Tuesday, August 27. 2019What is the Jupiter?
Jupiter is the fifth planet from the Sun and the largest planet in the Solar System. It is a gas giant with thick bands of brown, yellow, and white clouds. Its atmosphere is made up of hydrogen and helium gas, just like our Sun, and if it was much more massive, it could become a star! Jupiter took shape when the rest of the solar system formed about 4.5 billion years ago, when gravity pulled swirling gas and dust in to become this gas giant. Jupiter took most of the mass left over after the formation of the Sun, ending up with more than twice the combined material of the other bodies in the solar system. In fact, Jupiter has the same ingredients as a star, but it did not grow massive enough to ignite. As a gas giant, Jupiter doesn’t have a true surface. The planet is mostly swirling gases and liquids. While a spacecraft would have nowhere to land on Jupiter, it wouldn’t be able to fly through unscathed either. The extreme pressures and temperatures deep inside the planet crush, melt and vaporize spacecraft trying to fly into the planet. Giant planet Jupiter is the king of solar system. It is an amazing 143,000 km (89,000 miles) wide. Jupiter is so large that all of the other planets could fit inside it! The planet is mostly made of hydrogen and helium surrounding a dense core of rocks and ice, with most of its bulk likely made up of liquid metallic hydrogen, which creates a huge magnetic field. Jupiter is visible with the naked eye and was known by the ancients. Its atmosphere consists mostly of hydrogen, helium, ammonia and methane. Juno Mission NASA’s Juno spacecraft is helping scientists to understand how Jupiter formed. It is orbiting closer to the gas giant than any spacecraft has before. Juno's mission is to measure Jupiter's composition, gravity field, magnetic field, and polar magnetosphere. It will also search for clues about how the planet formed, including whether it has a rocky core, the amount of water present within the deep atmosphere, mass distribution, and its deep winds, which can reach speeds up to 618 kilometers per hour (384 mph). Juno is the second spacecraft to orbit Jupiter, after the nuclear powered Galileoorbiter, which orbited from 1995 to 2003. Unlike all earlier spacecraft sent to the outer planets, Juno is powered by solar arrays, commonly used by satellites orbiting Earth and working in the inner Solar System, whereas radioisotope thermoelectric generators are commonly used for missions to the outer Solar System and beyond. For Juno, however, the three largest solar array wings ever deployed on a planetary probe play an integral role in stabilizing the spacecraft as well as generating power. Beneath the clouds Any spacecrafts that passed through Jupiter’s clouds would be crushed and melted by the huge pressure. Scientists believe that beneath the clouds there is a giant ocean made of liquid metal. Jupiter’s rings Jupiter has three thin rings, called the Jovian Rings. They are mostly made of dust and can only be seen when viewed from behind Jupiter, when they are lit up by the Sun. The main ring is flattened. It is about 20 miles (30 km) thick and more than 4,000 miles (6,400 km) wide. The inner cloud-like ring, called the halo, is about 12,000 miles (20,000 km) thick. The halo is caused by electromagnetic forces that push grains away from the plane of the main ring. This structure extends halfway from the main ring down to the planet's cloud tops and expands. Both the main ring and halo are composed of small, dark particles of dust. The third ring, known as the gossamer ring because of its transparency, is actually three rings of microscopic debris from three of Jupiter's moons, Amalthea, Thebe and Adrastea. It is probably made up of dust particles less than 10 microns in diameter, about the same size of the particles found in cigarette smoke, and extends to an outer edge of about 80,000 miles (129,000 km) from the center of the planet and inward to about 18,600 miles (30,000 km). Great Red Spot One of the Jupiter’s most famous features is the Great Red Spot. It is a huge storm, more than three times the size of Earth, that has been raging for hundreds of years! The red colour of the Great Red Spot is thought to be caused by organic molecules, red phosphorous or other elements that come from inside Jupiter. Some theories propose that the colour is caused by reactions between these chemicals in Jupiter’s atmosphere, or by lightning striking the molecules. The colour is not always the same, either: sometimes it is dark red, while at other times it is a pale pink colour, or even white! Perhaps Jupiter’s Great Red Spot is not so red after all!
