Galileo Galilei
06-08-2009, 01:51 PM
The incredible Galileo Galilei
The International Year of Astronomy
By: DAVID CANAVAN
Published: 9/06/2009 at 12:00 AM
Newspaper section: Learningpost
This year has been chosen to be the International Year of Astronomy (IYA2009) as it marks the 400th year since Galileo Galilei first used a telescope to observe the skies.
Galileo Galilei
The goals of IYA2009 are to increase interest in astronomy, to know your place in space, and to increase scientific awareness and popularity. They are aimed mainly at young people, but the celebration is something that could and should be of interest to everyone and anyone. I'm all for it, hence all the space-related articles recently!
Why is Galileo so important?
Born in 1564, Galileo Galilei was nothing short of a genius. In fact, it is for the same reasons that I admire Charles Darwin that I do Galileo; that is, both of them questioned accepted "facts" at the time, based on their own observations and research.
For Darwin it didn't work out very well, though, as he suffered ridicule and dissent, but, for Galileo, it was much worse!
Controversial conformity
Galileo is probably most remembered for his rejection of the geocentric view of the universe, and instead conforming to the Copernican, heliocentric view of the universe. Basically, the religious bodies at the time taught that the Earth was the centre of the universe, around which everything, including the sun, orbited.
Galileo, after much telescopic study of the night sky, concluded that the sun was the centre of our galaxy and that the Earth and other celestial bodies revolve around the sun. The Catholic Church, however, didn't agree with this philosophy and vehemently rejected his research.
In 1633, the Catholic Church convicted Galileo of heresy and sentenced him to life in prison, but, due to his advancing years, he was allowed to serve his sentence in his house near Florence. Galileo eventually went blind and died at the age of 78 in 1642, which was, incidentally, the year Sir Isaac Newton was born.
Galileo's work proved hugely influential to Newton, especially in Newton's work on forces. Undoubtedly, when Newton said, "If I have seen further, it is by standing on the shoulders of giants", he must have had Galileo in mind.
A feat of engineering
As mentioned, IYA2009 was chosen as it is 400 years since Galileo first used a telescope, but it has much more significance than merely that. Galileo didn't just use a telescope; he revolutionised it.
He had heard of a design in Holland, whereby, through the use of lenses, distant things were seen closer than they actually were. From this mere idea, he started to experiment with his own lenses, grinding and polishing them to produce telescopic images far clearer and superior to any other telescopes previously made.
From his own telescopes, he could initially view the heavens with up to three or four times magnification, but this led him to develop telescopes with eight to nine times magnification, and later, up to 30 times magnification. This new outlook on the world led to incredible discoveries.
He was the first person to see Jupiter's moons, four of them in this case. He also observed that Venus orbited the sun, based on its phases, which was one of his reasons for discounting the geocentric view of the universe.
He observed Saturn and its rings, and also the sunspots on the sun. Based on shadows and light, he identified that the moon had craters and that it was rough on the surface, like Earth. He also observed that the Milky Way was composed of stars and not just clouds of dust, which was the prevailing thought.
Galileo also used modified telescopic devices to observe insects at close range, and thus made a compound microscope. His work in optics was simply revolutionary.
Physics
Galileo was not only an astronomer. He was also a very accomplished physicist. Before Galileo, many of the world's ideas were based on Aristotle's teachings. Galileo famously proposed that if two objects of the same material but of different mass were dropped from the Tower of Pisa, they would fall at the same rate.
This is contrary to what Aristotle stated, that heavier objects fall at a quicker rate than lighter ones. Galileo stated that all objects fall with a uniform acceleration when air resistance is negligible or if they were to fall in a vacuum.
Although Galileo never actually carried out an experiment at the Tower of Pisa, Commander David Scott proved Galileo's theory of falling bodies on his Apollo 15 moon mission in 1971. Commander Scott dropped a hammer and a feather at the same time and they fell at the same rate and hit the surface of the moon at exactly the same time.
They did so because there is no atmosphere on the moon, and therefore no air resistance.
Although they fell at a slower rate, due to the force of gravity being about one-sixth of that on Earth, the point is, Galileo was right, and all objects fall at the same rate in a vacuum. Brilliant!
Thought experiments
Galileo's object-drop from the Tower of Pisa is known as a thought experiment, and Galileo had a few of these. Another classic thought experiment is that if you roll a ball down an inclined plane that slopes up at an equal angle on the other side in a V shape, with no friction, it will roll up the other side to the exact same height at which it started.
Then, if you reduce the angle of the slope on which it rolls up, it will still roll up to the height it started, but this time the length of the upward slope would be longer. If you continue to reduce the angle until it is almost flat, the ball will keep rolling with no added energy until it got to the original height, essentially rolling on forever!
This developed into the law of inertia, which states that objects with mass resist changes in their motion. Aristotle stated that moving objects will eventually come to rest, whereas Galileo, and later Newton, building upon Aristotle's ideas, stated that objects come to rest because of friction and not as a natural tendency.
In summary, Galileo was an amazing man and a radical thinker. His works influenced many other great scientists. But most importantly, he stood by what he knew was right in the face of his critics.
Visit http://www.astronomy2009.org to learn more about the International Year of Astronomy.
