How science has driven our technology and economy

i’m a scientist

i do astrophysics i study the laws of

nature

how gravity creates stars and planets

from interstellar gas and dust

i studied the evolution of the universe

but that’s not what i want to talk to

you

about today i want to talk about

how curiosity and science

has driven a series of technological

revolutions that has profoundly altered

the way we live on this planet

let me use a few examples from astronomy

and physics

our ancestors were familiar with the sky

they knew

the changes of the stars with the

seasons

the five planets you could see with

naked eye how they moved how the moon

and sun

change their positions in the sky when

the sun moved north if you’re living in

northern hemisphere

it was time to plant when the sun moved

south in its annual motion

it was time to harvest this was

practical

because it aided farming it in fact was

essential for survival

but the nature of the objects in the sky

remained unknown until relatively

recently

bit by bit science and curiosity

led us to understand the forces of

nature her laws

her principles exploitation of these

principles

led to a series of technological

revolutions

ever since roman times most people

thought that the earth was a centered

universe but then in the 1500s

nikolai copernicus had a better idea he

thought that the sun

was at the center of our solar system

and the earth

revolved around that sun just like the

other planets a wealthy nobleman

from denmark tycho brahe built an

observatory because he thought that

copernicus’s ideas

were heretical he wanted to disprove

them he built an observatory

to make precision measurements as

precise as could be in those days

with the naked eye of the motions of the

planets the moon and the sun

a young protege johannes kepler took

this data

derived the laws of planetary motion

laws we still use today

these laws allowed you to predict the

future positions of the planets with

enough precision

to predict eclipses a few years later

galileo galilei used a brand new

invention to telescope

to first look at the objects in the sky

in 1610 he discovered craters on the

moon

phases of the planet venus facing the

sun dark spots on the sun

and most remarkably four moons orbiting

the planet jupiter

like a miniature solar system showing to

him

that copernicus was probably right in

his model

this made galileo curious about the laws

of motion here on earth

he devised a series of experiments and

discovered the laws of mechanics

a few decades later isaac newton

found the mathematics underlying the

laws of mechanics

this started a scientific revolution

that continues

through today newton’s work

was published in the principia

mathematica

this became one of the most influential

books in the late 17th century

newton’s physics newton’s view of the

world

revolutionized how we viewed our

universe

forces acted on objects to produce

motion

machines replace the power of muscle

first windmills then water wheels

then levers and gears eventually be

harnessed the heat

of gases or hot gases we invented the

steam engine

the industrial revolution was a result

one to two centuries

later let me move forward to the

beginning of the 19th century

since antiquity we knew about some

processes like

static electricity lightning certain

minerals having

magnetic properties but these phenomena

were not explored in any detail until

the beginning of the 19th century

michael faraday performed a series of

experiments

he found that moving static electric

charges

produced electric currents electric

currents produced magnetic fields

and if you moved a magnetic material

magnet changing magnetic fields produced

electric currents

a few decades later the mathematician

james clerk maxwell

unified the laws of electricity

magnetism and derived

four equations in 1864.

