Re: The James Webb Space Telescope will be 100 times as powerful as the Hubble.

On 9/25/2021 1:34 PM, a425couple wrote:
> from
> https://www.vox.com/science-and-health/22664709/james-webb-space-telescope-launch-date-december-science-hubble 
> 
> 
> 
> The largest space telescope in history is about to blow our minds
> 
> The James Webb Space Telescope will be 100 times as powerful as the 
> Hubble. It will change how we see the universe.
> 



Can't wait, I'll be on pins and needles during launch and
deployment until the first images.




> By Brian Resnick@[email protected]  Sep 22, 2021, 9:30am EDT
> 
> Exploring strange new worlds. Understanding the origins of the universe. 
> Searching for life in the galaxy. These are not the plot of a new 
> science fiction movie, but the mission objectives of the James Webb 
> Space Telescope, the long-awaited successor to the Hubble Space 
> Telescope. NASA is building and launching the Webb in partnership with 
> the European Space Agency and Canada.
> 
> The launch, which will propel the Webb to nearly a million miles away, 
> is now scheduled for December 18, 2021. When it fully deploys in space, 
> the Webb will usher in a new age of astronomy, scientists say, and show 
> humanity things it has never seen before.
> 
> “The Webb represents the culmination of decades, if not centuries, of 
> astronomy,” says Sara Seager, a planetary scientist and astrophysicist 
> at MIT. “We’ve been waiting for this a very long time.”
> 
> Scientists started thinking about a follow-up even before the Hubble 
> Space Telescope launched in 1990. After more than three decades in 
> space, it’s unclear how much longer this boundary-breaking satellite 
> will be able to scan and photograph the universe.
> 
> 
> The Webb was originally supposed to launch in 2010 and cost around $1 
> billion. Its price tag has since ballooned to $10 billion, and it’s way 
> overdue. But the wait will be worth it, at least according to the 
> scientists who expect new and revealing glimpses of our universe.
> 
> “We’re going right up to the edge of the observable universe with Webb,” 
> says Caitlin Casey, an assistant professor of astronomy at the 
> University of Texas at Austin. “And yeah, we’re excited to see what’s 
> there.”
> 
> The Webb will surpass the Hubble in several ways. It will allow 
> astronomers to look not only farther out in space but also further back 
> in time: It will search for the first stars and galaxies of the 
> universe. It will allow scientists to make careful studies of numerous 
> exoplanets — planets that orbit stars other than our sun — and even 
> embark on a search for signs of life there.
> 
> The Webb is a machine for answering unanswered questions about the 
> universe, for exploring what has been unexplorable until now. Here’s a 
> guide to what the Webb is capable of.
> 
> The Webb’s golden mirror is a giant leap for telescopes of its kind
> 
> These are two Hubble images of the Pillars of Creation. The right shows 
> what it looks like in infrared, which is closer to what the Webb 
> telescope will see. NASA, ESA, the Hubble Heritage Team (STScI/AURA), A. 
> Nota (ESA/STScI), and the Westerlund 2 Science Team
> 
> The launch of the Hubble Space Telescope, named after famed astronomer 
> Edwin Hubble, was itself a huge leap forward for astronomy. Here on 
> Earth, astronomers seek out remote mountaintops and deserts to build 
> major telescopes for the best chance of viewing a dark sky away from 
> pollution and bright lights. But their view is still marred by the 
> slight haze and luminescence of the Earth’s atmosphere. Space is “the 
> ultimate mountaintop,” as NASA explains. There’s no better view of space 
> than the one from, well, space.
> 
> Hubble has meant so much during its 30-year run. For one thing, it’s 
> sent us unforgettable, jaw-droppingly beautiful images like those of the 
> Lagoon Nebula and the Pillars of Creation.
