Astrophysicists from IIT Kanpur and the National Centre for Radio Astrophysics (NCRA) Pune have discovered a powerful new way to measure the distance of pulsars, which are dead stars that act like cosmic lighthouses by spinning and emitting regular flashes of radio waves.
For decades, measuring how far these stars sit from Earth has been one of the toughest puzzles in astronomy. While we can see exactly where they are in the sky, calculating the depth of space between us is a different challenge altogether.
The research, published in the Monthly Notices of the Royal Astronomical Society, offers a clever solution.
HOW DID THE TEAM MEASURE PULSAR DISTANCES?
Instead of relying on old, often inaccurate models of the Milky Way Galaxy, the team used two specific effects that happen to radio waves as they travel through space: dispersion and scattering.
Dispersion occurs when radio waves from a pulsar are delayed by different amounts based on their wavelength as they pass through free electrons in space.
Scattering happens when these same signals hit clumps of turbulent gas, causing the radio waves to take slightly different paths and arrive at Earth as a smeared or broadened pulse.
As a pulsar signal travels to Earth, it passes through a thin mist of particles called the interstellar medium.
This mist acts like a cosmic obstacle course. It delays the signal based on its wavelength and scatters the light, causing the pulses to smear out.
By measuring both these effects at once, the researchers can determine exactly how much material the signal passed through.
This allows them to calculate distance much more reliably than before.
The team tested their theory on the Gum Nebula, a massive cloud of gas in the southern sky.
Their results show that this method could be applied to hundreds of other pulsars already known to science. It might even help us understand Fast Radio Bursts, which are powerful flashes coming from far beyond our Milky Way.
This Indian breakthrough does more than just measure distance. It helps astronomers understand the true brightness and speed of these stars, providing a clearer map of our galactic neighbourhood.
By removing the guesswork from older models, the IIT Kanpur and NCRA Pune team has given the global scientific community a sharper lens to view the universe.
HOW DO PULSARS HELP US MAP THE MILKY WAY?
Pulsars act like cosmic lighthouses, sending out regular flashes that reveal the hidden particles floating between stars.
Space looks empty, but it is filled with electrons that distort light, making it difficult to tell if a star is faint or just very far away.
The massive gas structure serves as a perfect laboratory for Indian scientists to test how radio waves scatter over long distances.
By using the same logic applied to pulsars, researchers hope to pinpoint the origin of mysterious radio flashes from other galaxies.
