Lecture2 part1 video
Summary
TLDRThis lecture delves into the origins of astronomy, the oldest of sciences, highlighting its significance in ancient civilizations for timekeeping and navigation. It underscores the practical applications of tracking celestial bodies for agricultural purposes and religious ceremonies. The script explores how the days of the week are named after celestial bodies, reflecting astronomy's deep-rooted influence on human culture. Historical examples, from Stonehenge to ancient Chinese observations of supernovae, illustrate humanity's meticulous astronomical observations over millennia, emphasizing astronomy's foundational role in the development of science.
Takeaways
- 🌟 Astronomy is the oldest science, primarily used for practical reasons such as timekeeping and navigation.
- 🌱 The need for agriculture drove the development of astronomy to track seasons and aid in crop cultivation.
- 🌐 The importance of astronomy is embedded in our language, with days of the week named after celestial bodies.
- 📅 Ancient civilizations like the Egyptians, Aztecs, and Pueblo people used structures to create calendars and clocks.
- 🌌 The North Star's position relative to the horizon can indicate one's latitude, showcasing astronomy's role in navigation.
- 🗺️ Structures like Stonehenge and the Sun Dagger were used to mark significant astronomical events, such as solstices and equinoxes.
- 🌕 Central Africans used the moon's crescent to determine seasons, highlighting early astronomical observations.
- 🌌 The Polynesians used star charts for navigation across the vast Pacific Ocean, demonstrating advanced astronomical knowledge.
- 🌠 Chinese astronomers as far back as 1400 BC recorded supernovae, showing meticulous observation of the sky.
- 🔭 Throughout history, people have been meticulously observing celestial events, which has been crucial for the advancement of astronomy.
Q & A
Why is astronomy considered the oldest of the sciences?
-Astronomy is considered the oldest of the sciences because it was crucial for practical reasons such as timekeeping, tracking seasons for agriculture, and navigation, which were essential for the development of civilizations.
How do the days of the week relate to astronomy?
-The days of the week are named after celestial bodies and deities associated with them, reflecting the importance of astronomy in timekeeping. For example, Sunday is named after the Sun, Monday after the Moon, and so on, with each day representing a planet or a celestial entity.
What role did astronomy play in ancient agriculture?
-Astronomy was vital for ancient agriculture as it helped in tracking seasons, which was essential for planting and harvesting crops. Knowledge of the sky allowed people to build calendars and predict seasonal changes, thus supporting the shift from hunter-gatherer societies to agrarian civilizations.
How was astronomy used for navigation in the past?
-Astronomy was used for navigation by observing the positions of stars and other celestial bodies. For instance, the North Star could be used to determine latitude, and the movement of stars across the sky could help sailors and travelers determine their direction and location.
What is the significance of the Egyptian obelisk in the context of astronomy?
-The Egyptian obelisk served as a calendar and a clock. The shadow it cast at different times of the day indicated the time, and the length of the shadow throughout the year helped determine the season.
How did Stonehenge function as a calendar?
-Stonehenge functioned as a calendar by aligning with the sunrise on the equinoxes and solstices. The position of the sun at these times of the year would rise between specific stones, marking the change of seasons and allowing people to track the year.
What is a Kiva and how does it relate to astronomy?
-A Kiva is a round, underground structure used by Pueblo people in the Southwest United States. It often contains slits that align with the sun's rays on specific days, such as the summer solstice, effectively functioning as a calendar.
Why were the Nazca Lines in Peru significant in terms of astronomy?
-The Nazca Lines are significant in astronomy because many of the geoglyphs are aligned with stars, suggesting that they may have been used for astronomical observation or as part of religious ceremonies related to the sky.
How did ancient Polynesians use astronomy for navigation?
-Ancient Polynesians used star charts for navigation across the vast Pacific Ocean. These charts helped them determine their location and navigate to distant islands, which was crucial for their survival and exploration.
What does the recording of supernovae by Chinese astronomers around 1400 BC indicate about their astronomical observations?
