THE UNIVERSE IS MUCH LARGER THAN WE THOUGHT

Edwin Hubble announces the discovery of  other galaxies, revealing that the universe is much larger than we thought.

          Until the 1920s, it was widely assumed that the galaxy of stars of which our sun is one was the only galaxy in existence. Astronomers, however, had already begun to suspect that there might be other structures farther out in space. One such Astronomer was a young American from Missouri, Edwin Powell Hubble. He focused on nebulae - clouds of interstellar dust and gas-- and from 1919 studied them at the Mount Wilson Observatory in California. He discovered that some object thought to be nebulae were actually large-scale aggregates of stars, or galaxies like our own. In 1923, for example, he found thirty-six stars inside the Andromeda nebulae, which he subsequently calculated to be 900,000 light years away from us and an enormous distance beyond our own galaxy's edge. The astronomers published hi research result on the first day of 1925.
           Hubble classified the galaxies into three main types- spiral, elliptical, and irregular. He not only demonstrated that the universe is immensely bigger than previously thought, but went want to show that it is expanding, meaning that the other galaxies are moving away from us. In 1929, he found that the speed at which the galaxies recede increases with their distance from us (Huble's Law) and established a ratio (Hubbles Constant) between the speed and the distance. Subsequent investigations suggest that ratio has not always remained the same, but over time has decelerated and accelerated.
             Hubble continued working at Mount Wilson virtually until his death in 1953. The Hubble space Telescope was named in his honor. 

THE MASTERY OF THE SEAS

The HMS Dreadnought gives Britain the lead in the race for global naval supremacy

          As Britain new warship HMS Dreadnought slid into the water at Portsmouth dockyard in 1906, the nature of the world's navies changed. All existing Battleships were now obsolete. Its design was so radical that it gives it name to a whole new style of ship. Inspired by the thinking of Admiral Fisher, once commander - in-chief of the Mediterranean fleet and now First Sea Lord, The professional head of the Royal Navy,  the design brought together all the recent developments in propulsion, armor, and gunnery to create a fast, powerful ship capable of destroying  any other ship. All future British warships would follow this model.
           Other maritime nations - including the U.S,Japan,France,Italy and Russia - were obliged to follow this design if they were to project maritime power. But the major repercussions were felt in the new German Empire, where  Kaiser Wilhelm II, supported by his navy minister, Admiral Tirpitz, had a policy of noval rivalry with Britain in the hope of challenging her predominance in the world's oceans. Both nations invested in more such ships with ever more sophisticated designs. The imperial German ship program was major worry for the British. In World War I, the two fleets would eventually face each other at the battle of Jutland, although although the outcome proved inconclusive.
             The Dreadnought concept dominated the world's navies until the new technologies of submarines, aircraft and carriers. By the end of  the World War II, the Dreadnought was obsolete.