The Webb Area Telescope is 100x as highly effective because the Hubble. It would change astronomy.

Exploring unusual new worlds. Understanding the origins of the universe. Trying to find life within the galaxy. These are usually not the plot of a brand new science fiction film, however the mission targets of the James Webb Area Telescope, the long-awaited successor to the Hubble Area Telescope.

On Christmas, NASA launched the Webb from French Guiana in partnership with the European Area Company and the Canadian Area Company. Now the telescope is on its approach to a degree practically one million miles away from the Earth.

On its journey, the telescope has to finish a tough mechanical maneuver: assembling itself. The telescope is so giant it wanted to launch folded up inside a rocket. Over the course of a number of weeks, it must unfurl its varied elements, from its sunshield to its mirrors. According to NASA, greater than 300 potential technical issues, or “single level failures,” may probably doom the mission.

However when it totally deploys in area, the Webb will usher in a brand new age of astronomy, scientists say, and present humanity issues it has by no means seen earlier than.

“The Webb represents the end result of many years, if not centuries, of astronomy,” says Sara Seager, a planetary scientist and astrophysicist at MIT. “We’ve been ready for this a really very long time.”

Scientists began fascinated with a follow-up even earlier than the Hubble Area Telescope launched in 1990. After greater than three many years in area, it’s unclear how for much longer this boundary-breaking satellite tv for pc will be capable of scan and {photograph} the universe.

The Webb was initially speculated to launch in 2010 and price round $1 billion. Its price ticket ballooned to $10 billion, and it’s approach overdue. However the wait shall be value it, not less than in response to the scientists who anticipate new and revealing glimpses of our universe.

“We’re going proper as much as the sting of the observable universe with Webb,” says Caitlin Casey, an assistant professor of astronomy on the College of Texas at Austin. “And yeah, we’re excited to see what’s there.”

The Webb will surpass the Hubble in a number of methods. It would permit astronomers to look not solely farther out in area but additionally additional again in time: It would seek for the first stars and galaxies of the universe. It would permit scientists to make cautious research of quite a few exoplanets — planets that orbit stars apart from our solar — and even embark on a seek for indicators of life there.

The Webb is a machine for answering unanswered questions concerning the universe, for exploring what has been unexplorable till now. Right here’s a information to what the Webb is able to.

The Webb’s golden mirror is a big leap for telescopes of its variety

These are two Hubble photographs of the Pillars of Creation. The appropriate reveals what it appears to be like like in infrared, which is nearer to what the Webb telescope will see.
NASA, ESA, the Hubble Heritage Group (STScI/AURA), A. Nota (ESA/STScI), and the Westerlund 2 Science Group

The launch of the Hubble Area Telescope, named after famed astronomer Edwin Hubble, was itself an enormous leap ahead for astronomy. Right here on Earth, astronomers search out distant mountaintops and deserts to construct main telescopes for the perfect probability of viewing a darkish sky away from air pollution and shiny lights. However their view continues to be marred by the slight haze and luminescence of the Earth’s ambiance. Area is “the last word mountaintop,” as NASA explains. There’s no higher view of area than the one from, nicely, area.

Hubble has meant a lot throughout its 30-year run. For one factor, it’s despatched us unforgettable, jaw-droppingly lovely photographs like these of the Lagoon Nebula and the Pillars of Creation.

The Hubble Area telescope captures the Lagoon Nebula in 2018.

It’s additionally taught us concerning the age of the universe, about what occurs when stars explode, about black holes. It helped set up lots of the boundaries that the Webb hopes to push. Most powerfully, its observations have led scientists to imagine the universe is increasing at an accelerating price, propelled by one thing so mysterious that scientists merely name it “darkish vitality.”