> 
> The Hubble Space telescope captures the Lagoon Nebula in 2018. NASA, 
> ESA, and STScI
> 
> It’s also taught us about the age of the universe, about what happens 
> when stars explode, about black holes. It helped establish many of the 
> boundaries that the Webb hopes to push. Most powerfully, its 
> observations have led scientists to believe the universe is expanding at 
> an accelerating rate, propelled by something so mysterious that 
> scientists simply call it “dark energy.”
> 
> The Webb, named for the man who led NASA in the decade leading up to the 
> moon landing, is set to take all this a step further. “What we’re going 
> to get is a telescope that’s about 100 times more powerful than Hubble,” 
> says Amber Straughn, an astrophysicist at NASA who works on the Webb.
> 
> Webb Telescope and Hubble Telescope primary mirror comparison with 
> person as reference. Michael McClare/Aaron E. Lepsch/Krystofer Kim via 
> NASA’s Goddard Space Flight Center
> How?
> 
> The Webb improves on Hubble in two key ways. The first is just its size: 
> Hubble was about the size of a school bus, whereas Webb is more like the 
> size of a tennis court. “This thing is enormous,” Straughn says. “Webb 
> is by far the biggest telescope NASA’s ever attempted to send into space.”
> 
> But it’s not just the total size of the contraption that matters. When 
> it comes to reflecting telescopes, the key component is the size of its 
> curved mirror. “You could sort of think of a telescope mirror like a 
> light bucket,” Straughn says. The more light you can collect in this 
> bucket, the fainter and farther-away things you can see in the universe.
> 
> 
> Hubble’s mirror was an impressive 7.8 feet in diameter. Webb’s 
> beautiful, gold-hued mirrors combine for a diameter of 21.3 feet. 
> Overall, that amounts to more than six times the light-collecting area.
> 
> A drawing of the Hubble mirror beside the Webb mirror, with a person for 
> reference. The Hubble mirror is smaller.
> NASA
> What does that mean in practice? Well, consider one of Hubble’s most 
> famous images, the Deep Field. In 1995, scientists set the Hubble to 
> stare off into a teeny-tiny patch of sky (about the size of the head of 
> a pinhead, held at arm's length from the viewer) and capture as much 
> light as it could from that one spot.
> 
> The image that came back was astounding. Hubble uncovered thousands of 
> galaxies in this teensy patch of sky, helping us refine the number of 
> galaxies thought to exist in the universe.
> 
> 
> The Hubble Deep Field image shows that even in a tiny patch of sky, 
> there are thousands of galaxies. NASA, ESA, R. Bouwens, and G. Illingworth
> This photograph also revealed Hubble’s larger power — as a time machine. 
> In astronomy, the farther away things are, the older they are (because 
> light from faraway places takes a very long time to travel to Earth). 
> That means this Hubble Deep Field is not only a snapshot of space: It 
> also contains the history of our universe. Galaxies in this image appear 
> to us as they were billions of years ago.
> 
> “What Webb will do is take that field and go even further,” UT Austin’s 
> Casey explains. “So the tiny specks of light in the background of the 
> Hubble Deep Field will brighten and become more detailed, we’ll be able 
> to see spiral arms, we’ll be able to see structure, and then we’ll get 
> more specks of light even further in the past. We’re seeing farther back 
> in time with Webb.”
> 
> 
> With Webb, astronomers like Casey will be able to see so far back that 
> they’ll potentially spot the very first stars and galaxies. Hubble has 
> seen light dating to about 400 million years after the Big Bang, which 
> took about 13.3 billion years to reach us.
> 
> “That’s far! But Webb has the capability to take us to 250 million years 
> after the Big Bang,” explains Casey, who has been approved to work with 
> the Webb Space Telescope. “It might not sound like a big difference. 
> What’s a few hundred million years between friends? Actually, it’s the 
> difference between seeing the first stars that ever turned on [and] 
> arriving a bit too late after the funeral.”
> 
> The world needs more wonder
> The Unexplainable newsletter guides you through the most fascinating, 
> unanswered questions in science — and the mind-bending ways scientists 
> are trying to answer them. Sign up today.
