Some galaxies glow with sweeping spiral arms, while others are shaped by violent collisions, powerful black holes, and explosive bursts of star formation. A newly released collection of 16 images from NASA’s Chandra X-ray Observatory and other telescopes reveals the extraordinary diversity of these cosmic structures.
Like precious gemstones, galaxies come in many shapes and sizes, each with characteristics that tell a story about its history. Astronomers generally classify them into three major groups. Spiral galaxies, including our Milky Way, have winding arms extending from their centers. Elliptical galaxies typically contain older stars and are often thought to form through galactic mergers. Irregular galaxies have less orderly structures and can display a wide variety of cosmic activity.
Much as gemstones preserve clues about the geological processes that shaped Earth over billions of years, galaxies hold evidence of the forces that have shaped the universe. Studying these distant systems helps astronomers piece together the Milky Way’s history and better understand what may await our galaxy in the distant future.
NASA Combines Chandra, Webb, and Hubble to Reveal Galactic Secrets
The new gallery features 16 images that bring together observations from some of the world’s most powerful telescopes. Each includes X-ray measurements gathered by Chandra during its decades of operation in space.
These observations are combined with data from NASA’s James Webb and Hubble Space Telescopes, IXPE (Imaging X-ray Polarimetry Explorer), the Neil Gehrels Swift Observatory, NuSTAR (Nuclear Spectroscopic Telescope Array), and additional observatories operating on Earth and in space.
X-ray observations are especially valuable because they reveal extreme activity that other types of light can miss. Chandra can detect enormous clouds of gas heated to millions of degrees by powerful winds from massive stars, material expelled by supermassive black holes, and debris from stellar explosions. These processes also help spread chemical elements through space, including elements that ultimately become part of planets, the air we breathe, and our own bodies.
By combining X-rays with observations at other wavelengths, astronomers can see more of what is happening inside galaxies. The resulting images reveal how these vast systems form stars, interact with their surroundings, and change over billions of years.
Spiral Galaxies Reveal Explosive Star Formation
Several images highlight the remarkable activity taking place inside spiral galaxies. Messier 33 and NGC 3938 are viewed almost directly from above, allowing astronomers to examine their sweeping arms and identify regions containing energetic pairs of stars and the aftermath of stellar explosions.
Other galaxies reveal how their internal structures can help drive the birth of new stars. NGC 1672 and NGC 1385 are barred spiral galaxies, meaning they contain elongated central structures made of stars, gas, and dust. These bars can channel material toward the inner regions, providing fuel for intense episodes of star formation.
NGC 4725 demonstrates another way galaxies can produce new stars. Its observations reveal how an earlier encounter with another galaxy can disturb gas and stimulate star formation.
The collection also includes dramatic side views of NGC 4631 (the Whale Galaxy) and Messier 82 (the Cigar Galaxy). These galaxies feature enormous halos and powerful winds of gas heated to millions of degrees. Driven by intense stellar explosions, these outflows can carry material thousands of light-years into space, spreading important chemical elements into the regions between galaxies.
Supermassive Black Holes Blast Energy Across Galaxies
Some of the most dramatic features in the gallery come from the enormous black holes lurking at the centers of galaxies.
When these black holes actively consume surrounding material, their central regions become extremely energetic. Known as active galactic nuclei, these bright and powerful galactic cores can launch jets of particles and enormous outbursts that influence conditions across their host galaxies.
Centaurus A provides a striking example. Observations from Chandra and IXPE reveal a powerful stream of high-energy particles shooting tens of thousands of light-years into space from the galaxy’s central region.
In Messier 106, jets launched from the central supermassive black hole interact with and heat surrounding gas. This activity produces unusual spiral structures that differ from the familiar arms normally associated with spiral galaxies.
The famous Sombrero Galaxy (Messier 104) offers another remarkable view. A supermassive black hole sits within its immense central concentration of stars, while Chandra’s X-ray observations reveal a widespread halo of gas heated to millions of degrees and the hot remains of stars. These features surround the galaxy’s prominent bands of dust, providing a deeper look at the energetic environment hidden within its elegant appearance.
Violent Galaxy Collisions Offer a Glimpse of the Milky Way’s Future
Not every galaxy evolves peacefully. Some undergo enormous transformations as gravity pulls neighboring galaxies together, distorts their structures, or strips away the gas needed to create new stars.
Arp 143 captures the aftermath of a particularly dramatic encounter. A direct galactic collision produced an expanding ring, similar to ripples spreading outward after an impact. The disturbance also triggered waves of new star formation.
Other images show the chaotic consequences of galaxies merging. NGC 3256 and II Zw 096, the latter containing a powerful burst of star formation hidden behind thick dust, provide examples of the violent interactions that were especially common in the early universe.
These collisions also offer clues about the Milky Way’s possible future. Our galaxy is expected to merge with the neighboring Andromeda galaxy billions of years from now, and observing other galactic mergers helps scientists understand how such an encounter could unfold.
The gallery includes several other unusual systems. NGC 1569 serves as a nearby example for investigating the intense episodes of star formation that occurred in young galaxies billions of years ago. NGC 660 displays a rare “polar ring” structure, with a ring of stars orbiting around the galaxy’s poles rather than following its main plane.
Messier 90 illustrates a different kind of galactic transformation. As it travels through the Virgo Cluster, the galaxy is losing the gas it needs to form new stars. Its movement through the cluster strips away this material, potentially changing how the galaxy evolves.
Together, these 16 cosmic portraits show that galaxies are far from static collections of stars. They are constantly influenced by gravity, stellar explosions, black holes, and interactions with neighboring systems. By revealing these processes in remarkable detail, NASA’s Chandra and its partner telescopes are helping astronomers understand the forces that shape galaxies, including our own.