A strange lack of stellar orbits around the core of the Small Magellanic Cloud (SMC) mystified astronomers for decades. Not only that, but the SMC has a strange, irregular shape, and sports a tidal. Now, a team of observers led by graduate student Himansch Rathore at the University of Arizona, has tracked down the reason why the stars don’t orbit. It’s because the SMC crashed directly through its neighbor, the Large Magellanic Cloud (LMC), in the distant past. That huge collision disrupted stellar motions and sent them on wildly different trajectories. It also disturbed the clouds of gas within the SMC and created a tail of gas stretching out across space.

The team’s work provides unique insights into how galaxies change over time. “We are seeing a galaxy transforming in live action,” said Rathore. “The SMC gives us a unique, front-row view of something very transformative of a process that is critical to how galaxies evolve.”

A Closer Look at the SMC

The Small Magellanic Cloud is one member of a trio of interacting galaxies that includes our own Milky Way, in addition to the Large Magellanic Cloud. The SMC lies about 200,000 light-years away, while the LMC is about 158,000 light-years distant. Both have sites of active star formation. The SMC is categorized as a dwarf irregular galaxy and has a mass equivalent to about 7 billion solar masses. Not all that mass is in stars, however. Most of the SMC’s mass is in giant gas clouds that eventually become sites of starbirth. That happens as the clouds cool and contract. If conditions are right, the process creates hot, young stars that astronomers can study as they seek to understand the process of star formation.

This visible light mosaic shows the LMC and SMC in context with the plane of our own galaxy, the Milky Way. Dusty filaments create dark traces across the bright central plane of the Milky Way, visible across the top of the image. Below it, separated by about 21 degrees, lie the LMC and SMC, the closest major galaxies to our own. The LMC and SMC orbit each other as well as our own Milky Way galaxy. Credit: Axel Mellinger, Central Michigan University (via NASA Goddard Scientific Vizualization Studio).

Astronomers have measured the motion of the stars that exist in the SMC, using the data from the Hubble Space Telescope and the Gaia mission. That’s when they found that the SMC’s stars don’t orbit around that galaxy’s center the way stars in most other galaxies do. That lack of orbital activity was puzzling, until Rathore’s team considered the effects of a collision on the SMC and LMC. A few hundred million years ago, the SMC crashed directly through the LMC’s disk. The LMC’s gravity disrupted the SMC’s internal structure and sent its stars into random, disordered motion. In addition, the gas in the LMC applied a tremendous amount of pressure to the SMC’s gas and destroyed its gas rotation.

Since the LMC, SMC, and Milky Way Galaxy are interacting with each other, astronomers want to understand how that interaction affects all three galaxies. Astronomers found a bridge of gas between the LMC and SMC, likely pulled from one of the galaxies by during tidal interactions between the two galaxies. That bridge is busily forming stars in the shocked gas.

Large and Small Magellanic Clouds from GAIA data. Image credit: ESA/Gaia/DPAC – CC BY-SA 3.0 IGO.

Solving the Puzzle of Disrupted Stellar Orbits

The crash between the LMC and SMC did a lot of damage to both, according to Gurtina Besla, a senior author on a paper about the finding. “The SMC went through a catastrophic crash that injected a lot of energy into the system. It is not a ‘normal’ galaxy by any means,” Besla said. To understand that crash, the team turned to computer simulations. First, they matched the known properties of the SMC and the LMC – their gas content, total star mass, and positions relative to the Milky Way. They paired the simulations with theoretical calculations of how collision affected the SMC’s gas as it plowed through the LMC’s dense gas environment. They also developed new methods for reading the scrambled star motions in a post-collision galaxy, tools that can now be used to properly interpret what telescopes actually measure in the SMC.

That matters because the SMC is small, gas-rich and low in heavy elements, which are properties that made it a standard yardstick for the kinds of galaxies that existed early in the Universe. A galaxy still reeling from a collision may not be a clean reference point, Besla said. However, it can give information about the effects collisions and interactions have had on galaxies throughout time.

