A stellar history of modern astronomy
-
0:00 - 0:06In 1987, a Chilean engineer
named Oscar Duhalde -
0:06 - 0:09became the only
living person on the planet -
0:09 - 0:12to discover a rare astronomical event
-
0:12 - 0:13with the naked eye.
-
0:14 - 0:18Oscar was a telescope operator
at Las Campanas Observatory in Chile. -
0:18 - 0:22He worked with the astronomers who came
to the observatory for their research, -
0:22 - 0:26running the telescopes and processing
the data that they took. -
0:27 - 0:29On the night of February 24th,
-
0:29 - 0:31Oscar stepped outside for a break
-
0:31 - 0:34and looked up at the night sky
and he saw this. -
0:34 - 0:36This is the Large Magellanic Cloud.
-
0:36 - 0:40It's a satellite galaxy very near
our own Milky Way. -
0:40 - 0:42But on that February night,
-
0:42 - 0:45Oscar noticed that something
was different about this galaxy. -
0:45 - 0:46It didn't quite look like this.
-
0:46 - 0:48It looked like this.
-
0:49 - 0:51Did you see it?
-
0:51 - 0:52(Laughter)
-
0:52 - 0:57A small point of light had appeared
in one corner of this galaxy. -
0:57 - 1:00So to explain how amazing it is
that Oscar noticed this, -
1:00 - 1:02we need to zoom out a bit
-
1:02 - 1:05and look at what the southern
sky in Chile looks like. -
1:05 - 1:09The Large Magellanic Cloud
is right in the middle of that image, -
1:09 - 1:12but despite its name, it's really small.
-
1:12 - 1:16Imagine trying to notice
one single new point of light -
1:16 - 1:18appearing in that galaxy.
-
1:18 - 1:20Oscar was able to do this
-
1:20 - 1:24because he had the Large Magellanic Cloud
essentially memorized. -
1:24 - 1:28He had worked on data
from this galaxy for years, -
1:28 - 1:30poring over night after night
of observations -
1:30 - 1:32and doing it by hand,
-
1:32 - 1:35because Oscar had begun
his work in astronomy -
1:35 - 1:39at a time when we stored all of the data
that we observed from the universe -
1:39 - 1:42on fragile sheets of glass.
-
1:43 - 1:45I know that today's theme is "Moonshot,"
-
1:45 - 1:48and as an astronomer, I figured
I could start us out nice and literally, -
1:48 - 1:50so here's a shot of the Moon.
-
1:50 - 1:51(Laughter)
-
1:51 - 1:55It's a familiar sight to all of us,
but there's a couple of unusual things -
1:55 - 1:56about this particular image.
-
1:56 - 1:58For one, I flipped the colors.
-
1:58 - 2:00It originally looked like this.
-
2:01 - 2:04And if we zoom out, we can see
how this picture was taken. -
2:04 - 2:08This is a photograph
of the Moon taken in 1894 -
2:08 - 2:11on a glass photographic plate.
-
2:11 - 2:15This was the technology that astronomers
had available for decades -
2:15 - 2:18to store the observations
that we took of the night sky. -
2:19 - 2:23I've actually brought an example
of a glass plate to show you. -
2:23 - 2:26So this looks like a real secure way
to store our data. -
2:27 - 2:30These photographic plates
were incredibly difficult to work with. -
2:30 - 2:34One side of them was treated
with a chemical emulsion that would darken -
2:34 - 2:36when it was exposed to light.
-
2:36 - 2:40This is how these plates were able
to store the pictures that they took, -
2:40 - 2:45but it meant that astronomers
had to work with these plates in darkness. -
2:45 - 2:47The plates had to be cut
to a specific size -
2:47 - 2:50so that they could fit
into the camera of a telescope. -
2:50 - 2:53So astronomers would take
razor-sharp cutting tools -
2:53 - 2:56and slice these tiny pieces of glass,
-
2:56 - 2:58all in the dark.
-
2:58 - 3:01Astronomers also had all kinds of tricks
that they would use -
3:01 - 3:04to make the plates
respond to light a little faster. -
3:04 - 3:07They would bake them or freeze them,
they would soak them in ammonia, -
3:07 - 3:09or they'd coat them with lemon juice --
-
3:09 - 3:10all in the dark.
-
3:10 - 3:13Then astronomers would take
these carefully designed plates -
3:13 - 3:14to the telescope
-
3:14 - 3:16and load them into the camera.
