# Rubin vs Webb Telescopes - What's the Difference Between Them?

## Метаданные

- **Канал:** Curious Droid
- **YouTube:** https://www.youtube.com/watch?v=QZZqtgUAxX0
- **Источник:** https://ekstraktznaniy.ru/video/42774

## Транскрипт

### Segment 1 (00:00 - 05:00) []

Today's video is sponsored by Delete Me. First, there was Hubble, the telescope that literally brought us images from almost the beginning of the universe as we know it with unbelievable visions of the most distant objects we had ever seen at the time. Then came the James Web Space Telescope. This was like Hubble on steroids and has gone back even farther into the history of the universe and shown us things which we still don't quite understand and threatened to upend our theories on how stars and galaxies were first formed. Then in the last week, we had the Vera Rubin Observatory releasing its first images which cover a huge amount of the night sky in ways we've never really seen before. So why do we need so many different ways of looking at the same thing? basically the night sky and the stars and galaxies that exist out there in the universe. In this video, I thought we'd look at the differences between the James Webb telescope and the Vera Rubin telescope and why the two really do go hand in hand. Now, just in case you haven't been following developments in space for the last few years or more, the James Web Space Telescope was launched effectively to stand on the shoulders of a Hubble Space Telescope and see fainter objects that go back deeper in time than it's ever been possible before. by looking at small patches of the sky with probably the most sensitive piece of optical equipment anyone has yet built. The light it looks for has traveled so far for so long that it's been redshifted from the visible light spectrum into the infrared spectrum which we feel as heat. And to be able to detect it, the JWSD camera sensors needed to be as cold as possible and work at just 7° Kelvin above absolute zero. This means that it couldn't be in a low Earth orbit like the Hubble as the infrared heat from the Earth and the constant heating and cooling from going from full sun to full shade as it orbits the Earth would swamp out the infrared signals coming from the edge of the visible universe. So it's in a special orbit near the second sun earth lrangege point L2 which lies approximately 1 and a half million km or a million miles from Earth on the far side of the earth from the sun where the gravitational forces of the Earth, Sun and Moon and orbital motion of the JWST balance each other as it effectively hovers out there without being in an orbit. Here, the large multi-layer heat shield that protects it from the sun. And with cryogenic cooling equipment, the JWST can reach its 7 degree Kelvin target. Web's first deep field image was taken with a near infrared camera and showed thousands of galaxies, including the faintest objects ever observed at the time in the infrared spectrum in an area of sky that would be about the size of a grain of sand held at arms length. You could fit about 600 of these images into an area the size of your thumbnail held up at arms length. This was a composite image made up of images at different wavelengths and a total exposure time of 12 1/2 hours. And this is what the James Web specializes in. Looking at an incredibly small piece of sky, which to us here on Earth would look like it was completely empty. And yet we found it contains thousands of galaxies going back to just after the Big Bang in the tiny patches of apparent nothingness. But if we wanted to survey the entire sky using the JWST, taking similarsized images, but with much faster exposure times, you would need over 25 million such images. Even if you took one image every minute, it would take you over 47 years to image the entire sky once. Clearly something which is not a practical proposition. And this is where the Vera Rubin Observatory comes in. It's designed to take images of the entire southern night sky in just a few days. And it does it from here on Earth looking through our atmosphere from a location as an altitude of about 2,672 m in the Kwimbo region of northern Chile alongside other large optical telescopes. The Vera Rubin telescope with its 3. 2 2 gigapixel camera which takes hundreds of images every night creates a huge amount of data into the pabytes per year which is not dissimilar to the amount of tracking data is captured from you and I by the tech giants as we use the internet. This is merged with existing data about each one of us to servers with personalized ads with what they think we want to see, hear and read. But at the bottom of all this are data brokers, companies that buy and sell data to anyone that wants

