It’s a twist on a tale as old as cosmic time: Large galaxies like Cartwheel and the Milky Way were born when galactic bodies merged. Astronomers seek information about this evolutionary process when they glance at oddballs like Cartwheel that sort themselves out in peculiar shapes.
The new JWST imagery published on Tuesday highlights the uniqueness of the Cartwheel Galaxy, which was likely forged when a smaller galaxy careened into a bigger one that triggered a “cosmic tsunami” traveling 200,000 miles per hour away from the collision.
JWST looked at this “rare sight” 500 million light-years away in the Sculptor constellation and used two instruments to gather information about Cartwheel’s active and puzzling scene. This is according to the European Space Agency (ESA), which collaborates with NASA and the Canadian Space Agency on the new telescope.
The big idea — This new image is gorgeous, no doubt. Its beauty is also functional, because it can help answer modern questions about how galaxies morph over time. About 25 percent of all galaxies are currently merging with others, and even more are probably gravitationally interacting, according to the Harvard and Smithsonian Center for Astrophysics.
It’s our destiny, too: The Milky Way will collide and merge with the Andromeda Galaxy billions of years from now, and it may be exchanging stars with closer celestial bodies.
Why it matters — The Cartwheel Galaxy boasts several fascinating features.
Astronomers call Cartwheel a “ring galaxy,” after the bright inner ring (the hub of the wheel) and outer ring that surrounds the galaxy’s edge (like a tire). Its overall structure is less common than that of a spiral galaxy. ESA officials describe the two rings, borne out of the galactic collision, “like ripples in a pond after a stone is tossed into it.”
The inner ring is a core filled with clusters of young stars. The outer rim looks more fluffy because supernovas and star formation dominate it. ESA officials write that the outer ring has expanded for roughly 440 million years.
What they did — Astronomers used Webb’s Mid-Infrared Instrument (MIRI) to detect the silicate dust wafting through the galaxy, which takes on the shape of spoke-like strands stretching outward. MIRI data, colored red here, adds to past Hubble Space Telescope views of Cartwheel to make these features more prominent.
JWST’s primary imager, the Near-Infrared Camera (NIRCam), provided data on the regions colored in blue, orange, and yellow. These are places where stars are forming, which look clumpier when compared to the “smooth distribution or shape of the older star populations.”
Impressive images like this elucidate how Cartwheel has changed over billions of years.