Picture Credit : Google
Tuesday, August 27. 2019What is Asteroid belt?
Between the planets Mars and Jupiter lies the asteroid belt. It is home to tens of thousands of asteroids. These rocky objects are leftovers from the early Solar System, and are too small to be considered planets. They come in different shapes and sizes with the smallest being less than 1 km (0.6 miles) wide. Some asteroids have moons and one even has rings! Most of the asteroids in the Main Belt are made of rock and stone, but a small portion of them contain iron and nickel metals. The remaining asteroids are made up of a mix of these, along with carbon-rich materials. Some of the more distant asteroids tend to contain more ices. Although they aren't large enough to maintain an atmosphere, but there is evidence that some asteroids contain water. Some asteroids are large, solid bodies — there are more than 16 in the belt with a diameter greater than 150 miles (240 km). The largest asteroids, Vesta, Pallas and Hygiea, are 250 miles (400 km) long and bigger. The region also contains the dwarf planet Ceres. At 590 miles (950 km) in diameter, or about a quarter of the size of our moon, Ceres is round yet is considered too small to be a full-fledged planet. However, it makes up approximately a third of the mass of the asteroid belt. Other asteroids are piles of rubble held together by gravity. Most asteroids aren't quite massive enough to have achieved a spherical shape and instead are irregular, often resembling a lumpy potato. The asteroid 216 Kleopatra resembles a dog bone. Asteroid orbits Not all of the asteroids in our Solar System are found in the asteroid belt. Some asteroids pass near other planets, including Earth. Asteroids that come close to Earth are called Near Earth Objects. The planet Jupiter even shares its orbit around the Sun with two groups of asteroids, which are called Trojans. If something slows an asteroid, it may "fall" towards the Sun, towards Mars, or towards Jupiter. As both Jupiter and Mars move past the asteroids in their orbits, they may be pulled slightly towards those huge bodies in their orbits. In fact, Phobos and Diemos, the two tiny moons of Mars, may be captured asteroids. Some scientists believe that the asteroid belt was made when a planet that was there exploded or collided with something else and broke up. Other scientists believe that the material making the asteroids never came together into a planet at all. Craters Craters are nicknamed “Snowman” because they look just like a snowman! They are on Vesta, one of the largest asteroids in the asteroid belt. Many impact craters are found on the Earth’s surface, although they can be harder to detect. One of the best-known craters on Earth is Meteor Crater, near Winslow, Arizona. The crater was created instantly when a 50-meter (164-foot), 150,000-ton meteorite slammed into the desert about 50,000 years ago. Meteor Crater is 1.2 kilometers (0.75 miles) in diameter and 175 meters (575 feet) deep. Impact craters are found on most of the solar system’s rocky planets and moons. The so-called “gas giants” of the solar system—Jupiter, Saturn, Uranus, and Neptune—don’t have craters. These planets are made up almost entirely of gases, so there is no hard surface for a meteor to impact. Meteors entering the atmosphere of a gas giant simply break up. Ceres By far the largest object in the asteroid belt is Ceres. Made mostly of rock is Ceres. Made mostly of rock and ice, it was the first asteroid ever discovered. It has since been classed as a Dwarf Planet, because it is more like a planet than its neighbours in the main asteroid belt. Ceres takes 1,682 Earth days, or 4.6 Earth years, to make one trip around the sun. As Ceres orbits the sun, it completes one rotation every 9 hours, making its day length one of the shortest in the solar system. Ceres' axis of rotation is tilted just 4 degrees with respect to the plane of its orbit around the sun. That means it spins nearly perfectly upright and doesn't experience seasons like other more tilted planets do. Ceres formed along with the rest of the solar system about 4.5 billion years ago when gravity pulled swirling gas and dust in to become a small dwarf planet. Scientists describe Ceres as an "embryonic planet," which means it started to form but didn't quite finish. Nearby Jupiter's strong gravity prevented it from becoming a fully formed planet. About 4 billion years ago, Ceres settled into its current location among the leftover pieces of planetary formation in the asteroid belt between Mars and Jupiter.