The Webb is, controversially, named for the person who led NASA within the decade main as much as the moon touchdown. James Webb, its namesake, was a authorities bureaucrat at a time when it was federal coverage to fireside homosexual staffers. Whereas present NASA administrator Invoice Nelson has stated that the company has “discovered no proof at the moment that warrants altering the identify of the James Webb Area Telescope,” greater than 1,700 folks have signed a petition accusing Webb of complicity in a discriminatory coverage.

Namesake apart, the technological achievement of NASA’s latest telescope is uncontroversial. It’s set to take the success of the Hubble a step additional.

“What we’re going to get is a telescope that’s about 100 occasions extra highly effective than Hubble,” says Amber Straughn, an astrophysicist at NASA who works on the Webb.

Webb Telescope and Hubble Telescope major mirror comparability with individual as reference.
Michael McClare/Aaron E. Lepsch/Krystofer Kim by way of NASA’s Goddard Area Flight Heart


The Webb improves on Hubble in two key methods. The primary is simply its dimension: Hubble was concerning the dimension of a faculty bus, whereas Webb is extra like the dimensions of a tennis courtroom. “This factor is gigantic,” Straughn says. “Webb is by far the largest telescope NASA’s ever tried to ship into area.”

Nevertheless it’s not simply the entire dimension of the contraption that issues. In the case of reflecting telescopes, the important thing element is the dimensions of its curved mirror. “You might type of consider a telescope mirror like a light-weight bucket,” Straughn says. The extra gentle you may acquire on this bucket, the fainter and farther-away issues you may see within the universe.

Hubble’s mirror was a powerful 7.8 toes in diameter. Webb’s lovely, gold-hued mirrors mix for a diameter of 21.3 toes. General, that quantities to greater than six occasions the light-collecting space.

A drawing of the Hubble mirror beside the Webb mirror, with a person for reference. The Hubble mirror is smaller.


What does that imply in apply? Properly, think about certainly one of Hubble’s most well-known photographs, the Deep Area. In 1995, scientists set the Hubble to stare off right into a teeny-tiny patch of sky (concerning the dimension of the pinnacle of a pinhead, held at arm’s size from the viewer) and seize as a lot gentle because it may from that one spot.

The picture that got here again was astounding. Hubble uncovered 1000’s of galaxies on this teensy patch of sky, serving to us refine the variety of galaxies thought to exist within the universe.

The Hubble Deep Area picture reveals that even in a tiny patch of sky, there are literally thousands of galaxies.
NASA, ESA, R. Bouwens, and G. Illingworth

This {photograph} additionally revealed Hubble’s bigger energy — as a time machine. In astronomy, the farther away issues are, the older they’re (as a result of gentle from faraway locations takes a very very long time to journey to Earth). Which means this Hubble Deep Area isn’t solely a snapshot of area: It additionally comprises the historical past of our universe. Galaxies on this picture seem to us as they had been billions of years in the past.

“What Webb will do is take that area and go even additional,” UT Austin’s Casey explains. “So the tiny specks of sunshine within the background of the Hubble Deep Area will brighten and develop into extra detailed, we’ll be capable of see spiral arms, we’ll be capable of see construction, after which we’ll get extra specks of sunshine even additional previously. We’re seeing farther again in time with Webb.”

With Webb, astronomers like Casey will be capable of see up to now again that they’ll probably spot the very first stars and galaxies. Hubble has seen gentle relationship to about 400 million years after the Large Bang, which took about 13.3 billion years to succeed in us.

“That’s far! However Webb has the potential to take us to 250 million years after the Large Bang,” explains Casey, who has been authorised to work with the Webb Area Telescope. “It may not sound like an enormous distinction. What’s just a few hundred million years between buddies? Really, it’s the distinction between seeing the primary stars that ever turned on [and] arriving a bit too late after the funeral.”

Astronomers name this era when the first starlight shone by means of the universe “cosmic daybreak.” With the Webb, humanity will be capable of glimpse at it for the very first time.

