Download Branches of Astronomy

University Mohamed Khider- Biskra
Faculty of letters and Languages
Department of Foreign Languages
Division of English
English for Specific Purposes
Level: Third year
Instructor: Mrs.SAID SALHI -A
Astronomy
Webster’s Dictionary defines Astronomy as “the study of objects and matter outside the earth's atmosphere and of their physical
and chemical properties.” Truthfully, though, you could say that astronomy is the study of everything, because everything is a part
of the Universe.
There are many fields within Astronomy. Cosmologists study the Universe as a whole, including its beginnings. Astrometrists
measure great distances. Planetologists study planets within our own Solar System as well as those orbiting distant stars. Radio
Astronomers use radio-telescopes to study the Universe. There are also Mathematical Astronomers who use numbers, calculations
and statistics to explain the universe.
Astronomy is not a “stand-alone” science. It combines areas from a number of other fields, including mathematics, chemistry,
geology, biology and physics. In fact, physics is such an integral part of the field that many astronomers are also known as
Astrophysicists.
Why should we study the Universe? As mentioned above, everything is part of the Universe, and that includes us. The Earth circles
the Sun, which is a star called Sol, and just like all the other stars it is part of Outer Space. Hopefully, as you learn more about the
subject, you’ll appreciate just how much astronomy has affected and continues to affect your life.
Astronomy, derived from the Greek words for star law, is the scientific study of all objects beyond our world. It is also the process
by which we seek to understand the physical laws and origins of our universe.
Astronomy is a natural science that is the study of celestial objects (such as moons, planets, stars, nebulae, and galaxies), the
physics, chemistry, mathematics, and evolution of such objects.
Pioneers of Astronomy
Over the centuries there have been countless innovators that have contributed to the development and advancement of astronomy.
Some of these key individuals include:
Nicolaus Copernicus (1473 - 1543)
Tycho Brahe (1546 - 1601)
Johannes Kepler (1571 - 1630)
Galileo Galilei (1564 - 1642)
Isaac Newton (1642 - 1727)
Albert Einstein (1879 - 1955)
Edwin Hubble (1889 - 1953)
Stephen Hawking (1942 -
)
Branches of Astronomy
There are really two main branches of astronomy: optical astronomy (the study of celestial objects in the visible band) and non-optical
astronomy (the use of instruments to study objects in the radio through gamma-ray wavelengths).
1. Optical Astronomy: Today, when we think about optical astronomy, we most instantly visualize the amazing images
from the Hubble Space Telescope (HST), or close up images of the planets taken by various space probes. What most people
don’t realize though, is that these images also yield volumes of information about the structure, nature and evolution of
objects in our Universe.
2. Non-optical Astronomy: While optical telescopes are sometimes considered the only pure instruments for doing
astronomy research, there are other types of observatories that make significant contributions to our understanding of the
Universe. These instruments have allowed us to create a picture of our universe that spans the entire electromagnetic
spectrum, from low energy radio signals, to ultra high energy gamma-rays. They give us information about the evolution
and physics of some of the Universe’s most dynamic treasures, such as neutron stars and black holes.
Subfields of Astronomy
There are so many types of objects that astronomers study, that it is convenient to break astronomy up into subfields of study.
1. Planetary Astronomy: Researchers in this subfield focus their studies on planets, both within and outside our solar
system, as well as objects like asteroids and comets.
2. Solar Astronomy: While the sun has been studied for centuries, there is still a significant amount of active research
conducted. Particularly, scientists are interested in learning how the Sun changes, and trying to understand how these
changes affect the Earth.
3. Stellar Astronomy: Simply, stellar astronomy is the study of stars, including their creation, evolution and death.
Astronomers use instruments to study different objects across all wavelengths, and use the information to create physical
models of the stars.
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Galactic Astronomy: The Milky Way Galaxy is a very complex system of stars, nebulae, and dust. Astronomers study the
motion and evolution of the Milky Way in order to learn how galaxies are formed.
Extragalactic Astronomy: Astronomers study other galaxies in the Universe to learn how galaxies are grouped and
interact on a large scale.
Cosmology: Cosmologists study the structure of the Universe in order to understand its creation. They typically focus on
the big picture, and attempt to model what the Universe would have looked like only moments after the Big Bang.
Glossary of Basic Astronomy Terms
Annular eclipse - a type of solar eclipse in which a ring (annulus) of sunlight remains visible.
Asteroid - a "minor planet" ,a chunk of rock smaller than planet-size but larger than a meteoroid, in orbit around a star.
Asteroid belt - a region of the solar system, between the orbits of Mars and Jupiter, in which most of the asteroids orbit.
Astronomical Unit (A.U.) - The average distance from the Earth to the Sun.
Astrophysics - The science of applying the laws of physics to the universe.
Belts - Dark bands around certain planets, like Jupiter.
Black hole - A region of space that nothing, not even light, can escape from.
Coma - The region around the head of a comet.
Comet - A object orbiting the sun that when it gets close to the sun shows a coma and may show a tail.
Constellation - one of 88 areas that the sky has been divided into to make finding a star or other object easier.
Continental drift - The slow movement of the continents across the Earth’s surface.
Core - The center of a star or planet.
Double Star - A binary star; two or more stars orbiting each other.
Dust tail - the dust left behind a comet, reflecting sunlight.
Eclipse - When one "body" (like the moon) passes through the shadow of another.
Fireball - an very bright meteor.
Full moon - The phase of the moon when the side facing the earth is completely lit by sunlight.
Geology - the study of the Earth.
Giant planets - Jupiter, Saturn, Uranus, and Neptune.
Gibbous moon - the phases between half moon and full moon.
Great Red Spot - Thel large red storm going around like a tornado on Jupiter.
Highlands - Places on the moon that are above the level that may have been smoothed by flowing lava.
Light year - the distance that light travels in one year.
Lunar eclipse - When the moon passes into the earth’s shadow.
Meteor - A streak of light in the sky from rock or dust burning up as it falls through the earth’s atmosphere.
Meteorite - An chunk of rock from space after it hits a planet or moon, especially on the earth.
Meteoroid - An chunk of rock from space that is smaller than an asteroid.
New moon - The phase when the side of the moon facing the earth is the side that is not lit at all by sunlight.
One Year - the length of time the Earth takes to orbit the Sun.
Radio telescope - An antenna or set of antennas that is used to detect radio radiation from space.
Shooting stars - Meteors.
Showers - When many meteors enter our atmosphere at once, or almost at once.
Spring tides - The tides of the ocean are at their highest when the earth, moon, and sun are in a line.
Star - a ball of gas that makes its own light and heat because of nuclear reaction in its center.
Tail - Gas and dust left behind as a comet orbits close to the sun. The sunlight makes the tail bright.
Terrestrial Planets - Mercury, Venus, Earth and Mars.
Very Large Array (VLA) - The National Radio Astronomy Observatory’s set of radio telescopes in New Mexico.
Astronomy vs. Astrology
Astrology has little in common astronomy. Astronomy is a science. Astrology is not. Astrology claims to study the effect heavenly
bodies have on human events. Astrologers believe that all things in the cosmos are connected to one another, and that by tracking
astronomical phenomena they can learn things about human events. Astrologers are known for believing that the position of the
stars during birth has an effect on each person’s personality traits. This popular form of astrology is well known to most people in
the form of the Horoscope. Astrology is considered by the scientific community to be nothing more than a ‘psuedoscience’. The
findings of astrology cannot be demonstrated scientifically.