Fast Radio Bursts – Still an Enigma

Don’t blink. Like cruising through a one traffic blinker town, it’s here and gone before you realize it.

The first Fast Radio Burst (FRB) was discovered in 2007, by David Narkevic, a student working under astronomy professor Duncan R. Lorimer at West Virginia University. Not unusual. Also typical, the find was buried in an archived data set collected  years earlier, in 2001, at the Parks Radio Dish (Australia). Gotta love it!

FRBs are transient, high-energy pulses of radio frequency energy. They can be as brief as fractions of a millisecond or as lengthy as several seconds. An FRB can unleash as much energy in a millisecond as our Sun does in 3 days! Just don’t blink. It’s a good thing astronomers have instruments recording the radio night sky.

For the most part, FRBs are extragalactic, that is, most of the ones detected so far were in other galaxies. Our Milky Way isn’t being ignored, the CHIME radio telescope in British Columbia bagged one in April 2020.

The continuing enigma – what causes them? They appear very distant, yet very powerful. Getting a fix on location is challenging too. For a while, astronomers were concerned they originated from somewhere on Earth, appearing to come from space. Studies performed by the MOST (Molonglo Observatory Synthesis Telescope) radio telescope in Hoskinstown, near the Molonglo River, in Australia, confirmed the signals come from space.

So, what are they? At this time the speculation is leaning toward…well, not really anything. The candidates are:

  • Magnetars: Magnetars are a special class of Neutron star that spin wildly and have immensely strong magnetic fields. They are thought to go through convulsions periodically as the magnetic fields and spin cause their surface to fracture, releasing a blast of energy.
  • Merging Neutron stars or Black Holes: These mergers produce gravitational waves as well and release immense energy.
  • Gamma Ray Burst (GRB) Association: GRBs are the most energetic events we know about, occurring in very distant galaxies, we’re talking about billions of light years away! But guess what, candidates for GRBs include Magnetars, and Wolf-Rayet stars (high-mass stars near the end of their lives – on the verge of becoming a black hole), or black holes in the process of forming.
  • Extraterrestrial Intelligence: An advanced civilization might have the ability to mimic violent natural phenomena, maybe used to communicate or to misdirect?

So far, over 800 FRBs have been detected, more every day. The farthest, from 8 billion light years away! Another big challenge, getting an optical image to confirm the radio image since the bursts last but seconds at best…but so far, the Hubble Space Telescope has imaged galaxies with repeating FRBs and found what appears to be the optical equivalent. We’ll see.

What’s in the Sky? – Daylight Savings Ends on November 5th, at 2am

The five gas giants are lined up in our southern sky so get binoculars, spotter, telescope. Go out about an hour after sunset. Saturn and Neptune are south, Jupiter and Uranus are southeast. See the chart below. See the Pleiades to the upper left (east) of Uranus.