HONG KONG: Pulsars, the left-over remains of exploded stars, are considered some of the most accurate natural timekeepers in the universe, but even these excellent cosmic clocks aren’t perfect. A new study suggests that pulsars occasionally exhibit a “glitch” in their timing because they are filled with a “superfluid” that can flow over any surface without friction.
When massive stars grow old and die, they explode, sometimes leaving behind a neutron stars — a small, incredibly dense nugget of collapsed, leftover star material. A pulsar is a special type of neutron star that spins at hundreds of revolutions per second. Pulsars also emit a steady beam of light, often as radio waves, which may sweep across the Earth, creating the illusion that the pulsar is blinking on and off. The timing of this blinking is so regular that pulsars are among the most accurate timekeepers in the universe.
But once in a while, pulsars exhibit a “glitch,” suddenly spinning faster for a short time and thus increasing the rate of their “pulsing” light. The new study gives more support to the theory that these glitches are created by an interaction between the pulsar’s outer shell and the “superfluid” inside it, which has zero viscosity. A zero-viscosity fluid can store momentum, and would explain where the extra energy to speed up the pulsar comes from.
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