Show 96. Notes for April 23rd
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Our past guest, senior astronomer Seth Shostak is in a tizzy… Could Kepler 186f be earth’s twin? It is 500 light years way, yet SETI is pointing their telescope array toward it to see if they can find radio signal. http://www.huffingtonpost.com/seth-shostak/kepler-186f-is-it-inhabit_b_5186220.html?utm_hp_ref=science
In the past few weeks we have talked about the lives of stars. Their deaths often result in white dwarfs or black holes. Another outcome for high mass stars are neutron stars, discovered by Jocelyn Bell in 1967.
Once the core of the star starts burning iron, energy production stops and the core collapses, squeezing electrons and protons together to form neutrons. The density is equivalent to that of an atomic nucleus. At this point, the neutrons occupy the smallest space possible. If the core is less than three solar masses, they exert what is known as neutron degeneracy pressure. This is still capable of supporting a star and if its magnetic field is favourably aligned with its spin axis it appears as a neutron star.
Neutron stars are extreme objects and have a radius of about 15 kms. A teaspoon of one would weigh around a billion tonnes. Imagine squeezing twice the mass of the Sun into an object the size of a city! Hence, gravity at the surface of the neutron star is one thousand times stronger than Earth’s, and an object would have to travel at about half the speed of light to escape. The Crab nebula and pulsar is such an object first noted by Chinese astronomers in 1054.
Such neutron stars rotate extremely rapidly and if they are part of a binary system that can reach over 600 times per second! Astronomers measure these rotation rates by detecting electromagnetic radiation ejected through the poles of the magnetic field. These magnetic poles are generally misaligned with the rotation axis of the neutron star and so the radiation beam sweeps around as the star rotates.
Neutron stars do not necessarily exist in isolation, and those that form part of a binary system usually emit strongly in X-rays. X-ray binaries typically result from the transfer of material from a main sequence companion onto the neutron star. Short-duration gamma ray bursts are thought to result from the merger of two neutron stars.
Our guest is Matty Beckerman, Director of movie, Alien Abduction, which is based on the Brown Mountain Lights, movie trailer below.
Music by Kerry Lloyd Whitehouse