-
3:16 - 3:20They had to be loaded with that
chemically emulsified side pointed out -
3:20 - 3:22so that the light would hit it.
-
3:22 - 3:26But in the dark, it was almost impossible
to tell which side was the right one. -
3:26 - 3:30Astronomers got into the habit
of tapping a plate to their lips, -
3:30 - 3:34or, like, licking it, to see
which side of the plate was sticky -
3:34 - 3:36and therefore coated with the emulsion.
-
3:36 - 3:39And then when they actually
put it into the camera, -
3:39 - 3:41there was one last challenge.
-
3:41 - 3:42In this picture behind me,
-
3:42 - 3:45you can see that the plate
the astronomer is holding -
3:45 - 3:46is very slightly curved.
-
3:46 - 3:51Sometimes plates had to be bent
to fit into a telescope's camera, -
3:51 - 3:56so you would take this carefully cut,
meticulously treated, very babied plate -
3:56 - 3:59up to a telescope, and then you'd just ...
-
3:59 - 4:02So sometimes that would work.
Sometimes they would snap. -
4:02 - 4:06But it would usually end
with the [plate] loaded into a camera -
4:06 - 4:07on the back of a telescope.
-
4:07 - 4:09You could then point that telescope
-
4:09 - 4:11to whatever patch of sky
you wanted to study, -
4:11 - 4:13open the camera shutter,
-
4:13 - 4:15and begin capturing data.
-
4:15 - 4:18Now, astronomers couldn't just
walk away from the camera -
4:18 - 4:19once they'd done this.
-
4:19 - 4:23They had to stay with that camera
for as long as they were observing. -
4:23 - 4:26This meant that astronomers
would get into elevators -
4:26 - 4:29attached to the side
of the telescope domes. -
4:29 - 4:31They would ride the elevator
high into the building -
4:31 - 4:34and then climb into
the top of the telescope -
4:34 - 4:38and stay there all night
shivering in the cold, -
4:38 - 4:40transferring plates
in and out of the camera, -
4:40 - 4:41opening and closing the shutter
-
4:41 - 4:44and pointing the telescope
to whatever piece of sky -
4:44 - 4:46they wanted to study.
-
4:46 - 4:49These astronomers worked with operators
who would stay on the ground. -
4:49 - 4:51And they would do things
like turn the dome itself -
4:51 - 4:54and make sure the rest
of the telescope was running. -
4:54 - 4:56It was a system that usually
worked pretty well, -
4:56 - 4:59but once in a while,
things would go wrong. -
4:59 - 5:02There was an astronomer observing
a very complicated plate -
5:02 - 5:06at this observatory,
the Lick Observatory here in California. -
5:06 - 5:08He was sitting at the top
of that yellow structure -
5:08 - 5:11that you see in the dome
on the lower right, -
5:11 - 5:15and he'd been exposing
one glass plate to the sky for hours, -
5:15 - 5:17crouched down and cold
-
5:17 - 5:20and keeping the telescope
perfectly pointed -
5:20 - 5:23so he could take this precious
picture of the universe. -
5:23 - 5:25His operator wandered
into the dome at one point -
5:25 - 5:28just to check on him
and see how things were going. -
5:28 - 5:31And as the operator stepped through
the door of the dome, -
5:31 - 5:37he brushed against the wall
and flipped the light switch in the dome. -
5:37 - 5:40So the lights came blazing on
and flooding into the telescope -
5:40 - 5:42and ruining the plate,
-
5:42 - 5:45and there was then this howl
from the top of the telescope. -
5:45 - 5:48The astronomer started yelling
and cursing and saying, -
5:48 - 5:50"What have you done?
You've destroyed so much hard work. -
5:51 - 5:53I'm going to get down
from this telescope and kill you!" -
5:53 - 5:56So he then starts moving the telescope
-
5:56 - 5:57about this fast --
-
5:57 - 5:58(Laughter)
-
5:58 - 5:59toward the elevator
-
5:59 - 6:02so that he can climb down
and make good on his threats. -
6:02 - 6:04Now, as he's approaching the elevator,
-
6:04 - 6:06the elevator then suddenly
starts spinning away from him, -
6:06 - 6:09because remember, the astronomer
can control the telescope, -
6:09 - 6:11but the operator can control the dome.
-
6:11 - 6:12(Laughter)
-
6:12 - 6:14And the operator is looking up, going,
-
6:14 - 6:18"He seems really mad. I might not want
to let him down until he's less murdery." -
6:18 - 6:21So the end is this absurd
slow-motion game of chase -
6:21 - 6:24with the lights on and the dome
just spinning around and around. -
6:24 - 6:26It must have looked completely ridiculous.
