When you step outside the crystal clear night sky and look up
in awe as you see black velvet from horizon to horizon, scattered with
thousands of perfect pinpoints of light, you are doing astronomy. Depending on where you look you can be
looking hundreds, thousands or millions of years into the past, looking at
planets millions of miles away, light from newborn stars reaches your eyes at
the same time as the dazzling nova of a star in its death throes. The night sky
is huge, beautiful, inspiring and full of things to discover, understand and
see. It wasn�t until people stopped
looking in wander at this mesmeric spectacle and started using their ingenuity
to analyse it that astronomy ceased being another philosophy and became a
science.
Astronomy
is derived from two Greek words astron meaning
�star� and nomos meaning �law�.
Astronomy as a science is very old
indeed. Ancient cultures dating from
thousands of years BC used to make regular and accurate observations of the
night sky. Artefacts from these areas have been discovered dating back to 3,300
BC and possibly earlier. To begin with a
astronomers simply used their eyes, then tools such as quadrants and sextants.
It wasn�t until the invention of the telescope by Hans Lipperhey though, that astronomy
blossomed and grew into the diverse range of interrelated sciences that it is
today.
The two things that have driven
progress in astronomy are undoubtedly the advance move and enhancement in
technology over the last 10 to 15 years, as well as enthusiasm of the
astronomers, astrophysicists, cosmologists, and engineers dedicated to this
field.
Astronomy is predominantly concerned
the study of phenomena outside the Earth�s atmosphere, such as the cosmic background
radiation, quasars, exoplanets, and the diverse range of celestial bodies
including Planets, moons stars and nebula. The majority of these multitudinous
specializations fall into two general categories, theoretical and observational
astronomy. The majority of
observational astronomy is based on observing different parts of the
electromagnetic spectrum, such as infrared and visible light. However more recently there are also branches
of astronomy that do not rely on conventional techniques, such as neutrino
detectors. Theoretical astronomy is concerned with making predictions, or
creating rules to explain what is observed by observational astronomers, such
as the cosmic background radiation, quasars, and exoplanets. Often the two
fields interrelate and reinforce each other, but it gets much more exciting
when they disagree. Astronomy is one of the few sciences that amateurs can
still make great contributions towards.
In fact many discoveries, even recently, have been or are being made amateurs.
Before
astronomers began augmenting their vision with the telescope astronomy
comprised of observations and predictions of the behaviour of visible
objects. Strong evidence of this exists
in structures such as Stonehenge which is capable of tracking the motion of
multiple celestial bodies accurately. It
is likely such structures to monitor the passing of seasons, which would be
useful information when trying to determine when to plant crops, or to track
the passage of time and predict special days such as the summer and winter
solstice.
Some of
the greatest early astronomers hail from the Middle East from countries such as
Persia and India. Civilisations in
Greece, Egypt, China and many other places also constructed astronomical
observatories. These early sun centred
where the nature of the universe was investigated predominantly occupy
themselves with astrometry. It IS from
these ancient observatories that geocentrism originated, where the sun and Moon
and other heavenly bodies were believed to rotate around the Earth.
Some
notable discoveries in astronomy include the discovery of the saros by the
Chaldeans, the cycle upon which lunar eclipses repeat. Another example was the discovery of planets
passing through the signs of the zodiac (the word planet literally translates
as wanderer, because the Greeks and notice them wandering through the night
sky). Quite possibly the greatest discovery was that the debunking off Aristotle’s
(original) and Ptolemy’s (modified) geocentric universe, during the renaissance
by Nicolaus Copernicus, with observational data from Galileo Galilei,
revolutionising astronomy with the telescope. To the frustration of the old
Catholic Church, these observations were supported by their own astronomer
Tycho Brahe, whose assistant Johannes Kepler discovered that the planets
orbited the sun not in perfect circles, but ellipses instead.
Kepler
first devised a system that described the motion of planets with the sun at the
centre. It wasn’t until Newton divides
the laws gravity and celestial mechanics that this system could be
explained. It was also Newton to develop
the reflecting telescope (also known as Newtonian reflectors)