Cosmic engine by Chris Rusnak

keep it simple science

St Johns Park High School SL#802444

Worksheet 1 Fill in the Blanks. Check your answers at the back. Brahe’s student r)....................................................... got access to the data after Brahe died, and used it to develop a Heliocentric model in which the planetary orbits were s)....................................... instead of circles.

A a)................................................. model of the Universe places the Earth at the centre, with everything revolving around us. The other main model is called b)......................................................, which places the c)................................... at the centre.

Galileo was the first to make observations with a t).................................. He saw that the planet Jupiter has u)................................................... ................................................... and that Venus went through v)........................................ like the Moon. These observations conflicted with the w)....................................................... model, and supported the x)....................................................... model.

Aristotle proposed a d).............................................. model. This basic concept was accepted for almost e)............................ years. f).................................................. was the first person to propose a g)............................................ model. His idea was not accepted because “parallax” could not be observed in the stars, which were thought to be quite close to the Earth.

It was Sir y)............................................................. who finally proved that the z)...................................................... model is correct. His mathematical theory of aa)........................................... explained how things could be in ab)............................. without needing crystal spheres. More importantly, he could prove mathematically that ac)............................................’s Laws of Planetary Motion were in agreement with gravity.

Claudius h)........................................ developed a mathematically accurate model which could predict i)......................................... and the motions of the planets. His model was j)....................................... and imagined all the “heavenly bodies” to be carried around the k)............................................ by crystal spheres. He had to add smaller spheres, called l)............................................, in order to explain the m)........................................................ motion of the planets. This model was accurate (for the time) and so was accepted for about 1400 years.

All the models developed before the time of Galileo were limited by the available technology. Without ad)...................................., all observations were by ae)................................................... and of limited af).................................................... For example, it is impossible to measure any ag)............................................ even in nearby stars, without a telescope. Since ag)................................... could not be observed, it was logical to accept the ah).......................................................... models of Aristotle and Ptolemy.

Nicholas n)................................................ was the first in (relatively) modern times to propose a o)................................................ model. Tycho Brahe’s contribution was the gathering of p)................................................................................... He hoped it would prove Copernicus to be q)...................................

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