Your Astronomy Now

The sun is the star nearest to us.

It is a giant ball of gases. Many studies have been made of the sun, and it is now kept under constant observation. Some of the most interesting studies have had to do with sunspots. These are dark spots that can be observed on the sun’s surface. The spots are storms that occur in the hot, swirling gases of the sun. In 1826, Heinrich S. Schwabe, a German astronomer, began to count sunspots. He counted them for 43 years - and was rewarded with the discovery of the sunspot cycle. He found that space. This flow is the solar wind. It streams past the earth, changing the shape of the earth’s magnetic field. It also causes the glowing auroras (the northern and the southern lights) when it reaches the top of the earth’s atmosphere.

What makes the sun hot? One old idea was that it burns like a flame. Another was that it gives off heat by contracting slowly. In this century, scientists have shown that the sun’s enormous heat is produced deep in its interior, by nuclear fusion. The process of fusion is the coming-together (union) of atomic nuclei. On the sun, the union is mainly that of the nuclei of hydrogen atoms, joining to form helium nuclei. Heat and light are given off during this process. It is the same process that takes place in the explosion of a hydrogen bomb. Scientists are working to find ways to control the fusion process, so that its heat may be used to generate electricity.

Tags: Astronomer, Heinrich S. Schwabe, Sun, Sunspot cycle

Pluto was discovered by Clyde W. Tombaugh, a United States astronomer, in 1930. He completed the search begun by Percival Lowell, another U.S. astronomer, who had predicted the existence of the planet. It was a long, hard job.

Photographic plates were exposed to the sky at night and examined during the day. Ninety million star images were examined before on tiny, shifting point of light was found. This was Pluto. It seems to be at the edge or solar system-5,900,000,000 (billion) kilometers (3,666,000,000 miles) from the sun.

In the 18th century, astronomers thought that there was an undiscovered planet between Mars and Jupiter. They began a search of the space between the two planets. In 1801, Giuseppe Piazzi, an Italian astronomer, discovered a small body that he thought to be the missing planet. Its name is Ceres. Later many more small bodies were found between Mars and Jupiter. They are called asteroids or planetoids. They are at least 40,000 of these, and most of them are chunks of stone or iron.

Tags: Asteroids, Astronomer, jupiter, mars, Planets, pluto, Solar system

From the days of Hipparchus down to the present hour the science of astronomy has steadily grown.

One great observer after another has appeared from time to time, to reveal some new phenomenon with regard to the celestial bodies or their movements, while from time to time one commanding intellect after another has arisen to explain the true import of the facts of observations. The history of astronomy thus becomes inseparable from the history of the great men to whose labours its development is due.

There may have been other discoverers who have done more for science than ever Ptolemy accomplished, but there never has been any other discoverer whose authority on the subject of the movements of the heavenly bodies has held sway over the minds of men for so long a period as the fourteen centuries during which his opinions reigned supreme. The doctrines he laid down in his famous book, “The Almagest,” prevailed throughout those ages. No substantial addition was made in all that time to the undoubted truths which this work contained. No important correction was made of the serious errors with which Ptolemy’s theories were contaminated. The authority of Ptolemy as to all things in the heavens, and as to a good many things on the earth (for the same illustrious man was also a diligent geographer), was invariably final.

Though every child may now know more of the actual truths of the celestial motions than ever Ptolemy knew, yet the fact that his work exercised such an astonishing effect on the human intellect for some sixty generations, shows that it must have been an extraordinary production. We must look into the career of this wonderful man to discover wherein lay the secret of that marvellous success which made him the unchallenged instructor of the human race for such a protracted period.

Tags: Astronomer, Astronomers