### Astronomy

Stars, comets, planets, they are all visible when you look up past our atmosphere. What if I told you that there were objects up there that you could not see, but had more gravity than an object 500 time larger than our sun. Objects, that are capable of swallowing whole planets within a split second of time. An object that would steal light right out of thin-air. These objects are more powerful than anything man made. Black holes are the most popular unknown object in science. A black hole is an area of space that has so much mass crammed in it that there is no way for an object to escape its gravitational pull.

Pretend that you are standing on the surface of a planet. You throw a rock straight up into the air. Assuming you don’t throw it too hard, it will rise for a while, but eventually the pick up of speed due to the planet’s gravity will make it start to fall down again. If you threw the rock hard enough, you could make it escape the planet’s gravity entirely.

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It would keep on rising forever. The speed that you need to throw the rock in order that it just barely escapes the planet’s gravity is called the “escape velocity.” The escape velocity depends on the size of the planet. If the planet is extremely large, then its gravity is very strong, and the escape velocity is high. A smaller planet would have a smaller escape velocity.

The Earth’s escape velocity 25,000 miles per hour, while the Moon’s is only 5300 miles per hour. Now imagine an object with such a large concentration of mass in such a small radius that its escape velocity was greater than the speed of light. Because nothing can go faster than the speed of light, a beam of light would be pulled back by gravity and would be unable to escape the black hole.

Black holes are not visible from the Earth nor any other planet in our solar system, but Black holes have more gravity than any other object known to man. Your probably asking yourself how this can be? Its as simple as this; Black holes are formed from a large star that dies and then gives in to its own gravitational pull dragging in everything around it. The star becomes so small that it can no longer be seen, but as it gets smaller its gravitational pull becomes greater. It is like taking a piece of bread and molding it between your hands until it is as small as a pea. As you were making your piece of bread smaller you were adding more and more stuff to the center. When you add more to the core of something it increases the gravitational pull.

### astronomy

Space exploration has been going on since the 1960s.

Both women and men have traveled in space. Every day we are discovering different things about space from satellites and astronauts, and every day more people are landing on the moon. The first human, the first animal, and the first spacecraft in orbit, were all Soviet achievements. There are many reasons why space is explored and why people take the time to explore the solar system. One reason is that we want to find out how our solar system was created and how it works, and another reason is that we want to find out how all the planets move and how they change rotations. We also want to learn about everything on the planets and how to make advanced enough spacecrafts so that we can visit all the planets. The first man to travel in space was Yuri Gagarin.

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He made history on April 12, 1961, by orbiting the earth in the Votsok 1. His flight was one hour and 48 minutes long, going at a speed of about 17,000 mph on the Votsok 1 as he circled the earth. Gagarin was later killed in a crash of a test airplane.

Neil Armstrong was the first person to ever land on the moon. He was born in Wapakoneta, Ohio, and after he graduated from college in 1955 he joined NASA. In 1962 he became the first civilian to enter an astronaut training program. In 1969 Armstrong lead the Apollo 11 mission and became the first person to set foot on the moon. His companions were Edwin E. Aldrin, Jr., and Michael Collins.

In 1971 Armstrong became a professor of aerospace engineering at the University of Cincinnati.Valentina Vladimora Nikolayeva Tereshkova was the first woman to be in space. She joined a Soviet training program in 1961 and in 1963 she successfully orbited the earth 48 times in the Votsok 6. “Born Galileo Galilei, his main contributions were, in astronomy, the use of the telescope in observation and the discovery of sunspots, lunar mountains and valleys, the four largest satellites of Jupiter, and the phases of Venus.” In December 1609, Galileo built a telescope of 20 times magnification, and with it he could see craters and mountains on the moon. He also saw that the Milky Way was made up of stars and looked at the four largest satellites of Jupiter.Herman Oberth, a German, was the second theoretician, with perhaps the greatest vision. His work had the biggest impact on the new and exciting field of rocket science and space exploration.

His first book, published in 1923, was his most famous, and was called “The Rocket into Interplanetary Space.” It includes proofs about the movement of rockets through space and atmosphere. “Tsiolkovsky, Konstantin Eduardovich (1857-1935), Russian scientist and inventor, a pioneer in rocket and space research.