-The recording of supernovae by Chinese astronomers around 1400 BC indicates that they were conducting meticulous observations of the sky. They were able to detect new stars that appeared for a few months and record their positions, which shows a high level of astronomical knowledge and the importance of keeping detailed astronomical records.
Outlines
🌟 The Origins and Importance of Astronomy
This paragraph introduces the topic of astronomy as the oldest science, highlighting its practical applications in ancient civilizations. The speaker explains how astronomy was crucial for tracking time and seasons, which were essential for agriculture and the development of civilizations. The paragraph also touches on the religious and ceremonial significance of observing the sky. The importance of astronomy is further illustrated by its influence on the names of the days of the week, which are derived from celestial bodies. The speaker also provides historical examples, dating back to 6500 BC, of how people used the moon's phases for seasonal predictions, emphasizing the discipline's long-standing role in timekeeping and navigation.
🗺️ Ancient Astronomical Observatories and Calendars
The second paragraph delves into ancient structures that served as astronomical observatories and calendars. Egyptian obelisks functioned as sundials, casting shadows that indicated the time of day and year. Stonehenge, a stone structure in England, is described as a calendar that could mark equinoxes by the position of the sunrise between its pillars. The paragraph also mentions similar constructions by the Aztecs and the Pueblo people, including a Kiva with sunlight slits that marked specific days. The 'Sun Dagger' of Chaco Canyon is highlighted as a precise calendar marker for the summer solstice. The speaker discusses long-term lunar cycles observed in ancient Scottish Stonehenge and the alignment of structures in Peru with stars, suggesting a deep-rooted connection between astronomy and cultural practices.
🛳️ Navigation and the Historical Observation of the Sky
This paragraph discusses the role of astronomy in navigation, particularly among the Polynesian people who used star charts for oceanic travel. The speaker emphasizes the importance of accurate navigation to avoid getting lost in the vast Pacific Ocean. The paragraph also touches on evidence of astronomical observation dating back to 18,000 BC, found in cave paintings that are believed to depict lunar phases. The speaker concludes with an example from 1400 BC, where Chinese astronomers recorded the positions of supernovae, demonstrating the meticulous observation of the sky throughout history. The paragraph underscores the significance of astronomy not only for practical purposes but also for the development of predictive models based on observations.
Mindmap
Keywords
💡Astronomy
💡Calendars
💡Seasons
💡Navigation
💡Agricultural Society
💡Religious and Ceremonial Reasons
💡Days of the Week
💡Stonehenge
💡Eclipses
💡Supernovae
Highlights
Astronomy is considered the oldest science due to its practical applications in ancient times.
Ancient humans used astronomy to track time and seasons, which was crucial for agricultural societies.
Religion and ceremony were also significant drivers for early astronomical observations.
Astronomy played a key role in navigation, allowing people to determine their latitude using stars.
The days of the week are named after celestial bodies, reflecting the importance of astronomy in timekeeping.
Evidence from 6500 BC shows people in central Africa used the moon's tilt to determine seasons.
Ancient structures like obelisks functioned as calendars and clocks, demonstrating advanced astronomical knowledge.
Stonehenge is an example of an ancient calendar that aligns with the sun on the equinoxes.
The Aztecs and Pueblo people also built structures that functioned as calendars, indicating a widespread interest in astronomy.
Ancient Scottish Stonehenge was used to track an 18.6-year lunar cycle, showing long-term astronomical observation.
Peruvian mounds are aligned with stars, suggesting a religious and astronomical purpose.
Polynesians used star charts for navigation, highlighting the practical applications of astronomy in seafaring cultures.
Cave paintings from 18,000 BC depict lunar phases, indicating early human interest in the sky.
Chinese astronomers from 1400 BC recorded supernovae, showing detailed astronomical observation and record-keeping.
Astronomy's historical importance is evident in its role as the first science, with people making models to predict future events.
