Astronomer
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An astronomer or astrophysicist is a person whose area of interest is astronomy or astrophysics. Image:Johannes Helvelius.jpg
Cultures around the world appear to have taken an interest in the sky since prehistoric times. Independently, some of these cultures began to support groups of scribes or priests who dedicated themselves to the observation of objects in the heavens. The observation of the motions of the planets, and prediction of their future motions, was the chief occupation of ancient astronomy. In the west, astronomy is generally thought to have begun in ancient Mesopotamia. Recent studies of Babylonian records have shown them to be extremely accurate for the ancient night sky.
It is important to recognize that before about 1750, astrology was considered to be a science closely allied to astronomy. In some times and places, the two have been regarded as identical.
Astronomers, unlike most scientists, cannot interact with the objects that they study. They instead must resort to detailed observation in order to make discoveries. Generally, astronomers use telescopes or other imaging equipment to make such observations. The job itself is involved with travel to remote locations to study as well.
A sampling of famous astronomers
| Astronomer | Contribution |
|---|---|
| Hipparchus and Ptolemy | Determined the positions of about 1,000 bright stars, tried to explain the puzzles of astronomy without refuting only believed geocentric model of universe and classified stars by magnitude. |
| Aristarchus of Samos | First known person to propound the heliocentric model of universe. Attempted to calculate the sizes and distances of the Sun and Moon. |
| Nasir al-Din al-Tusi | This Persian astronomer gave the first extant exposition of the whole system of plane and spherical trigonometry. Made very accurate tables of planetary movements and named many stars. Developed the Tusi-couple which resolves linear motion into the sum of two circular motions. He also calculated the value of 51' for the precession of the equinoxes and contributed to construction and usage of astrolabe. |
| Nicolaus Copernicus | First exponent of heliocentrism in modern times. |
| Tycho Brahe | Did develop many important astronomical instruments, and achieved accurate measurments of the heavens by improving scentific methodology and by designing instruments on a large scale. His measurements of the orbit of Mars were very important to the development of astronomy. |
| Johannes Kepler | Suggested the elliptical orbits of planets, and propounded his Laws of Planetary Motion. |
| Galileo Galilei | Was the first to use the telescope to observe the sky. Condemned to house arrest for his discoveries by Inquisitional edict, which was lifted 359 years later by Pope John Paul II. |
| Isaac Newton | Published Philosophiae Naturalis Principia Mathematica (1687), containing the "Newton's laws of motion", which are fundamental to mechanical physics, and which explained Kepler's laws of planetary motion. Predicted the orbits of the planets. |
| Subrahmanyan Chandrasekhar | Extensive work on the internal mechanisms of stars, particularly known for determining the effect of special relativity on stars, including being the first to calculate the Chandrasekhar limit, which he did, without a calculator, on a boat journey. |
| Henrietta Swan Leavitt | Catalogued Cepheid variable stars in the Magellanic Clouds, in 1912 discovered the relationship between luminosty and periodicity in Cepheids -- leading to Hertzprung's later work. |
| Ejnar Hertzsprung | determined the distance to several Cepheids, when Cepheids were detected in other galaxies such as the Andromeda galaxy, the distance to those galaxies could then be determined. |
| Edwin Hubble | Discovered the expansion of the universe. (Hubble's Law) The Hubble Orbiting Space Telescope was named in his honor. |
See also
There is also a well-known painting by Johannes Vermeer titled The Astronomer, which is often linked to Vermeer's The Geographer. These paintings are both thought to represent the growing influence and rise in prominence of scientific inquiry in Europe at the time of their painting, 1668-69.
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