Imagine the universe as a giant puzzle. Most of its pieces are hidden in the form of dark matter, a mysterious substance that makes up over 80% of all matter.
It’s invisible, doesn’t shine or reflect light, and is really hard to detect.
But researchers at The University of Alabama in Huntsville (UAH) have found a clever way to learn more about it by studying special stars called pulsars.
Pulsars are like cosmic lighthouses. They’re dead stars that spin very fast, sending out beams of radiation that sweep across space.
If Earth is in the path of this beam, astronomers see it as regular pulses of light, hence the name “pulsar.”
Some pulsars have partners, making them binary pulsars, and this duo acts like a space lab for testing gravity theories.
Dr. Sukanya Chakrabarti and Dr. Tom Donlon at UAH are using these pulsars to measure something incredibly small: the tiny pulls of gravity in our galaxy. These pulls are so slight that measuring them has been really tough until now.
Thanks to pulsars acting as precise cosmic clocks and the help of NANOGrav—a team using big telescopes to catch gravitational waves—these measurements are now possible.
Their research shows that our galaxy, the Milky Way, has a much more dramatic history than previously thought. It’s been shaken up by encounters with smaller galaxies, kind of like a boat rocking on waves caused by passing ships.
By looking at how binary pulsars move together, and how their orbits change over time, the scientists can test how well our theories of gravity match what we see in space.
But the really cool part of their work is about dark matter. Even though we can’t see dark matter, it has gravity, affecting how stars and galaxies move. By studying the tiny changes in how binary pulsars move, the researchers can figure out where dark matter is and how much there is. It’s a bit like seeing shadows move in a room and figuring out what’s casting them, without ever seeing the objects directly.
Donlon is excited about the future.
As we find and observe more pulsars, we’ll get even better at mapping the unseen parts of our galaxy. This could reveal not just where dark matter hides, but also how it clumps together and shapes the universe.
This research is like finding a new way to read a map of the stars, one that lets us see beyond the light into the dark corners of the cosmos.
It’s a step towards solving one of the biggest mysteries of the universe: what is dark matter, and where is it hiding?