-
6:27 - 6:30When I tell people about using
photographic plates to study the universe, -
6:30 - 6:32it does sound ridiculous.
-
6:32 - 6:33It's a little absurd
-
6:33 - 6:37to take what seems like a primitive tool
for studying the universe -
6:37 - 6:40and say, well, we're going
to dunk this in lemon juice, lick it, -
6:40 - 6:43stick it in the telescope,
shiver next to it for a few hours -
6:43 - 6:45and solve the mysteries of the cosmos.
-
6:45 - 6:48In reality, though,
that's exactly what we did. -
6:48 - 6:50I showed you this picture before
-
6:50 - 6:53of an astronomer perched
at the top of a telescope. -
6:53 - 6:56What I didn't tell you
is who this astronomer is. -
6:56 - 6:58This is Edwin Hubble,
-
6:58 - 7:01and Hubble used photographic plates
-
7:01 - 7:04to completely change
our entire understanding -
7:04 - 7:06of how big the universe is
and how it works. -
7:07 - 7:11This is a plate
that Hubble took back in 1923 -
7:11 - 7:14of an object known at the time
as the Andromeda Nebula. -
7:14 - 7:16You can see in the upper
right of that image -
7:16 - 7:20that Hubble has labeled a star
with this bright red word, "Var!" -
7:20 - 7:23He's even put an exclamation
point next to it. -
7:23 - 7:25"Var" here stands for "variable."
-
7:25 - 7:28Hubble had found a variable star
in the Andromeda Nebula. -
7:28 - 7:30Its brightness changed,
-
7:30 - 7:32getting brighter and dimmer
as a function of time. -
7:32 - 7:36Hubble knew that if he studied
how that star changed with time, -
7:36 - 7:39he could measure the distance
to the Andromeda Nebula, -
7:39 - 7:43and when he did,
the results were astonishing. -
7:43 - 7:46He discovered that this was not,
in fact, a nebula. -
7:46 - 7:48This was the Andromeda Galaxy,
-
7:48 - 7:51an entire separate galaxy
two and a half million light years -
7:51 - 7:53beyond our own Milky Way.
-
7:53 - 7:55This was the first evidence
of other galaxies -
7:55 - 7:57existing in the universe beyond our own,
-
7:57 - 8:02and it totally changed our understanding
of how big the universe was -
8:02 - 8:03and what it contained.
-
8:04 - 8:07So now we can look at
what telescopes can do today. -
8:07 - 8:10This is a modern-day picture
of the Andromeda Galaxy, -
8:10 - 8:12and it looks just like
the telescope photos -
8:12 - 8:14that we all love to enjoy and look at:
-
8:14 - 8:17it's colorful and detailed and beautiful.
-
8:17 - 8:19We now store data like this digitally,
-
8:19 - 8:23and we take it using
telescopes like these. -
8:23 - 8:26So this is me standing underneath
a telescope with a mirror -
8:26 - 8:28that's 26 feet across.
-
8:28 - 8:32Bigger telescope mirrors let us take
sharper and clearer images, -
8:32 - 8:35and they also make it
easier for us to gather light -
8:35 - 8:38from faint and faraway objects.
-
8:38 - 8:41So a bigger telescope literally
gives us a farther reach -
8:41 - 8:42into the universe,
-
8:42 - 8:45looking at things that we
couldn't have seen before. -
8:46 - 8:48We're also no longer strapped
to the telescope -
8:48 - 8:50when we do our observations.
-
8:50 - 8:52This is me during
my very first observing trip -
8:52 - 8:54at a telescope in Arizona.
-
8:54 - 8:56I'm opening the dome of the telescope,
-
8:56 - 8:59but I'm not on top
of the telescope to do it. -
8:59 - 9:01I'm sitting in a room
off to the side of the dome, -
9:01 - 9:04nice and warm and on the ground
-
9:04 - 9:06and running the telescope from afar.
-
9:06 - 9:08"Afar" can get pretty extreme.
-
9:08 - 9:11Sometimes we don't even need
to go to telescopes anymore. -
9:11 - 9:15This is a telescope in New Mexico
that I use for my research all the time, -
9:15 - 9:17but I can run it with my laptop.
