Nebulae

The world nebula (plural – nebulae) means mist. A nebula is a giant cloud of gas and dust in the space, of which many still exist in the universe. One famous example is the Great nebula in Orion visible to the naked eye and a magnificent sight through binoculars or a small telescope.

At the heart of nebula are several newborn stars and the light of these stars cause the nebula in space about 5,000 million years ago. Plied, the famous star cluster, formed only 50 million years ago, quite recently in astronomical term. Famous in space about telescopic photographs show the stars to be surrounded by traces of the nebula from which they were formed. French astronomer, Charles messier, first published a catalog of nebula in and dust. A French astronomer, now know a lot more about the nebulae.

Astronauts Live in Space

In space everything floats and there is no up or down. Astronauts wear special shoes that clip into grids on the floors and walls to stay in one place and work or eat. They do not need chairs to sit down and their beds are just sleeping bags fixed to the walls. They seem to sleep standing up.

Russian and American astronauts have lived in space because human bodies are suited to life on the earth held down by the force of gravity. The atmosphere process down the bodies provide humans air to breathe and protect them from the earth away from astronaut were found deed, when they returned from Salyut I space station in Soyuz II after spending 23 days in the orbit. The Skylab astronauts grew taller in space, but they returned back to the earth and suffered no lasting ill – effects.

Stars

The giant clouds of gas and dust, called nebula are the sites of star formation. The stellar formation, as the star formation is referred to, is due to compression waves which travel around the galaxy, or the shock waves from the supernova explosion.

Eventually the pro-star starts in its center and it begin its independent existence as a true star. It is now called a T. Taurus type star and release energy produced as a result of nuclear fusion. The rest of the clouds are blown away. Most stars, like the sun, spend their life quietly converting hydrogen to helium in its core. The pressure at the center keeps the star expanded. This is a stable period in a star’s life. It is called main sequence star. The star’s luminosity increase, i.e., it gives out more energy as its core becomes denser and hotter.

Space Stations

The space age began about twelve years before the first man landed on the moon on October 4, 1957, with the launching of first artificial satellite sputnik by the then soviet union, Gradually both the US and Soviet Union started sending artificial satellites into the space to study the universe and its expanse. They also felt the need of a permanent station to be built in the space so as to facilitate the studies of the outer space.

Today space stations orbit the earth and one day we or our children may live in space. A station is a special kind of satellite in which astronomers or space scientist live and work for week or even months. The first space station, Salyut 1 was launched by the USSR in April 1971.

Skylab was first US space station put into orbit in 1973. Nine astronauts in three crews spent 28, 59 and 84 days respectively; in the Earth’s orbit abroad Skylab. Skylab stayed in space for six years and studied the sun the earth’s orbit aboard Skylab. Skylab stayed in space station was launched in to orbit on February 20, 1986. A soviet space and set record of and it has been devised to sink it in to pacific by March 2000.

Hubble’s law

In 1929, Edwin Hubble found that the distant galaxies in the universe are moving away from the earth. He found that the speed of moving of moving galaxies depends on their distance from the earth. If a galaxy is ten times as far away as another, it is moving ten times faster than the other. This is what is called Hubble’s in other words, more distant galaxies are moving away from the earth than the ones closer to it. If a galaxy, 1000 light years. Away from the earth, are moving at about 177 km pr sec, moves twice that speed, i.e., 354 km per sec and soon.