It was a much different time when the Hubble Space Telescope took off aboard the space shuttle Discovery on this day in 1990. But much like how we've ditched our Umbros for Under Armour and traded our slap bracelets for Apple Watches, Hubble has come a long way since then.
The space telescope created by NASA and ESA has taught us countless things about the universe that surrounds us, and its breathtaking images have inspired a whole new generation of scientists. (And yes, they also make great computer wallpapers.) For much of Hubble's early life in space, however, it was easy to look at the project as a failure. Outlets at the time called it "a national joke." A tiny imperfection in the mirror meant that all of the images it took were fuzzy and out of focus, and it took five separate repair missions to get it to the excellent shape it's in today. (One of those astronauts, Mike Massimino, wrote a particularly excellent first-person account in 2013 of what it was like to repair the telescope 353 miles above Earth.)
Engineers inspect Hubble's main mirror.
Being the 25th anniversary, the amount of tributes on the internet to Hubble is vast. Nature spoke to more than a dozen scientists and Hubble team members to compile a wonderful oral history of the telescope. Phil Plait, who runs Slate's "Bad Astronomer" blog and worked on Hubble for a number of years, wrote some great explanations of some of the most famous images to come from the project. The New York Times put together a good explainer video of how the Hubble works and spoke to some astronomers about their favorite images they took with the space telescope. Lee Billings took some time at Scientific American to laud Hubble's unsung images, the ones that won't necessarily wow you but mean a great deal to the project and to our understanding of the universe.
Elsewhere, Vox has a great breakdown of one of Hubble's most famous images, Discover assembled a detailed timeline, and National Geographic tells you why Hubble images appear in color (they're really photographed in black and white) and includes a must-see interactive feature that breaks down how the telescope works, piece by piece.
Hubble's days are numbered, but it's not totally clear when it will close its eye for the final time; one thing NASA is excellent at is getting extra value out of its missions. After all, the Opportunity rover, which landed on Mars in 2005, is still roaming the surface and gathering data — even though it was only supposed to last around 90 days. And the Kepler Space Telescope has been helping us find other planets in our own galaxy since 2009, even after a massive mechanical failure. If Hubble can avoid another one of those, it's likely the telescope will continue to operate well into the 2020s.
One thing we do know is that the Hubble's successor, the James Webb Space Telescope, is going to be even better. It has a mirror that is six times larger than Hubble's and will be at least 100 times as powerful. The Webb telescope will peer even deeper into the night sky, bringing us closer to seeing the very first stars ever formed. That won't happen until at least 2018, however, and it's a mission that — like many — has already suffered delays and gone way over budget. And the Webb telescope is going much further out into space than Hubble, meaning there will be no chance for humans to visit it for repairs should anything go wrong.
Until that gets off the ground, scientists around the world will continue to use Hubble to stare out in space and back in time as they try to figure out how — and why — we're all here. With that in mind, here is just a small collection of some of the best and most important images taken by the Hubble Space Telescope.
All images courtesy of NASA and ESA.
- Hubble's biggest image ever: Andromeda This is a 1.5 billion pixel image of our nearest neighbor in the universe: M31, otherwise known as the Andromeda galaxy. Published at the beginning of 2015, it is the biggest Hubble image ever released, and it shows a 40,000 light-year section of Andromeda that contains over 100 million stars. Be sure to check out the interactive version (click here).
- Hercules A (2012) Let your eyes scan the edges of this image first, because dozens of galaxies dot the background. Then look at the tiny bright center of the image — that's a galaxy known as Hercules A, the home of a supermassive black hole. The purple jets and the red plumes on either side are actually invisible to our eyes because they are made of high-energy plasma beams, subatomic particles and magnetic fields. That material — illuminated here with help from the Very Large Array radio telescope — was ejected outward by the powerful black hole, accelerated to near the speed of light. The resulting structure measures more than one million light-years wide. Hubble was instrumental in advancing our knowledge of the nature and frequency of black holes.
- The Lagoon Nebula (2010) Since the beginning of time, stars have been created from clouds of gas and dust like we see here in this beautiful closeup image of the Lagoon Nebula. In these stellar factories, the radiation of young stars illuminate the different elements in the surrounding clouds.
- Eta Carinae Eta Carinae is one of the first interstellar objects that the Hubble Space Telescope imaged. It has also been imaged many times over the years. The first image seen here was taken in 1991, just a year after Hubble launched, and the subsequent images were taken in 1994, 1996, and 2012.
- NG 1073 (2012) We have no way of seeing our own Milky Way galaxy from the outside — it would take tens of thousands of years to reach the edge of it traveling at light speed — so we instead use Hubble to study galaxies similar to ours, like this one.
- The Cat's Eye Nebula (2004) Hubble has been used to find some of the most recognizable shapes in the universe, and — like with the constellations in our night sky — familiar names are given to familiar shapes. One of the best-known cases is with NGC 6543, known as the Cat's Eye Nebula.
- The Horsehead Nebula (2013) Hubble has taken many images of the Horsehead Nebula over the years, but this most recent one (published on Hubble's 23rd anniversary) is probably the most spectacular. The infrared view finally let us peer at the clouds of gas and dust that make up the nebula in a way we never had, and it offers us a taste of the kinds of images we might get when Hubble's successor — the infrared-only James Webb Space Telescope — launches in a few years.