Dave Canavan has an MSc in Behavioural Ecology and is the Head of Secondary at Garden International School. Dave is fascinated by science and loves animals, especially the dangerous kind! You may contact Dave at davidc@gardenbangkok.com .
http://www.bangkokpost.com/life/education/18162/the-incredible-galileo-galilei
The International Year of Astronomy
By: DAVID CANAVAN
Published: 9/06/2009 at 12:00 AM
Newspaper section: Learningpost
This year has been chosen to be the International Year of Astronomy (IYA2009) as it marks the 400th year since Galileo Galilei first used a telescope to observe the skies.
Galileo Galilei
The goals of IYA2009 are to increase interest in astronomy, to know your place in space, and to increase scientific awareness and popularity. They are aimed mainly at young people, but the celebration is something that could and should be of interest to everyone and anyone. I'm all for it, hence all the space-related articles recently!
Why is Galileo so important?
Born in 1564, Galileo Galilei was nothing short of a genius. In fact, it is for the same reasons that I admire Charles Darwin that I do Galileo; that is, both of them questioned accepted "facts" at the time, based on their own observations and research.
For Darwin it didn't work out very well, though, as he suffered ridicule and dissent, but, for Galileo, it was much worse!
Controversial conformity
Galileo is probably most remembered for his rejection of the geocentric view of the universe, and instead conforming to the Copernican, heliocentric view of the universe. Basically, the religious bodies at the time taught that the Earth was the centre of the universe, around which everything, including the sun, orbited.
Galileo, after much telescopic study of the night sky, concluded that the sun was the centre of our galaxy and that the Earth and other celestial bodies revolve around the sun. The Catholic Church, however, didn't agree with this philosophy and vehemently rejected his research.
In 1633, the Catholic Church convicted Galileo of heresy and sentenced him to life in prison, but, due to his advancing years, he was allowed to serve his sentence in his house near Florence. Galileo eventually went blind and died at the age of 78 in 1642, which was, incidentally, the year Sir Isaac Newton was born.
Galileo's work proved hugely influential to Newton, especially in Newton's work on forces. Undoubtedly, when Newton said, "If I have seen further, it is by standing on the shoulders of giants", he must have had Galileo in mind.
A feat of engineering
As mentioned, IYA2009 was chosen as it is 400 years since Galileo first used a telescope, but it has much more significance than merely that. Galileo didn't just use a telescope; he revolutionised it.
He had heard of a design in Holland, whereby, through the use of lenses, distant things were seen closer than they actually were. From this mere idea, he started to experiment with his own lenses, grinding and polishing them to produce telescopic images far clearer and superior to any other telescopes previously made.
From his own telescopes, he could initially view the heavens with up to three or four times magnification, but this led him to develop telescopes with eight to nine times magnification, and later, up to 30 times magnification. This new outlook on the world led to incredible discoveries.
He was the first person to see Jupiter's moons, four of them in this case. He also observed that Venus orbited the sun, based on its phases, which was one of his reasons for discounting the geocentric view of the universe.
He observed Saturn and its rings, and also the sunspots on the sun. Based on shadows and light, he identified that the moon had craters and that it was rough on the surface, like Earth. He also observed that the Milky Way was composed of stars and not just clouds of dust, which was the prevailing thought.
Galileo also used modified telescopic devices to observe insects at close range, and thus made a compound microscope. His work in optics was simply revolutionary.
Physics
Galileo was not only an astronomer. He was also a very accomplished physicist. Before Galileo, many of the world's ideas were based on Aristotle's teachings. Galileo famously proposed that if two objects of the same material but of different mass were dropped from the Tower of Pisa, they would fall at the same rate.
This is contrary to what Aristotle stated, that heavier objects fall at a quicker rate than lighter ones. Galileo stated that all objects fall with a uniform acceleration when air resistance is negligible or if they were to fall in a vacuum.
Although Galileo never actually carried out an experiment at the Tower of Pisa, Commander David Scott proved Galileo's theory of falling bodies on his Apollo 15 moon mission in 1971. Commander Scott dropped a hammer and a feather at the same time and they fell at the same rate and hit the surface of the moon at exactly the same time.
They did so because there is no atmosphere on the moon, and therefore no air resistance.
Although they fell at a slower rate, due to the force of gravity being about one-sixth of that on Earth, the point is, Galileo was right, and all objects fall at the same rate in a vacuum. Brilliant!
Thought experiments
Galileo's object-drop from the Tower of Pisa is known as a thought experiment, and Galileo had a few of these. Another classic thought experiment is that if you roll a ball down an inclined plane that slopes up at an equal angle on the other side in a V shape, with no friction, it will roll up the other side to the exact same height at which it started.
Then, if you reduce the angle of the slope on which it rolls up, it will still roll up to the height it started, but this time the length of the upward slope would be longer. If you continue to reduce the angle until it is almost flat, the ball will keep rolling with no added energy until it got to the original height, essentially rolling on forever!
This developed into the law of inertia, which states that objects with mass resist changes in their motion. Aristotle stated that moving objects will eventually come to rest, whereas Galileo, and later Newton, building upon Aristotle's ideas, stated that objects come to rest because of friction and not as a natural tendency.
In summary, Galileo was an amazing man and a radical thinker. His works influenced many other great scientists. But most importantly, he stood by what he knew was right in the face of his critics.
Visit http://www.astronomy2009.org to learn more about the International Year of Astronomy.
Dave Canavan has an MSc in Behavioural Ecology and is the Head of Secondary at Garden International School. Dave is fascinated by science and loves animals, especially the dangerous kind! You may contact Dave at davidc@gardenbangkok.com .
http://www.bangkokpost.com/life/education/18162/the-incredible-galileo-galilei