It was the early ’90s when, on a trip to the Space Telescope Science Institute, Dave Meyer was met by an urgent message.
“You’ve got to see this.”
Elsewhere in the building, image after image was being downloaded onto closely monitored computers — and with each one, scientist onlookers grew conscious of their breathing. “What is that?” Meyer exclaimed, aware of an echo. He found himself staring at dark backgrounds scattered with deceptively small galaxies, floating at distances the human mind simply cannot grasp.
The Hubble Space Telescope had begun to reveal the deep universe. And it was exhilarating.
“You’d see these weird things,” said Meyer, a Northwestern University professor focused on Hubble discoveries. Among galaxies that were carbon-copies of what you might find in an astronomer’s imagination, there were many that didn’t look like wispy spirals or ellipticals characteristic of realms closer to ours. That’s when Meyer realized what he was looking at.
This was visual proof of our universe’s evolution, courtesy of a telescope we’d just flung into space. “That really blew me away,” he said. At the time, it was as if humanity had seen as far as it could see.
But soon after, in 1995, Hubble broke its own record when NASA publicly released its first deep field. A seemingly blank section of the sky had shockingly turned out to hold a menagerie of galaxies far, far away. “That very first Hubble deep field image was revolutionary,” said Morgan Van Arsdall, systems and deputy program manager for the Hubble Space Telescope at Lockheed Martin. “To look at a ‘dark’ sliver of the sky and see so many stars and galaxies really drives home how much we still have to learn about the universe.”
A high-resolution version of Hubble’s First deep field, taken over the course of 10 days in 1995. These aren’t stars you see. These are entire galaxies.
And for the next 27 years, as we indeed learned more, “Hubble” would be the name attached to almost every stunning piece of the remote cosmos brought to our eyes.
Then came July 11, 2022 — the day we managed to travel even further, and see even deeper. Without Hubble.
Welcome, James Webb Space Telescope
Just last week, NASA dominated the headlines of possibly every news publication. That’s because US President Joe Biden had awkwardly pointed at a magnificent, modern rendition of Hubble’s decades-old deep field, elevated by the lens of the agency’s brilliant James Webb Space Telescope.
Then, a day after that jaw-dropping broadcast, there were even more JWST images to fawn over. “I believe I verbally uttered some words your editor would not find fit to print,” Matt Caplan, an assistant professor of physics at Illinois State University, told me of seeing these pictures for the first time — a reaction I’d bet resonates with many.
Unlike Hubble, built to sit 340 miles above our atmosphere and reveal the visible universe, JWST is constructed to live a million miles from Earth and uncover the invisible. To give us these images, it had to scour for cosmic bits emanating luminescence elusive to human eyes, otherwise known as infrared light. Across the globe, emotional highs rightfully ensued as humanity once again gained a new perspective on the external universe, and on itself.
It was a glorious week for astronomy.
But amid our celebrations, we might want to consider what we did to Hubble over the past several days.
We’ve openly cast our once trailblazing, beloved telescope as a gaunt “before” model to underscore JWST’s beautiful “after” transformation. I’m guilty of it too. Hundreds of articles, Reddit threads and Twitter posts are dedicated to this very concept, and though this isn’t without reason, it seems to have created a false narrative. It feels like we’re implying Hubble is dead.
In 2020, NASA and ESA marked the Hubble Space Telescope’s 30th anniversary with the Cosmic Reef image of two nebulae.
Which is why, as we prepare for an inevitable influx of JWST masterpieces, it bears reflecting that without Hubble, we wouldn’t have accessed NASA’s “after” images at all. “The entire landscape of research is defined by what Hubble saw, and left us speculating about what we might learn if we could see just a little more,” Caplan said.
And even though it might feel like it, Hubble certainly isn’t dead.
“We will absolutely still need Hubble,” said Cornell University astronomer Nikole Lewis. “In fact, I’m in the process of trying to put together a budget for a large treasury program on Hubble.” Lewis is after something Hubble has but JWST lacks. She studies exoplanets and intends to use visible and ultraviolet light wavelengths to decode clouds and hazes of foreign worlds — the type of light JWST isn’t sensitive to. “There’s a lot of important information at those wavelengths.”
This 2017 Hubble image shows the “spindly, spidery filaments of gas” in the Tarantula Nebula. Look closely in the lower left corner and you’ll see a series of bubblelike formations that make up the more innocuously named Honeycomb Nebula.
Despite JWST’s clout, Hubble is also still the top candidate for scrutinizing galaxies moving along the X or Y axis, rather than the Z axis. “While galactic motion ‘toward’ and ‘away’ from Earth is very easy to measure with redshift,” a JWST specialty, “‘side to side’ motion is harder,” Caplan said.
In truth, this unique Hubble power turns out to be how we realized a pretty massive detail about galaxies. Many of them are on a crash course right now.
By staring at Andromeda over the years — the galaxy that Hubble’s namesake used as evidence in 1923 to prove our universe extends beyond the Milky Way — and measuring how its light on individual pixels transferred from one to the next, JWST’s predecessor showed us that this galaxy isn’t just orbiting ours. “They really will collide,” Caplan explained. Would JWST have caught that?
A cropped portion of the Hubble image of Andromeda — showing more than 100 million stars and thousands of star clusters embedded in a section of the galaxy’s pancake-shaped disc, which stretches across over 40,000 light-years. You’d need more than 600 HD television screens to display the whole image.
Nonetheless, all of this is to say that as JWST continues to flood the internet with colorful depictions of space’s outer reaches, we should remember that it isn’t Hubble’s replacement. JWST is its successor. It’ll work in tandem with Hubble and wouldn’t exist in a world without it.