Past which can be obstacles by means of which even the Webb can’t see. Previous to the primary starlight, the universe was shrouded by a “dense, obscuring fog of primordial fuel,” because the Nationwide Science Basis explains. There’s no gentle that reaches our telescopes from this time, which is known as the cosmic darkish ages.

(There’s some background radiation from the Large Bang known as the cosmic microwave background, a faint glow that shines to us from earlier than the darkish ages. However for essentially the most half, the darkish ages is a clean spot in our timeline of the universe.)

Casey and different astronomers hope the Webb will assist them perceive the tip of the darkish ages and determine what brought on this fog to raise, ushering in cosmic daybreak. Scientists suspect the starlight from the earliest galaxies did it.

“If in case you have a cloud of fuel and it encounters energetic gentle, that energetic gentle will ionize that fuel and disassociate that cloud,” Casey says. “And so if that gentle simply has turned on, it then hits that fuel and actually transforms the whole universe from a darkish place to a light-weight place.”

The Webb telescope sees infrared gentle — which will be very, very previous

The James Webb Area Telescope beneath building in 2016.
NASA/Chris Gunn

The Webb’s different benefit is the kind of gentle it collects.

Mild is available in a whole lot of totally different varieties. The human eye can see solely a slim band often known as seen gentle, however the universe comprises tons and many gentle outdoors this vary, together with the higher-frequency, higher-energy varieties: ultraviolet, gamma rays. Then there’s the lower-energy gentle with longer wavelengths: infrared, microwaves, radio.

Hubble may observe somewhat little bit of infrared gentle, however Webb takes it a lot additional.
NASA and J. Olmstead (STScI)

The Hubble Area Telescope collects seen gentle, ultraviolet, and somewhat little bit of infrared. The Webb is primarily an infrared telescope, so it sees gentle that’s in an extended wavelength than what our eyes can see. This appears nerdy and technical, but it surely’s truly what permits Webb to look additional again in time than the Hubble.

Infrared gentle is usually very previous gentle, resulting from a phenomenon name redshifting. When a light-weight supply is shifting away from a viewer, it will get stretched out, morphing into an extended and longer wavelength, rising redder. (The other is true as nicely: As a light-weight supply grows nearer, the wavelengths shorten, rising bluer.) It’s just like what occurs when a siren goes by: The pitch will increase because the siren approaches, then decreases because it trails away.

As a result of area is continually increasing, the farthest issues away from us within the universe are shifting away from us. “And as gentle travels by means of area from these distant galaxies, the sunshine is actually stretched by the enlargement of area,” Straughn says.

Because the universe expands, it stretches the wavelengths of sunshine together with it, a course of known as redshift. The farther away an object is, the extra the sunshine from it has stretched by the point it reaches us.
NASA/JPL-Caltech/R. Harm (Caltech-IPAC)

Think about a star that’s actually distant. The sunshine from that star might begin off within the seen spectrum, but it surely will get stretched on its journey to us. It grows redder and redder. “So after we see distant galaxies with Hubble, they’re type of these little, tiny crimson nuggets,” Straughn says. Ultimately, these very distant, previous galaxies develop so crimson that they drop into the infrared spectrum. Webb can see this historical gentle that has develop into invisible to the human eye.

Conveniently, infrared gentle has different makes use of as nicely. It’s a very good sort of sunshine to make use of to take a look at exoplanets. As an illustration, for those who had been on a planet that orbits one other star and needed to see Earth, seen gentle wouldn’t be your greatest wager.

“The Earth peaks within the infrared,” says Johns Hopkins Utilized Physics Laboratory astronomer Kevin Stevenson, who plans to make use of the Webb in his analysis. So if we would like to have the ability to examine an Earth-like planet in one other photo voltaic system, “What we actually wish to do is observe at infrared wavelengths, as a result of that’s the place the sunshine from the Earth is being emitted.”

