The Parkes radio telescope, one of the telescopes comprising CSIRO’s Australia Telescope National Facility. Credit: CSIRO
This year’s International Astronautical Congress is being held in Adelaide, Australia and the opening ceremonies of this meeting of ‘all things space’ included a special announcement. The Australian government announced that it will establish a new national space agency, with the hopes of growing Australia’s already vibrant space industry.
Michaelia Cash, Australian’s acting Minister of Industry, Innovation and Science was quoted as saying that Australia will not have a NASA but an agency “right for our nation, right for our industry … that will provide the vehicle for Australia to have a long-term strategic plan for space – a plan that supports the innovative application of space technologies and grows our domestic space industry, including through defense space procurement.”
Australia’s space industry is worth about $4 billion and already employs about 11,500 people. But proponents for creating a space agency for the country say it will help coordinate and expand the efforts.
Of course Australia has been very active in space exploration, being part of every deep-space mission NASA has flown with tracking and communications as part the Deep Space Network and the precursor system of dishes around the world. The tracking and communications dish at Parkes, Honeysuckle Creek, Tidbinbilla and Canberra were notoriously part of the Apollo missions, and several other large radio dishes in Australia have been listening to space to tease out astronomical details. Additionally, the Square Kilometer Array being built in Australia, New Zealand and South Africa will help us answer fundamental questions in astronomy and cosmology.
But still, many have said that Australia is one of the few major developed countries that do not have a space agency. New Zealand established their space agency last year. You can see a list of all the world’s space agencies from Heather Archuletta’s Pillownaut website.
Reportedly, the plan is to double the size of Australia’s current space capacity within five years and add thousands of new jobs, while taking advantage of new technology such as cubesats.
“We have longstanding ties with NASA, exploring space together and generating all of these jobs. And that’s the key point, it is a jobs industry-first agency,” astrophysicist Alan Duffy told ABC. “It’s designed to create satellites and new uses for the images that come from those satellites, and I don’t mean giant, bus-sized satellites of the ‘60s and ‘70s. Thanks to smartphones something the size of a toaster has the same capabilities as some of these historic launches. So we get to space cheaper and we can do more when we’re there.”
Reportedly, more details of the new space agency will be announced this week during the IAC, which is a gathering of thousands of global space experts, heads of other space agencies and private companies.
An artist's impression of the cosmic web, the filamentary structure that fills the entire Universe. Credit: M. Weiss/CfA
When astronomers first noted the detection of a Fast Radio Burst (FRB) in 2007 (aka. the Lorimer Burst), they were both astounded and intrigued. This high-energy burst of radio pulses, which lasted only a few milliseconds, appeared to be coming from outside of our galaxy. Since that time, astronomers have found evidence of many FRBs in previously-recorded data, and are still speculating as to what causes them.
Thanks to subsequent discoveries and research, astronomers now know that FRBs are far more common than previously thought. In fact, according to a new study by a team of researchers from the Harvard-Smithsonian Center for Astrophysics (CfA), FRBs may occur once every second within the observable Universe. If true, FRBs could be a powerful tool for researching the origins and evolution of the cosmos.
As noted, FRBs have remained something of a mystery since they were first discovered. Not only do their causes remain unknown, but much about their true nature is still not understood. As Dr. Fialkov told Universe Today via email:
“FRBs (or fast radio bursts) are astrophysical signals of an undetermined nature. The observed bursts are short (or millisecond duration), bright pulses in the radio part of the electromagnetic spectrum (at GHz frequencies). Only 24 bursts have been observed so far and we still do not know for sure which physical processes trigger them. The most plausible explanation is that they are launched by rotating magnetized neutron stars. However, this theory is to be confirmed.”
For the sake of their study, Fialkov and Loeb relied on observations made by multiple telescopes of the repeating fast radio burst known as FRB 121102. This FRB was first observed in 2012 by researchers using the Arecibo radio telescope in Puerto Rico, and has since been confirmed to be coming from a galaxy located 3 billion light years away in the direction of the Auriga constellation.