-
9:17 - 9:19I can sit on my couch in Seattle
-
9:19 - 9:21and send commands from my laptop
-
9:21 - 9:23telling the telescope where to point,
-
9:23 - 9:25when to open and close the shutter,
-
9:25 - 9:28what pictures I want it
to take of the universe -- -
9:28 - 9:30all from many states away.
-
9:30 - 9:34So the way that we operate
telescopes has really changed, -
9:34 - 9:37but the questions we're trying to answer
about the universe -
9:37 - 9:38have remained the same.
-
9:39 - 9:44One of the big questions still focuses
on how things change in the night sky, -
9:44 - 9:47and the changing sky was exactly
what Oscar Duhalde saw -
9:47 - 9:51when he looked up
with the naked eye in 1987. -
9:51 - 9:56This point of light that he saw appearing
in the Large Magellanic Cloud -
9:56 - 9:58turned out to be a supernova.
-
9:58 - 10:01This was the first naked-eye supernova
-
10:01 - 10:05seen from Earth in more than 400 years.
-
10:05 - 10:07This is pretty cool,
-
10:07 - 10:10but a couple of you might
be looking at this image and going, -
10:10 - 10:11"Really? I've heard of supernovae.
-
10:11 - 10:13They're supposed to be spectacular,
-
10:13 - 10:16and this is just like a dot
that appeared in the sky." -
10:16 - 10:19It's true that when you hear
the description of what a supernova is -
10:19 - 10:20it sounds really epic.
-
10:20 - 10:25They're these brilliant, explosive deaths
of enormous, massive stars, -
10:25 - 10:27and they shoot energy
out into the universe, -
10:27 - 10:29and they spew material out into space,
-
10:29 - 10:31and they sound, like, noticeable.
-
10:31 - 10:32They sound really obvious.
-
10:33 - 10:35The whole trick about
what a supernova looks like -
10:35 - 10:37has to do with where it is.
-
10:37 - 10:40If a star were to die as a supernova
-
10:40 - 10:43right in our backyard in the Milky Way,
a few hundred light years away -- -
10:43 - 10:45"backyard" in astronomy terms --
-
10:45 - 10:47it would be incredibly bright.
-
10:47 - 10:50We would be able to see
that supernova at night -
10:50 - 10:52as bright as the Moon.
-
10:52 - 10:54We would be able to read by its light.
-
10:54 - 10:58Everybody would wind up taking photos
of this supernova on their phone. -
10:58 - 11:00It would be on headlines
all over the world. -
11:00 - 11:02It would for sure get a hashtag.
-
11:02 - 11:07It would be impossible to miss
that a supernova had happened so nearby. -
11:07 - 11:09But the supernova that Oscar observed
-
11:09 - 11:12didn't happen a few hundred
light years away. -
11:13 - 11:18This supernova happened
170,000 light years away, -
11:18 - 11:20which is why instead of an epic explosion,
-
11:20 - 11:22it appears as a little dot.
-
11:23 - 11:25This was still unbelievably exciting.
-
11:25 - 11:27It was still visible with the naked eye,
-
11:27 - 11:29and the most spectacular supernova
-
11:29 - 11:32that we've seen since
the invention of the telescope. -
11:32 - 11:35But it gives you a better sense
of what most supernovae look like. -
11:36 - 11:39We still discover and study
supernovae all the time today, -
11:39 - 11:43but we do it in distant galaxies
using powerful telescopes. -
11:43 - 11:45We photograph the galaxy multiple times,
-
11:45 - 11:47and we look for something that's changed.
-
11:47 - 11:50We look for that little
pinprick of light appearing -
11:50 - 11:52that tells us that a star has died.
-
11:53 - 11:56We can learn a great deal
about the universe and about stars -
11:56 - 11:57from supernovae,
-
11:57 - 12:00but we don't want to leave
studying them up to chance. -
12:00 - 12:03We don't want to count on
happening to look up at the right time -
12:03 - 12:06or pointing our telescope
at the right galaxy. -
12:07 - 12:09What we ideally want is a telescope
-
12:09 - 12:12that can systematically
and computationally -
12:12 - 12:15do what Oscar did with his mind.
-
12:16 - 12:18Oscar was able to discover this supernova
-
12:18 - 12:21because he had that galaxy memorized.
-
12:22 - 12:23With digital data,
-
12:23 - 12:27we can effectively memorize
every piece of the sky that we look at, -
12:27 - 12:29compare old and new observations
-
12:29 - 12:32and look for anything that's changed.
-
12:33 - 12:36This is the Vera Rubin Observatory
-
12:36 - 12:37in Chile.
