Our Own Backyard

After Newton’s time, astronomy branched out. The problem of planetary motion was over and it was now studies as celestial mechanics. The telescope, already invented was improved exponentially, leading to huge advances in astronomy.

Planets became much more in focus and surface detail became visible. The 19th century brought the invention of a device called the spectroscope by Joseph von Fraunhofer, able to determine the chemical compositions and movement of bodies. This along with the discovery that each chemical element produced a unique spectrum, or set of spectral lines, incidentally named Fraunhofer lines, made possible the chemical analysis of heavenly bodies. Studying spectral data from the sun and other bodies has revealed that they are composed of the same elements found here on Earth. Clues to surface temperatures, surface gravities, and bodily motion have also been provided by spectral studies.

The advancement in telescopes allowed visual proof of predictions made by Newton’s law of gravitation. If large forces of attraction occurred between the sun and the planets, then smaller forces must occur between the planets themselves and the sun and other objects, like comets. These forces caused deviations in their elliptical orbits. These irregularities were only visible with the aid of a telescope.

Telescopes led the discovery of several of the outer planets. Sir William Herschel, in 1781, discovered Uranus. Independent of each other, both the British astronomer John Couch Adams and the French astronomer Urbain Jean Joseph Leverrier discovered Neptune in 1846. In 1930, an American astronomer, Clyde William Tombaugh saw Pluto.

The number of satellites around these planets are increasing as we get better looks and as we send more and more unmanned flybys.

Our Neighbors-The Stars

Long thought to be just a backdrop to our solar system, with the invention of the telescope, stars became alive.

Stars are all hot gaseous bodies, just like our sun, though differ in many ways. Some of their important properties are their intrinsic brightness, size, mass, and chemical composition.