Since it was discovered, additional bursts have been detected coming from its location, making FRB 121102 the only known example of a repeating FRB. This repetitive nature has also allowed astronomers to conduct more detailed studies of it than any other FRB. As Prof. Loeb told Universe Today via email, these and other reasons made it an ideal target for their study:
“FRB 121102 is the only FRB for which a host galaxy and a distance were identified. It is also the only repeating FRB source from which we detected hundreds of FRBs by now. The radio spectrum of its FRBs is centered on a characteristic frequency and not covering a very broad band. This has important implications for the detectability of such FRBs, because in order to find them the radio observatory needs to be tuned to their frequency.”
Image of the sky where the radio burst FRB 121102 was found, in the constellation Auriga. You can see its location with a green circle. At left is supernova remnant S147 and at right, a star formation area called IC 410. Credit: Rogelio Bernal Andreo (DeepSkyColors.com)
Based on what is known about FRB 121102, Fialkov and Loeb conducted a series of calculations that assumed that it’s behavior was representative of all FRBs. They then projected how many FRBs would exist across the entire sky and determined that within the observable Universe, a FRB would likely be taking place once every second. As Dr. Fialkov explained:
“Assuming that FRBs are produced by galaxies of a particular type (e.g., similar to FRB 121102) we can calculate how many FRBs have to be produced by each galaxy to explain the existing observations (i.e., 2000 per sky per day). With this number in mind we can infer the production rate for the entire population of galaxies. This calculation shows that an FRB occurs every second when accounting for all the faint events.”
While the exact nature and origins of FRBs are still unknown – suggestions include rotating neutron stars and even alien intelligence! – Fialkov and Loeb indicate that they could be used to study the structure and evolution of the Universe. If indeed they occur with such regular frequency throughout the cosmos, then more distant sources could act as probes which astronomers would then rely on to plumb the depths of space.
For instance, over vast cosmic distances, there is a significant amount of intervening material that makes it difficult for astronomers to study the Cosmic Microwave Background (CMB) – the leftover radiation from the Big Bang. Studies of this intervening material could lead to a new estimates of just how dense space is – i.e. how much of it is composed of ordinary matter, dark matter, and dark energy – and how rapidly it is expanding.
Gemini composite image of the field around FRB 121102, the only repeating FRB discovered so far. Credit: Gemini Observatory/AURA/NSF/NRC
And as Prof. Loeb indicated, FRBs could also be used to explore enduring cosmlogical questions, like how the “Dark Age” of the Universe ended:
“FRBs can be used to measure the column of free electrons towards their source. This can be used to measure the density of ordinary matter between galaxies in the present-day universe. In addition, FRBs at early cosmic times can be used to find out when the ultraviolet light from the first stars broke up the primordial atoms of hydrogen left over from the Big Bang into their constituent electrons and protons.”
The “Dark Age”, which occurred between 380,000 and 150 million years after the Big Bang, was characterized by a “fog” of hydrogen atoms interacting with photons. As a result of this, the radiation of this period is undetectable by our current instruments. At present, scientists are still attempting to resolve how the Universe made the transition between these “Dark Ages” and subsequent epochs when the Universe was filled with light.
This period of “reionization”, which took place 150 million to 1 billion years after the Big Bang, was when the first stars and quasars formed. It is generally believed that UV light from the first stars in the Universe traveled outwards to ionize the hydrogen gas (thus clearing the fog). A recent study also suggested that black holes that existed in the early Universe created the necessary “winds” that allowed this ionizing radiation to escape.
To this end, FRBs could be used to probe into this early period of the Universe and determine what broke down this “fog” and allowed light to escape. Studying very distant FRBs could allow scientists to study where, when and how this process of “reionization” occurred. Looking ahead, Fialkov and Loeb explained how future radio telescopes will be able to discover many FRBs.
The planned Square Kilometer Array will be the world’s largest radio telescope when it begins operations in 2018. Credit: SKA
“Future radio observatories, like the Square Kilometer Array, will be sensitive enough to detect FRBs from the first generation of galaxies at the edge of the observable universe,” said Prof. Loeb. “Our work provides the first estimate of the number and properties of the first flashes of radio waves that lit up in the infant universe.”