This plot shows the simulated gas distribution of the Magellanic System resulting from the tidal encounter between the Large Magellanic Cloud (LMC) and Small Magellanic Cloud (SMC) as they orbit our home Milky Way Galaxy. The solid line shows the calculated path of the LMC and the dotted line is the path of the SMC. Plot by G. Besla, Milky Way background image by Axel Mellinger (used with permission)

Other Effects of a Collision

Another study published by the team in 2025 showed that the collision also left a physical mark on the LMC that could help scientists probe dark matter. The LMC has a bar-shaped structure at its center, and that bar is tilted out of the plane of the galaxy because of the collision. Rathore, the 2025 study’s lead author, said the degree of the tilt is tied to how much dark matter the SMC contains, giving researchers a new way to measure a substance that has never been directly detected, only inferred from its gravitational effects.

“We are used to thinking of astronomy as a snapshot in time,” Rathore said. “But these two galaxies have come very close together, gone right through one another, and transformed into something different.”

In addition, the interaction between the LMC, SMC, and the Milky Way affects our galaxy’s shape. It appears that the LMC is causing a warp in the shape of the Milky Way’s stellar disk. It’s also pulling on the core of our galaxy, disturbing the halo, and accelerating its velocity through space. The SMC also contributes to this warping and pulling, and helps create the Magellanic Stream. That’s a trail of gas and stars that’s helping to populate the Milky Way.

For More Information

A Galactic Transformation — Understanding the SMC’s Structural and Kinematic Disequilibrium

A Galaxy Next Door is Transforming, and Astronomers can see it Happening

An eerie silence had settled.

As word evidently reached activists in the last few weeks that disturbing allegations of sexual abuse against Chicano civil rights icon Cesar Chavez were forthcoming, things started to happen without much explanation.

Groups began to cancel long-planned parades, dinners, lectures and fundraisers scheduled for Chavez’s birthday on March 31. People who I’ve known for years suddenly weren’t returning calls or texts about what was going on. Longtime defenders of Chavez — who stood by their hero even as revelations in this paper and in biographies over the past generation showed there was a dark side to the man — suddenly became hard to reach.

When the United Farm Workers and the Cesar Chavez Foundation put out statements Tuesday morning that “troubling allegations” against their patriarch were considered credible enough for them to offer help to his victims, the silence transformed into dread. There was a discomfort similar to waiting for a tsunami — that whatever was coming would change lives, shake institutions and make people question values and principles that they had long held dear.

And like a natural disaster, what emerged about Chavez was far worse than anyone could’ve expected.

Wednesday morning, the New York Times published a story where two women whose families marched alongside Chavez in the fields of California during the 1960s and 1970s disclosed that he sexually abused them for years when they were girls. Just as shocking was the revelation by Dolores Huerta, Chavez’s longtime compatriot and a civil rights legend, that he had once raped her at a time when their leadership in the fight to bring dignity to grape pickers earned national acclaim and amounted to a modern-day Via Dolorosa.

The silence has transformed into screams. Politicians and organizations that long commemorated Chavez and urged others to follow his ways are releasing statements by the minute. My social media feed is now a torrent of friends and strangers expressing empathy for Chavez’s victims and outrage, disgust and — above all —disappointment that someone considered a secular saint by many for decades turned out to be a human more terrible than anyone could’ve imagined.

There will be questions and soul-searching about these horrifying disclosures in the weeks, months and years to come. We will see a push for the renaming of the dozens of schools, parks and streets that bear Chavez’s name across the country and even the rebranding of Cesar Chavez Day, a California state holiday since 2000 devoted to urging people to give back to their communities and the least among us.

The reckoning is only right. Much of the Latino civil rights, political and educational ecosystem will have to grapple with why they held up Chavez as a paragon of virtue for too long above others just as deserving and, as it turns out, nowhere near as compromised.