Picture Credit : Google Tuesday, August 27. 2019Why it is important to explore Mars?
Scientists have always longed to explore Mars. They believe that in the past the Red Planet could have been far warmer and wetter than it is now. There may once have even been life on Mars, and tiny life forms, such as bacteria, could live on the planet today. Many spacecraft have already visited Mars and in the future humans will too. Understanding whether life existed elsewhere in the Universe beyond Earth is a fundamental question of humankind. Mars is an excellent place to investigate this question because it is the most similar planet to Earth in the Solar System. Evidence suggests that Mars was once full of water, warmer and had a thicker atmosphere, offering a potentially habitable environment. While life arose and evolved on Earth, Mars experienced serious climate change. Planetary geologists can study rocks, sediments and soils for clues to uncover the history of the surface. Scientists are interested in the history of water on Mars to understand how life could have survived. Volcanoes, craters from meteoroid impacts, signs of atmospheric or photochemical effects and geophysical processes all carry aspects of Mars’ history. Samples of the atmosphere could reveal crucial details on its formation and evolution, and also why Mars has less atmosphere than Earth. Water on Mars In 2015, NASA found the strongest evidence yet that liquid water exists on Mars. This was a hugely exciting discovery because scientists looking for life in our Solar System think that where there is liquid water, there could be life. Many lines of evidence indicate that water ice is abundant on Mars and it has played a significant role in the planet's geologic history. The present-day inventory of water on Mars can be estimated from spacecraft imagery, remote sensing techniques and surface investigations from landers and rovers. Geologic evidence of past water includes enormous outflow channels carved by floods, ancient river valley networks, deltas, and lakebeds; and the detection of rocks and minerals on the surface that could only have formed in liquid water. Numerous geomorphic features suggest the presence of ground ice (permafrost) and the movement of ice in glaciers, both in the recent past and present. Gullies and slope linear along cliffs and crater walls suggest that flowing water continues to shape the surface of Mars, although to a far lesser degree than in the ancient past. Curiosity Rover The photo of the Curiosity rover was taken on the surface of mars. The six-wheeled, car-sized robot lives and works on the planet, operated by a team of scientists back on earth. Their instructions take about 15 minutes to reach Mars! Curiosity has other instruments on board that are designed to learn more about the environment surrounding it. Among those goals is to have a continuous record of weather and radiation observations to determine how suitable the site would be for an eventual human mission. Curiosity's Radiation Assessment Detector runs for 15 minutes every hour to measure a swath of radiation on the ground and in the atmosphere. Scientists in particular are interested in measuring "secondary rays" or radiation that can generate lower-energy particles after it hits the gas molecules in the atmosphere. Gamma-rays or neutrons generated by this process can cause a risk to humans. Additionally, an ultraviolet sensor stuck on Curiosity's deck tracks radiation continuously. Human exploration To reduce the cost and risk for human exploration of Mars, robotic missions can scout ahead and help us to find potential resources and the risks of working on the planet. Before sending astronauts, we need to understand the hazards. Inevitably, astronauts would bring uncontained martian material when they return to Earth, either on their equipment or on themselves. Understanding any biohazards in the soil and dust will help the planning and preparation of these future missions. Going to Mars is hard and it is even harder for humans because we would need to pack everything to survive the trip to our neighbouring planet and back. Designing a Mars mission would be easier if we could use resources that are already available locally. Water is a valuable resource for human expeditions, both to consume by astronauts and for fuel. Samples gathered by robots could help to evaluate where potential resources are available for future human explorers and how to exploit them.
Picture Credit : Google |
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