- The Caterpillar (2013) Another example of this is IRAS 20324+4057, or "The Caterpillar."
- The Tarantula Nebula (2014) Set against a backdrop of amber-colored stars, this massive formation can be found in the Large Magellanic Cloud, one of the small satellite galaxies that orbits our own Milky Way. The version seen above was created with images from the 20-person team behind the Hubble Tarantula Treasury Project, which used 60 of Hubble's orbits to closely study the star formation happening deep inside the Tarantula nebula.
- The Whale Galaxy (2011) If this edge-on galaxy view looks at all familiar, it's because it bears a striking resemblance to the view we have of our own Milky Way galaxy when we look up at the night sky. This is actually NGC 4631, or the "Whale Galaxy." Galaxies may be like snowflakes — no two are the same — but the Whale Galaxy is a reminder of how uniform our universe is at the largest scales. (As an aside, if you have never seen the Milky Way shine in the night sky in person, you should check out the International Dark Sky Association or r/darksky to find out more about the best observation locations in the US.
- The Cigar Galaxy (2006) Stars are being born 10 times faster in the massive and awe-inspiring M82, known as the Cigar Galaxy, than they are in our own Milky Way.
- Stephan's Quintet (2009) You can find multiple galaxies in almost any image taken with Hubble, but you're hard-pressed to find a better view than this one. Hickson Compact Group 92 is more commonly known as "Stephan's Quintet" because of the five prominent galaxies. While you may only see four at first glance, the lower-right "galaxy" is actually two galaxies in the middle of a collision. This was the first compact group of galaxies ever discovered, and was originally spotted back in the 1800s.
- The Red Spider Nebula (2001) The spider-like NGC 6537 can be found in the constellation Sagittarius, and is "only" 6000 light-years away from us, a relatively close distance when compared to the scale of the cosmos.
- The Carina Nebula (2007) A vast mosaic of star birth, the Carina Nebula is often referred to as the "Grand" or "Great" nebula. This particular image was originally released on Hubble's 17th anniversary, and if you look really close you can find a smaller nebula known as "the finger of God," so named because of its resemblance to a common expression of vulgarity.
- The Eskimo Nebula (1999) This bizarre collection of stars and gas was the first thing the Hubble after a 1999 servicing mission was needed to fix the telescope's gyroscopes.
- The Cygnus Loop (2000) The best photos taken with Hubble are often the most unbelievable. This twist of blue is a filament on the outskirts of The Cygnus Loop nebula (the full view of which is equally spectacular).
- A beautiful mistake (2014) One of Hubble's most beautifully abstract images was actually an accident. The telescope typically locks on to what are known as "guide stars" to keep its aim true, but in this instance the telescope appeared to lock onto a not-so trustworthy guide star — likely a binary star system. The Hubble's alignment was off, and therefore it drifted ever so slightly while the camera made its exposure, resulting in these strange, striking streaks of starlight.
- The collision of NGC 2207 and IC 2163 (1999) The gravitational forces at play are distorting the shapes of each galaxy, and billions of years from now they will have settled together as one.
- The Antenna Galaxies The telescope has given us our best look yet at massive galactic collisions, like this one known as the Antennae Galaxies. Since galaxies contain so much empty space, the stars don't actually impact each other, but many are flung out into space because of the immense forces involved.
- NGC 3314 Sometimes, however, it is just an illusion. This looks like a collision at first glance, but the two galaxies — collectively called NGC 3314 — are nearly 30 million light years apart.
- The Egg Nebula (2003) Filters of different colors block or allow different light to be seen. This makes it easier to understand the behavior of cosmic objects.
- The Orion Nebula (1990) Even though Hubble spent its first few years taking fuzzy images, we still learned a great deal about some of the most famous parts of the sky. This image, for example, gives us a close look at just one small section of the the Orion nebula, located just 1500 light-years away from us.
- The Hubble Extreme Deep Field (2012) This image might not immediately grab your attention as much as the others, but it tells perhaps the most important story about our universe. It's called the "extreme deep field," named after the "deep field" images before it. Every so often, Hubble is pointed away from known targets to a particular and completely black patch in the sky, and scientists keep it trained on that spot for days. Slowly, it collects light from the faintest galaxies at the farthest reaches of the universe. (This video will give you a better sense of just how small a patch of the sky we're talking about here.)There are more than 5000 galaxies in this image alone, and uses 10 years of data collected for the other deep field images.
- Looking at an Einstein Ring (2011) See that near perfect circle around the bright spot on the right? That's actually the light from a galaxy that's behind the massive, yellowish galaxy in the center. When galaxies align like this, massive ones in the foreground can warp the light of what's behind them. That process is called "gravitational lensing," and this particular version of it is referred to as an "Einstein ring." In the right circumstances, gravitational lensing can actually show us a decent view of what's behind certain galaxies, essentially increasing how far Hubble can see into the past.
- NGC 6872 (2014) If this galaxy looks more massive than others, that's because it is. From end to end it measures 500,000 light-years across, five times the size of our own galaxy. Its distorted shape can be attributed to the gravity of the smaller galaxy seen above it.