### Segment 2 (05:00 - 10:00) [5:00]

it. This includes emails, names, current and past addresses, phone numbers, age, occupation, and more. And this is where the problem lies and where our sponsor, Delete Me, can help you. If anyone can buy data about you or your family, it can become a security or even a personal safety risk. If you work in sensitive places like the government, the military, civil services, or you have a high profile. While you can request that these companies delete the data they hold on you, with over 750 data brokers around the world, where do you start? And this is where Delete Me comes in. Delete Me has been helping normal people like you and I get their personal information removed from data brokers since 2010 in the US, UK, and Europe. Delete Me is simple to use. You just select the plan you want, fill in the online application, and delete me will contact the hundreds of data brokers to remove you from their lists. You receive regular privacy reports that show how much data was found, where it was found, and where it was removed from. You can do this for yourself or for your family. And if you use the joindeme. com/link in the description below, or you scan the QR code next to me today, you will receive a 20% discount. Now you might say, why do we want to take continuous pictures of the sky? Well, if we do so, we can then see the universe in motion over time and how things change over a matter of hours, days, and even eventually years. Many astronomical phenomena are short-lived, like supernova, gammaray bursts, or gravitational wave counterparts. Rubin will take images in quick succession over a 10-year and now possibly 12 year predicted period, allowing us to capture things within maybe minutes or hours of them actually happening and have a record of what happened before as well as after the event. Rumin will see much more than just distant events, though. It will become the most effective tool for finding and tracking potentially hazardous asteroids and measuring their motion, speed, and orbit to see if they will become Earth impact events. In fact, within just 10 hours of observing the night sky, Reubin had already found more than 2,000 new asteroids, including a few near Earth objects. The Reubin Observatory will also carry on the work of a woman whose name they gave to the observatory, namely Vera Rubin. She was the first person to work out that the outer edges of galaxies were moving much faster than there should have been for the amount of mass they had and there was some other hidden mass which was accounting for this discrepancy. And this has become known as dark matter. This is something which we cannot see or detect but we know is out there because we can see the gravitational effect of it on astronomical objects like stars and galaxies. By continuously taking pictures of the entire night sky, we can track the movements of stars and galaxies and therefore work out where this dark matter might be and map it over time. As the project goes on, it will build up a fourdimensional map with space being the three dimensions and time being the fourth. This catalog will eventually cover 6 million solar system objects and their orbits and approximately 37 billion sky objects, including 20 billion galaxies and 17 billion stars, each with more than 200 attributes. But to image this amount of sky, each image is going to be much bigger than an image from the JWST and be taken in much quicker time. And it will be using the largest camera sensor yet built. To give you an idea of the difference between the sensors, the Reubin contains 3. 2 GPI compared to 42 megapixels of JWST. That's 76 times larger. And the Reubin takes an image every 30 seconds. The main sensor panel is comprised of 189 CCD detectors, each with 16 megapixels, and is cooled to - 100° C to help reduce noise. In this image, a lifesize model of the focal plane array is shown with the equivalent size of the moon in its field of view. The telescope uses three lenses, the primary one being 8. 4 m across with an aperture of f1. 8. The secondary lens is 3. 4 m across with an aperture of f1 and the third 5 m across with an aperture of f. 83. The light then goes through three corrector lenses with the first one being 1 1/2 m in diameter. The largest of this type of lens ever built. Unlike some other large telescopes which actively compensate for the atmospheric effects because the images are taken very quickly with just a 5-second gap

### Segment 3 (10:00 - 14:00) [10:00]

between each one. It's not long enough to do this type of correction. And because of the extremely short focal length, it would make it a very difficult technical challenge as well. The sensor is not a full color sensor either. It's monochromatic and uses six different filters which are placed between the secondary and tertiary mirrors and separate filtered images eventually build up the full color images which we see. The wavelength bands for the filters are U for ultraviolet, B for blue, V for visual, R for red, and I for infrared. Although the JWST can see some visible light, it's primarily designed to detect near infrared and mid- infrared, allowing it to see objects that are obscured by dust and gas clouds and the very earliest galaxies where the visible light has been redshifted into the infrared spectrum. But the size and quantity of the images produced by the Rubin's camera also brings a whole new set of other issues, namely data processing and storing. With about 30 terabytes of data being generated every day, there's simply too much information for humans to process it by hand. So, a whole system had to be created that would process the images automatically. If an object changed its brightness or position relative to an archived image, an alert could be created. so that it can then be manually inspected. This is done within 60 seconds of the observation taking place to ensure that important events are acted on as fast as possible. Because the images that the camera takes cover such a wide field of view, a lot of man-made objects will also be captured in each image, including aircraft, satellites, and now satellite constellations like Starlink. These have to be detected and removed automatically to avoid them being inadvertently labeled as nearear asteroids or meteorites. This process cuts out a 30 pixel area and path around each object. So there is a little bit of image loss, but that could be filled in from other images. Another thing it will capture are secret military operations taking place in space, not only by the US, but by other countries putting objects into orbit. These also have to be removed as the information is released to the public shortly after the processing. Anyone with access to the raw information could track potentially secret space hardware. So, a classified US government facility in California removes any known secret spacecraft for 3 days before allowing the unredacted versions to be released to the public. The way in which researchers and scientists have access to the two telescopes is also radically different. For the JWST, researchers have to put in a request sometimes years in advance, and then only the best and most worthy of a telescope's time are acted upon. With Vera Rubin, it will be gathering data for the main survey for 90% of its time. The other 10% will then be set aside for special projects. But most of the researchers will use this vast data archive to do their future research on using whatever tools or AI may become available in the future. So in the end, the main differences between the Vera Rubin Observatory and the JWST is that the Vera Rubin will build up a complete image of the southern sky and Milky Way and discover things happening on a day-to-day basis, as well as objects moving around our solar system, such as many of the undiscovered asteroids that could be a threat to us here on Earth. The JWST, on the other hand, will focus not only on teasing out information from the beginning of our universe with highly detailed images, but research into exoplanets, looking for the telltale signs of life in their atmospheres as they pass by their local stars and revealing what is hidden in the vast clouds of intergalactic dust that we can only see through in the infrared spectrum. Either way, we are on the cusp of a whole new era of discovery about space. From the beginning of time to what's going on in our cosmic backyard. It's certainly going to be an amazing journey. So, thanks for watching and I hope you enjoyed the video. And if you did, then please thumbs up, share, and subscribe. And a big thank you goes out to all our patrons for their ongoing support.