Full transcript
0:00we're ready to start moving on to the
0:02more recent models of the universe and
0:06how we actually understand the universe
0:07and nicolaus copernicus is one of the
0:10more famous early astronomers he really
0:15helped push forward the idea of the
0:17heliocentric or sun-centered model the
0:21idea that earth is not the center the
0:24Sun is again he was definitely not the
0:26first person to suggest this idea but he
0:29really started getting the conversation
0:30going again you can see it's now been
0:32hundreds and hundreds of years we left
0:34off at about a hundred and forty ad with
0:37Ptolemies model that was very
0:40complicated but did a pretty good job of
0:42describing the motion of objects but by
0:45this point they've started to get more
0:46and more observations that see that his
0:49model still doesn't fit perfectly and so
0:52people like Copernicus we really started
0:54pushing forward the idea of the
0:55heliocentric model and actually he
0:57published a book in the book he wrote
0:59was published the year he died in 1543
1:02and started getting this conversation
1:04going now this model was still a little
1:08flawed they still believe the circle was
1:10a perfect shape and so they said that
1:13sure we were rotating around the Sun but
1:17we were doing so in a perfect circle and
1:19so were the other planets so a bit of a
1:22mistake but it was still pushing forward
1:25a much better way it could describe the
1:26retrograde motion the planets we saw a
1:28much much nicer because that's actually
1:30what was happening so it was a simpler
1:32cleaner model and that was one of its
1:34appeals and it started the conversation
1:36going
1:38of course Galileo Galilee is also very
1:42very famous he was early scientist
1:45really and he studied mechanics
1:47mechanics is really studying the motion
1:49of objects and the forces causing those
1:53motions and he started actually making
1:55some very good observations started
1:58making some great conclusions for one
2:00thing what he found was that when he
2:03studied objects that were moving objects
2:07that were moving say falling through the
2:09air or rolling down a ramp he found that
2:13the
2:13acceleration was the same was a uniform
2:17acceleration an acceleration is the
2:20change of speed or direction so if
2:23something speeding up when your car
2:25speeds up or slows down that's
2:27acceleration when it changes direction
2:29that's technically acceleration as well
2:31so he's found that this acceleration was
2:35uniform for these falling objects
2:37something that is kind of important
2:39we'll talk more about later but he also
2:44found that objects tend to stay either
2:50moving or at rest up tonin everyone kind
2:54of thought the idea was things at rest
2:56was the natural state but he had this
2:57idea that look if you could get slippery
2:59enough surface it would keep sliding and
3:02I mean this idea where I'm not gonna go
3:04into too much right now because we're
3:05gonna see it more in Chapter three when
3:07we started talking about Newton but it
3:09isn't worth no-neck Galileo actually
3:11started talking about these ideas first
3:13so he's much more famous though for what
3:18he did with astronomy because he
3:22actually ended up building a telescope
3:24he wasn't the first person in milled a
3:26telescope but it was neat because he
3:29heard the description of what a
3:30telescope was and from that built one
3:33never actually saw it but built one
3:36himself and he eventually realized he
3:38could turn this towards the skies and
3:39study objects that hadn't been studied
3:42before the objects that were too faint
3:44for the human eye to see he could turn
3:46and look at them and see things in much
3:49more detail he could magnify these
3:51objects and see them as they were much
3:54much closer much larger so this was one
3:57of his very early telescopes and he saw
4:01their idea of things again he was a
4:04proponent of the heliocentric model he
4:07thought hey this makes sense and he said
4:10about trying to prove it again a very
4:13good first early scientist started
4:15trying to prove it and he's noticed a
4:17few things one of the things he saw is
4:19that there was moons orbiting Jupiter
4:22the we'll see talk about these later he
4:25found moon
4:26orbiting Jupiter and right away this was
4:29a bit of a challenge to the earth center
4:31model we had thought everything revolves
4:34around the earth but here he was able to
4:36see something rotating around something
4:38else so he showed there was something
4:42spinning around Jupiter moons it had its
4:45own moon so all of a sudden already and
4:47pointing out main Aerith isn't so
4:48special in fact Juber had more moons
4:51than we did great well he also studied
4:55the moon and what he found was a bit
4:57surprising he saw a lot of craters and
4:59mountains valleys basically a lot of the
5:01features we associate with earth and it
5:04started being clear that maybe earth
5:06wasn't so special these features were on
5:08another object as well and so maybe they
5:11even have a similar history maybe earth
5:14isn't so special isn't it the center of
5:16everything but the true death Knoll -
5:21the geocentric model this idea that
5:25Earth is the center well Galileo studied
5:29the phases of Venus and now just like
5:33our Moon can go through phases Venus can
5:35go through phases remember
5:37Venus or like our Moon was only lit to
5:40us from the Sun the Sun shines light
5:43reflects off the moon and thus we see it
5:45same with Venus we see Venus because of
5:48a reflection of light from the Sun and
5:50so it also goes through phases as we
5:54both orbit the Sun the thing was it
5:57could go through phases if it was
6:00rotating around Earth but not the phases
6:04that Galileo observed Galileo observed
6:08phases of Venus that couldn't be
6:11explained in the geocentric model it was
6:14not possible this was the defining key
6:19observation that showed geocentric model
6:21was wrong it couldn't explain this you
6:25could put as many deference and
6:27epicycles and weird complicated models
6:29as you wanted but this was the end this
6:32couldn't be described so geocentric
6:35model was wrong
6:36heliocentric model was right
6:38and you would think that's when it
6:40should have ended the debate should have
6:43ended unfortunately not unfortunately
6:47the geocentric model was very popular
6:49the Roman Catholic Church was very
6:52powerful and he was actually forced to
6:55go in front of the Inquisition he was
6:59forced to go in front the Inquisition
7:00they told him he had to retract his
7:03claims that he had to say nope that the
7:05earth was the center which he refused to
7:07do and so as a result he was placed
7:10under house arrest for his life he was
7:13locked away in his house also his books
7:18I mean again this was a defining
7:21characteristic showing that no
7:23geocentric model was wrong but still
7:261836
7:27hundreds of years later his books were
7:30still banned by the church because he
7:33was said to have been here ethical his
7:36work was here a C heresy it was against
7:40the teachings now it was in 1992 the
7:45church did admit that they'd handled
7:46this incorrectly but yeah it's worth
7:51noting that this man actually did suffer
7:55for his work he lost his freedoms and he
7:59was right his work was right he was
8:01trying to advance our understanding of
8:03the world and gave up his freedom to do
8:06so so we take these bits of knowledge
8:10for granted we know the earth is not the
8:13center but others had to fight for this
8:15knowledge and for this advancement to
8:17take place it's worth noting that