Transcripts
hello everyone and welcome to part 1 of
lecture 2 now in this lecture were to
talk about the rise of astronomy how
astronomy became a science and it really
became the very first of sciences and
we're to talk today or in this part of
this lecture about really ancient
history of astronomy then in part 2
we'll transition and talking about what
the Greeks were up to a couple thousand
years ago and then talk about the rise
of modern astronomy
so astronomy astronomy is really the
oldest of the sciences a and it is the
oldest of Sciences for very practical
reasons there are two basic things that
human beings used to use astronomy for
and these are hugely important first of
all you could keep track of time and
seasons okay and this mostly has to do
with human beings coming into
agriculture okay if you're gonna be
growing crops and and you know weeping
crops you're gonna have to know the
times of the year because of the seasons
alright and if you're gonna have
civilization you really have to have
agriculture so keeping track of time
becomes hugely important as humans start
to build civilizations okay now there
are also of course religious and
ceremonial reasons why people kept track
of what was going on in the sky okay but
a really agriculture was huge keeping
track of the seasons keeping
understanding what time of year it is is
really important now you can also use
astronomy for navigation if you know
what stars are gonna be this in the sky
when you can use those as a navigational
tool they just as an example today the
North Star if you look at the North Star
the height the North Star is above your
horizon how many degrees it is above
your horizon well that's your latitude
the earth and so you can use that to
figure out not only where North is but
where on the earth you are up and down
okay so navigation is a huge part of
what astronomy used to be used for
okay so astronomy really comes into use
because people need to use astronomy for
building calendars and figuring out
where they are on the earth and where
they need to go now
just to give you an idea of just how
important astronomy is to civilization
today let's look at the days of the week
okay
Sunday that's literally named after the
Sun Monday the moon Tuesday named after
Mars okay that twos is a teutonic
version of well it's the name they used
for that particular planet okay but if
you look at like Latin versions of
Tuesday Marty and Marquez okay
named after Mars Wednesday is mercury a
Thursday Jupiter so again this is a
Teutonic version Thurs refers to Thor a
Thor is day Venus is Friday Saturday is
Saturn okay so even baked into the
language we use about time is astronomy
that's how important astronomy was to
timekeeping okay the names that we use
for the days of the week are named after
things in the sky now if you go back in
history and talk about what people were
doing in various places on the earth
throughout time if you look back as far
back as 6500 BC we have evidence that
people in central Africa we're using the
tilt of the crescent moon to figure out
the seasons now in central Africa that's
near the equator so they don't have the
full four seasons okay
winter summer fall and spring but they
have our two seasons rainy and dry but
still rainy and dry it's important to
know especially for your hunter-gatherer
Society your move
around a lot you want to know when it's
gonna start being really rainy because
you're gonna want to build shelter okay
so it's important to keep track of time
and again astronomy use for timekeeping
daily timekeeping seasons and calendars
yeah you could monitor cycles and
planets and stars where they were
predicting when eclipses would happen a
some of this stuff monitoring especially
the planets and eclipses that stuff was
largely religious in nature but still
astronomy was hugely important and you
can see it all over the place so for
example this this is an Egyptian obelisk
okay it's basically a calendar and a
clock a watch
okay this is a sundial and where the
shadow was actually cast so right here
the shadow
okay the pillar it's cast on tells you
the time of day
furthermore the length of the shadow how
long the shadow is tells you the time of
year because I remember I'd say you know
any time of day in the winter the Sun is
gonna be lower in the sky than it is in
the summer when the Sun gets higher in
the sky so in the summer it's gonna cast
a shorter shadow than in the winter okay
so this is a calendar and a clock and
you find things like this there's a
stone hinge which is found in England
completed around you know 1550 BC or so
this is also a calendar if you stand in
the middle of Stonehenge okay on the
equinox the Sun will rise between a
particular set of pillars because
remember different times of the year the
Sun rises in sets different places on
the horizon in the summer it will be
north of East where it rises and it sets
north of West and the winter it's the
opposite so you can use this if you're
standing in the middle and you see the
run sunrise directly between one set of
pillars well you know that right then
that day is the summer equinox
for example so it's a calendar it lets
you keep track of what time of year it
is
and these kinds of things so like the
Aztecs in Mexico they had similar
structures built into their their
temples so you would have a room that
was basically like Stonehenge you stand
in the middle of the room on a certain
