Explain how the solar system was formed:
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Our solar system formed about 4.5 billion years ago from a dense cloud of
interstellar gas and dust.
The cloud collapsed, possibly due to the shockwave of a nearby exploding
star, called a supernova.
When this dust cloud collapsed, it formed a solar nebula—a spinning, swirling
disk of material.
Apply the knowledge of Ptolemy to describe the geocentric model of the solar
system:
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In the geocentric system, the Earth is considered to be the center of
the solar system.
The Moon, the planets, the Sun, and the stars all rotate around the Earth
(which stays still), with uniform circular motion.
They compose the heavens, which are considered to be ethereal and
unchanging.
Apply the knowledge of Copernicus to describe the heliocentric model of the solar
system:
In 1543, Nicolaus Copernicus (1473 – 1543) published “On the Revolutions of the
Celestial Spheres”, in which he explained what many had suspected: that the sun is
at the centre of the universe and we move around it along with all the other planets.
This is called the Heliocentric Model.
Explain how the observations and views of Tycho Brahe, Johannes Kepler, and
Galileo Galilei contributed to our current understanding of the solar system:
Tycho Brahe:
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Tycho Brahe was an astronomer whose personal life was as varied as his
astronomical one.
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Brahe had issues with the Copernican model and proposed a Geo-Heliocentric
Model where the Moon and Sun orbited Earth but everything else orbited the
Sun.
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He believed Earth was too 'lazy' a body to move and his arguments were both
religious and based on observation.
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Brahe made thousands of naked eye observations over many years. He said
that no parallax was visible
Johannes Kepler:
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Kepler was Tycho Brahe's assistant in Prague.
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Despite this he was influenced by Copernicus's writings.
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He refined the heliocentric theory.
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Armed with Tycho's observations he noticed planets did not follow circular
orbits but were elliptical - this became one of his later laws that we shall look
at later.
Galileo Galilei:
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Galileo was the first telescopic observer to make published astronomical
observations.
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He found two discoveries to provide evidence to support the heliocentric
theory including:
Discovery of Jupiter's main moons - if everything orbited Earth, why did these obviously orbit Jupiter?
Venus had phases - How could this occur if it orbited Earth rather than the Sun.
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His publications meant he got into trouble with the Church at the time but his
work ensured the heliocentric became widely accepted after.
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By the time of Isaac Newton the theory had been proved and accepted as fact.
Understand and describe the different moon phases:
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Crescent refers to phases where the Moon is less than half-illuminated, while
gibbous means more than half is illuminated.
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Waxing means “growing” or expanding in illumination, and waning means “shrinking”
or decreasing in illumination.
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After new Moon, a slice of reflected sunlight becomes visible as a waxing crescent.