What is a pulsar?

A type of exploding star that pulses in brightness A rapidly rotating neutron star that emits beams of electromagnetic radiation from its magnetic poles A young star that flickers as material falls onto it from a protoplanetary disk A binary star system where two stars regularly pass in front of each other

Who discovered pulsars, and when?

Albert Einstein predicted pulsars in his general theory of relativity in 1916 Jocelyn Bell Burnell, a graduate student, detected the first pulsar signal in 1967 Galileo Galilei observed the first pulsar through his telescope in 1609 NASA discovered pulsars in 1990 using the Hubble Space Telescope

Why was the first pulsar signal initially nicknamed LGM-1?

The discoverers thought it was a green-colored nebula visible in optical telescopes The pulses were so perfectly regular that researchers briefly joked it might be a signal from an extraterrestrial civilization (Little Green Men) The signal came from the direction of the constellation Leo the Lion (the green lion) The signal was green-wavelength light, which was unusual for a radio source

How fast does the Crab Pulsar rotate?

Once per year — the same rate as Earth orbiting the Sun Once per second — the standard rotation rate for all pulsars About 30 times per second About 1,000 times per second — it is one of the fastest known pulsars

What is a millisecond pulsar?

A pulsar that has just formed and is still slowing down from its initial fast spin A pulsar that sends out pulses lasting only a millisecond each A pulsar that rotates hundreds of times per second, spun up to extreme speeds by accreting material from a companion star A very young pulsar that formed only a few milliseconds ago

Why are millisecond pulsars described as the most accurate natural clocks in the universe?

Their pulses are powered by nuclear fusion, which is extremely regular They are so close to Earth that timing measurements are very precise Their enormous mass and rapid, stable rotation make their pulse timing more precise than even the best atomic clocks on Earth Their magnetic fields shield them from any disturbances that could affect timing

What is a magnetar?

A neutron star that rotates much faster than a millisecond pulsar A neutron star with an extraordinarily strong magnetic field — up to 1,000 times stronger than a typical pulsar A black hole that generates magnetic fields strong enough to deflect light A magnetized asteroid in the asteroid belt between Mars and Jupiter

How much energy can a magnetar release in a single starquake event?

About the same energy as one minute of the Sun's output More energy in 0.2 seconds than the Sun will emit in 250,000 years About the same energy as a large earthquake on Earth About the same energy as a supernova explosion

What causes a pulsar to gradually slow down over time?

Material falls onto the pulsar from surrounding space and adds weight The neutron star gradually cools, which causes it to contract and slow down The radiation and particles it emits carry energy away, slowly reducing the rotation rate over millions of years Friction with the interstellar medium acts like a brake on the spinning pulsar

How are pulsars useful to astronomers beyond simply being interesting objects?

Pulsars emit light that helps other stars form nearby Their extremely precise timing can be used to detect gravitational waves and test general relativity Pulsars generate radio signals that help spacecraft navigate in deep space Studying pulsars helps us understand how to build better atomic reactors on Earth