Repeating “Fast Radio Bursts” Detected in Another Galaxy — Probably Not Aliens, Interesting Anyway

green-bank
The Green Bank Radio Telescope (NRAO)

A radio astronomy project intended to find signals from intelligent aliens has announced the intriguing detections of “repeating” fast radio bursts (FRBs) from a single source in a galaxy three billion light-years distant. This is definitely an exciting development, but probably not for the reasons you think.

The ambitious $100 million Breakthrough Listen project aims to scan a million stars in our galaxy and dozens of nearby galaxies across radio frequencies and visible light in hopes of discovering a bona fide artificial signal that could be attributed to an advanced alien civilization. But in its quest, Breakthrough Listen has studied the signals emanating from FRB 121102 — and recorded 15 bursts — to better understand what might be causing it.

FRBs remain a mystery. First detected by the Parkes Radio Telescope in Australia, these very brief bursts of radio emissions seemed to erupt from random locations in the sky. But the same location never produced another FRB, making these bizarre events very difficult to understand and impossible to track.

Hypotheses ranged from powerful bursts of energy from supernovae to active galactic nuclei to (you guessed it) aliens, but until FRB 121102 repeated itself in 2015, several of these hypotheses could be ruled out. Supernovae, after all, only have to happen once — this FRB source is repeating, possibly hinting at a periodic energetic phenomenon we don’t yet understand. Also, because FRB 121102 is a repeater, in 2016 astronomers could trace back the location of its source to a dwarf galaxy 3 billion light-years from Earth.

Now we ponder the question: What in the universe generates powerful short bursts of radio emissions from inside a dwarf galaxy, repeatedly?

Using the Green Bank Telescope in the West Virginia, scientists of Breakthrough Listen recorded 400 TB of data over a five hour period on Aug. 26. In these data, 15 FRBs were recorded across the 4 to 8 GHz radio frequency band. The researchers noted the characteristic frequency dispersion of these FRBs, caused by the signal traveling through gas between us and the source.

Now that we have dedicated and extremely detailed measurements of this set of FRBs, astrophysicists can get to work trying to understand what natural phenomenon is generating these bursts. This is the story so far, but as we’re talking radio emissions, mysteries and a SETI project, aliens are never far away…

Probably Not Aliens

It may be exciting to talk about the possibility of aliens generating this signal — as a means of communication or, possibly, transportation via beamed energy — but that avenue of speculation is just that: speculation. But to speculate is understandable. FRBs are very mysterious and, so far, astrophysicists don’t have a solid answer.

But this mystery isn’t without precedent.

In 1967, astronomers Jocelyn Bell Burnell and Antony Hewish detected strange radio pulses emanating from a point in the sky during a quasar survey to study interplanetary scintillation (IPS). The mysterious pulses had an unnaturally precise period of 1.33 seconds. At the time, nothing like it had been recorded and the researchers were having a hard time explaining the observations. But in the back of their minds, they speculated that, however unlikely, the signal might be produced by an alien intelligence.

During a dinner speech in 1977, Bell Burnell recalled the conundrum they faced:

“We did not really believe that we had picked up signals from another civilization, but obviously the idea had crossed our minds and we had no proof that it was an entirely natural radio emission. It is an interesting problem – if one thinks one may have detected life elsewhere in the universe how does one announce the results responsibly? Who does one tell first? We did not solve the problem that afternoon, and I went home that evening very cross here was I trying to get a Ph.D. out of a new technique, and some silly lot of little green men had to choose my aerial and my frequency to communicate with us.”

This first source was nicknamed “LGM-1” (as in “Little Green Men-1”), but far from being an artificial source, the duo had actually identified the first pulsar — a rapidly-spinning, highly magnetized neutron star that generates powerful emissions from its precessing magnetic poles as it rotates.

This is how science works: An interesting signal is detected and theories are formulated as to how that signal could have been generated.

In the case of LGM-1, it was caused by an as-yet-to-be understood phenomenon involving a rapidly-spinning stellar corpse. In the case of FRB 121102, it is most likely an equally as compelling phenomenon, only vastly more powerful.

The least likely explanation of FRB 121102 makes a LOT of assumptions, namely: aliens that have become so incredibly technologically advanced (think type II or even type III on the Kardashev Scale) that they can fire a (presumably) narrow beam directly at us through intergalactic space over and over again (to explain the repeated FRB detections) — the odds of which would be vanishingly low — unless the signal is omnidirectional, so they’d need to access way more energy to make this happen. Another assumption could be that intelligent, technologically advanced civilizations are common, so it was only a matter of time before we saw a signal like FRB 121102.

Or it could be a supermassive black hole (say) doing something very energetic that science can’t yet explain.

Occam’s razor suggests the latter might be more reasonable.

This isn’t to say aliens don’t exist or that intelligent aliens aren’t transmitting radio signals, it just means the real cause of this particular FRB repeater is being generated by a known phenomenon doing something unexpected, or a new (and potentially more exciting) phenomenon that’s doing something exotic and new. It doesn’t always have to be aliens.

h/t:

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We’re Really Confused Why Supermassive Black Holes Exist at the Dawn of the Cosmos

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ESO

Supermassive black holes can be millions to billions of times the mass of our sun. To grow this big, you’d think these gravitational behemoths would need a lot of time to grow. But you’d be wrong.

