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Magnetic Ropes Surround 'Whale Galaxy' 80,000 Light-Years Across

An image shows magnetic filaments in the Whale Galaxy.
An image shows magnetic filaments in the Whale Galaxy. (Image credit: Composite image by Jayanne English of the University of Manitoba, with NRAO VLA radio data from Silvia Carolina Mora-Partiarroyo and Marita Krause of the Max-Planck Institute for Radioastronomy. The observations are part of the project Continuum HAlos in Nearby Galaxies -- an EVLA Survey (CHANG-ES). The optical data were from the Mayall 4-meter telescope, collected by Maria Patterson and Rene Walterbos of New Mexico State University. Arpad Miskolczi of the University of Bochum provided the software code for tracing the magnetic field lines.)

If you're feeling all tied up with obligations this holiday season, perhaps a newly studied galaxy feels the same way.

A new image of NGC 4631, more popularly known as the "Whale Galaxy," shows ropes of magnetic filaments extending above and below the disk of the galaxy. The filaments, which show up in green and blue in the picture, reach far into the galaxy's halo of gas and dust. The green filaments have a magnetic field pointing away from Earth; the blue ones have a field pointing toward our planet.

Also visible is the galaxy's star disk, which is shown in pink.

Related: Stunning Photos of Our Milky Way Galaxy (Gallery)

The researchers behind the image are still trying to understand how the galaxy's magnetic structure works, according to a statement released with the image. They would like to know how common these sorts of magnetic fields are in galactic halos and what shapes the fields take.

Studying such magnetic fields can also help astronomers understand how galaxies develop magnetic fields, and whether fluid motion in a galaxy, which scientists call the dynamo effect, generates the magnetic field.

The observations were made with the Karl G. Jansky Very Large Array, a telescope operated by the National Radio Astronomy Observatory (NRAO).

"We are a little bit like the blind men and the elephant, since each time we look at the galaxy in a different way, we reach a different conclusion about its nature," co-author Richard Henriksen, an astrophysicist at Queen's University in Canada, said in a NRAO statement

"However, we seem to have one of those rare occasions where a classical theory, about magnetic generators called dynamos, predicted the observations of NGC 4631 quite well," he added. "Our dynamo model produces spiraling magnetic fields in the halo that are a continuation of the normal spiral arms in the galaxy's disc."

The galaxy lies about 25 million light-years away from Earth in the constellation Canes Venatici. It is 80,000 light-years across and has a small companion (NGC 4627). An additional small elliptical galaxy is visible in the new image.

A research paper based on the work, led by Queen's astrophysicist Judith Irwin, was published in the December 2019 issue of Astronomy & Astrophysics. The theoretical models were described in a May 2019 article in the Monthly Notices of the Royal Astronomical Society, led by Queen's graduate researcher Alex Woodfinden.

Correction: A previous headline for this article stated the Whale Galaxy was 80,000 light-years from Earth. It is 80,000 light-years across and 25 million light-years from Earth.

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Elizabeth Howell

Elizabeth Howell, Ph.D., is a contributing writer for since 2012. As a proud Trekkie and Canadian, she tackles topics like spaceflight, diversity, science fiction, astronomy and gaming to help others explore the universe. Elizabeth's on-site reporting includes two human spaceflight launches from Kazakhstan, and embedded reporting from a simulated Mars mission in Utah. She holds a Ph.D. and M.Sc. in Space Studies from the University of North Dakota, and a Bachelor of Journalism from Canada's Carleton University. Her latest book, NASA Leadership Moments, is co-written with astronaut Dave Williams. Elizabeth first got interested in space after watching the movie Apollo 13 in 1996, and still wants to be an astronaut someday.