Twenty-five years ago today, Hubble launched into space, nestled in the bay of the Space Shuttle Discovery. Over those years, the space telescope produced the most inspiring images of the cosmos we humans had ever seen.
A great many of those eye-candy photos were created by one man, Zolt Levay, who joined the then-newly-formed Hubble organization in 1983 and has been there ever since. He’s the guy who takes the data that scientists collect with the telescope and re-mixes it into images made for public consumption.
When we decided to honor Hubble’s heritage with a gallery of 26 photos—one for each year of its orbital tenure, plus the official 25th-anniversary image—Levay seemed like the ideal person to curate it. Here are his picks.
1990: Supernova 1987A
In 1987, a star exploded in a nearby galaxy, giving astronomers their best view ever of a supernova. This picture, from three and a half years after the blast, shows a ring of material that was created by the pre-explosion star. The supernova heated that ring so much that it now glows brightly.
1991: Detail Of The Orion Nebula
The Orion Nebula is the nearest giant-star nursery to Earth, so it was an important early target for Hubble. Many of the small dots here are stars with disks of dust around them, probably with planets forming inside. The discovery of the first planets outside our solar system would be announced the next year, in 1992. Strong evidence that stars with planets are common—a fact hinted at by the abundance of planet-forming disks here—is just being uncovered today.
1992: Black Hole At A Galaxy’s Core
When this image was taken, the existence of actual black holes were still uncertain enough that the Hubble press release called them “theoretical objects.” At the time, this was the best pic astronomers had of a candidate black hole. The orange light in the image is glowing gas and dust at the very center of a galaxy called NGC 4261. It’s bright at the very center because the gas heats up and glows just before being swallowed by the black hole.
1993: Cygnus Loop
The blue and red streaks in this image are material that was sent flying into space 15,000 years ago when a star in the constellation Cygnus exploded as a supernova. The blue loop left the star after the red one did, and is still catching up. Where they’re crossing, the blue gas (oxygen) heats the red gas (sulfur) so it glows brightly.
1994: A Crystal-Clear Spiral Galaxy
On December 2, 1993, the crew of the Space Shuttle Endeavour began a 12-day mission to correct a flaw in Hubble’s vision. This image of the Whirlpool Galaxy celebrated the success of Servicing Mission One, as it was called, by showing off Hubble’s new view. Compare this image against the pre–servicing mission pic of the same galaxy.
1995: The Pillars of Creation
A small cluster of stars burn hot and bright, just off the top edge of this image. Their high-energy light blows away the gas and dust enveloping the still-forming stars of this stellar nursery, which are exposed as small fingers and teardrops at the edges of the great pillars of gas. Even two decades later, the phrase “pillars of creation” brings this image immediately to mind for those of us who might have then been high-school students dreaming of futures as astronomers.
1996: The Hubble Deep Field
Remember when Robert Williams, the then-director of the Space Telescope Science Institute (that’s the folks who oversee Hubble) used a good chunk of his own observing time to point at a seemingly blank patch of sky for 10 days straight? And an unfathomably huge number of galaxies revealed themselves? And changed astronomers’ understanding of how the early universe worked? Wasn’t that awesome? Sometimes the big gamble pays off.
1997: Spectrum Of A Black Hole
This psychedelic smudge is actually evidence of a black hole at the center of the galaxy M84. It was made with Hubble’s spectrograph, which shows the velocity of the material it images. It reveals those velocities along just one line, determined by how astronomers position the telescope. The squiggle halfway down means that stars are spinning very quickly around the galaxy’s center. And from that, astronomers could tell the black hole at the center of M84 is 300 million times as massive as the sun.
1998: A Rosy Ring of Stars
The bright, colorful ring here is made of hot clumps of star-forming gas in the galaxy NGC 4314. The picture is a close-up of the galaxy’s center, but further out, wispy spiral arms are funneling dust and gas toward the ring. The ring’s stronger gravity traps the gas and dust and squashes it into globs so dense they collapse into stars.
1999: Mars Has Its Close-Up
In the spring of 1999, Mars came closer to Earth than it had since Hubble’s launch, and the space telescope snapped plenty of pictures of the Red Planet. This one shows the water-ice polar cap of Mars’s northern hemisphere, light clouds of early morning along the left limb, and a cyclone churning near the pole. The landing site of the Mars Pathfinder rover, which had bounced onto the planet’s surface two years earlier, is at the center of the image—at the bottom of the big dark patch just below the icy north pole.
2000: The Eskimo Nebula
On November 13, 1999, one of Hubble’s gyroscopes failed. The gyros are six-inch-long cylinders that spin at 19,200 RPM, suspended in fluid. They detect and correct for tiny movements in the spacecraft, allowing Hubble to stare steadily at a single spot and take clear pictures. A single gyro failing isn’t a big deal—Hubble has six and only needs three to be operational at any moment—but the one that stopped spinning on that November day was the fourth one to break, and it sent Hubble into automatic shutdown. To fix the telescope, NASA fast-tracked a servicing mission it had been planning since the third gyro failure. A crew of astronauts went up in late December aboard the shuttle Discovery. They replaced all six gyroscopes, and Hubble resumed observing on January 10, 2000. This is the first picture it took.
