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---------------------- 2264 - Fast Radio Bursts, what are they?
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- These signals are different than “pulsars” . Pulsars originate when supernovae leave behind a spinning core of neutrons, a neutron star. These cores spin several times a second and radiate beams exiting out their poles. These beams can be oriented to sweep by the Earth. The beam then appears as a repetitive pulse of radio or light energy.
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- These FRB radio bursts are different. First the radio beam is broadband covering a wide range of frequencies. Secondly, the lower frequencies arrive slightly later than the higher frequencies. The beams must travel great distances and the lower frequencies interact with elements in space while the more energetic higher frequencies fly past. The greater the delay the greater distances the signal has traveled. Astronomers call this a signal dispersion measurement.
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- Dispersion measurements on signals from a nearby galaxy are about 200. These FRB dispersion measurement are 790, meaning they are billions of lightyears away. For the signal to be so bright and that far away it must be extremely powerful.
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- Recent observations have found a source for these repeating radio bursts. It appears to be a dwarf galaxy that is 3 billion lightyears away. Its size is only about 10% that of our Milky Way Galaxy. This is contrary to astronomer’s speculation that FRB’ should be large, super massive blackholes at the center of galaxies.
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- Another speculation is that the source could be a “magnetar” , a fast spinning neutron star with an extraordinary magnetic field.
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- Only a couple FRB’s sightings have been found an identifying source. Astronomers need to find several more so further study can fine tune the theories.
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- Astronomers need to find more FRB’s. They need to learn if they all from the same phenomena or some different creations all together? Do all FRB’s repeat? Is there any pattern if they do repeat? Are they the same phenomena or are there several ways radio bursts are creating these signals?
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- Perhaps they are Neutron stars? Perhaps there exists some new physics that we need to learn? The wide dispersion of the radio signals may help us learn the composition of space between the galaxies? The dispersion may offer a method to study magnetic fields in space? What else will we learn?
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- It was in 1973 that the U.S. military declassified the existence of gamma-ray bursts that had been detected by their military satellites. They were found by accident since the satellites were looking for nuclear weapon tests starting in the 1960’s. After years of study these gamma ray bursts were found to be super massive stars collapsing into supernovae. In 10% of the cases the sources were determined to be 2 neutron stars that were merging.
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- Supernovae themselves have been found to have a multiple of origins. The most common is the large star that runs out of fuel and collapses in a giant explosion leaving behind a neutron star, or a blackhole.
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- Smaller supernovae occur when white dwarf stars gain mass and reignites as a supernovae. Because these explosions have predictable mass and resulting explosions are used as “standard candles” to measure distances throughout the universe.
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- Some call the mystery of fast radio bursts the greatest mystery in radio astronomy. A good scieice research project for some graduating student to become famous. A single burst lasting a millisecond has more energy that the Sun releases in 24 hours. That has got to be something incredible to learn about.
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- Other Reviews available:
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- 1222- Facebook and Twetter, are you monitoring your web identity?
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- 679 - The rise of Islamic fascists terrorism.
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- 1879 - Fermi Bubbles and radio bursts. Another puzzle astronomers need to solve.
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- ----- Femtoseconds, time is gettng short. Written before I started numbering them
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- 1626 - Feynman’s lecture “ There is plenty of room at the bottom” about atomic structure and how to use it.
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- 1302 - Finance, why the U.S. finances went bust.
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- 1473 - Fine Structure Constant, the math that makes the atom work.
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- 1336 - The mystery of the Find Structure Constant.
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- 2134 - The force Carriers, gluons, bosons, and photons.
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- February 9, 2019
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-------------------------- Saturday, February 9, 2019 --------------------------
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