crab nebula expanding structured clouds of purple red and blue with a bright purple point in the center with a bright jet shooting out it and bright concentric circles around it
The Crab Nebula, the result of a bright supernova explosion witnessed by astronomers in 1054 A.D. Chandra sees the rings around its center with jets blasting into space (bright purple).
  • NASA's Chandra X-ray Observatory is one of its most scientifically productive space missions.
  • The telescope has been in space for 25 years, discovering black holes and dark matter.
  • Chandra's best images show how it reveals details that other telescopes can't see.

NASA has been using X-rays to crack the invisible secrets of the universe for decades.

The Einstein Observatory pioneered X-ray astronomy in the late '70s, but the crown jewel of this science field is the Chandra X-ray Observatory, which has been in space for the last 25 years.

Here are some of Chandra's most stunning images and groundbreaking discoveries of the invisible X-ray universe.

NASA's Chandra X-ray Observatory has been capturing the invisible universe for 25 years.
bright star with diffraction spikes cutting through a red billowing cloud in space surrounded by smaller purple stars
A rare type of Wolf-Rayet star — a bright, massive star experiencing a short-lived phase in its evolution. The purple dots are stars detected with Chandra.

The space telescope launched aboard the space shuttle Columbia on July 23, 1999. It was the heaviest payload the shuttle had ever carried.

"Chandra's discoveries have continually astounded and impressed us over the past 25 years," Eileen Collins, commander of that Columbia mission, said in a press release on Monday.

X-rays are not in the visible range of light, but they often point to dramatic events in space.
purple turbulent nebula in space against a royal blue starry background
The Tarantula Nebula, imaged by the Chandra and Webb space telescopes. Chandra's X-ray observations (in royal blue and purple) reveal gas that was heated to millions of degrees by shock waves from the wind of massive stars.

X-rays are especially valuable to astronomers because they often come from objects that are extremely hot or events that generate a lot of energy — like the debris flying out from an exploding star, or the superheated material swirling around a black hole.

Chandra often reveals new details that other telescopes can't see.
pillars of creation nebula finger shaped clouds of dust reach into dark orange and purple space with multicolored stars filling the background
The Pillars of Creation, imaged by the James Webb Space Telescope, with a colorful array of stars scattered across the area, imaged by Chandra.

In this image that combines data from the James Webb Space Telescope and Chandra, Webb's observations paint an ethereal picture of the Pillars of Creation, a cloud formation that's constantly birthing new stars.

Chandra's contribution reveals a sea of young stars burning bright in X-rays. These are the multi-colored pinpoints of light scattered across the image.

Take the bright purple spots in this galaxy, for example. Those are X-ray-emitting objects that Chandra identified.
purple spiral galaxy with lots of purple stars inside and a bright white center
Messier 74, nicknamed "the Phantom Galaxy" for its dimness, comes to life when Chandra revealed its X-ray activity (purple) alongside observations from Hubble and Webb.

"Often you get like a gas cloud that's glowing, and then there's this X-ray source in the middle that's pumping the energy into it that's causing it to glow," Jonathan McDowell, an astrophysicist who leads science data systems for Chandra, previously told Business Insider.

"If you don't have Chandra, you can't see that. So you're missing a big part of the story," he said.

Chandra's X-ray vision revealed that the universe is teeming with black holes.
faint dark purple swirl in space with a bright jet shooting out of its center
A supermassive black hole at the center of the Centaurus A galaxy shoots an enormous jet of particles into space. Chandra resolved both the jets and the faint blue bubble surrounding the galaxy.

Chandra's other landmark achievements include the first-ever direct evidence for the existence of dark matter, which is a completely invisible, mysterious substance that makes up about 27% of the universe.

Chandra was also the first to directly detect colliding neutron stars that were sending ripples in space-time — called gravitational waves — across the universe.

It also revealed the X-ray emissions from Jupiter's polar lights.
jupiter in space with a purple haze crowning its north pole and large purple blobs, some larger than the planet, to its left and right in distant space
Jupiter, pictured by the Hubble Space Telescope, with X-ray emissions detected by Chandra in purple.

On Earth, we call them the northern and southern lights, or aurora borealis and australis. They're the dancing, colorful ribbons of light that sometimes appear in polar skies and even occasionally come as close to the equator as Arizona.

The aurora is caused by charged particles from the sun, which create a similar effect on other planet's poles. Chandra spotted the phenomenon on Jupiter.

The image also shows clouds of X-ray emission surrounding the giant gas planet.

All in all, Chandra has made nearly 25,000 observations.
supernova remnant shiny pink bubble against starry background
A bubble of debris from a supernova, imaged with X-ray data from Chandra and optical data from the Hubble Space Telescope.

It's been one of NASA's most productive astrophysics missions. Scientists have written more than 10,000 peer-reviewed papers based on its data.

Some of the most stunning photos are collaborations with other observatories, like Webb.
supernova remnant colorful multi-layered bubble of wavy yellow green blue red purple in black space
Combined data from Chandra and Webb revealed new details of the supernova remnant Cassiopeia A.

Joining forces allowed scientists to identify the likely cause of a mysterious structure called the "Green Monster" inside the supernova remnant shown here. You can see it just right of center, where there's a green loop disrupting the blue and red billowing out into space.

Chandra data revealed an association between the Green Monster and the blast wave that shot out from the star when it exploded. They think the blast wave created the Green Monster when it slammed into material surrounding the star.

Chandra has even turned its gaze to the center of our galaxy.
milky way center with glowing purple and orange clouds peppered with bright white lights in black and purple space
A mosaic of the center of the Milky Way, using data from Chandra (shown in orange, green, and purple) and the MeerKAT radio telescope in South Africa (gray).

In May, astronomers using Chandra discovered a vent releasing hot gas from the center of the Milky Way. They believe the chimney of venting gas might come from eruptions from the galaxy's central supermassive black hole.

Here's a snapshot of the supermassive black hole at the center of the Milky Way.
starry space with faint red blue orange clouds dense in the center with a bright white spot in the middle labeled SGR A* as the supermassive black hole at the center of our galaxy
Chandra spotted Sagittarius A*, the supermassive black hole at the center of the Milky Way.

Chandra has also revealed that our galaxy's supermassive black hole, called Sagittarius A*, is spinning rapidly.

In fact, Chandra discovered, the black hole is spinning so fast that it's squishing space-time down like a football.

Chandra may be nearing the end of its mission after drastic budget cuts.
brilliant red and purple clouds blanket a black sky packed with stars
In the Cat's Paw nebula, where stars are forming in the Milky Way galaxy, X-rays from Chandra show populations of young stars.

NASA's 2025 budget request slashed Chandra's funding from $68 million to $41 million. After that, the budget proposes to give the observatory $26.6 million per year until a drastic plummet to $5.2 million in 2029.

Chandra's operating team has said that's just the amount it would need to decommission the telescope and end its operations.

Chandra is still fully functional, though, and continues to make visually stunning discoveries.
swirling diamond shaped cloud of blue dust with purple and lots of red along the edges in space with a bright spot at the center and countless distant galaxies in the background
This supernova remnant is the leftovers from an exploded star called 3C 58. The bright, elongated, white object at the center is a dense, fast-spinning neutron star.

By studying Chandra detections of the X-ray emissions of neutron stars — like the one at the center of this supernova remnant —scientists recently discovered that neutron stars may contain a new type of ultra-dense matter.

Chandra could reveal even more invisible secrets of the cosmos in its remaining years.

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