The universe’s missing mass may not be entirely invisible. Dark matter may have ‘fingerprints’

New Delhi: Scientists at the University of York have discovered that dark matter may not be as invisible as we thought. Dark matter is a mysterious substance that makes up about 25 percent of our universe, but until now, scientists believed it was invisible. It has mass, but doesn’t interact with regular matter and passes right through it. Yet we know about dark matter because we know it has a gravitational pull, and it is the reason galaxies stay in place.

Now, a new study from the University of York, published in Physics Letter B journal on 7 October says that this dark matter could slightly change the colour of light that passes through it, leaving a faint red or blue “fingerprint”. The paper proposes that dark matter influences light indirectly—through a chain of interactions wi