Our Sun is a 4.5 billion-year-old star a hot glowing ball of hydrogen and helium at the center of our solar system. The Sun is about 93 million miles (150 million kilometers) from Earth, and without its energy, life as we know it could not exist here on our home planet.
The Sun is the largest object in our solar system. The Sun’s volume would need 1.3 million Earths to fill it. Its gravity holds the solar system together, keeping everything from the biggest planets to the smallest bits of debris in orbit around it. The hottest part of the Sun is its core, where temperatures top 27 million degrees Fahrenheit (15 million degrees Celsius). The Sun’s activity, from its powerful eruptions to the steady stream of charged particles it sends out, influences the nature of space throughout the solar system.
Mercury is the smallest planet in our solar system only slightly larger than Earth's Moon.
Mercury is the planet that orbits the closest to the Sun.
Mercury is the fastest planet in our solar system – traveling through space at nearly 29 miles (47 kilometers) per second. The closer a planet is to the Sun, the faster it travels. Since Mercury is the fastest planet and has the shortest distance to travel around the Sun, it has the shortest year of all the planets in our solar system – 88 days.
It is unlikely that life as we know it could survive on Mercury due to solar radiation, and extreme temperatures.
Venus is the second planet from the Sun and is Earth’s closest planetary neighbor. It’s one of the four inner, terrestrial (or rocky) planets, and it’s often called Earth’s twin because it’s similar in size and density. These are not identical twins, however – there are radical differences between the two worlds.
Venus has a thick, toxic atmosphere filled with carbon dioxide and it’s perpetually shrouded in thick, yellowish clouds of sulfuric acid that trap heat, causing a runaway greenhouse effect. It’s the hottest planet in our solar system, even though Mercury is closer to the Sun. Surface temperatures on Venus are about 900 degrees Fahrenheit (475 degrees Celsius) – hot enough to melt lead. The surface is a rusty color and it’s peppered with intensely crunched mountains and thousands of large volcanoes. Scientists think it’s possible some volcanoes are still active.
Our home planet is the third planet from the Sun, and the only place we know of so far that’s inhabited by living things.
While Earth is only the fifth largest planet in the solar system, it is the only world in our solar system with liquid water on the surface. Just slightly larger 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 at least 1,000 years old. All of the planets, except for Earth, were named after Greek and Roman gods and goddesses. However, the name Earth is a Germanic word, which simply means “the ground.”
The brightest and largest object in our night sky, the Moon makes Earth a more livable planet by moderating our home planet's wobble on its axis, leading to a relatively stable climate. It also causes tides, creating a rhythm that has guided humans for thousands of years. The Moon was likely formed after a Mars-sized body collided with Earth.
Earth's Moon is the fifth largest of the 200+ moons orbiting planets in our solar system.
Earth's only natural satellite is simply called "the Moon" because people didn't know other moons existed until Galileo Galilei discovered four moons orbiting Jupiter in 1610.
Mars is the fourth planet from the Sun a dusty, cold, desert world with a very thin atmosphere. Mars is also a dynamic planet with seasons, polar ice caps, canyons, extinct volcanoes, and evidence that it was even more active in the past.
Mars is one of the most explored bodies in our solar system, and it's the only planet where we've sent rovers to roam the alien landscape.
NASA currently has two rovers (Curiosity and Perseverance), one lander (InSight), and one helicopter (Ingenuity) exploring the surface of Mars.
These robotic explorers have found lots of evidence that Mars was much wetter and warmer, with a thicker atmosphere, billions of years ago.
Jupiter is the fifth planet from our Sun and is, by far, the largest planet in the solar system – more than twice as massive as all the other planets combined. Jupiter's stripes and swirls are actually cold, windy clouds of ammonia and water, floating in an atmosphere of hydrogen and helium. Jupiter’s iconic Great Red Spot is a giant storm bigger than Earth that has raged for hundreds of years.
With a radius of 43,440.7 miles (69,911 kilometers), Jupiter is 11 times wider than Earth. If Earth were the size of a nickel, Jupiter would be about as big as a basketball.
From an average distance of 484 million miles (778 million kilometers), Jupiter is 5.2 astronomical units away from the Sun. One astronomical unit (abbreviated as AU), is the distance from the Sun to Earth. From this distance, it takes Sunlight 43 minutes to travel from the Sun to Jupiter.
Uranus is about four times wider than Earth. If Earth were a large apple, Uranus would be the size of a basketball.
Uranus orbits our Sun, a star, and is the seventh planet from the Sun at a distance of about 1.8 billion miles (2.9 billion kilometers).
Uranus is an ice giant. Most of its mass is a hot, dense fluid of "icy" materials water, methane and ammonia above a small rocky core.
Uranus has an atmosphere made mostly of molecular hydrogen and atomic helium, with a small amount of methane.
Dark, cold, and whipped by supersonic winds, ice giant Neptune is the eighth and most distant planet in our solar system. More than 30 times as far from the Sun as Earth, Neptune is the only planet in our solar system not visible to the naked eye. In 2011 Neptune completed its first 165-year orbit since its discovery in 1846.
Neptune is so far from the Sun that high noon on the big blue planet would seem like dim twilight to us. The warm light we see here on our home planet is roughly 900 times as bright as sunlight on Neptune.
Neptune's environment is not conducive to life as we know it. The temperatures, pressures, and materials that characterize this planet are most likely too extreme and volatile for organisms to adapt to.
Pluto is a dwarf planet in the Kuiper Belt, a donut-shaped region of icy bodies beyond the orbit of Neptune. There may be millions of these icy objects, collectively referred to as Kuiper Belt objects (KBOs) or trans-Neptunian objects (TNOs), in this distant region of our solar system.
Pluto which is smaller than Earth’s Moon has a heart-shaped glacier that’s the size of Texas and Oklahoma. This fascinating world has blue skies, spinning moons, mountains as high as the Rockies, and it snows but the snow is red.
On July 14, 2015, NASA’s New Horizons spacecraft made its historic flight through the Pluto system – providing the first close-up images of Pluto and its moons and collecting other data that has transformed our understanding of these mysterious worlds on the solar system’s outer frontier.