The Hidden Family of the Pleiades

The classic Pleiades (M45)

On a crisp winter night, step outside, face the constellation Taurus, and let your eyes adjust to the darkness. There, high in the sky, you’ll spot a tiny, sparkling dipper-like group of stars — the Pleiades, or as they’re affectionately known, the Seven Sisters. This dazzling jewel box has captivated stargazers for millennia. Even in light-polluted cities, its brightest members shine through, a reminder of the universe’s ancient beauty.

But in November 2025, everything we thought we knew about this iconic cluster changed forever. Astronomers announced that the Pleiades isn’t just a compact family of a few hundred stars. It’s the brilliant core of a vast, dissolving stellar superfamily called the Greater Pleiades Complex. Spanning nearly 2,000 light-years across the sky — from horizon to horizon on a clear night — this hidden structure contains 3,091 confirmed member stars, all born from the same cosmic nursery about 100–125 million years ago.

What we see with the naked eye? That’s less than 5% of the real family. The rest are fainter siblings, scattered far and wide by the Milky Way’s gravitational tides.

As lead researcher Andrew Boyle from the University of North Carolina at Chapel Hill put it:

We didn’t just find a few extra members — we found thousands of long-lost siblings scattered across the entire sky.

This isn’t just a bigger cluster; it’s a paradigm shift.

Why the Pleiades Have Always Been Special

Few celestial objects have woven themselves so deeply into human culture as the Pleiades.

In Greek mythology, the Seven Sisters were the daughters of Atlas and Pleione. Japanese culture immortalized them in the Subaru logo. For the Māori, the cluster is Matariki, heralding the new year. In Hindu tradition, they’re the Krittika, the six mothers of the war god Kartikeya.

And the eternal mystery: why ``seven'' sisters when most people can only see six bright ones? Ancient legends speak of the ``lost Pleiad'' — a myth that lives on in art and tattoos today.

Modern culture hasn’t let go either: Subaru cars, songs, album covers, video games — the Pleiades symbolize youth and mystery.

Matariki is the Māori name for a group of 7 stars known as the Pleiades star cluster

Subaru logo

What We Thought We Knew

Textbooks traditionally described the Pleiades (also known as Messier 45 or M45) as a young open star cluster about 444 light-years away, roughly 100–125 million years old, and containing around 1,000–1,500 stars spread across a region about 100 light-years wide. Born from the same cold, dense molecular cloud, these stars formed together and drift through space as a loose family.

For generations, astronomers considered open clusters like M45 to be short-lived structures that slowly evaporate under the pull of the Milky Way’s tidal forces. The Pleiades, bright and nearby, seemed like the perfect laboratory for studying that process.

About six of its stars are easily visible to the naked eye from October to April, forming the familiar pattern in the constellation Taurus. This grouping has been known since ancient times as the Seven Sisters, though the seventh star is now too faint for most observers.

What we’re learning now is that we were wrong about the scale of this system.

The 2025 Breakthrough — What Actually Happened

The discovery came from a team led by Andrew W. Boyle (UNC-Chapel Hill), Luke G. Bouma, and collaborators. They combined data from two powerful space missions:

• NASA’s TESS, which can measure how fast a star spins, and since stars slow down as they age, their spin rate is a surprisingly reliable way to estimate how old they are.

• ESA’s Gaia, which precisely tracks where stars are and how they move through space

Using these together, researchers set out to find stars that were born with the famous Pleiades star cluster about 125 million years ago.

How they did it

1. Find stars that spin like the Pleiades.Young stars spin at specific speeds, so matching their rotation rates is like matching fingerprints.

2. Check if they move the same way.Stars born together tend to travel through space in similar directions.

3. Rewind their motions back in time.With Gaia’s precise measurements, scientists can run the stars’ orbits backward 125 million years to see if they all came from the same region.

They identified 3,091 stars that were almost certainly born with the Pleiades — not just the small cluster we see today, but a giant, spread-out family of stars now stretching nearly 1,900 light-years across the sky.

Why This Discovery Matters

1. Rewrites open-cluster evolution: many are born huge and dissolve into giant streamearly.

2. Our Sun was likely born in a similar scattered association.

3. Provides thousands more young stars for exoplanet and stellar-formation studies.

4. Proves we can now find ``ghost clusters'' all over the Milky Way.

How to See the New Pleiades Yourself

You can still spot the familiar core of the Pleiades with just your eyes — it’s the only part bright enough to see unaided, and it looks best on clear evenings from November to March. If you have a pair of binoculars, you’ll notice dozens of additional faint stars sparkling around the main group.

The newly discovered “extended family” of the Pleiades stretches across such a huge region of the sky — and many members are so faint — that most amateur telescopes won’t show them. But sky-mapping apps like Stellarium can plot the full, expanded structure so you can appreciate its incredible size.

Want an even better view?

If you’re in Mumbai, ARC Educators’ AstroCamp offers guided stargazing sessions with a powerful 16-inch telescope — one of the largest available in the city. Their expert team helps you explore star clusters, nebulae, planets, and of course the Pleiades, with clarity you simply can’t get from home. It’s a wonderful way to experience the night sky up close.

M45, credit: ARC archives

Conclusion — A Bigger, More Mysterious Sky

For millennia, the Pleiades were a cozy family of seven bright sisters. In 2025 they became a galactic diaspora of over 3,000 siblings. Next time you look at that tiny dipper in Taurus, remember: thousands of brothers and sisters are hiding in plain sight all around it. The night sky just got a lot more connected — and infinitely more beautiful.

This image shows what the “Greater Pleiades” would look like if every one of its stars were bright enough to see with the naked eye. The classic seven Pleiades stars are highlighted in green, and all the newly identified members are shown in white. For reference, the Big Dipper, Orion, and Taurus are outlined in blue. Under the viewing conditions shown, about half of the 3,091 Pleiades-family stars are above the horizon. The view is oriented the way you’d see it when facing south. Credit: BOYLE ET AL.

• - Sayyed Danish (M. Sc. Astrophysics)