a remarkable consequence of these

equations was

that it predicted the existence of an

electromagnetic wave

moving at the speed of light maxwell

realized that

light is a specific wavelength

of electromagnetic waves this

understanding led to a revolution

the invention of generators of electric

motors

the electrification of our planet

a few decades later it led to

communications near the speed of light

first through wires but then through

air and through space at the speed of

light the invention of radio

a century later television this is what

i call the electromagnetic revolution

it led to a host of electronic devices

we use today

beginning of the 20th century attention

turned

from the giant orbits of planets to the

microscopic

world of atoms and molecules by that

time we realized that

atoms consist of very small particles

called electrons

orbiting a heavier nucleus made of

protons and neutrons

scientists like max planck niels bohr

albert einstein were interested in how

light electromagnetic waves

interacted with atoms they discovered

that instead of just being particles

electrons

and in fact neutrons and protons were

also waves

in 1905 albert einstein realized that

light which maxwell had claimed as a

wave

also acts like a particle it depends on

how you look at it

you know you’ve all seen a cartoon of

atoms where the electrons orbit the

nucleus like a miniature solar system

that picture is wrong if that picture

were correct

maxwell’s equations predicted that atoms

would collapse

the electrons would spiral into the

nucleus within one microsecond

and you and i would not be here to talk

about it

because electrons are waves atoms are

stable

this understanding underlies our modern

understanding of matter

with radio we needed some way of

amplifying electrical signals

we invented the transistor in a mid-1948

time frame

that led to uh micro circuits

eventually computers your cell phone

today is the outgrowth of the quantum

mechanics revolution of the early

20th century our devices the internet

could not exist without this

understanding that matter consists of

waves on the microscopic scales

so where’s our current understanding of

the universe taking us what are the

future technologies

let’s turn again to astronomy we live in

the golden age of the subject because

you and i are part of the first

generation to see the universe

in all wavelengths of the spectrum

up until the 1930s everything we knew

about the cosmos came to us from a

narrow sliver of that spectrum

visual light before 1880 literally by

looking at the sky

either with your naked eye or to a

telescope

then we invented photography so we’d

record our images

but with the invention of radio in the

1930s we discovered

cosmic radio waves this is the first new

window on the cosmos

in the 1960s we gained access to space

with rockets

we could for the first time fly above

the atmosphere which absorbs

almost all the wavelengths of

electromagnetic light that we can see

in latter part of the 20th century we

launched dozens of satellites with

telescopes that could see this

universe throughout all the entire

spectrum from gamma rays to x-rays to

ultraviolet

through the infrared and i show it

behind me

a picture of the sky the winter sky with

the orion just below the middle the

pleiades cluster in the upper right

at visual wavelengths with a long time

exposure

i will then retune your eyes and your

brains to a wavelength 200 times

visual light to show you what the

infrared sky looks like

courtesy of our satellites the stars

have disappeared to be replaced by

interstellar clouds of gas and dust

if i zoom into a certain patch of sky

in this case the eagle nebula here shown

with a hubble space telescope view at

visual wavelengths

if i then retune your eyes to a

wavelength four times

in longer near infrared those pillars of

dust become translucent and a myriad of

stars appears in the background which

were hidden

by that cosmic dust we opened up an

entirely new type of window on the

cosmos

waves of gravity were discovered from

merging black holes and neutron stars

exactly 100 years after einstein

predicted the existence of those waves

our generation of scientists are doing

for the cosmos

what the great voyages of discovery did

for geography

500 years ago magellan and other

voyagers discovered new continents new

oceans new cultures

our generation is discovering the

universe we are the first to see the

universe in all its wavelengths

and man is a changing our view of the

world

before the 1920s most scientists said

the universe

is more or less static but then edwin

hubble

and vesto schleifer georges lemaitre

discovered that the galaxies those great

systems of stars like our milky way

are moving away from each other the

universe is expanding

in the 1960s vera rubin

studied galaxies she realized

that there’s five times more stuff in

these galaxies than can be accounted for

by ordinary matter made of atoms and

molecules

this stuff does not interact with light

or any form of electromagnetic radiation

because of that we call it dark matter

but it influences the gravitational

field it influences the way stars move

and it bends light in this picture you

see

two clusters of galaxies in white in

purple

you see the distribution of dark matter

which makes up five times as much stuff

as the mass in the ordinary matter in

the galaxies

dark matter we don’t know what it is we

are developing new technologies

to explore it in the latter half of the

20th century

astronomers expected that the universe

would slow down its expansion why

because gravity attracts

all the mass in the cosmos should slow

down that expansion we are looking for

that

slowing down by the 1990s

we were in for a root surprise

universe’s expansion was not slowing

down

it was accelerating the galaxies are

moving away

ever faster how do we know because

telescopes are like

time machines you see because of the

finite speed of light

when you look into space you see further

back in time

when you see the sun you don’t see the

way it is now you see it the way it was

eight minutes ago

if you’re in the southern sky and you

look at the nearest star alpha centauri

you see it the way it was four years ago

in the spring you look to the east you

see the andromeda galaxy the

nearest system of stars like our milky

way that’s as large as the milky way

you’re seeing light with your eyes that

left two million years ago

to further look into space the further

back in time

we can see we can see the 14 billion

year evolution of the cosmos

and what we learned is in recent five

billion years

the acceleration of the universe has

been increasing as an

empty space was pushing the galaxies

apart

so what does this imply for our future

why can we

can we afford to do this research into

exotic materials like dark matter dark

energy

we cannot afford not to do it

we live in the middle of a pandemic

yet in one year we developed vaccines

to combat this scourge of covet 19. this

is only made possible because for over a

century

thousands of researchers have invested

their careers in researching biology and

understanding the molecular basis of

life

the genetic code of dna and rna how

viruses interact with humans

that’s why we could develop this vaccine

so quickly it would not have been

possible without a century-long

investment in science

we face climate change we can understand

it

in part because we can model the earth’s

atmosphere we can also study

other planets and how their climates

behave we actually know

how the emission of gases by human

activity

is altering our climate we know what we

have to do the question is do we have

the will

what will the current set of cosmic

mysteries lead to

honestly i do not know but what i do

know

is that the last 500 years of human

experience has told us

is that the exploration of these cosmic

mysteries has been the foundation of our

technology

our economy and our very way of life on

this planet