Lecture2 part4 video
Summary
TLDRIn this lecture, the focus shifts to Galileo's pivotal contributions to astronomy in the early 1600s, particularly his use of the telescope to observe celestial bodies. His observations, including the moon's craters, Jupiter's moons, and Venus' phases, contradicted Greek beliefs and supported Kepler's heliocentric model. Despite facing house arrest, Galileo's work laid the groundwork for Newton's advancements in physics, astronomy, and mathematics, marking the dawn of modern science.
Takeaways
- đ This lecture segment discusses the astronomical contributions of Galileo, who worked in southern Europe around the same time as Kepler.
- đ Galileo is renowned for being the first to use a telescope to observe celestial bodies, which significantly supported Kepler's laws of planetary motion.
- đ Galileo's observations of the moon's surface, including craters and mountains, contradicted the Greek belief in perfect, unblemished heavenly spheres.
- đȘ He discovered Jupiter's moons (the Galilean moons), which orbit Jupiter, demonstrating that Earth is not the sole center of motion in the universe.
- đ Galileo's observation of Venus's phases provided evidence against the Ptolemaic model and supported the Copernican heliocentric model, where the Sun is at the center.
- đ Despite living in a time when the Catholic Church held significant power, Galileo published his findings, which led to his house arrest but did not deter his scientific pursuits.
- đŹ Galileo's work laid the groundwork for what we now understand as the laws of motion, which Newton later built upon.
- đŽ Isaac Newton, born the same year Galileo died, continued Galileo's work and made groundbreaking contributions to physics, astronomy, and mathematics.
- đ Newton's laws of motion and his concept of gravity formed the basis of classical physics and remained unchallenged until the 20th century when Einstein introduced the theory of relativity.
- đź The lecture concludes with aéąć of upcoming topics, including Newton's laws, the nature of light, the evolution of telescopes, and the progression to modern astronomy.
Q & A
Who is the astronomer discussed in the last part of lecture 2?
-The astronomer discussed in the last part of lecture 2 is Galileo Galilei.
What were Kepler's laws of planetary motion?
-Kepler's laws of planetary motion include: 1) Planets move in ellipses, 2) A line segment joining a planet and the Sun sweeps out equal areas during equal intervals of time, and 3) The square of the orbital period of a planet is directly proportional to the cube of the semi-major axis of its orbit.
In what region of Europe did Galileo Galilei work?
-Galileo Galilei worked in southern Europe, specifically in Italy.
What was Galileo's contribution to the understanding of the moon?
-Galileo observed the moon through a telescope and discovered features like craters and mountains, demonstrating that the moon is not a perfect sphere as the Greeks believed, but has a landscape similar to Earth.
What are the Galilean moons, and how did Galileo discover them?
-The Galilean moons are the four largest moons of Jupiter: Europa, Io, Ganymede, and Callisto. Galileo discovered them by observing points of light around Jupiter through his telescope and recording their positions over time.
How did Galileo's observations of Jupiter's moons support the heliocentric model?
-Galileo's observations showed that Jupiter had moons orbiting it, which demonstrated that not everything revolved around Earth, supporting the heliocentric model where the Sun is the center of motion.
What did Galileo observe about Venus that challenged the Greek model of the universe?
-Galileo observed that Venus displayed phases similar to the moon, which was not predicted by the Greek model but was consistent with the Copernican model where Venus orbits the Sun.
What other scientific contributions did Galileo make besides astronomy?
-Galileo also worked on the laws of motion, which laid the groundwork for what is now attributed to Isaac Newton. He is considered one of the founders of modern science.
What was the consequence of Galileo's publications for him personally?
-Galileo was put under house arrest for the rest of his life due to his publications, as they conflicted with the religious views of the time.
Who was the scientist born in the same year that Galileo died, and what did he contribute to physics and astronomy?
-Isaac Newton was born in the same year that Galileo died. He contributed significantly to physics and astronomy by pioneering the laws of motion, the concept of gravity, and inventing calculus.
What are some of the advancements in astronomy that followed Galileo and Newton's work?
-Following Galileo and Newton's work, astronomy saw advancements such as the discovery of new planets like Uranus and Neptune, the introduction of new technologies like photography, and the development of modern telescopes.
