1. What evidence did astronomers have before the Space Age that Mars has wind? 2
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Question
1. What evidence did astronomers have before the Space Age that Mars has wind?
2. What are windstreaks? How do they form?
3. What are yardangs? How do they form?
4. How are dust and sand different? How are each carried by wind?
5. What is a dust devil? How do they form?
6. How fast are typical windspeeds on Mars? How does this compare to Earth?
7. What do the Namibian Desert in South Africa and Mars have in common?
8. How do scientists use the Grand Canyon to understand Mars’s climate?
9. What can scientists learn about Mars by studying the Great Sand Dunes in National Monument Park (Colorado)?
10. Why are Mars-bound rovers and robots tested in the Atacama Desert in Chile?
Explanation / Answer
1. What evidence did astronomers have before the Space Age that Mars has wind?
Ans - The white clouds (usually sparse) were also widely regarded as composed of tiny crystals of water ice, rather like cirrus in our atmosphere. Nearly all white clouds are small, and some sites on the surface have such clouds relatively often. On the Earth Mountain peaks and basins are favored cloud sites, and the same was thought to be the case for Mars. The yellow clouds were widely regarded as clouds of desert dust raised by strong winds. These cloud are often extensive, and sometimes obscure the whole Martian globe for several weeks.
2. What are windstreaks? How do they form?
Ans - Wind streaks are tear-shaped features appearing behind craters, ridges or cliffs. They may appear light colored or dark colored depending on the nature of the subsurface. These features are the result of wind erosion and deposition. Erosion might occur behind some obstacles where strong wind converged to sweep away fine particles, exposing lava plains underneath and resulting in dark streaks. On the other hand, some obstacles might create a wind shadow where wind speeds died down, creating an environment for deposition of suspended particles. Thus, light-colored streaks formed.
3. What are yardangs? How do they form?
Ans - Yardangs form in environments where water is scarce and the prevailing winds are strong, uni-directional, and carry an abrasive sediment load. The wind cuts down low-lying areas into parallel ridges which gradually erode into separate hills that take on the unique shape of a yardang.
4. How are dust and sand different? How are each carried by wind?
Ans - The dust on Mars could have been formed in many different ways. Impacts break up rock to form smaller particles, and they certainly contributed to the Martian dust. Dust can also be formed by wind abrasion, when particles carried by wind chisel away at rocks over time. Landslides will break up particles, as will chemical alteration of rocks exposed at the surface. If there was water on Mars, flowing water can also erode rocks and deposit fine-grained particles elsewhere. Volcanic eruptions can produce ash and dust as well. The Martian dust was probably created by some combination of these processes, and then mixed up over time by dust storms.
5. What is a dust devil? How do they form?
Ans - A dust devil is a strong, well-formed, and relatively long-lived whirlwind, ranging from small to large. The primary vertical motion is upward. Dust devils are usually harmless, but can on rare occasions grow large enough to pose a threat to both people and property. The Red Planet is constantly shaped by aeolian (wind-blown) processes, and in many regions dust devils are a common occurrence. Indeed, recent studies have shown that Martian dust devils, which can reach as high as several miles, play a key atmospheric role in transporting fine particles of dust from the surface, injecting it high into the atmosphere. This “dust cycle” could have implications for the planet’s global climate.
6. How fast are typical windspeeds on Mars? How does this compare to Earth?
Ans - Mars orbits beyond the Earth's trajectory, making it the fourth planet from the sun. Mars has a much thinner atmosphere than Earth, but the Red Planet's lower gravity allows for planet-wide weather phenomena. The winds on Mars can produce dramatic dust storms, with the dust taking months to dissipate. The low gravity of Mars allows for much greater wind speeds at times. Under the right weather conditions, the wind speed on Mars can reach up to 17 to 30 meters per second. The maximum speed of 30 meters per second (60 mph) w can be expected. Mars has some of the most dramatic dust storms of any planet in the solar system. The low gravity on Mars promotes much more powerful dust storms than those seen on Earth. Those on Mars are a vast, planet-wide phenomena. When the dust storms on Mars begin, they can envelope the planet's hemispheres for years at a time, creating a challenge for exploration.
7. What do the Namibian Desert in South Africa and Mars have in common?
Ans - On arid plains of the Namib Desert there are no trees or shrubs in this part of the Namib, only long stretches of sand baking under the merciless sun. This is one of the most extreme environments on Earth, with very little water and temperatures and unrelenting solar radiation that would kill most animals. But hidden under the rocks there is life a thin green-blue layer of cyanobacteria, a type of bacteria that converts the sun’s light into energy. These tiny microbial communities, sometimes known as extremophiles, are one of the pointers in our research into life on other planets like Mars.
8. How do scientists use the Grand Canyon to understand Mars’s climate?
Ans - Dramatic climate cycles on early Mars, triggered by buildup of greenhouse gases, may be the key to understanding how liquid water left its mark on the planet's surface. The long debate of how deep canyons and extensive valley networks like the kinds carved by running water over millions of years on Earth could form on Mars some 3.8 billion years ago, a time many believe the planet was frozen. It is suggested that a glacier-covered early Mars could have experienced long warm periods, lasting up to 10 million years at a time, caused by a thick atmosphere of carbon dioxide and hydrogen.
9. What can scientists learn about Mars by studying the Great Sand Dunes in National Monument Park (Colorado)?
Ans - The Great Sand Dunes National Park, is an excellent location for a simulated Mars mission. The terrain near the Sand Dunes creates an environment similar to what can be found on Mars. The association of Mars with the Great Sand Dunes continues. As recently as fall 2006, scientists were studying the movement of the dunes in an attempt to understand atmospheric conditions of that distant planet. Mars simulation may lead to new ideas that can address that need. The scientists were able to draw great conclusions on the simulation mode to handle robotic equipments on Mars.
10. Why are Mars-bound rovers and robots tested in the Atacama Desert in Chile?
Ans - The researchers say the desert, the driest spot on Earth, mimics the conditions of the Red Planet, and the agency has used it in the past to test space-bound equipment. The solar-powered 771-kilogram (1,700-pound) machine is equipped with cameras and a drill able to dig up to a meter (three feet) deep. It is testing its sensors, its cameras, and its ability to store energy, as it searches for evidence of microbial life in the desert.
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