And then there’s the Canadian Hydrogen Intensity Mapping Experiment (CHIME) at the at the Dominion Radio Astrophysical Observatory in British Columbia, which recently began operating. These and other instruments will serve as powerful tools for detecting FRBs, which in turn could be used to view previously unseen regions of time and space, and unlock some of the deepest cosmological mysteries.
“[W]e find that a next generation telescope (with a much better sensitivity than the existing ones) is expected to see many more FRBs than what is observed today,” said Dr. Fialkov. “This would allow to characterize the population of FRBs and identify their origin. Understanding the nature of FRBs will be a major breakthrough. Once the properties of these sources are known, FRBs can be used as cosmic beacons to explore the Universe. One application is to study the history of reionization (cosmic phase transition when the inter-galactic gas was ionized by stars).”
It is an inspired thought, using natural cosmic phenomena as research tools. In that respect, using FRBs to probe the most distant objects in space (and as far back in time as we can) is kind of like using quasars as navigational beacons. In the end, advancing our knowledge of the Universe allows us to explore more of it.
The Karl G. Jansky Very Large Array, located in central New Mexico. Credit: NRAO
In July of 2015, Russian billionaire Yuri Milner announced the creation of Breakthrough Listen, a decade-long project that would conduct the largest survey to date for signs of extra-terrestrial communications (ETI). As part of his non-profit organization, Breakthrough Initiatives, this survey would rely on the latest in instrumentation and software to observe the 1,000,000 closest stars and 100 closest galaxies.
Using the Green Bank Radio Telescope in West Virginia, the Listen science team at UC Berkeley has been observing distant stars for over a year now. And less than a week ago, they observed 15 Fast Radio Bursts (FRBs) coming from a dwarf galaxy located three billion light-years away. According to a study that described their findings, this was the first time that repeating FRBs have been seen coming from this source at these frequencies.
The team’s study, titled “FRB 121102: Detection at 4 – 8 GHz band with Breakthrough Listen backend at Green Bank“, was recently published in The Astronomers Telegraph. Led by Dr. Vishal Gajjar – a postdoctoral researcher at the University of California, Berkeley – the team conducted a detailed survey of FRB 121102. This repeating FRB source is located in a dwarf galaxy in Auriga constellation, some 3 billion light-years from Earth.
The NSF’s Arecibo Observatory, which is located in Puerto Rico, is the world largest radio telescope. Credit: NAIC
To clarify, FRBs are brief, bright pulses of radio waves that are periodically detected coming from distant galaxies. This strange astronomical phenomena was first detected in 2007 by Duncan Lorimer and David Narkovic using the Parkes Telescope in Australia. To honor their discovery, FRBs are sometimes referred to as “Lorimer Bursts”. Many FRB sources have been confirmed since then, some of which were found repeating.
The source known as FRB 121101 was discovered back on November 2nd, 2012, by astronomers using the Arecibo radio telescope. At the time, it was the first FRB to be discovered; and by 2015, it became the first FRB to be seen repeating. This effectively ruled out the possibility that repeating FRBs were caused by catastrophic events, which had previously been theorized.
And in 2016, FRB 121102 was the first FRB to have its location pinpointed to such a degree that its host galaxy could be identified. As such, the Listen science team at UC Berkeley was sure to add FRB 121102 to their list of targets. And in the early hours of Saturday, August 26th, Dr. Vishal Gajjar – a postdoctoral researcher at UC Berkeley – observed FRB 121102 using the Green Bank Radio Telescope (GBRT) in West Virginia.
Using the Digital Backend instrument on the GBRT, Dr. Gajjar and the Listen team observed FRB 121102 for five hours. From this, they accumulating 400 terabytes of data in the entire 4 to 8 GHz frequency band which they then analyzed for signs of short pulses over a broad range of frequencies. What they found was evidence of 15 new pulses coming from FRB 121102, which confirmed that it was in a newly active state.
