times the size of Earth. The average distance from the Sun to Mercury is about 58 million kilometers (36 million miles), or 0.39 astronomical units (AU). Mercury is primarily composed of rocky material, with a large iron core that makes up about 70% of its mass. This high metal content gives Mercury a high density, making it the second densest planet after Earth. Mercury's surface is covered in craters, similar to the Moon. It also has extensive plains and scarps, which are cliffs caused by the planet's contraction as its core cooled over time. The largest crater on Mercury is called the Caloris Basin, which is about 1,550 kilometers (960 miles) in diameter. Due to its proximity to the Sun, Mercury experiences extreme temperature variations. During its daytime, temperatures can reach up to 430 degrees Celsius (800 degrees Fahrenheit), while at night, temperatures can drop to -180 degrees Celsius (-290 degrees Fahrenheit). Mercury has a very thin and tenuous atmosphere, known as an exosphere. It consists of atoms and molecules that have been captured from the solar wind and impact from micrometeoroids. The lack of a substantial atmosphere means that Mercury does not have weather or significant air pressure. Mercury has an elliptical orbit around the Sun, with a period of about 88 Earth days. It also has a slow rotation, taking about 59 Earth days to complete one rotation on its axis. This means that a day on Mercury (sunrise to sunrise) is longer than its year (orbit around the Sun). Mercury has a weak magnetic field, about 1% of Earth's magnetic field strength. It is believed to be generated by the planet's molten iron core. Several spacecraft have visited Mercury, including NASA's Mariner 10 in the 1970s and the European Space Agency's (ESA) BepiColombo, which launched in 2018 and is expected to arrive at Mercury in 2025. These missions have provided valuable data and images of Mercury, helping scientists better understand its geology, surface features, and magnetic field.

- Distance from the Sun: 108.2 million km - Diameter: 12,104 km - Average Temperature: 462°C - Interesting Fact: Venus is often called Earth's "sister planet" due to its similar size and composition. Venus is the second planet from the Sun in our solar system and is often referred to as Earth's "sister planet" due to its similar size and composition. Here are some detailed facts about Venus. Venus has a diameter of about 12,104 kilometers (7,521 miles), making it the third smallest planet in our solar system. It is slightly smaller than Earth, with a size approximately 0.95 times that of our planet. Venus is located at an average distance of about 108 million kilometers (67 million miles) from the Sun, or 0.72 astronomical units (AU). Venus has a rocky composition similar to Earth, with a dense iron core and a silicate mantle. However, Venus has a much thicker atmosphere compared to Earth, composed mainly of carbon dioxide (about 96%) with traces of nitrogen and other gases. Venus has a relatively young surface with extensive volcanic activity. It is covered in vast plains, mountains, and thousands of volcanoes, including the massive shield volcano called Maat Mons. The surface also features numerous impact craters, although they are less common compared to other planets. Venus has a thick atmosphere composed mainly of carbon dioxide, which creates a strong greenhouse effect. This leads to extreme surface temperatures, with an average temperature of about 462 degrees Celsius (864 degrees Fahrenheit), making Venus the hottest planet in our solar system. The atmospheric pressure on Venus is about 92 times greater than Earth's, equivalent to the pressure experienced at a depth of about 1 kilometer (0.6 miles) in Earth's oceans. The thick atmosphere and high concentration of greenhouse gases on Venus have led to a runaway greenhouse effect, causing the planet's surface temperature to be hotter than that of Mercury, despite being farther from the Sun. This extreme heating has resulted in a surface devoid of liquid water and a hostile environment for life as we know it. Venus has a slow rotation, taking about 243 Earth days to complete one rotation on its axis. Interestingly, Venus rotates in the opposite direction to most other planets in our solar system, a phenomenon known as retrograde rotation. This means that Venus' day (sunrise to sunrise) is longer than its year (orbit around the Sun). Unlike most other planets in our solar system, Venus does not have any moons or natural satellites. Several spacecraft have been sent to Venus to study its atmosphere and surface. NASA's Mariner 2 was the first successful mission to Venus in 1962, followed by numerous other missions, including the Soviet Union's Venera program and NASA's Magellan mission, which mapped the planet's surface using radar. The European Space Agency's Venus Express mission also provided valuable data on the planet's atmosphere and climate.

