Latest Spin on Neutron Stars
I hope everyone had a happy St. Valentine's Day. The afternoon was spent huddling together by the ocean watching the sunset. The Sun is fascinating to contemplate. Though our lives depend on it, humans know shockingly little about how the sun works. We should remember on Valentine's Day how important the heart is.
In Larry Niven's story, Beowulf Schaeffer rides a spacecraft to the vicinity of a NEUTRON STAR. These stars are the created in the aftermath of huge supernovae. As this month's ASTRONOMY magazine reports, even the energy source of supernova explosions is a mystery! Neutron stars are dense enough to make atoms collapse, so their outer layers are composed of pure neutrons. A cubic centimetre of neutron star would weigh a hundred million tons. They are denser than any object except for a Black Hole, which should be clue #1.
As reported by SPACE.com, astronomers using the ESA INTEGRAL satellite have found that neutron star XTE J1739-285 spins at 1,122 revolutions per second. The neutron star drains materiel from a companion object, giving off X-rays that astronomers can measure. XTE J1739-285 spins faster than any known neutron star, and faster than any object save for a Black Hole. This ought to be clue #2.
Some neutron stars are pulsars, emitting spinning beams of radiation like a lighthouse. The first pulsar was discovered by astronomer Jocelyn Bell in 1967. Being a woman, she was denied proper credit for her discovery. The beams spin because the axis of the source is independent of the neutron star's spin axis. As Dr. Roger Blandford noted last week, the source of these coherent beams has been a complete mystery. Something hidden within creates the twin beams. This should be clue #3.
Recently some neutron stars have been discovered to be magnetars. Their magnetic fields are so powerful that astronomers aren't sure how strong they get. They are more powerful than the magnetic field of any object except a Black Hole. Do we have enough clues, Scooby Gang?
The birth of stars, including our Sun, is triggered when tiny singularities collide with gas clouds. The clouds contain the elements for stars, but cannot turn into stars on their own. Presence of singularities causes the clouds to collapse until nuclear fusion is ignited. Outward radiation pressure balances gravity's inward pull to create an equilibrium that can last billions of years. A Black Hole can comfortably exist in the second-last place humans would look for one, inside the Sun.
Only occasionally do Black Holes reveal their presence. When a star of greater than 1.4 solar masses uses up all its fuel, the equilibrium between radiation and gravity is abruptly broken. The star collapses at nearly one quarter of the speed of light into the singularity. This sudden infusion of mass produces a titanic explosion, a supernova.
In the aftermath of a supernova, only the most dense of materiels survive. Superdense neutrons form an outer layer. The heart of a neutron star is a Black Hole. If the Black Hole has enough spin, it produces a magnetic field and twin jets exactly as observed. The Black Hole spins independently of the outer neutron layers, emitting the spinning beams of a pulsar.
Lack of a Black Hole explains why humans have been unable to recreate conditions inside the Sun for any length of time. Nuclear fusion has been reproduced only for brief moments, as in a hydrogen bomb. Containing a stable reaction requires the attractive force of a Black Hole. If humans understood this simple principle, energy generation would not be a problem. Scientists should learn from Luke Skywalker, push the computer away and follow the heart.