March 8, 2001

2 min read

Google Logo Add Us On GoogleAdd SciAm

Stars Forged in Galactic Battle

By Kate Wong

Join Our Community of Science Lovers!

Image: NASA/ESA/R. de GRIJS

Around 600 million years ago, a nearby starburst galaxy known as M82 collided with its neighbor, M81, igniting a celestial clash of the titans that raged on for nearly 100 million years, according to a recent study. Researchers dated the event based on new infrared and visible-light images from NASA's Hubble Space Telescope. The findings appear in the February issue of the Astronomical Journal.

Specifically, Hubble homed in on more than 100 dense clumps of stars, called super star clusters, in the central region of M82 (right) that were apparently forged in the violent encounter. By determining the ages of clusters in an older "fossil starburst" region, Richard de Grijs of the University of Cambridge and his colleagues were able to assign a date to the start of the galactic interaction and to better understand its effects. "The last tidal encounter between M82 and M81 about 600 million years ago had a major impact on what was probably an otherwise normal, quiescent disk galaxy," de Grijs notes. "It caused a concentrated burst of star formation in the fossil starburst region. The active starburst taking place today is probably related to debris from M82 itself that has slowly 'rained' back on the galaxy since the interaction with M81."

On supporting science journalism

If you're enjoying this article, consider supporting our award-winning journalism by subscribing. By purchasing a subscription you are helping to ensure the future of impactful stories about the discoveries and ideas shaping our world today.

De Grijs says that star formation in such starburst regions may take place largely in these super star clusters, adding that the clusters in M82 may actually be very young globular clusters. Researchers once thought that globular clusters, which contain up to a million stars when mature, only formed early on in galaxy evolution¿billions of years ago. The new results, in combination with other Hubble observations, instead indicate that globular cluster formation continues today. This insight, de Grijs remarks, is "one of Hubble's main contributions to astrophysics to date."

Kate Wong is an award-winning science writer and senior editor for features at Scientific American, where she has focused on evolution, ecology, anthropology, archaeology, paleontology and animal behavior. She is fascinated by human origins, which she has covered for nearly 30 years. Recently she has become obsessed with birds. Her reporting has taken her to caves in France and Croatia that Neandertals once called home to the shores of Kenya’s Lake Turkana in search of the oldest stone tools in the world, as well as to Madagascar on an expedition to unearth ancient mammals and dinosaurs, the icy waters of Antarctica, where humpback whales feast on krill, and a “Big Day” race around the state of Connecticut to find as many bird species as possible in 24 hours. Wong is co-author, with Donald Johanson, of Lucy’s Legacy: The Quest for Human Origins. She holds a bachelor of science degree in biological anthropology and zoology from the University of Michigan. Follow her on Bluesky @katewong.bsky.social

More by Kate Wong

It’s Time to Stand Up for Science

If you enjoyed this article, I’d like to ask for your support. Scientific American has served as an advocate for science and industry for 180 years, and right now may be the most critical moment in that two-century history.

I’ve been a Scientific American subscriber since I was 12 years old, and it helped shape the way I look at the world. SciAm always educates and delights me, and inspires a sense of awe for our vast, beautiful universe. I hope it does that for you, too.

If you subscribe to Scientific American, you help ensure that our coverage is centered on meaningful research and discovery; that we have the resources to report on the decisions that threaten labs across the U.S.; and that we support both budding and working scientists at a time when the value of science itself too often goes unrecognized.

In return, you get essential news, captivating podcasts, brilliant infographics, can't-miss newsletters, must-watch videos, challenging games, and the science world's best writing and reporting. You can even gift someone a subscription.

There has never been a more important time for us to stand up and show why science matters. I hope you’ll support us in that mission.

Thank you,

David M. Ewalt, Editor in Chief, Scientific American

Subscribe