Pulsars are among the best clocks in the universe, second only to the most advanced chronometers humans have invented. Pulsars are a type of neutron star that forms after the death of a massive ordinary star.
They rotate rapidly and emit pulses of light, which mark the progress of the cosmic clock. These pulses can be used to find invisible objects in the Milky Way. New observations of pulsars have revealed mysterious objects that cannot yet be explained, writes Futurism.
For years, astronomers have used the extremely regular flashes of light from pulsars as cosmic beacons to keep track of time and detect gravitational waves.
However, there are times when the light pulses do not arrive on time. Scientists believe that a huge invisible mass could pass in front of pulsars, causing subtle delays in the signals at the microsecond level. What exactly these masses are is still unknown.
Study author John LoSecco of the University of Notre Dame, USA, studied pulsars and discovered these mysterious objects. When he presented his observations to a meeting of astronomers at the University of Hull, he was asked not to call them free-floating planets or clumps of dark matter.
For now, these objects are called mass concentrations, because it is not yet possible to determine exactly what they are.
“I’ve been warned not to call them planets, not to call them dark matter, but just call them mass concentrations, because you can’t tell what they are just by looking at the radio,” LoSecco says.
The scientist thinks it could be dark matter, a planet not associated with any star, a brown dwarf (a failed star that cannot initiate hydrogen fusion in its core), a white dwarf (the remnant of a star similar to the sun), or something completely different.
LoSecco and his colleagues have created a catalog of these mysterious mass concentrations that pass in front of pulsars, using data from ground-based radio telescopes. So far they have discovered 12 unknown objects.
According to LoSecco, the pulse of its light suddenly changes when a massive object passes in front of the pulsar, delaying these signals.
One of these invisible masses was only one-fifth the mass of the Sun, and LoSecco suggests it could be that elusive dark matter. Dark matter is believed to make up 85% of all matter in the universe, but has yet to be directly observed.
Much more observation is needed before it can be determined what causes minute discrepancies in pulsar signals and to understand what the mysterious mass concentrations actually are. This new research is also useful for improving the accuracy of space clocks.
