Introduction
The Solar System is a fascinating place full of wonders from the many planets and their moons, to the bright stars and distant galaxies. It is an incredible place to explore and learn about, and with every passing day we are learning more and more about the many planets and objects that comprise our Solar System. This article will focus on zooming in on the planets of our Solar System, providing a more detailed look at each of the 8 planets, their formation, and what makes them unique.
Formation of the Solar System
Before focusing on the individual planets, it’s important to first consider how our Solar System was formed. It all began about 4.6 billion years ago with a huge cloud of dust and gas called the solar nebula. This cloud was drawn inwards by its own gravity and began to spin, creating the shape of a spinning disc. This spinning disc began to flatten and condense as gravity took effect, with regions at the center becoming much denser than the outer regions. This caused the nebula to ignite, forming a protostar at its center—our Sun.
The material that was spinning around the Sun would then start to coalesce and form the planets, moons, asteroids, and comets of our Solar System. This material came from the same spinning disk—the protoplanetary disk—and was made up of both gasses and the rocky material that the planets and moons are made from. As different materials were pulled closer to the Sun, it would heat them up and cause them to body to melt and form clumps together. Planets, asteroids, and comets would then continue to form from this process of clumping together of materials. This is how our Solar System formed, now let’s dive into the individual planets.
Mercury
The planet closest to the Sun is Mercury. This tiny planet has a radius of 1515 miles and a mass of about 0.055 Earth masses. Mercury is quite different than Earth in that it is a vapor-covered, pockmarked planet with virtually no atmosphere. This means that sun radiation is much higher on Mercury than it is on Earth. The surface of Mercury has many craters and faults created during a bombardment of asteroids and comets during the formation of the Solar System.
Mercury also experiences extreme temperatures, with one side of the planet facing the Sun, while the other is away from the Sun. The temperature on the side of the planet facing the Sun can reach approximately 800 degrees Fahrenheit. In contrast, the temperature on the side away from the Sun can get as cold as -297 degrees Fahrenheit. This extreme temperature difference is likely the cause for the wrinkled nature of the planet, due to dramatic changes in the planet’s volume as temperatures rise and fall.
Venus
The second planet from the Sun is Venus. This planet is twice the size of Earth and has a mass of about 0.815 Earth masses. Venus is covered in a thick, sulfuric acid cloud that completely obscures the surface of the planet. This is likely why Venus is unable to hold onto heat, as the cloud prevents radiation from the Sun to reach the surface.
The lack of heat on Venus makes it one of the coldest planets in the Solar System, with average temperatures that hover around 464 degrees Fahrenheit. It is one of the hottest planets in the Solar System due to the amount of greenhouse gases that are abundant on the planet.
The surface of Venus is heavily scarred due to the bombardment of asteroids and comets that came during the formation of the Solar System. There are several large impact basins and numerous volcanoes on the surface of Venus, some of which are still active today.
Earth
Earth is the third planet from the Sun and is the only one known to support life. It is about twice the size of Mercury and has a mass of about 1.00 Earth masses. Earth has a unique atmosphere which allows for the existence of oxygen and other gases, which create a comfortable temperature range for life. The atmosphere also serves to protect against harmful radiation from the Sun.
The surface of Earth is mostly covered by water, with 71 percent of the surface being taken up by the oceans. The surface of Earth also features various types of features, from mountains, canyons and valleys to deserts, icecaps, and peninsulas. These features were created from the movement of tectonic plates over millions of years, as the planet’s surface slowly shifted and changed shape.
Mars
Mars is the fourth planet from the Sun and it has a radius of around 2550 miles and a mass of about 0.107 Earth masses. Mars has a much thinner atmosphere than Earth, and thus temperatures on Mars are much colder than on Earth. Average surface temperatures on Mars range from around -195 degrees Fahrenheit in the winter to around 70 degrees Fahrenheit during the summer.
The surface of Mars is much different than that of Earth. Mars has no oceans, and its surface is covered in vast, barren plains. The planet is also dotted with numerous impact craters, mountains, ridges, and volcanoes from its history of asteroid impacts and tectonic activity. The planet is believed to have once been much wetter, but any signs of running surface water have long since disappeared.
Jupiter
Jupiter is the fifth planet from the Sun and is the largest planet in the Solar System. This planet has a radius of around 43,440 miles and a mass of about 318 Earth masses. Jupiter is composed mostly of hydrogen and helium, forming a gas giant similar to a star that never quite managed to ignite. The atmosphere is made up of clouds of ammonia and water, giving Jupiter a recognizable striped pattern.
The surface of Jupiter is very dynamic and active, with massive storm systems and winds that can reach speeds of over 300 mph. Jupiter has a powerful magnetosphere generated by the high concentrations of hydrogen and helium in the atmosphere, creating a protective bubble around the planet that shields it from radiation from the Sun.
Saturn
Saturn is the sixth planet from the Sun and is the second-largest planet in the Solar System. This planet has a radius of around 36,400 miles and a mass of about 95.2 Earth masses.
Saturn is a gas giant and is composed mostly of hydrogen and helium like Jupiter, but also contains some methane and ammonia. The atmosphere of Saturn is composed of clouds of hydrogen, along with gaseous ammonia and methane, producing colorful yellow, brown, and orange bands in the atmosphere. The clouds in the atmosphere of Saturn are what make it look like it has rings—massive rings of dust and ice which are composed of many individual particles orbiting the planet.
The surface of Saturn has no known features, as the clouds of the atmosphere obscure any view of the planet below. Saturn is believed to have a rocky core much like Jupiter, but the exact composition and structure of the planet remain mostly a mystery.
Uranus
Uranus is the seventh planet from the Sun and is the third-largest planet in the Solar System. This planet has a radius of around 31,760 miles and a mass of about 14.536 Earth masses. Uranus is a gas giant composed mostly of hydrogen and helium, but also contains some methane, ammonia, and water.
Similar to Saturn, the clouds of Uranus are what gives the planet its unique blue color. The blue color is likely caused by the methane in the atmosphere, reflecting sunlight in a way that creates the blue hue. There are also white bands that run along the planet, which are caused by changing wind speeds and areas of turbulence in the atmosphere.
The surface of Uranus is also obscured, and no features have been seen on the planet. The temperature on Uranus is much colder than on the other planets, with an average of about -371 degrees Fahrenheit.
Neptune
Neptune is the eighth and farthest planet from the Sun in our Solar System. This planet has a radius of around 30,200 miles and a mass of about 17.147 Earth masses.
Neptune is a gas giant and is composed mostly of hydrogen and helium, but also contains some methane, ammonia, and water vapor. The atmosphere of Neptune is quite dynamic, with plenty of changes in temperature, wind speed and pressure. The planet displays a pattern of stripes caused by winds in the atmosphere. The ‘Great Dark Spot’ is a feature in the atmosphere which is believed to be caused by a pool of liquid methane in the atmosphere.
The surface of Neptune is also obscured by its atmosphere and no known features have been seen. The temperature on Neptune is much colder than on the other planets, with an average of about -360 degrees Fahrenheit.
Conclusion
As you can see, the planets of our Solar System are quite amazing, each with their own unique features and characteristics that set them apart. From the extreme temperatures of Mercury and Venus to the thick atmospheres and powerful storms of Jupiter and Saturn, there is always something new to explore. From our Solar System, we can learn a great deal about our universe and all the wonders it has to offer.