Placeholder Image

Subtitles section Play video

  • This is currently the world's largest optical lens ever builtMeasuring 1.55 meters in

  • diameter, this piece of glass is one of three lenses that will be the eyes for a new astronomical

  • cameraIt weighs over 3 tons and has an enormous field of view, where light from billions

  • of galaxies will come into focusWith decades in the making, this camera will be mounted

  • on a telescope in Chile to construct a time-lapse of the universeEvery 30 seconds we're going

  • to take a new picture of a different piece of the sky, and we're going to keep doing

  • that every night for 10 years. A single picture is 3.2 billion pixels. We're taking a movie

  • and making that available to anyone who wants to do science with itIt's a fantastic opportunity

  • to be living in a time where not only we have these profound questions of the universe,

  • but also we are building experiments that are capable of answering them.

  • One thing that is particularly fascinating about the universe is, in a way, how little of it we understand

  • at this pointRight now, we live in a really strange situation where we have a model of

  • our universe that's simple but weird. We just made up these components of the universe to

  • fit our data, and they kind of work but we don't really understand themIt's those

  • two elusive puzzles in cosmology: dark matter and dark energyThey greatly affect how

  • the universe evolves over time, how the universe expands over time, and how structures like

  • galaxies or clusters of galaxies form inside the universeAstronomy used to be a science

  • where a single scientist with a telescope could make a differenceBut, we're probably

  • now at a point where that's no longer feasible, where the resources you need to really find

  • out something new are so large that you can only afford them as a whole humanityUnsolved

  • Unsolved mysteries and international collaboration are driving this current era of super scopes.

  • They're massive projects that take decades of planning and technical innovation to bring

  • online. Each has a unique design pointed towards ambitious science goals, like imaging the

  • galactic center and peering back to cosmic dawn. This camera-telescope project will conduct

  • the Legacy Survey of Space and Time , with the Vera C. Rubin Observatory, named after

  • an astronomer who found more evidence of the universe's fundamental weirdnessShe discovered,

  • using observation of the rotation of galaxies, that there was much more material in them

  • than we could see. That, together with lots of other observations, led us to now be very

  • certain that there's this other type of material in the universe that we call dark matter.

  • What you need to do is you need to collect the light of many, many galaxies so you

  • can tell the small effects that dark energy and dark matter have on the light of those galaxies.

  • There was a desire to have a telescope that could observe the whole sky every few

  • days. That means it's operating just as a sort of a machine, just going click, click,

  • click across the whole skyIt looks like a searchlight It's very short and squat but

  • that actually helps keep the moment of inertia down and make it so you can actually move

  • fast. There are three mirrors in the telescope that collect the light from ancient photons

  • that then get focused to three lenses in the cameraAt

  • the heart of the camera is the focal plane, where light gets recorded into an imageThe

  • biggest feature of this camera is just how large of an area of the sky it can take a

  • picture of in a single shot. The area that we can take a sharp image of with this camera

  • in a single exposure is about 40 times the size of the full moonIf you want to have

  • that big of a field of view, that means that the size of the focal plane is 0.6 meters

  • in diameter. There's no detector that's that big. You're going to have to make a mosaic.

  • And you're going to have to tile that focal plane with those detectors just like you would

  • tile a bathroom floorCCDs were chosen for this. CCD stands for charge-coupled device;

  • it's a type of  imaging sensorCCDs were first developed in the 1970s. And the idea

  • is pretty simple. You want to take advantage of the fact with silicon as a semiconductor,

  • that if you shine light on it you can generate a signal. The CCD is a set of pixelsIn

  • this particular system there's 189 science CCDs and we want to tile this whole focal

  • plane. Well we can't just slap them on there. We need to come up with some modularity So

  • it was chosen to package them in sets of nine. So each set of nine CCDs was dubbed with the

  • name raft. Each raft is a self-contained, 144 million pixel cameraEach of these raft

  • tower modules gets mounted into a thing that's called the gridWhen you have a complex

  • optical system and you go to focus the light on this focal plane. Different wavelengths

  • of light could focus at different placesThe universe is expanding. And so the further

  • away you go, the spectrum of the object is shifted towards the red. As the light comes

  • through the atmosphere, it's going to bend a little bit, and the red light bends differently

  • than the blue light. If you had no filter and you tried to just image with the whole

  • visible spectrum it would blur the image because the blue light and the red light would focus

  • at slightly different positions. We've taken the visible spectrum and we split it up into

  • five partsSo the camera holds five filters.

