An international team of astronomers has discovered the first radio-bright tidal disruption event (TDE) occurring outside a galaxy’s center using the U.S. National Science Foundation National Radio Astronomy Observatory (NSF NRAO) Very Large Array (NSF VLA) and Atacama Large Millimeter/submillimeter Array (ALMA), along with several partner telescopes.
Recent News
First-ever Detection of “Heavy Water” in a Planet-forming Disk
The discovery of ancient water in a planet-forming disk reveals that some of the water found in comets—and maybe even Earth—is older than the disk’s star itself, offering breakthrough insights into the history of water in our Solar System.
Astronomers Detect Lowest Mass Dark Object Yet in Distant Universe
An international research team, using a worldwide network of radio telescopes, has detected an enigmatic dark object with a mass about one million times that of our Sun without observing any emitted light. This is the lowest mass dark object ever detected at a cosmological distance using only its gravitational influence.
Cosmic Tug-of-War: Gravity Reshapes Magnetic Fields in Star Clusters
This image from NASA’s Spitzer Space Telescope shows a star formation region in molecular cloud NGC 6334, also known as the Cat’s Paw Nebula. The colors correspond with emission at 3.6 microns (blue), 4.5 microns (green), and 8 microns (red). This cloud is actively forming massive stars, and is located in the constellation Scorpius, between 4,200 to 5,500 light-years from Earth. ALMA data overlaid on the image shows details of four specific areas that were observed (NGC6334I, NGC6334I(N), NGC6334IV and NGC6334V), revealing invisible forces of magnetism and gravity as they wrestle and shape the formation of stars deep within the giant molecular cloud. The color scale in the ALMA images represents the intensity of the dust emission at 1.3mm and the drapery lines represent the orientation of the magnetic field.
Image Credit: Credit for composite image: background, NASA/JPL-Caltech; overlay: ESO/NAOJ/NSF NRAO; image created by NSF/AUI/NSF NRAO/M. Weiss.
A record-breaking ALMA survey delivers the first statistical evidence that collapsing gas clouds realign their magnetic fields, tipping the cosmic balance in favor of gravity
Astronomers have captured the clearest picture yet of how massive stars are born, revealing a dramatic interplay between gravity and magnetic fields in some of our galaxy’s most dynamic star forming regions. A team led by Dr. Qizhou Zhang from the Center for Astrophysics | Harvard & Smithsonian used the Atacama Large Millimeter/submillimeter Array (ALMA) to conduct the largest and most detailed survey to date of magnetic fields in 17 regions where clusters of massive stars are forming. These observations, reaching down to just a few thousand astronomical units (about 10 times the distance from the Sun to Pluto) offer the first statistical insight into how the invisible forces of magnetism and gravity wrestle and shape the formation of stars deep within giant molecular clouds.
Star formation requires gas in space to be squeezed to densities more than ten trillion times greater than what’s typically found in interstellar clouds. But this epic collapse isn’t driven by gravity alone—magnetic fields and turbulence both push back, resisting the pull. For decades, astronomers have debated which force dominates as gas clouds shrink and stars ignite.
New ALMA observations by Zhang’s team have provided crucial answers. By measuring how the directions of magnetic fields change at different distances from young protostars, the researchers found that as gas becomes denser, gravity begins to win this cosmic tug-of-war. Magnetic fields, which start out mainly resisting gravity, are gradually pulled into alignment with infalling gas, showing a clear sign that gravity takes over as the leading force shaping the collapsing cloud.
This study marks the first time astronomers have statistically traced how magnetic fields behave as gravity pulls a star-forming cloud inward at precise measurements, in thousands of astronomical units, across a large sample of massive cluster-forming regions. The findings revealed a surprising pattern: the magnetic field orientations do not just occur randomly. Instead, they show two preferences: sometimes lining up with the direction of gravity, or sometimes perpendicular—evidence for a complex and evolving relationship between these two cosmic forces.
“With ALMA’s extraordinary sensitivity and resolution, we can now probe these cosmic birthplaces in unprecedented detail,” said Zhang. “We see that gravity actually reorients the magnetic field as clouds collapse, offering new clues about how massive stars—and the clusters they inhabit—emerge from the interstellar medium.”
Understanding how stars form is fundamental to almost every field of astronomy, shaping everything from the origins of our own Sun to the evolution of galaxies. This work not only settles long-standing debates about the relative importance of magnetic fields and gravity in massive star formation, but also gives scientists powerful new tools to test and refine theories about the life cycles of stars, planets, and cosmic clouds.
As the largest ALMA polarimetric study of its kind, this project sets a new standard for understanding both the visible and invisible components of our galaxy. The results reveal that while magnetic fields shape star-forming clouds, gravity ultimately takes the lead in birthing the most massive stars—an insight made possible by ALMA’s cutting-edge technology.
About NRAO
The National Radio Astronomy Observatory (NRAO) is a facility of the U.S. National Science Foundation, operated under cooperative agreement by Associated Universities, Inc.
About ALMA
The Atacama Large Millimeter/submillimeter Array (ALMA), an international astronomy facility, is a partnership of the European Southern Observatory (ESO), the U.S. National Science Foundation (NSF) and the National Institutes of Natural Sciences (NINS) of Japan in cooperation with the Republic of Chile. ALMA is funded by ESO on behalf of its Member States, by NSF in cooperation with the National Research Council of Canada (NRC) and the National Science and Technology Council (NSTC) in Taiwan and by NINS in cooperation with the Academia Sinica (AS) in Taiwan and the Korea Astronomy and Space Science Institute (KASI).
ALMA construction and operations are led by ESO on behalf of its Member States; by the National Radio Astronomy Observatory (NRAO), managed by Associated Universities, Inc. (AUI), on behalf of North America; and by the National Astronomical Observatory of Japan (NAOJ) on behalf of East Asia. The Joint ALMA Observatory (JAO) provides the unified leadership and management of the construction, commissioning and operation of ALMA.
This news article was originally published on the NRAO website on October 8, 2025.
Recent News
Astronomers Discover Fastest-Evolving Radio Signals Ever Observed from Black Hole Tearing Apart Star
An international team of astronomers has discovered the first radio-bright tidal disruption event (TDE) occurring outside a galaxy’s center using the U.S. National Science Foundation National Radio Astronomy Observatory (NSF NRAO) Very Large Array (NSF VLA) and Atacama Large Millimeter/submillimeter Array (ALMA), along with several partner telescopes.
First-ever Detection of “Heavy Water” in a Planet-forming Disk
The discovery of ancient water in a planet-forming disk reveals that some of the water found in comets—and maybe even Earth—is older than the disk’s star itself, offering breakthrough insights into the history of water in our Solar System.
Astronomers Detect Lowest Mass Dark Object Yet in Distant Universe
An international research team, using a worldwide network of radio telescopes, has detected an enigmatic dark object with a mass about one million times that of our Sun without observing any emitted light. This is the lowest mass dark object ever detected at a cosmological distance using only its gravitational influence.