- Distance from the Sun: 149.6 million km - Diameter: 12,742 km - Average Temperature: 15°C - Interesting Fact: Earth has a diameter of about 12,742 kilometers (7,918 miles), making it the fifth largest planet in our solar system. It is slightly larger than Venus, with a size approximately 1.05 times that of the "sister planet." Earth is located at an average distance of about 149.6 million kilometers (93 million miles) from the Sun, or 1 astronomical unit (AU). Earth has a layered composition, consisting of a solid inner core, a liquid outer core, a rocky mantle, and a thin outer crust. The core is primarily composed of iron and nickel, while the mantle is made up of silicate rocks. The Earth's atmosphere is predominantly composed of nitrogen (about 78%) and oxygen (about 21%) with traces of other gases. Earth has a diverse range of surface features, including continents, oceans, mountains, valleys, deserts, and polar ice caps. It is the only known planet to have large bodies of liquid water on its surface, covering about 71% of the planet's surface area. Earth has a relatively thin atmosphere compared to Venus. It consists of several layers, including the troposphere (where weather occurs), the stratosphere (containing the ozone layer), the mesosphere, and the thermosphere. The atmosphere helps regulate the planet's temperature and protects it from harmful solar radiation. Earth has a relatively moderate average temperature compared to Venus. The average surface temperature on Earth is about 15 degrees Celsius (59 degrees Fahrenheit), which allows for the existence of liquid water and supports a wide range of life forms. Earth rotates on its axis once every 24 hours, giving us day and night cycles. It takes approximately 365.25 days for Earth to complete one orbit around the Sun, resulting in our calendar year. Earth rotates in the same direction as most other planets in our solar system. Earth has one natural satellite, the Moon. It is the fifth largest moon in the solar system and is approximately 1/6th the size of Earth. The Moon plays a significant role in stabilizing Earth's rotation and tides. Earth has been extensively studied and explored by humans throughout history. However, space missions and satellites have provided valuable data and insights into various aspects of Earth, including weather patterns, climate change, geological features, and biodiversity.

- Distance from the Sun: 227.9 million km - Diameter: 6,779 km - Average Temperature: -87°C to -5°C - Interesting Fact: Mars has a diameter of about 6,779 kilometers (4,212 miles), making it the fourth smallest planet in our solar system. It is approximately half the size of Earth. Mars is located at an average distance of about 227.9 million kilometers (141.6 million miles) from the Sun, or 1.52 astronomical units (AU). Mars has a similar layered composition to Earth, consisting of a solid inner core, a liquid outer core, a rocky mantle, and a thin outer crust. The core is primarily composed of iron and nickel, while the mantle is made up of silicate rocks. The atmosphere on Mars is predominantly carbon dioxide (about 95%) with traces of nitrogen and argon. Mars is known for its distinctive red color due to iron oxide (rust) on its surface. It has a variety of surface features, including mountains, valleys, canyons, and impact craters. The largest volcano in the solar system, Olympus Mons, is located on Mars. The planet also has polar ice caps made up of water ice and frozen carbon dioxide. Mars has a thin atmosphere compared to Earth. It consists mainly of carbon dioxide and has a pressure about 0.6% that of Earth's atmosphere. The thin atmosphere contributes to the extreme temperature variations on Mars, with average surface temperatures around -63 degrees Celsius (-81 degrees Fahrenheit). Mars experiences extreme temperature variations due to its thin atmosphere and distance from the Sun. Average surface temperatures range from -87 degrees Celsius (-125 degrees Fahrenheit) at the poles to -5 degrees Celsius (23 degrees Fahrenheit) at the equator. However, temperatures can reach as high as 20 degrees Celsius (68 degrees Fahrenheit) during summer at the equator. Mars rotates on its axis once every 24.6 hours, which is similar to Earth's rotation period. It takes approximately 687 Earth days (or about 1.88 Earth years) for Mars to complete one orbit around the Sun. Mars has two small natural satellites, Phobos and Deimos. They are irregularly shaped and thought to be captured asteroids. Phobos is the larger of the two moons and orbits very close to Mars, while Deimos orbits further away. Mars has been a major focus of space exploration due to its potential for harboring past or present life and its similarities to Earth. Numerous missions, including rovers and orbiters, have been sent to Mars to study its geology, climate, and search for signs of water and life. Notable missions include the Mars rovers Spirit, Opportunity, and Curiosity, as well as the recent Perseverance rover mission.