Outlines
đ Galileo's Astronomical Discoveries
This paragraph discusses the significant contributions of Galileo to astronomy in the early 1600s. Despite working in southern Europe, where the Catholic Church's influence was still strong, Galileo corresponded with Kepler and was aware of his laws of planetary motion. Galileo is credited with being the first to use a telescope to observe the sky, which led to groundbreaking discoveries. He observed the moon's surface features like craters and mountains, contradicting the Greek belief in perfect celestial spheres. His observations of Jupiter's moons, now known as the Galilean moons (Europa, Io, Ganymede, and Callisto), demonstrated that celestial bodies other than Earth could have orbiting objects, supporting the heliocentric model. Galileo also observed the phases of Venus, which further supported the Copernican model over the Ptolemaic model. His work laid the foundation for modern science and was accessible to anyone with a telescope, emphasizing the empirical nature of his findings.
đ The Legacy of Galileo and the Dawn of Modern Physics
The second paragraph delves into Galileo's legacy and the transition to modern physics. Despite being put under house arrest in Italy for his publications, Galileo continued his studies, contributing to the early understanding of physics, which would later be formalized by Newton. The paragraph highlights the historical synchronicity of Galileo's death and Newton's birth in 1642, symbolizing a passing of the torch in scientific inquiry. Newton built upon Galileo's work, developing fundamental concepts in physics, astronomy, and mathematics, including the laws of motion, optics, and gravity, and inventing calculus. The paragraph also sets the stage for future lectures on the laws of motion and gravity, the nature of light, and the evolution of telescopes and modern astronomy, leading to a comprehensive understanding of the universe.
Mindmap
Keywords
đĄAstronomy
đĄCopernicus
đĄKepler's Laws of Planetary Motion
đĄGalileo
đĄTelescope
đĄJupiter's Moons
đĄVenus Phases
đĄHeliocentric Model
đĄPhysics
đĄIsaac Newton
đĄModern Astronomy
Highlights
Discussion of the contributions to astronomy by Galileo, a contemporary of Kepler, working in southern Europe around the early 1600s.
Galileo's correspondence with Kepler, where they exchanged ideas and letters.
Invention of the telescope, primarily for navigation and war, but Galileo was the first to use it for astronomical observations.
Galileo's observations of the moon, discovering craters and mountains, challenging the Greek belief in perfect celestial spheres.
Galileo's use of lunar shadows to calculate the height of moon's surface features.
Observation of Jupiter and the discovery of its four moons, later named the Galilean moons.
Galileo's recording of Jupiter's moons' positions over time, demonstrating that not everything revolves around Earth.
Galileo's support for the heliocentric model through his observations of Jupiter's moons.
Observation of Venus through the telescope, revealing phases similar to the moon, contradicting the Greek model and supporting the Copernican model.
Galileo's work on the laws of motion, which would later be attributed to Newton.
Galileo's house arrest in Italy due to his publications, yet he continued his studies.
Isaac Newton's birth in the same year Galileo died, and his continuation of Galileo's work.
Newton's contributions to physics, astronomy, and mathematics, including the laws of motion and gravity, optics, and the invention of calculus.
The transition from Newton's laws to Einstein's theories of relativity in the 20th century.
The impact of Galileo and Newton on the development of modern physics and astronomy.
The upcoming lectures on Newton's laws, the physics of motion, optics, and modern telescopes.
Transcripts
alright folks welcome to the last part
of lecture 2 in this part of the lecture
we're gonna discuss the contributions
made to astronomy by someone working in
southern Europe around the time of
Copernicus alright no sorry not
Copernicus Kepler now if you remember it
from the last part Kepler came up with
the laws of planetary motion so the idea
that planets move in ellipses that's the
first law the second law has to do with
how fast they move over time third law
has to do with how long it takes for one
plan to go once around the Sun now
Kepler was working in northern Europe
and Kepler was able to publish his work
because at this point Northern Europe
the Catholic Church had become much less
important and impressive but the person
were to talk about in this part of the
lecture is working in southern Europe in
the early 1600s
this is Galileo now galileo we know for
sure
correspondent he was a contemporary of
Kepler and corresponding with Kepler
they wrote letters back and forth and
Galileo knew what Kepler was doing now
in the early 1600s in northern Europe
the telescope is invented a telescope
was originally invented mostly I mean it
makes things that are far away look
closer so it was mostly invented for
navigation and war activities but
galileo is the first person we know of
to take a telescope at one he actually
built in his home laboratory once he had
heard how he could build something
he took a telescope and he pointed it at
the sky and what he observed became
hugely important in codifying the idea
that Kepler's laws of planetary motions
were correct because what Galileo does
is he observes things that are happening
in the sky of the telescope and is able
to demonstrate that a lot of the ideas
of the Greeks just aren't true and that
