In a galaxy far away, Indian-origin scientist finds her calling

US-based Indian origin astrophysicist Sukanya Charkrabarti has found her calling 260,000 light years away in a galaxy that can barely, if at all, be seen. Galaxy X, at a distance which is modest on the cosmic scale, is where she is perfecting her theoretical skills.

Dealing with structures of the Milky Way that seem to exist more by their gravitational signature than by actual observational fact, Chakrabarti, of the University of California, Berkeley, has perfected a technique that could give scientists some key answers to deeply troubling questions. The most baffling of them relates to dark matter, which forms over 80 percent of the universe.

Dark matter is a mysterious matter that cannot be seen because it does not interact with light. Its presence is inferred by the gravitational forces it exerts on matter that can be seen.

When an object that is hundreds of thousands of light years away from the earth and happens to be dimly lit the way Galaxy X is, scientists do not have much choice except to look for what they call gravitational perturbations. Chakrabarti deployed a method to predict Galaxy X that is similar to the way Neptune was discovered 160 years ago. Then Neptune was called Planet X, and hence the name Galaxy X for now.

At the heart of Chakrabarti’s work as a theoretical physicist is the conundrum arising from a major gap between what theory predicts should be the number of galaxies, known as satellite galaxies around the Milky Way, and what is actually observed. What can be seen is way less than what theory predicts.