Interacting Galaxies: The Antennae

Galaxy collision sets the stellar lifecycle in motion
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The Antennae Interactive

Indistinct clouds, brighter at the galaxy centers and colliding gas
Fuzzy swirl shape with two limbs Fuzzy swirl shape with two limbs
One large, one small, distorted spiral joined by thick bridge
Soft glow punctuated by bright spots and dark cavities
Distorted spirals joined together, surrounded by soft glow
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Areas of dense gas glow brightly in the crowded galactic centers and the region where the two galaxies meet.

Warm dust glows where new stars are forming, tracing the distorted shapes of the galaxies’ former spiral arms.

The gas of two spiral galaxies collides, sparking bright pink areas of star formation.

Bright points highlight a neutron star or black hole that is pulling gas from a companion star.

The life cycle of massive stars is displayed in one image, from formation in gas clouds to afterlife as compact X-ray sources.


A Story Of Interacting Galaxies: The Antennae

Together, multiple wavelengths of light provide a snapshot of the complete stellar lifecycle.

Galaxies are the universe’s cities of stars, and like cities they change over time in population, structure, and appearance. When galaxies are drawn toward each other by gravity, stars and planets can pass by each other unharmed, but the gas and dust between stars collide. The gas is compressed and heated, setting off waves of new star formation. Some of these new stars are massive and have a short, bright life, allowing multiple phases of a massive star’s “lifecycle” to be viewed together, if the correct wavelengths of light are combined.

The Antennae galaxies provide a stunning multi-wavelength view of galaxy interaction and all the resulting phases of the stellar lifecycle. Interacting galaxies typically swing by each other multiple times, each time compressing gas to form new stars. Telescope observations in different wavelengths show how the interaction has unfolded over time, with X-ray binary stars and diffuse X-ray gas indicating earlier waves of star formation. Humans have studied stars for thousands of years, but much of their formation process is still mysterious; interacting galaxies like the Antennae provide insight not only into how galaxies change over time, but also the cyclical pattern of stars, which seems to grow more wondrous the more it is understood.

Quick Facts: The Antennae

Also known as: NGC 4038 (upper galaxy) and NGC 4039 (lower galaxy)

Type of object: Spiral galaxies

Distance from Earth: 68 million light-years

Location in the sky: Corvus Constellation

Did you know: The interaction between these two galaxies is ongoing, and has already been occurring for more than 100 million years.

Explore More About Interacting Galaxies

Find out more with these additional resources from NASA’s Universe of Learning

Credits: The Antennae

Radio image from the ALMA telescope: ESO, NAOJ, NRAO

Infrared light image from the Spitzer Space Telescope: NASA, JPL-Caltech

Visible light image from the Hubble Space Telescope: NASA, ESA

X-ray light image from the Chandra X-ray Observatory: NASA, CXC, SAO

Multi-wavelength image, X-ray: NASA, CXC, SAO; Infrared: NASA, JPL-Caltech; Visible: NASA, ESA

Subject-matter expertise provided by Dr. Brad Whitmore

Produced by the Space Telescope Science Institute’s Office of Public Outreach