- Distance from the Sun: 778.3 million km - Diameter: 139,820 km - Average Temperature: -108°C - Interesting Fact: Jupiter is the largest planet in our solar system, with a diameter of about 139,820 kilometers (86,881 miles). It is more than 11 times the diameter of Earth. Jupiter is located at an average distance of about 778.5 million kilometers (484 million miles) from the Sun, or 5.2 astronomical units (AU). Jupiter is primarily composed of hydrogen and helium, similar to the composition of the Sun. It has a relatively small solid core, surrounded by a thick layer of metallic hydrogen, and an outer layer of molecular hydrogen. The core is estimated to be about 20 times the mass of Earth. Jupiter has a thick atmosphere made up mostly of hydrogen and helium, with traces of other compounds such as methane, ammonia, and water vapor. The atmosphere exhibits distinct cloud bands, with the most prominent being the colorful bands of clouds known as the "Great Red Spot" and the "Great Dark Spot." The Great Red Spot is a persistent high-pressure storm on Jupiter that has been observed for over 300 years. It is a large oval-shaped storm that is about two times the size of Earth. Despite its name, the Great Red Spot has been observed to change in color and size over time. Jupiter has a total of 79 known moons, making it the planet with the most moons in our solar system. The four largest moons, known as the Galilean moons, are Io, Europa, Ganymede, and Callisto. These moons are larger than Pluto and have diverse geological features, including active volcanoes on Io and a subsurface ocean on Europa. Jupiter has a strong magnetic field that is about 20,000 times stronger than Earth's magnetic field. This magnetic field creates intense radiation belts around the planet, known as the Van Allen belts, which can be hazardous to spacecraft and electronics. Jupiter has a faint ring system composed of small particles of dust and rock. The rings are not as prominent or well-defined as Saturn's rings, but they have been observed by spacecraft such as the Galileo probe. The origin of Jupiter's rings is still not fully understood. Jupiter has been visited by several spacecraft, including the Pioneer and Voyager missions in the 1970s, the Galileo orbiter in the 1990s, and the Juno spacecraft, which has been orbiting Jupiter since 2016. These missions have provided valuable data about Jupiter's atmosphere, magnetic field, moons, and other characteristics.

- Distance from the Sun: 1.4 billion km - Diameter: 116,460 km - Average Temperature: -139°C - Interesting Fact: Saturn is the second largest planet in our solar system, with a diameter of about 116,464 kilometers (72,367 miles). It is approximately nine times the size of Earth. Saturn is located at an average distance of about 1.4 billion kilometers (886 million miles) from the Sun, or 9.58 astronomical units (AU). Saturn is primarily composed of hydrogen and helium, similar to Jupiter. It has a solid core made up of rock and metal, surrounded by a thick layer of metallic hydrogen, and an outer layer of molecular hydrogen. The atmosphere of Saturn is mostly hydrogen, with traces of helium and other gases. Saturn is famous for its spectacular ring system, which consists of countless individual rings made up of ice particles and dust. These rings are believed to be remnants of comets, asteroids, or moons that broke apart due to gravitational forces. Saturn's rings are divided into several main sections, with gaps known as divisions between them. Unlike terrestrial planets like Earth, Saturn does not have a solid surface. Its outer layers consist of gas and clouds. However, scientists believe that beneath the thick atmosphere, there may be a solid core made up of rock and metal. Saturn's atmosphere is characterized by its vibrant bands and swirling storms. It has distinct cloud layers, with the uppermost layer composed mainly of ammonia ice crystals. Saturn's atmosphere also features a hexagonal-shaped jet stream at its north pole, known as the "hexagon." Saturn has a relatively fast rotation period, completing one rotation on its axis in about 10.7 hours. This rapid rotation causes Saturn to bulge at its equator and flatten at its poles. It takes approximately 29.5 Earth years for Saturn to complete one orbit around the Sun. Saturn has an extensive system of moons, with over 80 known satellites. The largest moon, Titan, is the second largest moon in the solar system and has a thick atmosphere. Other notable moons include Enceladus, known for its geysers of water vapor, and Mimas, which has a distinctive crater called Herschel. Saturn has been the target of several space missions, including flybys and orbiters. The Cassini-Huygens mission, a joint NASA-ESA project, spent over 13 years studying Saturn and its moons. The mission provided valuable data on Saturn's atmosphere, rings, and moons, including the discovery of potential habitable environments on Enceladus and Titan.

