Still in the Dark

In the 1600s, astronomers proposed the existence of objects in the universe that emit little or no light and can only be detected by the way their gravitational forces interact with other objects around them. Little did they know that this hypothesis was just the beginning of a mysterious saga that would haunt the world of physics for hundreds of years: what is dark matter?

Four centuries later and we still know very little about what dark matter is. We know it does not absorb or emit light, but its gravitational forces supposedly account for the unexplained bending or lensing of light from the galaxy observed in telescopes, which is the only way we can detect it as of now.

Gravitational lensing, when caused by unseen objects, implies the presence of dark matter. Image: NASA/ESA

Several candidates for dark matter have been proposed throughout the years. One study even explored the idea that dark matter is actually made of massive gravitons. This is complicated, seeing as scientists would be trying to explain a hypothetical particle using yet another hypothetical particle. Different teams of researchers have published many calculations on what dark matter is or isn’t and how we can capture the elusive particle, and yet even the world’s most sensitive detector—LUX, had nothing to show for it.

Cornering the Enigmatic Particle

In an interview with Scientific American, award-winning theoretical astrophysicist Priyamvada Natarajan shared that she is optimistic that we will be unmasking the enigmatic particles soon.

“What I think is entirely possible is that we are off in terms of our expected properties for the dark matter particle, which might account for why they remain elusive to date,” Natarajan said.

“We are really close to solving this mystery of the missing particle. This is akin to a crime scene, where we have the motive, the weapon as evidence but the body is missing! To me there are several exciting upcoming developments that I keenly look forward to in the coming 3-5 years or so that might break this intellectual impasse.”

Technology is currently progressing at a fast pace, allowing us to see far more than we used to. Physicists are positive we’ll corner the hypothetical particle. “I think we are poised to make an epistemic leap in terms of unraveling the true nature of dark matter very soon,” Natarajan says.

Read Natarajan's full interview with Scientific American here.

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