> 
> Beyond that are barriers through which even the Webb cannot see. Prior 
> to the first starlight, the universe was shrouded by a “dense, obscuring 
> fog of primordial gas,” as the National Science Foundation explains. 
> There’s no light that reaches our telescopes from this time, which is 
> called the cosmic dark ages.
> 
> (There is some background radiation from the Big Bang called the cosmic 
> microwave background, a faint glow that shines to us from before the 
> dark ages. But for the most part, the dark ages is a blank spot in our 
> timeline of the universe.)
> 
> Casey and other astronomers hope the Webb will help them understand the 
> end of the dark ages and figure out what caused this fog to lift. 
> Scientists suspect the starlight from the earliest galaxies did it.
> 
> “If you have a cloud of gas and it encounters energetic light, that 
> energetic light will ionize that gas and disassociate that cloud,” Casey 
> says. “And so if that light just has turned on, it then hits that gas 
> and really transforms the entire universe from a dark place to a light 
> place.”
> 
> The Webb telescope sees infrared light — which can be very, very old
> 
> The James Webb Space Telescope under construction in 2016. NASA/Chris Gunn
> The Webb’s other advantage is the type of light it collects.
> 
> Light comes in a lot of different varieties. The human eye can see only 
> a narrow band known as visible light, but the universe contains lots and 
> lots of light outside this range, including the higher-frequency, 
> higher-energy forms: ultraviolet, gamma rays. Then there’s the 
> lower-energy light with longer wavelengths: infrared, microwaves, radio.
> 
> 
> Hubble could observe a little bit of infrared light, but Webb takes it 
> much further. NASA and J. Olmstead (STScI)
> The Hubble Space Telescope collects visible light, ultraviolet, and a 
> little bit of infrared. The Webb is primarily an infrared telescope, so 
> it sees light that’s in a longer wavelength than what our eyes can see. 
> This seems nerdy and technical, but it’s actually what allows Webb to 
> look further back in time than the Hubble.
> 
> Infrared light is often very old light, due to a phenomenon call 
> redshifting. When a light source is moving away from a viewer, it gets 
> stretched out, morphing into a longer and longer wavelength, growing 
> redder. (The opposite is true as well: As a light source grows closer, 
> the wavelengths shorten, growing bluer.) It’s similar to what happens 
> when a siren goes by: The pitch increases as the siren approaches, then 
> decreases as it trails away.
> 
> 
> Because space is constantly expanding, the farthest things away from us 
> in the universe are moving away from us. “And as light travels through 
> space from those distant galaxies, the light is literally stretched by 
> the expansion of space,” Straughn says.
> 
> 
> As the universe expands, it stretches the wavelengths of light along 
> with it, a process called redshift. The farther away an object is, the 
> more the light from it has stretched by the time it reaches us. 
> NASA/JPL-Caltech/R. Hurt (Caltech-IPAC)
> Imagine a star that’s really far away. The light from that star may 
> start off in the visible spectrum, but it gets stretched on its journey 
> to us. It grows redder and redder. “So when we see distant galaxies with 
> Hubble, they’re sort of these little, tiny red nuggets,” Straughn says. 
> Eventually, these very distant, old galaxies grow so red that they drop 
> into the infrared spectrum. Webb can see this ancient light that has 
> become invisible to the human eye.
> 
> Conveniently, infrared light has other uses as well. It’s a really good 
> type of light to use to look at exoplanets. For instance, if you were on 
> a planet that orbits another star and wanted to see Earth, visible light 
> wouldn’t be your best bet.
> 
> “The Earth peaks in the infrared,” says Johns Hopkins Applied Physics 
> Laboratory astronomer Kevin Stevenson, who plans to use the Webb in his 
> research. So if we want to be able to study an Earth-like planet in 
> another solar system, “What we really want to do is observe at infrared 
> wavelengths, because that’s where the light from the Earth is being 
> emitted.”
