400 years of Astronomy

International Year of Astronomy
400 years of exploring the sky.


In late 1609, word of a Dutch lens maker’s invention, that could magnify distant objects, reached the Italian scientist, Galileo Galilei. The invention was made up of two lenses in a tube, the very first refractor telescope. Galileo created a telescope for himself and used it to view the night sky. With this, he was able to make discovery after discovery; a new world as it was deemed. Among his discoveries were craters and mountains on the Moon, four of the largest satellites of Jupiter (Io, Europa, Ganymede, and Callisto), phases of Venus, and the stars of the Milky Way.

Galileo formally released his observations in 1610, in his book The Starry Messenger. His discoveries astounded astronomers everywhere. But since the Church accepted the Ptolemaic system (Ptolemy’s Earth-centered view, rather than Copernicus’ Sun-centered belief), they denied the discoveries of Galileo and had him spend the last years of his life under house arrest.

In the year of Galileo’s death, Isaac Newton was born. He developed a new type of telescope in 1672, the reflector. Aside from that, Newton was able to produce a solid mathematical foundation to the astronomical views of Copernicus and Kepler, alongside his discovery of the laws of gravity.

By the end of the 18th century astronomers were observing the sky with improved telescopes, and have been surveying the sky for celestial objects. One of them is William Herschel who created large telescopes which he used to sweep the sky for objects beyond the solar system. This led to the discovery of Uranus, and many other celestial bodies.

Along came the spectroscope in the 1850s, which was invented by two German physicists, Kirchoff and Bunsen. With the spectroscope, astronomers were able to identify Herschel’s mysterious nebulas. The spectroscope introduced a new science, the marriage of astronomy to physics – astrophysics.

With new scientific discoveries, such as Einstein’s theory of relativity, and the development of larger and more powerful telescopes, such as George Hale’s glass giants, more things are discovered and explored in the night sky. We now have various telescopes designed to look at the various wavelengths of the electromagnetic spectrum. And with the rivalry of superpowers, many discoveries and firsts are made through space exploration.

Much has changed since the time of Galileo. In 400 years time, with the advancement in learning, we now know more than what Galileo knew. With our grasp reaching out into the endless space, now is the best time to venture into astronomy, be it amateur or professional. With the rate of discovery there is always something new for every seeking eye.