-
12:37 - 12:41Now, when I visited it back in March,
it was still under construction. -
12:41 - 12:44But this telescope
will begin observations next year, -
12:44 - 12:45and when it does,
-
12:45 - 12:50it will carry out a simple
but spectacular observing program. -
12:51 - 12:54This telescope will photograph
the entire southern sky -
12:55 - 12:56every few days
-
12:56 - 12:57over and over,
-
12:57 - 12:59following a preset pattern
-
12:59 - 13:01for 10 years.
-
13:02 - 13:05Computers and algorithms
affiliated with the observatory -
13:05 - 13:10will then compare every pair of images
taken of the same patch of sky, -
13:10 - 13:12looking for anything
that's gotten brighter or dimmer, -
13:12 - 13:14like a variable star,
-
13:14 - 13:16or looking for anything that's appeared,
-
13:16 - 13:17like a supernova.
-
13:17 - 13:22Right now, we discover about
a thousand supernovae every year. -
13:22 - 13:26The Rubin Observatory will be capable
of discovering a thousand supernovae -
13:26 - 13:28every night.
-
13:28 - 13:31It's going to dramatically change
the face of astronomy -
13:31 - 13:34and of how we study things
that change in the sky, -
13:34 - 13:36and it will do all of this
-
13:36 - 13:38largely without much
human intervention at all. -
13:38 - 13:40It will follow that preset pattern
-
13:40 - 13:44and computationally find
anything that's changed or appeared. -
13:45 - 13:47This might sound a little sad at first,
-
13:47 - 13:49this idea that we're removing
people from stargazing. -
13:50 - 13:51But in reality,
-
13:51 - 13:53our role as astronomers
isn't disappearing, -
13:54 - 13:55it's just moving.
-
13:55 - 13:58We've already seen
how we do our jobs change. -
13:58 - 14:00We've gone from perching atop telescopes
-
14:00 - 14:01to sitting next to them
-
14:01 - 14:05to not even needing to go to them
or send them commands at all. -
14:05 - 14:07Where astronomers still shine
-
14:07 - 14:10is in asking questions
and working with the data. -
14:10 - 14:13Gathering data is only the first step.
-
14:13 - 14:18Analyzing it is where we can really apply
what we know about the universe. -
14:18 - 14:21Human curiosity is what makes us
ask questions like: -
14:21 - 14:23How big is the universe?
How did it begin? -
14:23 - 14:26How's it going to end? And are we alone?
-
14:26 - 14:31So this is the power that humans
are still able to bring to astronomy. -
14:31 - 14:34So compare the capabilities
of a telescope like this -
14:34 - 14:38with the observations
that we were able to take like this. -
14:38 - 14:41We discovered amazing things
with glass plates, -
14:41 - 14:43but discovery looks different today.
-
14:43 - 14:46The way we do astronomy
looks different today. -
14:46 - 14:49What hasn't changed
is that seed of human curiosity. -
14:50 - 14:53If we can harness the power
of tomorrow's technology -
14:53 - 14:57and combine it with this drive
that we all have to look up -
14:57 - 14:59and to ask questions
about what we see there, -
14:59 - 15:02we'll be ready to learn
some incredible new things -
15:02 - 15:04about the universe.
-
15:04 - 15:05Thank you.
-
15:05 - 15:07(Applause)
- Title:
- A stellar history of modern astronomy
- Speaker:
- Emily Levesque
- Description:
-
Astronomers once gazed upon the night sky and counted every star in the galaxy by hand. The process has evolved since then, but the thirst for celestial knowledge remains the same. Join astrophysicist Emily Levesque for an anecdote-rich jaunt through the technological history of photographing the cosmos and learn about the one constant that makes it all work: human curiosity.
- Video Language:
- English
- Team:
- closed TED
- Project:
- TEDTalks
- Duration:
- 15:20
Erin Gregory edited English subtitles for A stellar history of modern astronomy | ||
Erin Gregory edited English subtitles for A stellar history of modern astronomy | ||
Erin Gregory approved English subtitles for A stellar history of modern astronomy | ||
Erin Gregory edited English subtitles for A stellar history of modern astronomy | ||
Camille Martínez accepted English subtitles for A stellar history of modern astronomy | ||
Camille Martínez edited English subtitles for A stellar history of modern astronomy | ||
Camille Martínez edited English subtitles for A stellar history of modern astronomy | ||
Joseph Geni edited English subtitles for A stellar history of modern astronomy |