2001: A Warped Galaxy
Usually galaxies are disks that lie pretty much flat. (Except the ones that are just unstructured globs of stars, but that’s a different story.) This galaxy boasts a very prominent curve. That’s because it recently collided with another, smaller galaxy that it’s in the process of subsuming into its belly, probably cackling “bwa-ha-ha” as it does so.
2002: The Tadpole
The name is apt: This is definitely a galaxy that looks like a tadpole. It had a run-in with the galaxy visible just behind it, and when galaxies collide (see previous) crazy things happen to them. Eventually, the long tail will break off entirely and become a mini galaxy that orbits the bigger ones.
2003: A Flare In Process
The star at the center of this picture—an obscure red one at the outer edge of the Milky Way—was, for a few days in 2002, the brightest star in the galaxy. Its crazy outburst didn’t last long, but the light the star created spent the next year reflecting off different parts of the dust cloud surrounding it—which made for some amazing pictures, like this one taken in October 2002.
2004: The Helix Nebula
Before this image, astronomers thought this nebula—gas and dust expelled from the star dying at its center—was donut-shaped. But with this 4.5-hour Hubble exposure and some other pictures taken from telescopes on the ground, they concluded it’s actually two disks of material sitting perpendicular to each other. And the disks may have been made by two stars instead of one. Even the most familiar objects in the sky have their secrets.
Most of Hubble’s iconic images—including this one, of the nearby Whirlpool galaxy—were taken by its Advanced Camera for Surveys, or ACS. Hubble has six instruments on board, each optimized for taking different sorts of measurements. The ACS takes sharp images with a wide field of view, which has made it the pretty-picture workhorse since it was installed during a servicing mission in 2002. After a repair during the 2009 servicing mission, ACS is still going strong.
2006: The Orion Nebula, Revisited
Hubble joined forces with a Chilean telescope to create this shot, which is built from nearly a dozen separate pictures taken at different wavelengths—and which puts to shame the faint smudge visible with a backyard telescope.
The bright blue stars at the center of this image are burning away the gas and dust they were born from, creating a lovely cocoon of material. If that scene sounds familiar, that’s because it’s a common one among Hubble targets. Gas and dust may not sound as thrilling as stars and galaxies, but they reflect and illuminate the objects of the heavens, creating some of space’s most memorable vistas.
2008: Galaxy Collision
Hubble caught these two galaxies mid-collision. One, stretched out in a line. The other, a ring-shaped shockwave of stars. Neither will ever be the same.
2009: Saturn And Four Of Its Moons
Titan—Saturn’s largest moon—is just at the top of the image, casting a shadow near Saturn’s north pole. From our view here on Earth, moons only cross in front of the planet when the rings lie in a nearly flat plane. The alignment, called a ring-plane crossing, happens every 14 or 15 years. Hubble captured a ring-plane crossing in 1995, and this one in 2009. The next will be in 2025—will Hubble still be around then? If not, perhaps its successor, the James Webb Space Telescope, will see it.
2010: Twenty-Year Spectacular
Hubble’s twentieth anniversary came a year after a dramatic servicing mission in May 2009 that replaced a few of its detectors and repaired others. Astronauts also replaced gyroscopes, computers, and other support equipment on the telescope. Since the space shuttle was to be retired in 2011, astronomers knew this would be the last upgrade Hubble would get—no other spacecraft could carry astronauts high enough. The twentieth-anniversary image is a detail shot of gas and stars in the Carina Nebula, which Hubble had imaged in truly stunning glory a few years earlier.
2011: By Any Other Name
UGC 1810 and UGC 1813 are a pair of interacting galaxies whose gravitational forces have stretched one another out across the sky. And hey, they look like a rose.
2012: A Dying Star
Stars spend most of their lifetimes as stable, solitary, shining orbs. But at their births, as they form from gas and dust, and at their deaths, as they return that gas and dust to into space, they create scenes that Hubble can’t resist photographing. This one is of a star not unlike our sun, in its death throes. Five billion years from now our own sun may be as lovely.
2013: Horsehead Nebula
In optical light, the Horsehead appears as a dark shadow against a pinkish glow. But this image was taken at longer wavelengths: the infrared, which is invisible to the human eye. (It was colorized after the fact to be visible to the human eye.) The longer infrared wavelengths slide through the dense gas where optical cannot, creating a different, more revealing image.
2014: Deep Look At A Galaxy Cluster
Hubble stared for 67 hours to create the deepest galaxy-cluster image ever taken. The big, bright foreground galaxies are bound together by their gravity, gravity that warps the light from the 3,000 background galaxies like a lens. Two other space telescopes flying at the time—Chandra, which takes pictures at x-ray wavelengths, and Spitzer, which catches longer-wavelength infrared glimpses—also turned to look at this patch of sky, creating picture of the cluster that’s nearly complete across the wavelengths of light.
2015: The Official 25th-Anniversary Image
Bright, hot, young stars light up the gas around them, the gas from which they were born (yup, it’s that old Hubble theme). Even after a quarter century spent flying around the Earth at about 18,000 MPH, plunging from glaring sunlight to near-total darkness every 50 minutes, and circling the Earth more than 135,000 times, the old telescope still churns out stunners.