Kepler's ideas make more
now first of all he looks at the moon
and what he finds are things like
craters and shadows cast that what he is
able to demonstrate as the moon is a
ball of rock it has landscape it has
craters and mountains and he's actually
able to use the shadows cast to figure
out the height of those craters and
mountains now this is important because
the Greeks believed the heavens were
perfect perfect spheres now you might
say well the moon looks like it's
covered in craters from our point of
view and the Greeks say yeah it looks
like that but it's just paint on a
perfect sphere Galileo is able to show
yeah no it's not
it has surface features okay
it's landscapes like the Earth's
landscape furthermore he observes
Jupiter now when he observes Jupiter he
notices points of light around Jupiter
and night after night after night he
records those points of light these are
actual recordings of Galileo's and what
those are are Jupiter's moons and over
time he realizes that he's watching
moons okay there four of them that he
can see with his telescope we call him
the Galilean moons they are Europa IO
Ganymede and Callisto and these are
objects that orbit Jupiter and Galileo
is able to watch them orbit Jupiter
night after night after night and what's
important about this is that this
demonstrates that the earth is not the
only centre of motion other objects can
have things that spin around them
furthermore Jupiter is not leaving those
things behind right Jupiter no matter
what you believe
if you believe the earth is the center
of the Sun is the center you believe
Jupiter is moving and Galileo
demonstrates that Jupiter not only is it
moving but it's holding onto moons while
it's moving so maybe the earth can do
the same okay this idea supports the
heliocentric model a Sun being the
center now Galileo
also observes Venus and when you look at
Venus
a telescope it doesn't look like a point
of light it looks like it sends kind of
a phase and this is understandable if
Venus orbits the Sun closer to the Sun
than the earth does so whenever we look
at Venus only part of Venus is lit up we
part of it's lit up we never see it full
because you know Venus being full would
be here you would have to look through
the Sun to see that now if you look at
the Venus phases Ptolemies model the
Greek model does predict Venus goes
through phases but not the same phases
so it makes a prediction that's wrong
again this is science if the prediction
you make is wrong something in your
model is wrong a the Copernican and
Kepler version predicts phases and they
predict them correctly and so we
consider Galileo to be one of the
founders of modern science and in part
what's important about his observations
was that anybody could do them all you
did was telescope you could look and see
does Jupiter have moons
oh it does you know does the surface of
the Moon have craters oh it does just
look through a telescope anyone can do
it now
Galileo also was working on other stuff
specifically physics and working on what
we now call the laws of motion which
today we attribute to Newton Galileo
actually deduced the first one and we'll
talk about that in the next lecture okay
the next lecture will be all about
Newton physics and gravity and how that
applies to astronomy Galileo is actually
the one who starts this inquiry now
Galileo does publish and because he
publishes he lives in southern Europe
and Italy he is put under house arrest
for the rest of his life although he
continues to study the skies and to work
on physics and during that time now
Isaac Newton
so gallileo gallileo dies in the year
1642 Isaac Newton is born that same year
a few months later effect
Galileo dies in early 1642 Newton is
born in like late 1642 and Isaac Newton
picks up where Galileo left off okay he
spends time in his estate in north of
London in the in particular the 1660s he
has to be there because at the time
there was well the plague and he could
it be in London but during this time he
takes for Galileo left off and runs he
figures out fundamental ideas in physics
astronomy and mathematics that are still
obviously in used a he pioneers motion
the physics of motion optics the idea of
gravity he invents calculus hey and it's
not until 20th century when we get to
Einstein that Newton's laws of motion
and gravity were modified into what we
now call a theories of relativity which
is where Einstein comes in and while we
know today that Newton's theories of
gravity gravity itself are inadequate
they don't describe how gravity works on
certain scales ein science gravity is
better but still his laws of motion well
those are still the laws of motion what
Newton learned about optics we still use
today in fact Newton came up with a
design for a telescope that we still use
today and this is basically the
beginning of a really huge uptick in
what we now think of as being modern
physics okay after after Galileo and a
Newton a we have discoveries and
astronomy like discoveries of planets so
Uranus and Neptune Earth's covered in
this time new technologies photography
comes into play
astronomy really takes off now before we
can get to truly modern astronomy there
are still a couple of things we need to
talk about specifically Newton and the
laws of motion and gravity and then
we're to talk about how light works and
then we'll talk about telescopes and
modern telescopes and how modern
astronomy works that would be the next
couple of lectures after that we will
start talking about what we know about
the universe overall so stay tuned
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