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| '''Astronomy''', which etymologically means ''laws of the ]'', is the science whose subject is the observation and explanation of events outside the earth. ''']''' | '''Astronomy''', which etymologically means ''laws of the ]'', is the science whose subject is the observation and explanation of events outside the earth. ''']''' | ||
| was born as the application of physics to the phenomena observed | was born as the application of physics to the phenomena observed | ||
| by astronomy, this was only possible once it was understood that the elements that made up the "celestial objects" were the same that made up the ], and that the same ] applied. Nearly all astronomers now have a strong background in physics, and the results of observations are always put in an astrophysical context, so | by astronomy, this was only possible once it was understood that the elements that made up the "celestial objects" were the same that made up the ], and that the same ] applied. Nearly all astronomers now have a strong background in physics, and the results of observations are always put in an astrophysical context, so | ||
| the distinction between astronomy and astrophysics almost doesn't exist anymore. | the distinction between astronomy and astrophysics almost doesn't exist anymore. | ||
| '''History''' | '''History''' | ||
| In the early part of its history, Astronomy involved only the | In the early part of its history, Astronomy involved only the | ||
| observation and predictions of the motions of the objects in the sky that could be seen with the naked eye. Astronomers were | observation and predictions of the motions of the objects in the sky that could be seen with the naked eye. Astronomers were | ||
| also usually priests, and for a long time it was believed that | also usually priests, and for a long time it was believed that | ||
| celestial phenomena had an influence on events on earth. | celestial phenomena had an influence on events on earth. | ||
| Greeks made some important contributions to astronomy, but | Greeks made some important contributions to astronomy, but | ||
| the progress almost stopped during the middle ages, except for | the progress almost stopped during the middle ages, except for | ||
| the work of some Arabic astronomers. The renaissance came to | the work of some Arabic astronomers. The renaissance came to | ||
| astronomy with the work of ], who proposed a | astronomy with the work of ], who proposed a | ||
| heliocentric system. His work was defended, expanded and corrected by the likes of ] and ]. Newton | heliocentric system. His work was defended, expanded and corrected by the likes of ] and ]. Newton | ||
| created ] with his ], | created ] with his ], | ||
| that finally explained the motions of the planets. Stars were | that finally explained the motions of the planets. Stars were | ||
| found much later to be far away objects, and with advent of | found much later to be far away objects, and with advent of | ||
| spectroscopy it was proved that they were similar to our own sun, | spectroscopy it was proved that they were similar to our own sun, | ||
| but with a range of temperatures, masses and sizes. The existence | but with a range of temperatures, masses and sizes. The existence | ||
| of our Galaxy, the Milky Way, as a separate group of stars was only proven in the 20th century, along with the existence of | of our Galaxy, the Milky Way, as a separate group of stars was only proven in the 20th century, along with the existence of | ||
| "external" galaxies, and soon after, the expansion of the universe seen in the recession of most galaxies from us. | "external" galaxies, and soon after, the expansion of the universe seen in the recession of most galaxies from us. | ||
| Cosmology, a discipline that has a large intersection with | Cosmology, a discipline that has a large intersection with | ||
| astronomy, made huge advances during the 20th century, | astronomy, made huge advances during the 20th century, | ||
| with the model of the hot ] heavily supported by the | with the model of the hot ] heavily supported by the | ||
| evidence provided by astronomy and physics. | evidence provided by astronomy and physics. | ||
| For a more detailed history of astronomy, see the ]. | For a more detailed history of astronomy, see the ]. | ||
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| '''Division by way of obtaining information''' | '''Division by way of obtaining information''' | ||
| Given its huge scope, astronomy is divided into different branches. | Given its huge scope, astronomy is divided into different branches. | ||
| The divisions are not unique, however, and the intersections, as | The divisions are not unique, however, and the intersections, as | ||
| well as astronomers who work in several areas, are the rule more | well as astronomers who work in several areas, are the rule more | ||
| than the exception. | than the exception. | ||
| In astronomy, the main way of obtaining information is through | In astronomy, the main way of obtaining information is through | ||
| the detection and analysis of ]. | the detection and analysis of ]. | ||
| A traditional division of astronomy is given by the region of | A traditional division of astronomy is given by the region of | ||
| the ] observed: | the ] observed: | ||
| *] refers to the techniques used to detect and analize light in and slightly around the ]s than can be detected with the ]s (about 400 - 800 nm). The most common tool is the ]. | *] refers to the techniques used to detect and analize light in and slightly around the ]s than can be detected with the ]s (about 400 - 800 nm). The most common tool is the ]. | ||