When looking back into the dawn of our universe, astronomers can see these monsters pumping out huge quantities of radiation as they consume stellar material. Known as quasars, these objects are the centers of primordial galaxies with supermassive black holes at their hearts.

Now, using the twin W. M. Keck Observatory telescopes on Hawaii, researchers have found three quasars all with billion solar mass supermassive black holes in their cores. This is a puzzle; all three quasars have apparently been active for short periods and exist in an epoch when the universe was less than a billion years old.

Currently, astrophysical models of black hole accretion (basically models of how fast black holes consume matter — likes gas, dust, stars and anything else that might stray too close) woefully overestimate how long it takes for black holes to grow to supermassive proportions. What’s more, by studying the region surrounding these quasars, researchers at the Max Planck Institute for Astronomy (MPIA) in Germany have found that these quasars have been active for less than 100,000 years.

To put it mildly, this makes no sense.

“We don’t understand how these young quasars could have grown the supermassive black holes that power them in such a short time,” said lead author Christina Eilers, a post-doctorate student at MPIA.

Using Keck, the team could take some surprisingly precise measurements of the quasar light, thereby revealing the conditions of the environment surrounding these bright baby galaxies.

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MPIA

Models predict that after forming, quasars began funneling huge quantities of matter into the central black holes. In the early universe, there was a lot of matter in these baby galaxies, so the matter was rapidly consumed. This created superheated accretion disks that throbbed with powerful radiation. The radiation blew away a comparatively empty region surrounding the quasar called a “proximity zone.” The larger the proximity zone, the longer the quasar had been active and therefore the size of this zone can be used to gauge the age (and therefore mass) of the black hole.

But the proximity zones measured around these quasars revealed activity spanning less than 100,000 years. This is a heartbeat in cosmic time and nowhere near enough time for a black hole pack on the supermassive pounds.

“No current theoretical models can explain the existence of these objects,” said Joseph Hennawi, who led the MPIA team. “The discovery of these young objects challenges the existing theories of black hole formation and will require new models to better understand how black holes and galaxies formed.”

The researchers now hope to track down more of these ancient quasars and measure their proximity zones in case these three objects are a fluke. But this latest twist in the nature of supermassive black holes has only added to the mystery of how they grow to be so big and how they relate to their host galaxies.

Supermassive black hole with torn-apart star (artist’s impress
A supermassive black hole consumes a star in this artist’s impression (ESO)

These questions will undoubtedly reach fever-pitch later this year when the Event Horizon Telescope (EHT) releases the first radio images of the 4 million solar mass black hole lurking at the center of our galaxy. Although it’s a relative light-weight among supermassives, direct observations of Sagittarius A* may uncover some surprises as well as confirm astrophysical models.

But as for how supermassive black holes can possibly exist at the dawn of our universe, we’re obviously missing something — a fact that is as exciting as it is confounding.

Why Are Clandestine Space Launches So Sexy?

A Delta IV Heavy launches... but to where? (AFSC)
A Delta IV Heavy launches... but to where? (AFSC)

Last weekend (Saturday, Jan. 17th), one of the most powerful rockets on the planet thundered to life at Cape Canaveral Air Force Station, carrying something into space. Although the world has a good idea as to what this something was, it was a reminder that even during these times of intense media scrutiny and the guise of government transparency that there is a lot going on in space that we may never know about. However, far from clandestine launches at the dead of night being a bad thing, they appear to whet the worlds appetite for finding out more about the top secret military payloads routinely being put into orbit…
Continue reading “Why Are Clandestine Space Launches So Sexy?”

A Mystery Aurora above Saturn’s Mysterious North Pole Hexagon

The aurora above Saturn's North Pole hexagon (NASA)

Not only does Saturn have a mysterious hexagonal shape etched into the bands of cloud above its north pole, it also has a unique magnetic structure. This is suggested by recent results recorded by the NASA Cassini probe that passed over the pole to see a huge active auroral region, much larger and more dynamic than expected. Interestingly, the NASA press release has not linked the strange aurora with the long-lived hexagonal shape in the gas giant’s atmosphere. Could the hexagon be formed by a unique magnetic structure above Saturn? Or could both phenomena be connected in some other way?
Continue reading “A Mystery Aurora above Saturn’s Mysterious North Pole Hexagon”

Tune into Paranormal Radio with Captain Jack Tonight at 9pm (EST): 10 Mysteries of the Solar System

Paranormal Radio with Captain Jack logo
Paranormal Radio with Captain Jack logo

For my fourth appearance on Captain Jack’s Paranormal Radio show, I’ve been invited back to discuss a recent Universe Today article I wrote detailing some of my favourite Solar System mysteries. These mysteries include the coronal heating problem, the “Mars Curse” and Uranus’ tilt. I don’t have many answers, but there should be some surprises thrown in. Most likely Jack and I will meander into different topics, so it should be fun to listen in!

For more information on the show, see tonight’s profile. Remember, the show will be airing live over several US cities, satellite radio and the Internet. For more information on where it will be airing, check out the Paranormal Radio homepage. To listen to the live podcast, starting at 6pm (PST), 9pm (EST) or 2am (GMT), download the .pls file to activate your podcast-listening software, or use the popup Media Player (plugin needed).

Cheers! Ian