day some will rise between a you know
through a certain window or whatever and
you find this kind of calendar so this
is an example of a Pueblo people
building I this may be in Chaco Canyon
this is known as a Kiva and in these
Kiva's these round buildings you often
found slits where on a certain day
sunlight would come through that slit
hit a certain spot on the other side of
the building and again it would be like
Stonehenge calendar definitely in Chaco
Canyon in the Southwest United States
you had devices like this again it's
basically a Stonehenge we're on a very
specific day in this case it's the
summer solstice a dagger of light this
is called the Sun dagger goes directly
through this curved coil of carved into
the rock okay
so basically a calendar on a specific
day it goes right through that coil and
you know it's a summer solstice and
people kept track of things in the sky
that are even much longer cycles than
that so for example you know the
Solstice the summer solstice happens
once a year but some of these hinges so
this is an example of a 4,000 year old
Stonehenge it's in Scotland but in this
particular Stonehenge the moon rises at
a particular spot between two pillars
but it only happens once every eighteen
point six years that's a really long
cycle now to notice that kind of a cycle
you would have to be keeping very
careful track of exactly where the moon
is rising over a period of at least 40
years right because you just see it
happened once and then see heaven again
and probably you want to see it happen a
third time so now we're talking like 60
years this is not something you would
notice over one lifetime probably but if
you're very carefully watching this
guy's and keeping track of what's going
on this is the kind of cycle you will
notice over time over lifetimes people
used to keep very careful track of what
was happening in the sky much more than
today there also we find this is in Peru
okay these are these are odd structures
we're not exactly sure what they're
meant to be
they're huge this is like a football
field across and they're basically
mounds of dirt that if you look at it
from above are they make up these
figures and while we don't know exactly
what they were the purpose was probably
some kind of religious thing but we do
know that a lot of these are aligned
with stars so they've actually more than
just this woman a lot of them are
aligned with stars so whenever they were
doing astronomy was part of it again
places like Machu Picchu you find
structures much like Stonehenge this
this is actually interesting this is uh
from Polynesian people's okay Pacific
Islanders what this is this is actually
a navigational chart it's a star chart
used for navigation and you can think
about it carefully you wouldn't really
want to be really sure about where
you're going if you're a Pacific
Islander right because you're leaving a
small island and you're in the middle of
Pacific you can't see the island you're
going to you're gonna want to know
exactly where it is though if you want
to get to it because you don't want to
get lost in the Pacific right it's a
huge ocean okay so navigation hugely
important okay if you're boating around
between Islands and this was a star
charter or this is a star chart used for
navigation if you go back even as far as
18,000 BC so 20,000 years ago there are
in cave paintings evidence that even you
know cavemen
we're watching what was going on the sky
these we think are drawings of lunar
phases so you know twenty thousand years
ago people were still thinking about
what was going on in the sky all right
now just one last example and I want you
to really think about this so as far
back as 1400 BC chinese astronomers
recorded the positions of supernovae now
we'll talk more about supernovae later
on in the class they have to do and when
certain kinds of stars die they explode
but from a human point of view here on
the earth what it would look like is a
new star appears in the sky and it's
there for a couple of months and then it
fades away disappears now I want you to
think about how carefully you have to be
watching the sky to notice a new star
appear and I don't mean it would be it
wouldn't necessarily be a hugely bright
star it would just be a regular star
it's there for a couple of months and
then it's dawn would you notice a new
star appearing in the night sky I mean
do you know where all the stars are in
the night sky what was the last time you
looked so what I'm trying to get across
here is that you know people throughout
history have been very carefully
watching this die watching it so
carefully that they noticed a new star
appear for a couple of months they wrote
down exactly where that star was in the
sky and we can use their data today that
position they wrote down we can point a
telescope of that spot in the sky and
sure enough we see a supernova remnant
again we'll talk more about that that is
later but they are very carefully
watching this guy so astronomy hugely
important throughout history it's why it
was the first of all the sciences okay
and what I mean by that is people
watching the sky trying to figure out
what's going on and then making models
based on what they observe models that
can predict what will happen in the
future
and
that's actually we're gonna go to next
when we talk about the Greeks
alright so stay tuned for part two
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