Hubble: Why James Webb Won’t Kill NASA’s Old Telescope


In the early 90s, on a trip to the Space Telescope Science Institute, Dave Meyer was greeted with an urgent and excited tone. “You have to see this.”

Elsewhere in the building, image after image is uploaded onto closely monitored screens, and each time you can hear the researchers breathing. “What is it ?” exclaims Meyer. He then looks at dark backgrounds dotted with small galaxies of deceptive size, floating at distances that the human mind simply cannot imagine.

These images came from the Hubble Space Telescope. He had finally begun to uncover the deep universe – and what he had just found was incredible.

“We saw strange things”, explains Mr. Meyer, a professor at Northwestern University who is interested in Hubble’s discoveries. Among the galaxies, which, by the way, were completely similar to what could be found in an astronomer’s imagination, many did not resemble the spirals characteristic of worlds closer to ours. Meyer quickly understood what he had in front of him.

It was visual proof of the evolution of our universe, thanks to a telescope we had just launched into space. “I was really blown away”, he said. Humanity saw much further now than it had done before.

But soon after, in 1995, Hubble broke its own record when NASA released its first deep field. A seemingly empty part of the sky turned out to contain a menagerie of galaxies far, far away. “This very first image of the Hubble Deep Field was groundbreaking”says Morgan Van Arsdall, systems and deputy program manager for the Hubble Space Telescope at Lockheed Martin. “Looking at a patch of ‘dark’ sky and seeing so many stars and galaxies shows how much we still have to learn about the universe.”

And for the next 27 years, as we learned more about the universe, “Hubble” was the name associated with almost all the wonders of the cosmos that have come down to our eyes. Then came 11 July 2022 – the day we managed to travel even further. But this time we did it without Hubble.

Welcome, James Webb Space Telescope

Last week, NASA made the front page of almost every headline. In fact, US President Joe Biden awkwardly showed a modern rendering of the decades-old Hubble Deep Field, conceived by the brilliant James Webb Space Telescope (JWST).

Then, a day after the astonishing broadcast, there were even more JWST images to admire. “I think I said words which your editor would not see fit to publish”says Matt Caplan, assistant professor of physics at Illinois State University, a reaction no doubt shared by many.

Unlike Hubble, built to be 547 km above our atmosphere and reveal the visible universe, JWST is built to live 1.6 million km from Earth and discover the invisible. To give us these images, he had to search for cosmic fragments originating from a source elusive to human eyes, in other words infrared light. Around the world, strong emotions were rightly felt as humanity once again gained new insight into the outer universe and into itself.

It was a brilliant week for astronomy. But in the midst of our celebrations, perhaps we should reflect on what we’ve been up to at Hubble over the past few days.

We openly presented our once groundbreaking and beloved telescope as a lean model to highlight the magnificent transformation of JWST. We are guilty of it too. Hundreds of articles, Reddit threads, and Twitter posts are devoted to it, and while not without reason, it seems to have created a false narrative. It’s like we’re implying that Hubble is dead.

That’s why, as we prepare for an inevitable flood of JWST masterpieces, it’s worth remembering that without Hubble, we would never have had access to these images. “The entire research landscape is defined by what Hubble has seen, and left us wondering what we could learn if we could just see a little more”, says Mr. Caplan. And although it seems that way, Hubble is certainly not dead.

“We’re still definitely going to need Hubble”explains Nikole Lewis, an astronomer at Cornell University. “Actually, I’m trying to come up with a budget for a big cash flow program on Hubble”. Lewis is looking for something that Hubble has, but JWST doesn’t. She studies exoplanets and intends to use the wavelengths of visible and ultraviolet light to decode the clouds and hazes of alien worlds—the kind of light JWST is not sensitive to. “There is a lot of important information on these wavelengths”.

Despite the influence of JWST, Hubble remains the best candidate for examining galaxies that move on the X or Y axis rather than the Z axis. While the movements of the galaxies “towards” and “long” of the soil is very easy to measure with “red shift”a JWST specialty, “movement”side to side “is harder”Caplan said.

In fact, it is thanks to this unique power of Hubble that we have been able to realize a rather important detail about the galaxies. Many of them are crashing right now.

By peering down at Andromeda—the galaxy that Hubble’s namesake used as evidence in 1923 to prove that our universe extends beyond the Milky Way—and measuring how its light is transferred from one pixel to another, JWST’s predecessor showed us, that this galaxy is not just orbiting ours. “They’re really going to collide”, Caplan explains. Would JWST have noticed?