  • That color information is very important to

  • be able to tell how far away the galaxy is from us how old the universe is at the point

  • we observe the galaxyWith a project this jam packed with electronics, another component

  • they have to build is a cooling or cryostat systemBecause heat can turn into unwanted

  • noiseSystematic distortions caused by the optics or the atmosphere trick you and make

  • you think that the universe is doing somethingSome of the most interesting things we're taking

  • pictures of are the faintest ones, and they look like little smudges. The lower you can

  • make your noise, the dimmer you can properly measure.

  • So we're integrating all these pieces. The camera body's coming together, the cryostat's

  • coming together And if we didn't have a pandemic, I think we would have been scheduled to bolt

  • them together by nowIt'll get shipped to Chile, and then it'll get transported up the

  • mountain, and then we will assemble it on the floor of the observatory, and we'll operate

  • it there before it gets put in the telescopeThere's been an enormous number of people that have

  • just poured their hearts into this thing, and it's been a long time. And so I hope that

  • we can make it workThe targeted operational date is 2022 for this world class sky survey.

  • And when the shutter opens, it'll take.. a deep, sharp, picture over a large, large

  • area, and keep repeating that process, keep taking new pictures of the same part of the

  • sky. If you just imagine it's 3 billion pixels every 30 seconds, that's a thousand

  • giant photos every night, for 10 yearsYou end up with hundreds of petabytes of data.

  • On the mountain, we're going to have a facility so that we can look at the images right away

  • and we'll do some really basic diagnostics. It should be 30 seconds or so after an image

  • comes out. Then the data goes down the mountain. The processing and the storage and the analysis

  • of that data is going to happen throughout the world, in Chile, in the U.S., in Europe, and

  • in AsiaWe often have to develop completely new ways of analyzing that data, just because

  • it is this huge amount and we need to analyze it very quickly. We also need to analyze it

  • very accuratelyOften times, artificial intelligence is a key to doing that. We cannot

  • afford to make even tiny mistakes just because it is so powerful a data set that we would

  • be overwhelmed by our little uncertainties.

  • There's a number of different things that you can

  • do with this sort of data that are unprecedented. We will see galaxy clusters forming, we will

  • see supernovae going off in unprecedented numbers, and we can use that information to

  • find out what dark energy is doing to drive the expansion of the universe. We will find

  • a million things that go bump in the night and they will be transmitted to astronomers

  • throughout the world. All those alerts then will be immediately available on the internet

  • you can subscribe to them.Then maybe it wakes you up and you run outside and open up and

  • turn on your telescopeWe're really building this experiment, as scientists always are,

  • to prove ourselves wrong, to find something we didn't expect. But how do you find something

  • you didn't expect? You have to be really carefulThe smoking gun in physics can be really small.

  • It can be just that your data looks a little bit different than you thought and there's

  • no way of explaining that other than to change your full understanding of the physics of

  • the cosmosWe could find that there is a little, just a little, less structure, there's

  • just fewer clusters of galaxies in the universe today than we would have thought. And that

  • would already mean that we got the whole picture wrong, there's really something fundamental

  • missing. And so that's what I think could happen, but who am I to predict that? So what

  • I'm really hoping we will find here is that that model is wrong, that it doesn't explain

  • some of the observations that we're making, and that that will give us a hint to what

  • really is happening in the universe.

This is currently the world's largest optical lens ever builtMeasuring 1.55 meters in

Subtitles and vocabulary

Operation of videos Adjust the video here to display the subtitles

B1 universe telescope camera focal data sky

This 3.2 Gigapixel Camera Will Record a Timelapse of the Universe

  • 0 1
    Summer posted on 2020/07/30
Video vocabulary