At the age of nine he lost his hearing almost completely and he studied mostly at home; he worked as a high school mathematics teacher until retiring in 1920. In the mid-1880s Tsiolkovsky began research in aerostatics, publishing articles containing plans for a metal dirigible (1892), an airplane (1894), and a spaceship (1903). During the 1920s he elaborated his theory of multistage rockets and of the flight of jet engines. He was made (1918) a member of the Soviet Academy. Among his books are Dreams of Earth and Sky (1895) and A Rocket into Cosmic Space (1903), in which he proposed the use of liquid-propellants for spaceships. A crater on the moon’s far side is named after him.” The Sputnik 1 was the first artificial satellite to orbit the earth. “Sputnik 1 was an aluminum sphere, 58 cm (23 in) in diameter, weighing 83 kg (184 lb).

It orbited the earth in 96.2 minutes.” At the end of 57 days the satellite re-entered earth’s atmosphere and was destroyed by aerodynamic frictional heat. Voyager 1 and Voyager 2 were both spacecraft that were launched to Jupiter. Voyager 2 was launched on August 20, 1977, and Voyager 1 was launched 2 weeks after on September 5, 1977.

Voyager 1 did make it to Jupiter before Voyager 2 because it took a shorter and quicker route.NEAR, the Near Earth Asteroid Rendezvous, is a spaceship, and NEAR’s mission is to explore an asteroid called Eros. The journey time to Eros is 35 months and the cost for launching and building is \$122 million. Four years of this operation will cost \$40 million. Eros was picked for a couple of reasons and one of them was that it might help solve a mystery. The mystery is: why do most meteorites not resemble their bigger brothers in space? For example, they’re not made from the same things. Photos from NASA’s (National Aeronautics and Space Administration) polar spacecraft show that Earth is being sprayed by a steady stream of water-bearing objects similar to small comets. These objects, which are said to be the size of a small house, pose no threat to astronauts or people on earth.

They break up and disintegrate into clouds of water vapor at 600 to 15,000 miles above the earth. These objects all do contain water and arrive at a rate of from 5 to 30 small comets a minute. This has all just recently been found, even though it’s been suggested before.

No one believed it, but now that there is proof people actually believe it. When Voyager 1 and 2 were heading back they got a few pictures of Saturn’s rings. These pictures amazed people because we always thought that there were only 3 or 4 rings around Saturn. It turns out that they are actually thousands of concentric ringlets. Pluto is the only planet that has not been visited by some sort of spacecraft.

However, we have used telescopes to find out that it’s about 2,320 km in diameter and its moon, Charon, is 1,270 km in diameter. In 1994 the Hubble telescope showed that 85 percent of Pluto’s surface is dark, and scientists believe that the bright areas are fields of nitrogen ice and that the dark areas are methane ice and craters. “Many astronomers think Pluto may be a former satellite of Neptune, knocked into a separate orbit during the early days of the solar system. Charon could be an accumulation of the lighter materials resulting from the collision.” Photos Voyager 1 and 2 took prove a couple of new facts about Jupiter.

One of them is that Jupiter has a ring around it, and also that Jupiter’s moon has a giant active volcano that spits out sulfur compounds. The moons around Jupiter were found to be icy, rocky balls, with fractures and craters. Uranus is the seventh planet in order from the sun, located between Saturn and Neptune. Uranus was accidentally discovered in 1871 by a British astronomer.

Uranus takes 84 years for a single orbit, and 17 hrs and 15 minutes for a complete rotation about its axis. Five rings encircle the equator of Uranus. These rings, discovered in 1977, are called Alpha, Beta, Gamma, Delta, and Epsilon. On the NASA missions still to come, new satellites will be launched, some so big that they’ll have to be assembled in outer space.

Communication satellites will be larger and more powerful, so that people will be able to use wrist telephones to talk to anyone, anywhere in the world. In the future we hope to make big enough and powerful enough spaceships so that we can send real people to explore Pluto instead of just robots. The first humans arriving on Mars would be a great start, but it hasn’t happened yet.

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