Space Notes

Space Planets of the Solar System: Mercury: Mercury is the smallest planet in our solar system and is the nearest to the Sun. Mercury has a thin exosphere. Its exosphere is composed of oxygen, sodium, hydrogen, helium, and potassium. Mercury’s surface resembles that of Earth’s moon, scarred by craters as a result of numerous collisions with meteoroids and comets. Day on Mercury: 59 Earth Days Year on Mercury: 88 Earth Days Venus: Venus is the second nearest planet to the Sun. Venus is known for its extreme temperatures and acidic clouds. These make the planet unstable for life as we know it. Venus’s solid surface is a volcanic landscape covered with extensive plains featuring high volcanic mountains and vast ridged plateaus. Venus rotates slowly in the opposite direction than most planets do. It is just one of the two planets that rotate from east to west rather than from west to east. Day on Venus: 243 Earth Days (longer than a Venus year) Year on Venus: 225 Earth Days Earth: Earth is the third planet from the Sun. Earth is a terrestrial planet with an atmosphere with just the right thickness to support life. The atmosphere of Earth is made up of mainly nitrogen and oxygen. The atmosphere protects our planet from incoming meteors that could harm us and our ecosystems. Earth has one moon and is the only planet with a number of moons this low. Day on Earth: A little under 24 hours Day on Earth: 326.25 days (the 0.25 translates to a leap year, which occurs once every four years) Mars: Mars is the fourth closest planet to the Sun. Mars’s surface is very rocky and has a reddish color. Dust storms are very common. Mars has a thin atmosphere. The winds pick up fine, dry particles of dust, creating large dust storms. These dust storms carry the particles at speeds of 33 to 66 miles per hour. Mars has two main moons called Phobos and Deimos. Day on Mars: A bit longer than 24 hours Year on Mars: 687 Earth Days The inner planets are much smaller in size than the outer planets. The outer planets include Jupiter, Saturn, Uranus, and Neptune. These are the gas giants of the planets. The inner planets are Mercury, Venus, Earth, and Mars. The asteroid belt is located in between the inner and outer planets. Jupiter: Jupiter is the fifth planet from the Sun. Jupiter is the biggest planet, being twice the size of all the other planets combined. It is known for its Great Red Spot, a large storm that has been raging on the planet for hundreds of years. The area of the spot is a high-pressure region which is what causes these storms. The spot is made up mostly of hydrogen and helium. Jupiter has fifty-three confirmed moons and four rings around it. These rings, formed of dust particles, are dark and difficult to see in most images. Day on Jupiter: About 10 hours Year on Jupiter: 4,333 Earth Days Saturn: Saturn is the sixth planet from the Sun. Saturn is a gas-giant planet with an atmosphere made up of mostly hydrogen and helium. Saturn is known for its icy ring. It is not the only planet to have rings, but none are as complex as Saturn’s rings. These rings are made up of pieces of comets, asteroids, or shattered moons that broke due to Saturn’s powerful gravitational force. It is also made up of billions of pieces of ice and rock that have been coated by other materials and particles. Day on Saturn: 10.7 hours Year on Saturn: 29 Earth years Uranus: Uranus is the seventh planet from the Sun. Uranus is unique in the fact that it rotates on its side. It rotates from east to west. Uranus is an ice giant planet and nearly four times larger than Earth. It has twenty-seven known moons, which are mostly named after literary characters. Just like the other planets in the outer circle, Uranus is a ringed planet. It has thirteen known rings. The inner rings are narrow and dark, and the outer rings, which are more visible, are brightly colored. The planet’s mass is made up of a dense fluid of icy materials (water, methane, and ammonia) and a small rocky core. Uranus has an atmosphere made mostly of hydrogen and atomic helium. It is also made up of small amounts of other gases. Uranus is the coldest planet in the solar system. The surface temperature is -300° Fahrenheit. There are strong winds and clouds made up of methane ice crystals. Day on Uranus: 17 hours Years on Uranus: 84 Earth years Neptune: Neptune is the final planet and is furthest from the Sun. Neptune is a gas giant. Its atmosphere is made of hydrogen, helium, and methane. These give the planet its bright blue color. The atmosphere is extremely thick and windy with winds blowing at speeds of more than 1200 miles (2000 kilometers) per hour. Neptune does not have a solid surface. At the core, Neptune can get extremely hot, especially compared to its surface temperature. However, the surface is about -392° Fahrenheit (200° Celsius). Day on Neptune: 16 hours Year on Neptune: 165 Earth years Celestial Objects: Comets: Comets are large cosmic snowballs of frozen gases, rock, and dust roughly the size of a small town. When a comet gets close to the sun, it heats up and spews dust and gases into a giant glowing head larger than some planets. The dust and gases form a tail that stretches from the Sun for millions of kilometers. There are two main types of comets: short-period comets and long-period comets. ❖ Short-period comets are found beyond Neptune in an icy belt of dark comets that orbit the Sun near Pluto, a dwarf planet. Occasionally, comets are pushed by gravity into other orbits that bring them closer to the Sun. When the comet gets close enough to the Sun, it becomes a shortperiod comet. ❖ Long-period comets are found in a region about 100,000 Astronomical Units away from the Sun called the Oort Cloud. Most comets stay a safe distance away from the Sun, but in some cases, comets called sungrazers crash into the Sun or come so near to the Sun that they evaporate into space. The Oort Cloud is a theoretical spherical cloud of billions of pieces of icy space debris three light years away first detailed by Dutch astronomer Jan Oort. It is located beyond Pluto and past the edges of the Kuiper Belt, surrounding the Sun, all eight of our planets, and the Kuiper Belt. Although scientists have not been able to actually observe it yet, there are enough logical predictions that have been made for us to know the basics of the Oort Cloud. The Voyager 1, a space probe launched in 1977, is said to reach the Oort Cloud, but that will not happen for at least 300 years. Scientists don’t know if they will have contact with the Voyager 1 by then, but as technology advances and new ideas and inventions take shape, it is hoped by astrophysicists, astronomers, and all other members of the space science community that we will be able to have solid information about the Oort Cloud in the future. The Kuiper Belt is similar to the Oort Cloud in the sense that it is made up of space debris and we do not know much about it. It is often compared to the Asteroid Belt, but the Kuiper Belt is tens of hundreds times larger than the asteroid belt. It is said to be composed of mainly comets, asteroids, and other icy space debris. Extremely far from Earth, the disc-shaped Kuiper Belt is predicted to be located about 30 Astronomical Units to 55 Astronomical Units away from our planet. This goes to show how large space really is and how much there is still left to experience and discover. - Asteroids: Asteroids are large rocky, airless objects that orbit our Sun, too small to be called planets. Tens of thousands of these minor planets are gathered in the main Asteroid Belt. The Asteroid Belt is located between the orbits of Mars and Jupiter. Asteroids that pass close to Earth are called near-Earth objects. Asteroids are able to have moons with them. So far, there are one hundred and fifty asteroids that are accompanied by either one or two moons. Asteroids are classified by where they are located in space. Those that are in orbit of larger planets are called Trojans. Meteors and Meteorites: Relatively small chunks of rock and debris in space are called meteoroids. They become meteors, or shooting stars when they fall through a planet’s atmosphere. This event is called a meteor shower. About thirty meteor showers occur each year. When this happens, they leave a bright trail as they are heated by the friction of the atmosphere. Pieces that survived the journey and hit the ground are called meteorites. Most meteorites found on Earth are pebbles to fist size, but on occasion they can be larger than buildings. Meteorites are made of silicon, oxygen, and heavier metals like nickel and iron.