Mysterious dark star clusters discovered

Scientists are baffled by the discovery of strange globular star clusters that are far more massive than expected for their level of luminosity.
Globular clusters are spherical groupings of stars that orbit galactic cores as satellites. Tightly bound by gravity, they have dense concentrations of stars at their centers.
Using the FLAMES instrument on the European Southern Observatory (ESO) Very Large Telescope at Chile’s Paranal Observatory, a team of astronomers obtained mass estimates for 125 globular clusters orbiting Centaurus A, a giant elliptical galaxy.

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> Using the FLAMES instrument on the European Southern Observatory (ESO) Very Large Telescope at Chile’s Paranal Observatory, a team of astronomers obtained mass estimates for 125 globular clusters orbiting Centaurus A, a giant elliptical galaxy.

Nice. I wouldn’t have thought of that. I assume they used redshift to get the orbital speed.

> Dark matter is a less likely possibility, as globular clusters are generally known for lacking that unexplained substance.

I’d say a more likely possibility.