Download Chapter 14 - Heritage Christian School

Chapter 14. Observing the Universe
astronomy – the study of objects in the universe beyond earth. It is
the oldest of sciences; it began as soon as man looked up and
wondered.
Early beliefs –
In the beginning there was little known about heavenly bodies and the
only tool was the unaided eye. Ancient peoples had their own ideas
about the universe and because it was mysterious, they developed
superstitions and religions centered on the sun, moon and stars. True
science began when men began to track the movements of these
heavenly lights. As result very complex and accurate calendars were
developed, allowing the ancients to predict events and assist in
planting of crops and keeping track of animal migrations. This was
handy as it helped them in the procuring of food.
They noted that:
•
Minor night ‘lights’ seemed to move around a single star (the
North or Polar Star)
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• The positions of the sun and moon repeated with the seasons –
this led to the development of very accurate calendars and
even to the prediction of such phenomena as the phases of the
moon and the solar eclipse.
The phases of the moon
A solar eclipse taken from Kruger National Park in
Zambia.
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A solar eclipse occurs when the moon passes between the Earth and the Sun. Please note that the
size of the sun is meant to show that it is a great distance away from the Earth.
• The Wandering Stars Not all of the minor night ‘lights’ moved
around the Polar Star. There were 5 brighter stars, which
seemed to have paths of their own. These were named after
Greek gods and are now known to be the planets
• Mercury
• Jupiter
• Venus
• Mars
• Saturn
(They were brighter because they were much closer to the Earth, and
traveled ‘weirdly’ because of their orbit around the sun. Stars are
extremely far away and do not orbit the sun.)
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Earth Centered Theory – because the moon, planets, sun and stars
appear to be moving around the Earth, it was felt that the Earth was
the center of the universe. This idea seemed logical to many in light
of how important man is to God (Crown of His creation…).
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Aside:
However, the idea that the Earth is the center of the universe runs
contrary to ancient religious thought. This is because hell was
considered to be at the center of the Earth; therefore, if Earth was the
center of the universe, then hell would in fact be at the center of the
universe. Secularists like to suggest that the Christian church was
supported the Earth Centered Theory and any views to the contrary
were strongly opposed by well meaning church people. A careful
study of history will in fact show this to not be the case. Much of the
momentum for scientific study was provided by the belief in divine
creation and that God’s desire was for us to ‘consider the heavens’.
Sun Centered Theory – from about 1500 AD, the concept that the
sun was at the center of our universe was held. This change occurred
because it explained why the Wandering Stars behaved the way
they did.
Now we believe that the sun is at the center of our solar system but
our solar system is in an unimportant part of one of many galaxies.
(More on that later!)
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Technology – Seeing Beyond
Prior to the 1600s, the only tools available for viewing celestial bodies
were the unaided eye, then in the early 1600s the first telescopes
were developed. From that time on , more and more powerful
methods have been developed for allowing us to look deep into
space. The following is a run - down of these advances.
1609 – Galileo uses a refracting telescope to view the moon. A
refracting telescope uses two or more lenses to gather and
concentrate light.
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1668 Sir Isaac Newton – built the first reflecting telescope. The
advantage was that it could collect and concentrate more light, so this
was a far better design.
1930s – Larger single-mirrored reflecting scopes were developed and
placed in large observatories situated at high elevations. These
extremely large scopes could collect huge amounts of light and
allowed man to see even more than before. Observatories were built
at high altitudes to avoid the pollution which tends to obscure vision.
This observatory is located high in the Swiss Alps. Note the Matterhorn!
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Multiple-mirror reflecting telescopes – the problem with single
mirror scopes is that it is hard to make mirrors that are really big
without having some imperfections in the glass. Not only that, but
glass is extremely heavy and difficult to maneuver. So many six-sided
mirrors were arranged in a curve. This meant that even larger scopes
were now possible.
Radio telescopes – humans can only see in a very narrow range of
the electromagnetic spectrum. This range we commonly call ‘light’.
However, stars give off many other types of rays that we cannot see
unless we have special equipment. Radio telescopes can ‘see’
some of these rays. The advantage is that radio waves go right
through clouds and is not easily obscured by cosmic dust etc. This
invention allows us to see farther and with more clarity than before.
Often many radio telescopes are arranged in groups called arrays.
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These function together like they were a single, humungous
telescope.
Part of an array of radio telescopes.
Hubble Space Telescope – In order to eliminate any atmospheric and
gravitational effects, the HST was launched as an orbiting
observatory. Many of our recent discoveries were attributed to this
piece of technology.
Think, what advantages would there be to eliminating atmospheric
and gravitational effects?
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The Hubble Space Telescope.
Some shots taken by the HST
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space probes – these are space craft that are sent into deep space,
to take pictures which are sent back to Earth. Even though they have
a ‘one-way ticket’ they give us views which are impossible to get from
Earth.
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Mariner II Space Probe. Launched in December 1962
and traveled to Venus. Confirmed that Venus was very hot
and was covered in a thick ammonia/methane cloud.
Binocular scopes - these are when two single scopes which are
separated by some distance are linked electronically together and
focus on the same thing. The image is a combined one.
What next?
How about ‘scopes on the moon?
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