Pulsars - The celestial lighthouse

Dr. Revathi Jambunathan

What you just heard was an orchestra of -- PULSARS

Imagine --

You are out there hiking in the wilderness and -- you lose your GPS signal.

Now, imagine having the same experience but, in space, in the vast darkness of the cosmic ocean and then -- you detect a re-assuring signal from a cosmic lighthouse letting you know where exactly you are! These remarkable objects are called PULSARS!

Pulsars were once massive stars that ran out of fuel and their core collapsed to form a compact dense object, now the size of Berkeley. After the collapse, they spin hundred times a second, emitting twin beams of light which get detected as a pulse every time it sweeps past Earth. In fact, this is how Jocelyn Bell first discovered them in 1967 -- This rhythmic nature of the signal - which you just heard -- was so bizarre --that they were initially nicknamed LGM1 - little green men -1 Briefly entertaining the thought that ET was trying to communicate with us.

But, even after 50 years of their discovery -- we still don't understand why pulsars emit light?

While, we can’t build an actual pulsar since a teaspoon weighs as much as Mt Everest, we can build a computer model.

This is the focus of my research.

Our objective is to capture both -- the spinning pulsar and its light beam.

However, this is challenging -- because -- the electron interactions driving the light beam are a million times smaller than the pulsar. Modeling these two length-scales simultaneously in a single simulation frame is like taking a picture of Berkeley from the sky and capturing the lemons growing in my garden. Existing models -- artificially enlarge electron interactions leading to inaccurate energies compared to an actual pulsar!

This is where my new approach comes in.

My team and I are bridging this energy gap using an adaptive approach on supercomputers. Instead of using high-resolution everywhere, we optimize and use finer resolution only where electron interactions are dominant - that is -- Only in the light beam. The highlight of our approach is that, the fine resolution pixels spin along continuously capturing the rotating light beam. With this method, we will probe the influence of strong rotating magnetic fields of the pulsar on the fundamental relation between electron interactions and the nature of light emissions -- we will better understand how pulsar emit light.

And may be some day -- soon -- these symphonies of the stars, heartbeats of our universe will navigate us in our cosmic journeys.