Astronomy

Astronomy is the oldest and most fascinating science. Since ancient times, people have tried to understand the universe and the earth’s position in it. It may have begun in superstition with attempts to foretell the future of individuals. But it has gradually explained the marvels of the heavens. About 4000 B.C., the Egyptians developed a Calendar based on the Chinese have recorded the eclipses of the Sun and the Moon. The Early astronomers whose names we were the Greek philosophers, like tales, Pythagoras, Eratosthenes heptarchs, Aristech’s and Ptolemy. The astronomers like Nicholas Copernicus. Tyco brave, Johannes keeper and astronomy. Edwin Hubble. Cecelia Payne – Gaposchkin, William hugging. Percival Lowell, Eleanor Helen, William Herschel are some of the modern astronomers.

Newton‘s laws of gravity established the science of celestial mechanics. Astronomy first centered on the solar system, later explored the stars and distant galaxies. By 1900, astronomers began taking photographs of heavenly bodies instead of making visual observations. With the discovery of structure of atom, the astronomers started of atom, the astronomer’s started the study of nature of stars by analyzing starlight. Today’s an astronomer is no longer person working in many fields of science but is a specialist on the specific aspect of science but is a specialist on the specific aspect of astronomers. Research in astronomy is of two types – theoretical and observational. Theoretical studied predict and interpret the behaviors of astronomical bodies while the observational work produces the facts on which theories must be based.

Bode's Galaxy

The Hubble Space Telescope has sent back the best view yet of a picture-perfect galaxy known as M81 or Bode's Galaxy, resolving single points of starlight as well as star clusters and glowing regions of fluorescent gas. The pronounced grand-design spiral galaxy M81 forms a most conspicuous physical pair with its neighbor, M82, and is the brightest and probably dominant galaxy of a nearby group called M81 group. A few tens of millions years ago, which is semi-recently on the cosmic time scale, a close encounter occurred between the galaxies M81 and M82. M81, which lies 11.6 million light-years away in the northern constellation Ursa Major, is a popular target for astronomers and amateur stargazers. It can be seen in clear, dark skies with binoculars or a small telescope. Using the Hubble Space Telescope, a team under Wendy Freedman of the Carnegie Institution of Washington has investigated 32 Cepheid variables in M81 and determined the distance to be 11.0 million light years, in 1993 well before the HST was refurbished. Together with the new distance scale correction implied by the results of ESA's Hipparcos satellite, the true distance of M81 is probably closer to 12.0 million light years

Mountains and Oceans on the Earth

The crust of the earth is its outer most surface layer which is about 6- 35 km thick. It is not an even surface but forms hollows that are full of water. These are called and ridges and wrinkles that are the great mountain chains. This outer surface of the Earth moves constantly producing the oceans and mountains.

Mountains also keep growing or eroding. But these are very slow processes that take several million years to occur. The vast Himalayan mountain range in Asia began to grow 50 million years ago, but it is so young that it is still being formed. The Aravalli range, in the south west of Delhi and in Rajasthan, is believed to be the oldest mountain range in the world. It is eroding and degenerating.

Plate Tectonic Theory

For several centuries it was believed that the continents were fixed permanently in their place. In 1965, an English scientist, Sir Edward Bullard using computer tested the fit of Africa and America and found that at a depth of 2000 meters the match was close indeed. It was then proved that continents are continually drifting away from each other on the surface of the earth like logs floating on water. This is called continental drift. Seabed is also recycled every 200 million years. Magma (molten rock) rises from inner layers of the earth at certain sites on ocean floor called ocean ridges.

The mid _Atlantic Ridge represents the boundary between two huge blocks of crystal material. The magma solidifies and moves outwards before being swallowed up at sites called ocean trenches. Thus new crust is being created by volcanic material welling up from below and spreading outwards. This process is called sea floor spreading and the boundary is called a constructive margin. These margins lie along ocean ridges. Since, the earth is not getting bigger this plates and are carried by their apart the continents. The edge of a plate where it is being destroyed is called destructive plate margin. These lie along ocean trenches.

Here, one block or plate or plate of crystal material is forced beneath another. This movement results in the earth quakes and volcanic activities. The idea of sea floor spreading combined with the idea of continental drift forms a theory what is called plate tectonics.

Earth natural satellite

The Moon is our only natural satellite. The young Earth had no moon, but soon after the Earth formed, a Mars-sized rogue planet struck it a huge glancing blow. A large chunk of Earth and most of the rogue planet were vaporized into a cloud that rose more than 22,000km in altitude, where it condensed gradually into the solid moon.Looking down from the north pole we would see the Moon orbiting counterclockwise from west to east. Neil Armstrong took that historical step of "one small step for man one giant step for mankind".The diameter of the moon is 2,160 miles. The Moon takes about 27 days, 7 hours, 43 minutes, 11.6 seconds to go all the way around the Earth and return to its starting position. The U.S.S.R. had made the opening gambit, sending the first artificial satellites into orbit, starting with the 83.5-kilogram Sputnik I in October 1957. Most planets are named for Roman gods but moons are named for Greek gods.The moon is slowly moving away from Earth. The current distance between the Earth and the moon is 384,000km but it was closer in the past.

Comet

Earth mostly regarded the comets as messengers of destruction and rarely as bringers of good or prosperity, while the scientists today think they might have played a key role in the formation of our planet and view them as carriers of possible information about the galaxy. Comets have been the most feared and admired sky spectacles of all. But while astronomers have been able to predict eclipses for thousands of years, only in the 1700s was a comet's return correctly predicted, by Edmond Halley. The comets that pass close to the Sun originally came from one of two places that either the Oort cloud or the Kuiper Belt. You can think of the Oort cloud as a giant spherical shell surrounding the Sun that's filled with about 1 million comets. In the early 1930 an Estonian astronomer proposed a structure formed of billions of comets which lie beyond the Kuiper belt. However, the theoretical structure one light year in radius equivalent to a quarter of the distance to the nearest star to the Sun, Proxima Centauri, has not been detected yet.

Apollo 11

Apollo 11 was scheduled to fulfill an age-old dream of mankind. July 16,1969, Was the fateful day when the Saturn V rocket carrying Apollo 11 rose gracefully into the air from cape Canaveral. Its crew whose names were to go down in history, Were all experienced astronauts from the Gemini programmed- Neil Armstrong, Michael Collins and Edwin Aldrin. Their launch and outward voyage to the Moon proved faultless, a good omen for their later success.

The Apollo flight plan required a space craft made up of three sections or modules. The three-man crew were housed in the command module (CM) linked to the main equipment section, the service module (SM). For the outward fight the CM was mated to the lunar module (SM). For the outward fight the CM was mated to

The lunar module (LM) when the craft reached Lamar orbit. Armstrong and Aldrin crawled into the LM nicknamed Eagle and separated it from the CM for the descent to the selected landing spot in the sea of tranquility one of the Moons land plains After their moon walk, they returned to dock with the CM orbiting above the LM was then discarded before the flight home.