> 
> 
> Exoplanet scientists like Stevenson are going to use the Webb to analyze 
> the atmospheres of these worlds: The Webb is capable of determining some 
> of the chemicals in their atmospheres. “We can detect water, CO, CO2, 
> methane,” Stevenson says. While those aren’t definitive signs of life on 
> their own, they could begin to ask fascinating questions: What created 
> that methane and carbon dioxide? Could it have been life?
> 
> “We all want to find another Earth, don’t we?” Stevenson says. “The 
> prospect of answering the question ‘are we alone?’ has been something 
> that we’ve been asking ourselves for centuries. And I think with James 
> Webb, this will provide us the first opportunity to really answer that 
> question.”
> 
> This $10 billion gadget better not break
> Scientists are clearly raring to go, but the Webb revolution has taken a 
> while. One reason for all the launch delays to the launch has to do with 
> contractor snafus. But a big source of all of them, NASA’s Straughn 
> says, is the complexity of the Webb itself.
> 
> “Because it’s so big, there aren’t any rockets that are big enough to 
> launch it fully deployed,” Straughn says. The telescope has to be folded 
> up to fit inside a rocket, and has to deploy itself in space. “So that 
> whole process of building a deployable telescope in space is the source 
> of a lot of the engineering challenges.”
> 
> Upping the stakes is the fact that while Hubble was launched to around 
> 340 miles above the Earth, Webb will be almost a million miles away — 
> four times the distance from the Earth to the moon.
> 
> That means once the Webb is launched, it will be unserviceable by human 
> hands if it breaks. That’s scary, considering the history of the Hubble. 
> Shortly after the Hubble launched in 1990, engineers realized there was 
> a problem with its mirror; the telescope’s initial images came back 
> fuzzy, and astronauts had to launch a space shuttle to fix it. That 
> won’t be possible with the Webb. It just has to work.
> 
> It will be far away for good reason. Because Webb is an infrared 
> telescope, it needs to be kept cold. The Earth itself is warm and glows 
> in infrared. “Anything warm glows in infrared light,” Straughn says. “If 
> the telescope was warm, it would just glow and see itself.”
> 
> 
> James Webb Space Telescope orbit as seen from above the Sun’s north pole 
> and as seen from Earth’s perspective. Michael McClare/Aaron E. 
> Lepsch/Josh Masters via NASA’s Goddard Space Flight Center
> Remarkably, any scientist around the world can apply to use the Webb 
> Space Telescope, provided they write up a project proposal that passes 
> peer review. It’s pretty competitive. Last year the Space Telescope 
> Science Institute, which operates space telescopes from John Hopkins 
> University in Maryland, put out a call for proposals for Webb’s first 
> observing run. About a quarter of the proposals were accepted.
> 
> “It feels like part of me is still stunned,” says Lisa Dang, a physics 
> PhD student at McGill University who was one of the lucky few to get 
> approved to use the Webb. “And the other part is having this imposter 
> syndrome — like, these data better be really amazing.”
> 
> Dang is set to study one of the most extreme planets ever discovered: 
> K2-141 b, a planet 202 light-years from Earth and so close to its host 
> star that its surface is believed to be covered by an ocean of lava. If 
> it has clouds, they are likely made out of vaporized rock, which could 
> then precipitate out “rock rain.” Not much is confirmed about this lava 
> planet, but Dang will use the Webb to study its atmosphere and see 
> what’s possible on this extreme world.
> 
> Winning the project proposal “made me feel like an astronomer for the 
> first time,” Dang says. “But it also makes K2-141 b very real suddenly.”
> 
> This is the power of an unprecedented telescope such as the Webb. It 
> will help astronomers like Dang fill in the blank spaces of the cosmos.
> 
> “It’s wild, when you think about it, that we’re able to piece together 
> the history of what happened before the Earth or the sun even existed,” 
> Casey says.
> 
> If all goes according to plan, these kinds of breakthroughs could come 
> in a matter of months. Astronomers around the world are waiting for the 
> countdown to begin.
> 
> 
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