Nicholas Jeffers
Big History
Mrs. Keehn
10/29/12
2.BHI Changing Minds
Part I
1. I changed my mind about playing the last football game of the season. I changed my mind because, even though my doctor suggested for me not to, I really wanted to and he signed my paper so I was able to. I think historians and scientist change their minds because their standards change. With them using newer and better technology they find new information and new discoveries which might make them change their minds about what they believed before. For example scientist changed their minds about Pluto being a planet. After more observation they decided what the standards were for being a planet
Part II
1. I think David Christian meant that Ptolemy's model didn't have all the answers to how the Universe works and other astronomers were starting to question his model when he said, "Some astronomers had pointed out that Ptolemy's model had tough time explaining some things, such as the fact that periodically planets seem to move backwards".
Yes the planets do seem to move in the night sky because of the angel it is from Earth and the planets' paths of travel. No, i have never seen the planets move backwards in the nigh sky
2. We can see Mercury, Venus, Mars, Jupiter, Saturn, and the stars with only our eyes. From where we are yes, it looks and seems like Earth is the center of the Universe because it looks like everything is around and circling us.
It looks like Mars makes a loop in a in the night sky because it's an illusion. This illusion happens because Earth is actually orbiting the Sun faster then Mars does and Earth does not obit the Sun on the same plane as Mars does.
Ptolemy Thought that Earth was the center of the Universe and that the Moon, Mercury, Venus, the Sun, Mars, Jupiter, and Saturn all revolved around the Earth in perfect circles. While they all obit the Earth they all also make epicycles which explains why some planets look like they go backwards. I think Ptolemy's answer is the best he could do with his eye. I think he thought very hard about how things could work and his theory explained almost everything. Not exactly, because he thought the planets moved in perfect circles and that doesn't explain how the Night sky changes over years. i think his explanation was so popular for over 1400 years because they didn't have the technology they need back then to get information and evidence to prove him wrong, and Ptolemy had a lot of evidence or enough for his answer to make some sense to people.
3. Copernicus changed his mind about the Universe and the Earth's place in it because he came up with the thought of the Sun being the center of the Universe which explains all the "unusual movements of the planets". With Earth spinning on axises and orbiting the Sun along with all the other planets it explains the illusion of the other planets, like Mars, going backwards. From calculations Copernicus found that Earth is the third planet from the Sun. Copernicus supported his claims with logic. With his calculations and the explanations his theory gives, like the Earth orbiting faster then Mars and that's why Mars seems to move backwards at times, supports his claims.
Galileo changed his mind about the Universe and the Earth's place in it because of Copernicus and how it makes more sense then Ptolemy's theory. Galileo tested his claim by examining the sky on five different nights using his telescope and seeing that the mons of Jupiter changed position every night but always seemed to be bright, close to jupiter, and in some form of a line. Yes, Galileo accepted Copernicus' authority. Galileo got more evidence though, by finding that Jupiter has moons it shows that smaller objects orbit the objects that have more mass and gravity like Earth orbiting the Sun.
Part III
1. My investigation of Ptolemy, Copernicus, and Galileo supported my initial conjecture by confirming what I thought I knew with facts, and extended it by explaining to me what retrograde motion is and that is why Copernicus declined Ptolemy's theory and came up with the idea of the Sun being the center of the Universe.
I think copernicus changed his mind because with the Sun being the center of the Universe and the Earth rotating on an axis, retrograde motion makes sense. My evidence would be that Copernicus came up with the idea of the Sun being the center of the Universe and the Earth rotating on an axis.
I think Galileo changed his mind because Copernicus' idea made sense and explained retrograde motion and also explained how Earth moved. My evidence would be that Galileo accepted Copernicus' authority.
Part IV
Copernicus was the astronomer who discovered that the Sun was the center of the Universe and that the Earth rotated on it axises. I think Copernicus rejected Ptolemy's geocentric view and his idea about epicycles because it couldn't explain the the reason for retrograde motion and all the other unusual movements from the planets. With the Earth orbiting the Sun with the other planets and moving faster then some explains why some planets seemed to move backwards. The Earth rotating on its axises explains night and day too. Copernicus was using logic to support his claim.
Galileo was another astronomer who studied the Universe as a Sun centered Universe. I think Galileo rejected Ptolemy's geocentric view of the Universe and his ideas of epicycles because of Copernicus' idea was able to explain more simply the data and evidence that was already there. Galileo supported Copernicus' claim by using his telescope and discovering Jupiter's four moons orbiting Jupiter. This shows that Jupiter also has objects orbiting it like Earth orbiting the Sun. Galileo supported his claim with evidence.
Scientist change their minds from more evidence and better logic. If a new claim explains more and has more evidence then scientist may change their minds. Scientist, astronomers, and people changed their minds about the geocentric Universe because the Sun centered Universe could explain the reasons for things more simply. Copernicus also was good with math and used some calculations to back up his claim for the Earth orbiting the Sun faster then other planets. Galileo accepted and agreed with Copernicus' authority and based his studies off of him which helped him change his mind.
Ptolemy, Copernicus, and Galileo were three of the best astronomers. These astronomers were the first to explain the Universe to people and explain how the Universe worked. Over time Ptolemy's claim was rejected by Copernicus who discovered that Earth was not the center of the Universe but that the Sun was. Copernicus was able to explain what Ptolemy couldn't about the unusual movements in the night sky. Galileo accepted Copernicus' claim. Also, with his telescope he discovered new moons around Jupiter.
