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