All this to say that as JWST continues to flood the Internet with colorful depictions of the outer reaches of space, we must remember that it is not a replacement for Hubble. JWST is its successor. It will work with Hubble and would not exist in a world without it.

“JWST’s science program will build on the legacy of more than three decades of Hubble science”, explains Van Arsdall. In a way, JWST can lean on the shoulder of a giant. Hubble only had the unknown.

The People’s Telescope

As was the case with Caplan, Lewis, Van Arsdall and Meyer, Hubble’s Azure Nebulae and Deep Ebony-Striated Fields have undoubtedly touched the careers of nearly every physicist, including the team behind NASA’s brand new JWST.

“Hubble’s deep field image was an inspiration to me as a child”recalls Jason Rabinovitch, a former engineer at the Jet Propulsion Laboratory and professor at the Stevens Institute of Technology, “and contributed to what would become a lifelong fascination with space and space exploration.”.

Even Hubble’s rather anxiety-inducing beginnings served as a reason for humanity to look at the cosmos. When the Silver Space Telescope was launched in 1990, everyone was so excited to see what they saw when it was unhindered by Earth’s atmosphere. Then… the first pictures arrived. “It looked like it was a disaster”said Mr. Meyer.

All early Hubble images were blurry. Nothing to do with JWST’s Carina Nebula, worthy of being Apple’s default screensaver, or Stephan’s Quintet, which brought more than one tear to the surface. It turned out to be a problem with the scope lens. It went badly. Everyone was stressed. But that didn’t stop NASA from tackling the problem.

The agency decided to send teams of astronauts aboard space shuttles to repair Hubble. In space. “People could see this in real time”says Mr. Meyer. “They could see NASA astronauts in space repairing a telescope. “It was moments like this that gave Hubble a cute nickname in its heyday: The People’s Telescope. And that’s what it was.

“I grew up fascinated by the shuttle program and was fascinated by the astronauts’ maintenance of Hubble”said Mr. Van Arsdall. “That’s what drove me to become an aerospace engineer.”

Thank you, Hubble, for giving us the stars

There’s no doubt that the Hubble Space Telescope, a giant cylinder that appears to be wrapped in Reynolds’ film, is a cultural icon. It permeates movies, books, photography, poetry, visual arts, television and maybe even wedding vows. As Caplan says, “He is a titan who defines the modern era”.

“I was one of those kids who watched Star Trek and you can see that there are Hubble images placed on the screens”notes Lewis. “There are people who love to be outdoors. Me, I love to be in space… and since I can’t walk around in space, the best way to do that is really through things like the Hubble Space Telescope.”

But falling in love with space, for people who together represent only a molecule of it, is not a new phenomenon. And it’s probably no coincidence. It is much more exciting to dream when reality resembles a fantasy.

Take Vincent Van Gogh’s Starry Night from 1889. This painting is an artist’s impression of a glittering nightscape, and it relies heavily on the pigment Prussian Blue.

Prussian blue is a color discovered in the 18th century by the scientist Johann Conrad Dippel, who, as Benjamin Labatut writes in his novel “When we stop understanding the world”was amazed because he thought he had discovered “original color of the sky”. But Dippel didn’t come up with this idea alone. It referred to the legendary shade the ancient Egyptians thought of.

Our obsession with space dates back centuries and will continue to exist for centuries. It’s just that Hubble—and even JWST, for that matter—catalyzed our excitement. When NASA was planning Hubble’s servicing missions, NASA genuinely wondered if it would be safe to send astronauts up there to repair it. “But the public demanded it”remembers Mr. Meyer.

“When I read the paper this morning, I remembered my thesis adviser’s point of view”says Neil Rowlands, an engineer at Honeywell Aerospace, about the day he saw the first results of JWST. “The only good story in the whole paper was the one about the JWST pictures.”

Having been a JWST engineer for nearly 25 years, Rowlands also points out: “I worked with the optical performance figures [de ce dernier] for such a long time […]. I’ve lost all sense of what those numbers actually mean in terms of image quality – at least until I see the amazing images.”

But as we observe the characteristics of our new astronaut friend, we should remember that his saga grew out of the one Hubble began when it launched in 1990.

And while the story of the James Webb Space Telescope began with a bang, we shouldn’t let Hubble end with a whimper. “There is no question of stopping Hubble”said Mr. Meyer. “We don’t think that will happen for another decade.”

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