| *] deals with using infrared light (wavelenghts longer than the red). Again, the most common tool is the ], but at longer wavelengths. Space telescopes are also used to eliminate noise from the atmosphere. | |||
| *] deals with using infrared radiation (wavelengths longer than the red light). Again, the most common tool is the ], but at longer wavelengths. Space telescopes are also used to eliminate noise ( electromagnetic interference) from the atmosphere. | |||
| *] uses completely different techniques: to detect radiation of wavelengths of mm to cm, the receivers are similar to those used in radio broadcast transmission (which uses those wavelengths of radiation). See also ]s. | |||
| *] uses completely different instruments to detect radiation of wavelengths of mm to cm. The receivers are similar to those used in radio broadcast transmission (which uses those wavelengths of radiation). See also ]s. | |||
| Optical and radio astronomy can be done using ground-based observatories, because the ] is transparent at those wavelengths. Infrared light is heavily absorbed by | Optical and radio astronomy can be done using ground-based observatories, because the ] is transparent at those wavelengths. Infrared light is heavily absorbed by | ||
| ], so infrared observatories have to be located in high, dry places or in space. | ], so infrared observatories have to be located in high, dry places or in space. | ||
| The ] is opaque at the wavelengths used by ], ], ] and ], and so observations | The ] is opaque at the wavelengths used by ], ], ] and ], and so observations | ||
| can be carried out only from balloons or ]. | can be carried out only from balloons or ]. | ||
| All the previous disciplines are based on the detection of ], but we also receive information from outside the earth carried by ], ], and, in the near future, ] (see ]). | All the previous disciplines are based on the detection of ], but we also receive information from outside the earth carried by ], ], and, in the near future, ] (see ]). | ||
| '''Division by subject''' | '''Division by subject''' | ||
| Astronomers study many objects including ], ], ], ], ], ], etc. but not every astronomer observes every kind of object. A different division can be made using the regions of space and problems addressed; among them | Astronomers study many objects including ], ], ], ], ], ], etc. but not every astronomer observes every kind of object. A different division can be made using the regions of space and problems addressed; among them | ||
| *] | *] | ||
| *] | *] | ||
| *] | *] | ||
| *] | *] | ||
| *] | *] | ||
| *] | *] | ||
| *] | *] | ||
| The study of the ] of the ] is (in recent times) | The study of the ] of the ] is (in recent times) | ||
| sometimes considered a different discipline, called ] or Planetology | sometimes considered a different discipline, called ] or Planetology | ||
| Also, there are other disciplines that may be considered part | Also, there are other disciplines that may be considered part | ||
| of astronomy, or are interdisciplinary sciences with astronomy | of astronomy, or are interdisciplinary sciences with astronomy | ||
| one of the disciplines: | one of the disciplines: | ||
| *] | *] | ||
| *] | *] | ||
| *] | *] | ||
| *] | *] | ||
| *] | *] | ||
| Astronomy is one of the few sciences where amateurs still play | Astronomy is one of the few sciences where amateurs still play | ||
| an active role. | an active role. | ||
| If your favorite area of research is not mentioned, feel free to | If your favorite area of research is not mentioned, feel free to | ||
| add it. | add it. | ||
| '''Organizations''' | '''Organizations''' | ||
| ] | ] | ||
| ] | ] | ||
| ] | ] | ||
| ] | ] | ||
| ---- | ---- | ||
| ''See also ], ], ].'' | ''See also ], ], ].'' | ||
| '''Basic Concepts''' | '''Basic Concepts''' | ||
| <br>(wikipedia is not a dictionary. Do not add a new page unless the subject deserves one) | <br>(wikipedia is not a dictionary. Do not add a new page unless the subject deserves one) | ||
| *] | *] | ||
| *obliquity of the ecliptic | *obliquity of the ecliptic | ||
| *] | *] | ||
| *rotation | *rotation | ||
| *] | *] | ||
| *] | *] | ||
| *] | *] | ||
| *] | *] | ||
| *retrograde orbit | *retrograde orbit | ||
| *prograde orbit | *prograde orbit | ||
| *] | *] | ||
| *] | *] | ||
| *] | *] | ||
| *] | *] | ||
| *] | *] | ||
| *] | *] | ||
| *revolution | *revolution | ||
| *eccentricity | *eccentricity | ||
| *] | *] | ||
| *] | *] | ||
| *] | *] | ||
| *] | *] | ||
| *] | *] | ||
| *] | *] | ||
| See also ]. | See also ]. | ||
| What are our priorities for writing in this area? To help develop a list of the most basic topics in Astronomy and Astrophysics, please see ]. | What are our priorities for writing in this area? To help develop a list of the most basic topics in Astronomy and Astrophysics, please see ]. | ||
| ---- | ---- | ||
| External links: | External links: | ||
| * | * | ||
| * | * | ||
| ---- | ---- | ||
| /Talk | /Talk | ||
Revision as of 01:33, 12 December 2001
Astronomy, which etymologically means laws of the stars, is the science whose subject is the observation and explanation of events outside the earth. Astrophysics
was born as the application of physics to the phenomena observed
by astronomy, this was only possible once it was understood that the elements that made up the "celestial objects" were the same that made up the Earth, and that the same laws of physics applied. Nearly all astronomers now have a strong background in physics, and the results of observations are always put in an astrophysical context, so
the distinction between astronomy and astrophysics almost doesn't exist anymore.