In any event, the myth has been punctured.

A portrait of Cesar Chavez on a mural on Farmacia Ramirez, 2403 Cesar E Chavez Ave. in East Los Angeles.

(James Carbone / Los Angeles Times)

Chavez’s biography always reads like an entry in the “Lives of the Saints” genre of books that Catholics used to read about the holy men of their faith. The son of farmworkers who became a Mexican American Moses trying to lead his people to the promised land of equity and political power. An internationally famous leader who lived a mendicant’s life. Who devoted decades to some of the most exploited people in the American economy. Honored with awards, plays, posters. Murals, movies and monuments. President Biden even kept a bust of Chavez at his Oval Office desk.

It was a beatific reputation that largely persisted even as the union he helped to create lost its influence in the fields of California and a new generation of activists looked down on Chavez for his long-standing opposition to immigrants who came to this country to work without legal status. Admirers kept him on a pedestal even as former UFW members alleged over the last two decades that the boss they once idolized purged too many good people in the name of absolute control. The hagiography continued even as a new generation of Latinos came of age not knowing anything about him other than an occasional school lesson or television segment.

I was one of those neophytes. I first heard his name at Anaheim High School in the mid-1990s and thought my teacher was talking about Julio Cesar Chavez, the famous Mexican boxer. I was thrilled to discover that someone had bravely fought for the rights of campesinos like my mom and her sisters, who toiled in the garlic fields of Gilroy and strawberry patches of Orange County as teenage girls in the 1960s, the same time that Chavez and the UFW were enjoying their historic wins.

“Who’s Cesar Chavez,” my Mami responded when I asked if his efforts ever made her work easier.

My admiration for Chavez continued even as I learned about some of his faults. I was able to separate Chavez the man from the movement for which he was a figurehead. Long-maligned communities seek heroes to emulate, to draw hope from, to hang on their walls and share their quotes on social media. We create them even as we ignore that they’re flesh and blood just like us.

Chavez seemed like the right man at the right moment as Mexican Americans rose up like never before to battle discrimination and segregation. Now, Latinos and others who admired Chavez have to grapple with his moral failings of the worst possible magnitude at the worst possible time: when there’s an administration doing everything possible to crush Latinos and we’re looking for people to look up to like never before.

He remains one of the few Latino civil rights leaders known nationwide — and Chavez is nowhere near as known as acolytes make him out to be. Some people will argue that it’s unfair he will likely get wiped away from the public sphere while other predatory men from the past and present largely maintain their riches and reputations.

But that’s looking at the abuse revelations the wrong way. For now, I will follow what those most directly affected by Chavez’s actions are telling us to do.

The UFW and Cesar Chavez Foundation were wise to not try to defend the indefensible in their statements and instead consider any victims first before deciding how to decide what’s next for them.

The Chavez family put out a news release that state “we honor the voices of those who feel unheard and who report sexual abuse.”

Huerta wrote in an online essay “Cesar’s actions do not reflect the values of our community and our movement. The farmworker movement has always been bigger and far more important than any one individual.”

Another of his victims told the New York Times of Chavez’s legacy, “It makes you rethink in history all those heroes. The movement — that’s the hero.”

The fountain in the Memorial Garden surrounds the gravesite of Cesar Chavez and his wife Helen Chavez at Cesar E. Chavez National Monument in Keene, Calif.

(Francine Orr)

The face of that movimiento brought inspiration to millions and improved the lives of hundreds of thousands. That’s why we shouldn’t cancel the good that Chavez fought for alongside so many; we should direct the adulation he once attracted and the anger he’ll now rightfully receive toward the work that still needs to be done.

To quote an old UFW slogan that Chavez transformed into a mantra, la lucha sigue — the fight continues. It’s a statement that’s more pertinent than ever, damn its imperfect messenger.