Science & Technology

This Is the Story of the Most Famous Space Image Ever

Imagine if your company had just built a billion-dollar gadget that — oops! — had a huge, unidentified flaw. Imagine that they then put even more money and energy into fixing that flaw. If at that point you asked to completely take over that brand-new, just-repaired gadget for days on end in order to do, well, basically nothing, your coworkers would probably think you had lost your mind. That's exactly the situation astronomer Robert Williams was in in 1995 when he asked to point the Hubble Space Telescope at an empty patch of sky. If he hadn't made such a brazen choice, who knows where our understanding of the universe would be today?

Hubble Bumble

In the '90s, NASA was a bit of a laughingstock. After spending $1.5 billion ($2.93 billion in today's dollars) to build and launch the Hubble Space Telescope in 1990, NASA received the glorious new telescope's first pictures to see ... they were blurry. The telescope's primary mirror had accidentally been ground too flat — by a depth less than the width of a human hair, admittedly, but too flat nonetheless. Late-night comics lampooned the disaster, editorial cartoonists compared Hubble to the nearsighted Mr. Magoo, and the Leslie Nielsen comedy "Naked Gun 2 ½" put the telescope in the same category as the Hindenburg and the Titanic.

Over the next few years, NASA concocted a solution to give Hubble its vision back. They rigged up a new series of mirrors to basically act like a pair of glasses, and in 1993, Hubble became fully operational, clear vision and all. It was just a couple of years later when Robert Williams, the director of the Hubble's science institute, decided he was going to take over this multibillion-dollar telescope and point it at the emptiest patch of sky he could find. For 100 hours. The first clear images Hubble had taken showed distant galaxies we'd never seen with ground-based telescopes, and Williams wanted to know just how far Hubble could see. The best way to do that was with no bright stars or galaxies in the way.

His colleagues thought it was a ridiculous idea, not only because most would kill for that amount of time to observe something actually worth observing, but because calculations suggested that his plan would be a failure anyway. Hubble was powerful, but not powerful enough to detect distant galaxies, they said. But they'd never tried and Williams wanted to know if it was possible.

"Scientific discovery requires risk," Williams told National Geographic. "And I was at a point in my career where I said, "If it's that bad, I'll resign. I'll fall on my sword.'"

Staring Into the Void

Just before Christmas in 1995, Williams and his team pointed Hubble at a region just above the Big Dipper that was no larger than a pinhead held at arm's length. Over the next 10 days, they collected 342 separate exposures adding up to more than 100 hours (most previous Hubble exposures were a few hours, max). This was the image that resulted:

All that exposure time helped Hubble capture thousands of galaxies, even those billions of light years away. That's important because when you look at a distant object in the sky, you're actually looking back in time. Because light takes time to travel such great distances, the light that reaches us from an object billions of light years away is a snapshot of that object billions of years ago. The furthest galaxies shown in the Hubble Deep Field image are 12 billion light years away. The entire universe, by comparison, is 13.8 billion years old. We got to see the baby pictures of some of the earliest galaxies in the universe, and they taught us a lot about how galaxies form.

The Hubble Deep Field image is amazing to behold, but what's even more amazing is how it changed astronomy. Until that point, scientific discoveries had been treated as intellectual property: people kept their data to themselves until it was ready to be published. But with the Hubble Deep Field, Williams and his team formatted and released the data immediately so that other astronomers could analyze it and use it for their own discoveries. "Nowadays," Williams told Vox, "it is much more common for people to take interesting observations and make the data available to the public even they might have a right to keep it for a certain period of time to themselves."

Since that iconic image and a similar one taken at a point in the southern sky, Hubble has benefitted from higher- and higher-resolution equipment that has achieved even more revealing images. But it all goes back to the original Hubble Deep Field. Unfortunately, time has taken its toll and Hubble is on its way out: it's set to retire in 2021. When the new James Webb Space Telescope launches in 2020, we'll have a new way of peering deep into the void just as Robert Williams did that historic Christmas in 1995.

For more glimpses at Hubble's discoveries, check out "Hubble's Universe: Greatest Discoveries and Latest Images" by Terence Dickinson. We handpick reading recommendations we think you may like. If you choose to make a purchase through that link, Curiosity will get a share of the sale.

The 1995 Hubble Photo That Changed Astronomy

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Written by Ashley Hamer April 20, 2018