Andromeda lies 2.5 million light-years away from the Milky Way, a spiral galaxy similar to our own that has allowed scientists to better understand our galactic home. A new composite image reveals our closest galactic neighbor in five different wavelengths of light, combined together to create a stunningly detailed view of Andromeda.
Telescopes capture images in different wavelengths by observing a specific part of the electromagnetic spectrum, from low-frequency radio waves to extremely high-frequency gamma rays. By using different wavelengths, astronomers are able to see far more of the cosmos, whether it be glowing dust and stars or colliding galaxies.
For the latest image of Andromeda, also known as M31, astronomers featured X-ray data from NASA’s Chandra Observatory, revealing the high-energy radiation around the supermassive black hole at the center of the galaxy.
The X-ray data, captured by the European Space Agency’s XMM-Newton, is shown in red, green, and blue. Ultraviolet data from NASA’s retired GALEX is in blue; infrared data from NASA’s retired Spitzer Space Telescope, the Infrared Astronomy Satellite, COBE, Planck, and Herschel is in red, orange, and purple; and radio data from the Westerbork Synthesis Radio Telescope is in red-orange, according to NASA. Astrophotographers Jakob Sahner and Tarun Kottary provided some optical data using ground-based telescopes.
Andromeda is a classic spiral, with graceful arms that rotate around a central bulge. It stretches across 220,000 light-years, twice the size of the Milky Way. The two galaxies are on an unfortunate collision course with one another and are expected to merge in about 4.5 billion years. Or maybe not, as research published earlier this month suggested.
Astronomers also converted the multi-wavelength data to sound, creating a beautiful tune from Andromeda’s dust lanes and star clusters. To create Andromeda’s new song, scientists separated the layers captured by each telescope and stacked them on top of each other horizontally, beginning with X-rays at the top and then moving through ultraviolet, optical, infrared, and radio at the bottom.
Each type of light is mapped to a different range of notes, from lower-energy radio waves all the way through the high energy of X-rays. The brightness of each source controls the volume of the galactic song, and the vertical location dictates the pitch.
The latest composite image of Andromeda was released in honor of legendary astronomer Vera Rubin, who discovered evidence for dark matter by measuring the velocity of stars in the spiral galaxy. In the 1960s, Rubin carefully observed Andromeda and determined that unseen matter was affecting how the galaxy’s spiral arms rotated. Earlier this week, the Vera C. Rubin Observatory, named after the pioneering astronomer, released its very first images of the cosmos.
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