Exoplanet scientists like Stevenson are going to make use of the Webb to investigate the atmospheres of those worlds: The Webb is able to figuring out a number of the chemical compounds of their atmospheres. “We are able to detect water, CO, CO2, methane,” Stevenson says. Whereas these aren’t definitive indicators of life on their very own, they might start to ask fascinating questions: What created that methane and carbon dioxide? May it have been life?

“All of us wish to discover one other Earth, don’t we?” Stevenson says. “The prospect of answering the query ‘are we alone?’ has been one thing that we’ve been asking ourselves for hundreds of years. And I believe with James Webb, it will present us the primary alternative to actually reply that query.”

This $10 billion gadget higher not break

Scientists are clearly raring to go, however the Webb revolution has taken some time. One motive for all of the launch delays needed to do with contractor snafus. However an enormous supply of all of them, NASA’s Straughn says, is the complexity of the Webb itself.

“As a result of it’s so huge, there aren’t any rockets which can be large enough to launch it totally deployed,” Straughn says. That’s why the telescope needed to be folded up to suit inside a rocket. “In order that entire means of constructing a deployable telescope in area is the supply of a whole lot of the engineering challenges.”

Upping the stakes is the truth that whereas Hubble was launched to round 340 miles above the Earth, Webb shall be nearly one million miles away — 4 occasions the space from the Earth to the moon.

It means Webb shall be unserviceable by human arms if it breaks. That’s scary, contemplating the historical past of the Hubble. Shortly after the Hubble launched in 1990, engineers realized there was an issue with its mirror; the telescope’s preliminary photographs got here again fuzzy, and astronauts needed to launch an area shuttle to repair it. That received’t be doable with the Webb. It simply has to work.

It will likely be distant for good motive. As a result of Webb is an infrared telescope, it must be saved chilly. The Earth itself is heat and glows in infrared. “Something heat glows in infrared gentle,” Straughn says. “If the telescope was heat, it could simply glow and see itself.”

The Webb will orbit round what’s known as a Lagrange level. This can be a level in area the place the telescope can maintain chilly and, critically, additionally keep in keeping with the Earth as each orbit across the solar.

James Webb Area Telescope orbit as seen from above the Solar’s north pole and as seen from Earth’s perspective.
Michael McClare/Aaron E. Lepsch/Josh Masters by way of NASA’s Goddard Area Flight Heart

Remarkably, any scientist all over the world can apply to make use of the Webb Area Telescope, supplied they write up a challenge proposal that passes peer assessment. It’s fairly aggressive. In 2020, the Area Telescope Science Institute, which operates area telescopes from John Hopkins College in Maryland, put out a name for proposals for Webb’s first observing run. A few quarter of the proposals had been accepted.

“It seems like a part of me continues to be surprised,” says Lisa Dang, a physics PhD pupil at McGill College who was one of many fortunate few to get authorised to make use of the Webb. “And the opposite half is having this imposter syndrome — like, these information higher be actually wonderful.”

Dang is about to check one of the vital excessive planets ever found: K2-141 b, a planet 202 light-years from Earth and so near its host star that its floor is believed to be coated by an ocean of lava. If it has clouds, they’re seemingly made out of vaporized rock, which may then precipitate out “rock rain.” Not a lot is confirmed about this lava planet, however Dang will use the Webb to check its ambiance and see what’s doable on this excessive world.

Profitable the challenge proposal “made me really feel like an astronomer for the primary time,” Dang says. “Nevertheless it additionally makes K2-141 b very actual all of the sudden.”

That is the ability of an unprecedented telescope such because the Webb. It would assist astronomers like Dang fill within the clean areas of the cosmos.

“It’s wild, when you concentrate on it, that we’re capable of piece collectively the historical past of what occurred earlier than the Earth or the solar even existed,” Casey says.

If all goes in response to plan, these sorts of breakthroughs may are available a matter of months.

Replace, January 4: This story has been up to date with information on the James Webb Area Telescope’s launch and the controversy surrounding the naming of the telescope.

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