Lecture2 part1 video

Summary

This 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

00:00

🌟 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.

05:02

🗺️ 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.

10:03

🛳️ 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.

Keywords

💡Astronomy

Astronomy is the scientific study of celestial objects, space, and the physical universe as a whole. In the context of the video, it is highlighted as the oldest of the sciences, primarily due to its practical applications in ancient civilizations for tracking time, seasons, and navigation. The video emphasizes that astronomy was crucial for agricultural societies to know the best times for planting and harvesting, and for navigational purposes to determine one's location on Earth.

💡Calendars

Calendars are systems used to organize days, weeks, months, and years. The video explains how ancient people used astronomical observations to create calendars, which were essential for agricultural societies to know the optimal times for planting and harvesting. Examples from the script include the use of Stonehenge and other ancient structures that functioned as calendars by aligning with the Sun's position at specific times of the year.

💡Seasons

Seasons are the distinct periods of the year characterized by particular weather conditions, resulting from the Earth's axial tilt and orbit around the Sun. The video discusses how tracking seasons was vital for early civilizations, especially for agriculture. The ability to predict seasonal changes helped societies plan their agricultural activities, such as planting and harvesting crops.

💡Navigation

Navigation is the process of determining one's position and planning a course to reach a destination. The video highlights the use of astronomy in navigation, particularly through the observation of stars and celestial bodies. For instance, the North Star's position relative to the horizon can indicate one's latitude, aiding in navigation at sea or on land.

💡Agricultural Society

An agricultural society is one that primarily relies on farming and the cultivation of land for its sustenance and economy. The video underscores the importance of astronomy in such societies, as the knowledge of seasons and time was critical for planning agricultural activities. The development of agriculture was a key factor in the rise of civilizations, and astronomy played a pivotal role in this development.

💡Religious and Ceremonial Reasons

Religious and ceremonial reasons refer to the cultural and spiritual practices that involve the observation of celestial events. The video mentions that while practical applications like timekeeping and navigation were significant, astronomy also held religious and ceremonial importance. Ancient cultures often associated celestial bodies with deities and used astronomical events in their rituals and festivals.

💡Days of the Week

The days of the week are a modern convention for organizing time, and their names have roots in astronomy. As explained in the video, the days are named after celestial bodies and gods associated with them in various mythologies. For example, Sunday is named after the Sun, Monday after the Moon, and so on, reflecting the deep historical connection between astronomy and the organization of time.

💡Stonehenge

Stonehenge is a prehistoric monument consisting of a ring of standing stones in England. The video uses Stonehenge as an example of an ancient calendar and astronomical observatory. It explains how the alignment of the stones with the Sun during the solstices and equinoxes allowed people to mark the changing of the seasons and thus keep track of time.

💡Eclipses

Eclipses are astronomical events that occur when one celestial body passes into the shadow of another, temporarily obscuring the view of the obscured body from Earth. The video mentions that ancient astronomers monitored and predicted eclipses, which were often of religious significance. The ability to predict such events demonstrates the advanced observational skills of early astronomers.

💡Supernovae

A supernova is a powerful and luminous explosion that occurs during the death of certain types of stars. The video notes that Chinese astronomers as far back as 1400 BC recorded the positions of supernovae, indicating the meticulous observation of the sky by ancient astronomers. These records are valuable for modern astronomers as they can still identify the remnants of these ancient explosions.

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