Mars Notes (v.2023) PDF

Mars Mars – the fourth planet from the Sun – is a dusty, cold, desert world with a very thin atmosphere. This dynamic planet has seasons, polar ice caps, extinct volcanoes, canyons, and weather. Mars is one of the most explored bodies in our solar system, and it's the only planet where we've sent...

Mars Mars – the fourth planet from the Sun – is a dusty, cold, desert world with a very thin atmosphere. This dynamic planet has seasons, polar ice caps, extinct volcanoes, canyons, and weather. 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 missions have found lots of evidence that Mars was much wetter and warmer, with a thicker atmosphere, billions of years ago. Mars was named by the Romans for their god of war because its reddish color was similar of blood. Even today, it is frequently called the "Red Planet" because iron minerals in the Martian dirt oxidize, or rust, causing the surface to look red. It is red because the soil looks like rusty iron. Potential for Life Scientists don't expect to find living things currently developing on Mars. Instead, they're looking for signs of life that existed long ago, when Mars was warmer and covered with water. Orbit and Rotation As Mars orbits the Sun, it completes one rotation every 24.6 hours, which is very similar to one day on Earth (23.9 hours). Martian days are called sols – short for "solar day." A year on Mars lasts 669.6 sols, which is the same as 687 Earth days. Like Earth, Mars has distinct seasons, but they last longer than seasons here on Earth since Mars takes longer to orbit the Sun (because it's farther away). And while here on Earth the seasons are evenly spread over the year, lasting 3 months (or one quarter of a year), on Mars the seasons vary in length because of Mars' elliptical, egg-shaped orbit around the Sun. Spring in the northern hemisphere (autumn in the southern) is the longest season at 194 sols. Autumn in the northern hemisphere (spring in the southern) is the shortest at 142 days. Northern winter/southern summer is 154 sols, and northern summer/southern winter is 178 sols. Moons Mars has two small moons, Phobos and Deimos (please click the links of these 2 moons), that may be captured asteroids. They're potato-shaped because they have too little mass for gravity to make them spherical. The moons get their names from the horses that pulled the chariot of the Greek god of war, Ares. Phobos, the innermost and larger moon, is heavily cratered, with deep grooves on its surface. It is slowly moving towards Mars and will crash into the planet or break apart in about 50 million years. Photo from NASA  Deimos is about half as big as Phobos and orbits two and a half times farther away from Mars. Oddly-shaped Deimos is covered in loose dirt that often fills the craters on its surface, making it appear smoother than pockmarked Phobos. Photo from NASA Formation When the solar system settled into its current layout about 4.5 billion years ago, Mars formed when gravity pulled swirling gas and dust in to become the fourth planet from the Sun. Mars is about half the size of Earth, and like its fellow terrestrial planets, it has a central core, a rocky mantle, and a solid crust. Surface Mars is home to the largest volcano in the solar system named Olympus Mons. It's three times taller than Earth's Mt. Everest. Mars appears to have had a watery past, with ancient river valley networks, deltas, and lakebeds, as well as rocks and minerals on the surface that could only have formed in liquid water. Some features suggest that Mars experienced huge floods about 3.5 billion years ago. There is water on Mars today, but the Martian atmosphere is too thin for liquid water to exist for long on the surface. Today, water on Mars is found in the form of water-ice just under the surface in the polar regions as well as in briny (salty) water, which seasonally flows down some hillsides and crater walls. Atmosphere Mars has a thin atmosphere made up mostly of carbon dioxide, argon, nitrogen, and a small amount of oxygen and water vapor. The temperature on Mars can be as high as 20 degrees Celsius or as low as about -153 degrees Celsius. And because the atmosphere is so thin, heat from the Sun easily escapes this planet. If you were to stand on the surface of Mars on the equator at noon, it would feel like spring at your feet (24 degrees Celsius) and winter at your head (0 degrees Celsius). Occasionally, winds on Mars are strong enough to create dust storms that cover much of the planet. After such storms, it can be months before all of the dust settles. Gravity on Mars A rock dropped on Mars would fall slower than a rock dropped on Earth. Things weigh less on Mars than they weigh on Earth. A person who weighs 100 pounds on Earth would only weigh about 38 pounds on Mars because of less gravity. Mars Exploration Mars is the only planet inhabited entirely by robots. It has 2 surface rovers, 1 helicopter, and 8 spacecraft in orbit. NASA has used both orbiting spacecraft (spacecraft that fly around the planet) and robots on the ground to learn more about Mars. In 1965, Mariner 4 was the first NASA spacecraft to get a close look at the planet. In 1976, Viking 1 and Viking 2 were the first NASA spacecraft to land on Mars. They took pictures and explored the ground. Since then, more spacecraft have flown near or landed on Mars. NASA’s Spirit and Opportunity rovers landed on Mars in January 2004. They found proof that water once flowed on Mars. Living things need water to survive. So, any sign of water on Mars would mean that there could be or could have been, life on the planet. Many missions have landed successfully on different areas of Mars. Photo from: NASA On the ground: Over the years, we’ve sent four robotic vehicles, or rovers, to learn more about Mars. And, NASA’s fifth Mars rover, Perseverance (please click this link), landed on the Red Planet in February 2021. Mission duration: ongoing Rovers have wheels and specialize in moving around. They land on the surface of Mars and drive around to different spots. Rovers are important because they help scientists in their search to understand what different parts of the planet are made of. Mars is made up of lots of different types of rocks, and each rock is made up of a mixture of chemicals. A rover can drive around to different areas, studying the different chemicals in each rock. These chemicals can tell scientists something about the environments that changed that rock over time. Please click this link below to find it more about each rover. The Mars Rovers | NASA Space Place – NASA Science for Kids NASA's InSight, a stationary lander, is probing the interior of Mars from a site on a flat smooth plain called Elysium Planitia. In the air: The Ingenuity helicopter (please click this link) Mars Helicopter flew to Mars attached to the belly of Perseverance. On April 19, 2021, Ingenuity became the first aircraft in history to make a powered, controlled flight on another planet. In orbit: NASA has three spacecraft in orbit: 1. Mars Reconnaissance Orbiter (MRO) NASA's Mars Reconnaissance Orbiter blasted off from Cape Canaveral in 2005, on a search for evidence that water persisted on the surface of Mars for long periods of time. Mission Duration: 2006 - ongoing 2. Mars Odyssey The 2001 Mars Odyssey mission is NASA's longest-lasting spacecraft at Mars. The spacecraft launched on April 7, 2001, and arrived at Mars on October 24, 2001. To find out what the planet is made of, detect water and shallow buried ice and study the radiation environment. Its mission includes making the first global map of the amount and distribution of many chemical elements and minerals that make up the Martian surface. Odyssey has found ice deposits that could be used by future astronauts. It’s studied radiation that could harm those same astronauts. And it’s scouted potential landing sites for missions to come. Mission Duration: 2001 - ongoing 3. MAVEN (Mars Atmospheric and Volatile EvolutioN) MAVEN is obtaining critical measurements of the Martian atmosphere to help understand dramatic climate change on the red planet over its history. Mission Duration: 2013 - ongoing Please click this link NASA Mars Exploration to see the pictures of the orbiters. Sources: https://science.nasa.gov/mars/ https://science.nasa.gov/mars/facts/ https://science.nasa.gov/mars/moons/ https://science.nasa.gov/mars/exploration/ https://www.nasa.gov/learning-resources/for-kids-and-students/what-is-mars-grades-k-4/ https://spaceplace.nasa.gov/all-about-mars/en/ https://spaceplace.nasa.gov/mars-rovers/en/