History
In the early part of its history, Astronomy involved only the
observation and predictions of the motions of the objects in the sky that could be seen with the naked eye. Astronomers were
also usually priests, and for a long time it was believed that
celestial phenomena had an influence on events on earth.
Greeks made some important contributions to astronomy, but
the progress almost stopped during the middle ages, except for
the work of some Arabic astronomers. The renaissance came to
astronomy with the work of Copernicus, who proposed a
heliocentric system. His work was defended, expanded and corrected by the likes of Galileo and Kepler. Newton
created celestial dynamics with his law of gravitation,
that finally explained the motions of the planets. Stars were
found much later to be far away objects, and with advent of
spectroscopy it was proved that they were similar to our own sun,
but with a range of temperatures, masses and sizes. The existence
of our Galaxy, the Milky Way, as a separate group of stars was only proven in the 20th century, along with the existence of
"external" galaxies, and soon after, the expansion of the universe seen in the recession of most galaxies from us.
Cosmology, a discipline that has a large intersection with
astronomy, made huge advances during the 20th century,
with the model of the hot big bang heavily supported by the
evidence provided by astronomy and physics.
For a more detailed history of astronomy, see the history of astronomy.
Division by way of obtaining information
Given its huge scope, astronomy is divided into different branches.
The divisions are not unique, however, and the intersections, as
well as astronomers who work in several areas, are the rule more
than the exception.
In astronomy, the main way of obtaining information is through
the detection and analysis of electromagnetic radiation.
A traditional division of astronomy is given by the region of
the electromagnetic spectrum observed:
- Optical Astronomy refers to the techniques used to detect and analize light in and slightly around the wavelengths than can be detected with the eyes (about 400 - 800 nm). The most common tool is the telescope.
- Infrared Astronomy deals with using infrared radiation (wavelengths longer than the red light). Again, the most common tool is the telescope, but at longer wavelengths. Space telescopes are also used to eliminate noise ( electromagnetic interference) from the atmosphere.
- Radio Astronomy uses completely different instruments to detect radiation of wavelengths of mm to cm. The receivers are similar to those used in radio broadcast transmission (which uses those wavelengths of radiation). See also Radio Telescopes.
Optical and radio astronomy can be done using ground-based observatories, because the atmosphere is transparent at those wavelengths. Infrared light is heavily absorbed by
water vapor, so infrared observatories have to be located in high, dry places or in space.
The atmosphere is opaque at the wavelengths used by X-ray Astronomy, gamma-ray Astronomy, UV Astronomy and Far Infrared Astronomy, and so observations
can be carried out only from balloons or space observatories.
All the previous disciplines are based on the detection of photons, but we also receive information from outside the earth carried by cosmic rays, neutrinos, and, in the near future, gravitational waves (see LIGO).
Division by subject
Astronomers study many objects including planets, stars, novae, star clusters, galaxies, nebulae, etc. but not every astronomer observes every kind of object. A different division can be made using the regions of space and problems addressed; among them
The study of the planets of the solar system is (in recent times)
sometimes considered a different discipline, called Planetary Sciences or Planetology
Also, there are other disciplines that may be considered part
of astronomy, or are interdisciplinary sciences with astronomy
one of the disciplines:
Astronomy is one of the few sciences where amateurs still play
an active role.
If your favorite area of research is not mentioned, feel free to
add it.
Organizations
International Astronomical Union
National Optical Astronomy Observatories
See also Astronomers and Astrophysicists, Amateur Astronomy, History of Astronomy.
Basic Concepts
(wikipedia is not a dictionary. Do not add a new page unless the subject deserves one)
- obliquity of the ecliptic
- rotation
- retrograde orbit
- prograde orbit
- revolution
- eccentricity
See also space science.
What are our priorities for writing in this area? To help develop a list of the most basic topics in Astronomy and Astrophysics, please see Astronomy and Astrophysics basic topics.
External links:
/Talk