Still, many hold out hope that we're getting close and that experiments such as the newly built Large Hadron Collider particle accelerator in Geneva may finally solve the puzzle.ĭark energy is possibly even more baffling than dark matter. "They went into this field thinking, 'OK, we're going to solve this problem and then we'll build from there.' But 15, 20 years later, they're saying, 'I've invested my career in this and I don’t know if I'm going to find anything in my lifetime.'" "I think on the dark matter side there is some discouragement among the people who are kind of mid-career," Panek said. However, try as hard as they might, scientists have yet to detect any of these particles, even with tests designed specifically to target their predicted properties. Yet their mass exerts a gravitational pull, just like normal matter, which is why they affect the velocities of stars and other phenomena in the universe. Yet, in the nearly 40 years that followed, researchers still haven't been able to figure out what dark matter is made of.Ī popular hypothesis is that dark matter is formed by exotic particles that don't interact with regular matter, or even light, and so are invisible.
If the stars and gas that we can see inside galaxies are only a small portion of their total mass, then the velocities make sense.Īstronomers nicknamed this unseen mass dark matter.
Ultimately, based on observations and computer models, scientists concluded that there must be much more matter in galaxies than what's obvious to us. "Something's missing here."īut research by other astronomers confirmed the odd finding. "It means that galaxies should be flying apart, should be completely unstable," Panek said. Instead, she found that all stars in a galaxy seem to circle the center at roughly the same speed. Yet Rubin's observations found no drop-off at all in the stars' velocities further out in a galaxy. Simple Newtonian physics predicted that stars on the outskirts of a galaxy would orbit more slowly than stars at the center. Vera Rubin, a young astronomer at the Department of Terrestrial Magnetism at the Carnegie Institution of Washington, observed the speeds of stars at various locations in galaxies. Some of the first inklings astronomers had that there might be more mass in the universe than just the stuff we can see came in the 1960s and 1970s.