We have atomic clocks that are highly accurate. But there are clocks in space too. In fact, they might be even more accurate.
Pulsing, rapidly spinning stars could be used as universe’s most accurate clocks.
For many years, astronomers have attempted to use these stars, named pulsars, as time-keepers. But, the contortion in their spins has prevented this from happening. However, a recent discovery and a new understanding could enable scientists to compensate for it.
When stars collapse and become dense enough that protons and electrons squish together to become neutrons, pulsars are created.
Once the stars’ mass is condensed into a small volume, conservation to angular momentum causes the pulsar to rotate up to hundreds of revolutions per second.
Pulsars radiate a steady ray of light which sweeps around and hence, their light seems to pulse on and off as it crosses our line of sight. This pulsing is not quite steady. Slight variations in the observed pulling rate were unexplained, until now.
Timing the cosmos
Lovell telescope in the United Kingdom has helped in explaining this phenomenon. These deviations are arising because the pulsars are slowly spinning down at two different rates. The switch between these two rates is unpredictable and abrupt.
Careful observation and measurement of a pulsar’s light at any particular time should tell us about its slowdown rate, and allow astronomers to calculate and correct it. This will largely improve the pulsars’ usefulness as cosmic clocks.
All the eminent clocks developed by humans need correction to accommodate for the variations in temperature, pressure, humidity or local magnetic field. Scientists claim that pulsars are a potential means of unerring an astrophysical clock.
Ripples in space-time
Scientists are hoping that pulsar clocks can be helpful in answering questions about the gravitational waves.
These waves were previously undetected, but pulsars may be the lead to finding them.
Einstein’s theory of general relativity suggests that events like a merging of 2 supermassive black holes will create wavelets in the space-time that stretch out through the entire universe.
For example, a gravitational wave would cause a change in the pulsing rate of a pulsar on passing through it. If we could measure these changes very precisely, we may be able to corroborate the existence of gravitational waves.
Gravitational waves are expected to be created by supermassive black holes in the universe. Observatories around the world are trying to use pulsars to detect these gravitational waves.
The new techniques may be successful in revealing the gravitational wave signals that are currently undetectable due to the non-uniformity in the pulsar rotation.