All About Mars： Astronomy and Space for Kids - FreeSchool

Mars, the fourth planet from the Sun, is the second smallest planet in the solar system, larger only than Mercury. Mars, as one of the five planets visible to the unaided eye, has been known to astronomers since ancient times. It was first recorded by ancient Egyptian astronomers about 4,000 years ago. Mars is often called the Red Planet because of its reddish color. Modern astronomers know that Mars is red because of large amounts of iron oxide, or rust, in the rocks and dust on the surface. But in ancient times, people associated its red color with warfare. That is why Mars was named for the ancient Roman god of war. Mars is a small, rocky planet, the last of the planets of the inner solar system. It is about 141 million miles, or more than 227 million kilometers from the Sun, so it gets less than half as much sunlight as the Earth does. Temperatures at the frozen poles may dip as low as negative 225 degrees Fahrenheit, or negative 143 degrees Celsius, but at the equator, it may get as warm as 95 degrees Fahrenheit, or 35 degrees Celsius. One reason that Mars has such different temperatures is that while it has an atmosphere made mostly of carbon dioxide with tiny amounts of oxygen, it is very thin, preventing it from holding on to much energy from the Sun. Mars has two moons, Phobos and Deimos. Compared to Mars, or even our own moon, they are very, very small. Phobos, the larger of the two, is only 14 miles, or 22 kilometers across at its widest point, which means that you could set it down inside Rhode Island and still have plenty of room to add Deimos. Because they are so small, they don't have enough gravity to pull themselves into spheres, and so Phobos and Deimos are lumpy and irregular. Scientists believe that they may be stray asteroids captured by Mars' larger gravity at some point in the past. Something interesting about Mars is that it is home to the highest known mountain in the solar system, Olympus Mons. Olympus Mons is more than three times higher than the tallest mountain on Earth, Mount Everest. It's so tall that it nearly reaches the top of Mars' thin atmosphere. There is no liquid water on Mars, but there are two polar ice caps made of large amounts of frozen water, and sometimes there are even clouds made of water vapor, much like on Earth. A day on Mars is very close to the same length as a day on Earth, too. Mars rotates in 24 hours and 37 minutes, only about 2.7 percent longer than an Earth day. Because Mars is farther from the Sun, however, Mars takes much longer to travel once around the Sun than the Earth does, almost 687 days. Because Mars is so close to the Earth, and is so similar in some ways, people have wondered for a very long time if life could survive there, or if something lived on Mars already. Back in 1877, astronomers thought they saw canals on the surface of Mars in long straight lines. If there were canals, they thought, someone must have made them. People wrote books and stories about aliens from Mars, and they called them Martians. Modern astronomers have not found any signs that anyone or anything has ever lived on Mars. If there was ever life on Mars, it was probably only small, simple kinds of life, like bacteria. Now people wonder if Mars could be made into a good place for humans to live. More than 50 space missions have been sent to or close to Mars to gather more information about this fascinating red planet. There are currently five orbiters circling Mars, and two rovers exploring its surface, all sending data back to Earth. People want to try to go to Mars someday, and it may happen in the next few decades. Until then, there is always more to learn about this exciting planet. I hope you enjoyed learning more about Mars today. Goodbye till next time!