- Distance from the Sun: 2.9 billion km - Diameter: 50,724 km - Average Temperature: -197°C - Interesting Fact: Uranus is unique as it rotates on its side, possibly due to a collision with another celestial object. Neptune is the eighth and farthest planet from the Sun and is classified as an ice giant. It is the fourth largest planet in our solar system, following Jupiter, Saturn, and Uranus. It was discovered using mathematical predictions before being observed directly. Johann Galle and Heinrich d'Arrest discovered Neptune in 1846, based on calculations by Urbain Le Verrier and John Couch Adams. Neptune has a diameter of approximately 49,528 kilometers (30,775 miles) at its equator, making it slightly larger than Uranus. The planet is known for its beautiful deep blue color, which is a result of the methane gas in its atmosphere. Methane absorbs red light, giving Neptune its distinct hue. Neptune takes around 165 Earth years to complete one orbit around the Sun. Since its discovery, it has only completed a little over one orbit. It has a tilt of about 29 degrees, causing it to experience seasonal changes similar to Earth but to a much greater extent. The atmosphere of Neptune is composed mainly of hydrogen and helium, along with traces of methane and other hydrocarbons. This composition gives rise to its hazy appearance. Similar to Uranus, Neptune has a faint and complex ring system, although it is not as prominent. The rings consist of dark particles and debris. Voyager 2 is the only spacecraft that has visited Neptune, making its closest approach to the planet in 1989. It provided detailed information about Neptune's atmosphere, weather, and moons. Neptune has 14 known moons, the largest of which is Triton. Triton has geysers erupting nitrogen gas and is one of the coldest places in the solar system. The planet has a dynamic weather system with strong winds reaching speeds up to 2,100 kilometers per hour (1,300 miles per hour). It has the strongest winds among all the planets in the solar system. Neptune emits more heat than it receives from the Sun, suggesting the presence of an internal heat source, possibly a result of its formation and the ongoing decay of radioactive elements. The temperature on Neptune can be as low as -218 degrees Celsius (-360 degrees Fahrenheit), making it one of the coldest places in our solar system.

- Distance from the Sun: 4.5 billion km - Diameter: 49,244 km - Average Temperature: -201°C - Interesting Fact: Neptune has the strongest winds in the solar system, reaching speeds of over 2,100 km/h. Neptune is the eighth and farthest planet from the Sun and is classified as an ice giant. It is the fourth largest planet in our solar system, following Jupiter, Saturn, and Uranus. It was discovered using mathematical predictions before being observed directly. Johann Galle and Heinrich d'Arrest discovered Neptune in 1846, based on calculations by Urbain Le Verrier and John Couch Adams. Neptune has a diameter of approximately 49,528 kilometers (30,775 miles) at its equator, making it slightly larger than Uranus. The planet is known for its beautiful deep blue color, which is a result of the methane gas in its atmosphere. Methane absorbs red light, giving Neptune its distinct hue. Neptune takes around 165 Earth years to complete one orbit around the Sun. Since its discovery, it has only completed a little over one orbit. It has a tilt of about 29 degrees, causing it to experience seasonal changes similar to Earth but to a much greater extent. The atmosphere of Neptune is composed mainly of hydrogen and helium, along with traces of methane and other hydrocarbons. This composition gives rise to its hazy appearance. Similar to Uranus, Neptune has a faint and complex ring system, although it is not as prominent. The rings consist of dark particles and debris. Voyager 2 is the only spacecraft that has visited Neptune, making its closest approach to the planet in 1989. It provided detailed information about Neptune's atmosphere, weather, and moons. Neptune has 14 known moons, the largest of which is Triton. Triton has geysers erupting nitrogen gas and is one of the coldest places in the solar system. The planet has a dynamic weather system with strong winds reaching speeds up to 2,100 kilometers per hour (1,300 miles per hour). It has the strongest winds among all the planets in the solar system. Neptune emits more heat than it receives from the Sun, suggesting the presence of an internal heat source, possibly a result of its formation and the ongoing decay of radioactive elements. The temperature on Neptune can be as low as -218 degrees Celsius (-360 degrees Fahrenheit), making it one of the coldest places in our solar system.