Astronomy and related astronomical terms

1. The branch of science that studies the universe beyond Earth's atmosphere.
2. The science of the celestial bodies including the sun, the moon, and the planets; the stars and galaxies; and all other objects in the universe.

Astronomy is concerned with the positions, motions, distances, and physical conditions and with the origins and evolution of the celestial bodies which were mentioned previously.

It is divided into such areas as astrophysics, celestial mechanics, and cosmology and it is one of the oldest recorded sciences with observational records from ancient Babylonia, China, Egypt, and Mexico.

Remarkable recent extensions of the powers of astronomy to explore the universe is in the use of rockets, satellites, space stations, and space probes; while the launching of the Hubble Space Telescope into permanent orbit in 1990 enabled the detection of celestial phenomena seven times more distant than by any earth-based telescope.

The development of astronomy can be divided into four primary periods

1. Ancient astronomy, dating from the first significant contributions of the earliest civilizations to the Almagest of Ptolemy.
2. Medieval astronomy, from the decline of Alexandrian culture to the Renaissance.
3. Modern astronomy, from the Copernican revolution to the present time.
4. The new astronomy of astrophysics, primarily a product of the 20th century.

Astronomy is the science of the celestial bodies; such as, the sun, the moon, and the planets; the stars and galaxies; and all of the other objects in the universe.

Astronomy is concerned with their positions, motions, distances, and physical conditions; as well as, with their origins and evolutions.

Astronomy is considered to be the oldest recorded science because there are records which can be examined from ancient Babylonia, China, Egypt, and Mexico.

As far as we can determine, the Greeks were the first "true astronomers" because they deduced that the earth was a sphere and they attempted to measure its size. A summary of Greek astronomy can be found in Ptolemy of Alexandria's Almagest which contains nearly all that is known of the astronomical observations and theories of the ancients.

The Almagest is also described as being a text on astronomy written by Ptolemy in the second century A.D. setting out his view of the universe with the earth at its center surrounded by spheres.

Ptolemy’s model of an earth-centered universe influenced astronomical thought for over 1,300 years.

In 1543, the Polish astronomer Copernicus demonstrated that the sun, not the earth is the center of our planetary system; and the Italian scientist, Galileo, was the first to use a telescope for astronomical study, in 1609-1610.

The 17th century saw several momentous developments; such as, Johannes Kepler's discovery of the principles of planetary motion, Galileo's application of the telescope to astronomical observation, and Isaac Newton's formulation of the laws of motion and gravitation.

The most remarkable recent extension of the powers of astronomy to explore the universe is in the use of rockets, satellites, space stations, and space probes; while the launching of the Hubble Space Telescope into permanent orbit in 1990 has enabled the detection of celestial phenomena seven times farther than by any earth-based telescope.

Use of photography in astronomical research or the art of photographing astronomical objects and events for astronomical studies.

The first successful photograph of a celestial object was the daguerreotype plate of the moon taken by John W. Draper (1811-1882) of the United States in March, 1840.

The first photograph of a star, Vega, was taken by U.S. astronomer William C. Bond (1789-1859) in 1850. Modern-day astrophotography now uses techniques; such as, charge-coupled devices (CCDs); forming images electronically.

1. The science concerning the physical properties of the universe; such as, light, chemical makeup, gravitational forces, etc.
2. A branch of astronomy dealing with the behavior, physical properties, and dynamic processes of celestial objects and phenomena.

A constellation of the northern hemisphere, represented as a charioteer.

Its brightest star is the first-magnitude Capella, about 45 light-years from Earth. Epsilon Aurigae is an eclipsing binary star with a period of 27 years, the longest of its kind.

Colored light in the night sky near the earth's magnetic poles, called aurora borealis , "northern lights" in the northern hemisphere and aurora australis in the southern hemisphere.

Although aurorae are usually restricted to the polar skies, fluctuations in the solar wind occasionally cause them to be visible at lower latitudes.

Aurorae are caused at heights of over 100 kilometers or 60 miles by a fast stream of charged particles from solar flares and low-density "holes" in the sun's corona.

"Southern lights" or colored lights in the night sky near the earth's magnetic pole in the southern hemisphere.

1. The colored lights seen in the skies around the North Pole.

Caused by the interaction between the solar wind, the earth's magnetic field and the upper atmosphere.

A similar effect happens in the southern hemisphere where it is known as the aurora australis.

2. "Northern lights" or colored lights in the night sky near the earth's magnetic pole in the northern hemisphere of the earth.

The intersection of the ecliptic and the celestial equator that the sun passes each year on its way to southern (negative) declinations which occurs on September 23.

An imaginary or theoretical line around which a body or object; such as, a planet, rotates.

1. Bright points of sunlight that briefly appear around the moon immediately before and after a total eclipse of the sun which are caused by sunlight shining through valleys on the moon.
2. A chain of several bright "beads" of white light, visible just before or after totality at a solar eclipse.

The effect occurs when bits of photosphere shine through valleys at the moon's edge.

Named after Francis Baily (1774-1844), a British astronomer.

The point at which all the mass in a system of masses; such as, in the earth-moon system, may be considered to be concentrated.

The Greek letters assigned to the stars in a constellation, usually in order of brightness as presented by Johann Bayer in his sky atlas (1603).

Johann Bayer was a German lawyer and uranographer (celestial cartographer or someone who maps stars, galaxies, and other celestial bodies). He is most famous for his star atlas Uranometria, published in 1603, which was the first atlas to cover the entire celestial sphere.

It introduced a new system of star designation which has become known as the "Bayer designation". It introduced twelve new constellations to fill in the far south of the sky, which was unknown to ancient Greece and Rome.

Dark bands in the clouds on giant planets; such as, Jupiter.

1. A theory of the origin of the universe in which all matter and space originated in a cataclysmic explosion, the remnant of which we see in the present expansion of the universe as a whole.
2. The hypothetical "massive explosive" event that is said to have marked the origin of the universe as we know it, about 18 billion years ago.

According to the theory, at the time of the Big Bang, the entire universe was squeezed into a hot, superdense state and the explosion threw the compact material outward, producing the expanding universe.