“The JWST science program will be based on the legacy of more than three decades of Hubble science,” Van Arsdall said. In a sense, JWST has a giant’s shoulder to stand on. Hubble had only the unknown.
If you zoom in to any section of that Andromeda picture, this is what you see.
The people’s telescope
Like with Caplan, Lewis, Van Arsdall and Meyer, Hubble’s azure nebulae and ebony-streaked deep fields have unambiguously touched the careers of nearly every physicist — including the team behind NASA’s shiny new JWST.
“The Hubble deep field image was inspiring to me when I was growing up,” said Jason Rabinovitch, former Jet Propulsion Laboratory engineer and a professor at Stevens Institute of Technology, “and helped contribute to what would continue to be a lifelong fascination with space and space exploration.”
A space shuttle mission in 1993 fixed Hubble’s eyes. From left, spiral galaxy M100 is seen in before and after images.
Even Hubble’s rocky, rather anxiety-inducing beginnings served as reason for humanity to gawk at the cosmos. When the silver space telescope launched in 1990, everyone was so excited to see what it saw while unobstructed by the Earth’s atmosphere.
Then… the first pictures came back. “It looked like it’s a disaster,” Meyer said.
All of Hubble’s paramount imagery was blurry. Nothing like JWST’s Carina Nebula, worthy of being Apple’s default desktop screensaver, or Stephan’s Quintet, which drew a tear out of me. It turned out to be an issue with the ‘scope’s lens — which, obviously, had been blasted into space already. Things were bad. Everyone was stressed. But that didn’t deter NASA from facing the blip head-on.
The agency decided to send crews of astronauts aboard space shuttles to fix Hubble. In space. “People could watch this in real time,” Meyer said. “They could see NASA astronauts in space, spacewalking, fixing a telescope.” It was moments like this that earned Hubble a lovely nickname in its prime: The people’s telescope.
And that it was.
Within weeks of the launch of the Hubble Space Telescope in 1990, images showed that there was a serious problem with the optical system. The primary mirror had been ground to the wrong shape, resulting in image quality that was drastically lower than expected. Here, astronauts work on installing Hubble’s corrective optics during STS-61 Servicing Mission 1.
“I grew up being fascinated by the Shuttle program and was mesmerized watching the astronauts service Hubble,” Van Arsdall said. “That was definitely part of my inspiration to become an aerospace engineer.”
NASA astronaut Story Musgrave, anchored on the Remote Manipulator System arm, prepares to be elevated to the top of the Hubble Space Telescope to install protective covers on the magnetometers in 1993.
Thank you, Hubble, for giving us the stars
It’s hard to deny that the Hubble Space Telescope, a giant cylinder that appears to be dressed in Reynolds Wrap, is a cultural icon. Its purpose permeates movies, books, photography, poetry, visual art, television, maybe even wedding vows. As Caplan puts it, “It is a titan which defines the modern era.”
“I was one of those kids that watched Star Trek, and you can see that there’s Hubble images they’ve placed on these screens all around,” Lewis said. “There are some people that love to be outdoors. I just love to be in space … and since I can’t take a walk in space, the best way to do that was really through things like the Hubble Space Telescope.”
This image compares two new views of the Eagle Nebula’s Pillars of Creation captured by Hubble. Left image: Pillars are seen in visible light. Right: This one’s taken in infrared light — which happens to be JWST’s superpower — and penetrates much of the obscuring dust and gas to unveil a less familiar view of the pillars.
But falling in love with space, for humans who collectively account for just a molecule of it, isn’t a new phenomena. And I’d argue that this duality probably isn’t a coincidence. It’s much more thrilling to fantasize about our lives when reality feels like a fantasy.
Take Vincent Van Gogh’s Starry Night from 1889. The painting is an artist’s impression of a sparkly evening canopy, and it relies heavily on Prussian Blue pigment.
Prussian Blue is a hue discovered in the 1700s by scientist Johann Conrad Dippel who, as Benjamin Labatut wrote in his novel “When We Cease to Understand the World,” was in awe because he believed he’d discovered “the original color of the sky.” But Dippel didn’t come up with that himself. He was referring to the legendary tint ancient Egyptians mused about.
Our space obsession traces back centuries, and will exist for centuries to come. It’s just that Hubble — and even JWST, for that matter — enabled our infatuation. During the planning of Hubble’s servicing missions, NASA expressed honest concern about whether it would be safe to send astronauts up there to mend it. “But the public demanded it,” Meyer relayed. “They said, ‘We want this telescope fixed.'”
NASA mission crew members monitoring the Hubble Space Telescope deployment checkout procedures from Space Shuttle Discovery, Orbiter Vehicle between April 24-29,1990.
“Reading the newspaper this morning, I was reminded of my thesis advisor’s perspective,” Neil Rowlands, an engineering fellow at Honeywell Aerospace, said of the day he saw the JWST’s first results. “The only good news article in the entire paper was the one on the JWST images.”
As Rowlands has been engineering JWST for nearly 25 years, he also points out, “I have been working with [its] optical performance numbers for so long … I lost touch with what these numbers actually mean in terms of exquisite image quality — at least until I saw the fantastic images.”
But as we watch our new space explorer friend’s legacy unfold, we might want to remember that its saga is born of the one Hubble initiated when it launched in 1990.
And though the James Webb Space Telescope’s story began with a bang, we ought not to let Hubble’s end with a whimper. “They’re not shutting Hubble down,” Meyer said.
“We still think that’s about a decade away.”
Thank you, Hubble.