The Green Bank Telescope, located in West Virginia. Credit: NRAO
In addition, their observations revealed that the brightest of these 15 emissions occurred at around 7 GHz. This was higher than any repeating FRBs seen to date, which indicated for the first time that they can occur at frequencies higher than previously thought. Last, but not least, the high-resolution data the Listen team collected is expected to yield valuable insights into FRBs for years to come.
This was made possible thanks to the Digital Backend instrument on the GBRT, which is able to record several GHz of bandwidth simultaneously and split the information into billions of individuals channels. This enables scientists to study the proprieties and the frequency spectrum of FRBs with greater precision, and should lead to new theories about the causes of these radio emissions.
So even if these particular signals should prove to not be an indication of extra-terrestrial intelligence, Listen is still pushing the boundaries of what is possible with radio astronomy. And given that Breakthrough Listen is less than two years into its proposed ten-year survey, we can expect many more sources to be observed and studied in the coming years. If there’s evidence of ETI to be found, we’re sure to find out about it sooner or later!
And be sure to check out this video of the Green Bank Telescope and the surveys it allows for, courtesy of Berkeley SETI:
Artist's impression of rocky exoplanets orbiting Gliese 832, a red dwarf star just 16 light-years from Earth. Credit: ESO/M. Kornmesser/N. Risinger (skysurvey.org).
Astronomers have been listening to radio waves from space for decades. In addition to being a proven means of studying stars, galaxies, quasars and other celestial objects, radio astronomy is one of the main ways in which scientists have searched for signs of extra-terrestrial intelligence (ETI). And while nothing definitive has been found to date, there have been a number of incidents that have raised hopes of finding an “alien signal”.
In the most recent case, scientists from the Arecido Observatory recently announced the detection of a strange radio signal coming from Ross 128 – a red dwarf star system located just 11 light-years from Earth. As always, this has fueled speculation that the signal could be evidence of an extra-terrestrial civilization, while the scientific community has urged the public not to get their hopes up.
The discovery was part of a campaign being conducted by Abel Méndez – the director of the Planetary Habitability Laboratory (PHL) in Peurto Rico – and Jorge Zuluaga of the Faculty of Exact and Natural Sciences at the University of Antioquia, Colombia. Inspired by the recent discoveries around Proxima Centauri and TRAPPIST-1, the GJ 436 campaign relied on data from Arecibo Observatory to look for signs of exoplanets around nearby red dwarf stars.
Arecibo Observatory, the world’s biggest single dish radio telescope, was and is still being used to image comet 45P/H-M-P. Courtesy of the NAIC – Arecibo Observatory, a facility of the NSF
In the course of looking at data from stars systems like Gliese 436, Ross 128, Wolf 359, HD 95735, BD +202465, V* RY Sex, and K2-18 – which was gathered between April and May of 2017 – they noticed something rather interesting. Basically, the data indicated that an unexplained radio signal was coming from Ross 128. As Dr. Abel Mendez described in a blog post on the PHL website:
“Two weeks after these observations, we realized that there were some very peculiar signals in the 10-minute dynamic spectrum that we obtained from Ross 128 (GJ 447), observed May 12 at 8:53 PM AST (2017/05/13 00:53:55 UTC). The signals consisted of broadband quasi-periodic non-polarized pulses with very strong dispersion-like features. We believe that the signals are not local radio frequency interferences (RFI) since they are unique to Ross 128 and observations of other stars immediately before and after did not show anything similar.”
They also conducted observations of Barnard’s star on that same day to see if they could note similar behavior coming from this star system. This was done in collaboration with the Red Dots project, a European Southern Observatory (ESO) campaign that is also committed to finding exoplanets around red dwarf stars. This program is the successor to the ESO’s Pale Red Dot campaign, which was responsible for discovering Proxima b last summer.
Images of the star systems examined by the GJ 436 Campaign. Credit: PHL/Abel Méndez
As of Monday night (July 17th), Méndez updated his PHL blog post to announced that with the help of SETI Berkeley with the Green Bank Telescope, that they had successfully observed Ross 128 for the second time. The data from these observatories is currently being collected and processed, and the results are expected to be announced by the end of the week.
In the meantime, scientists have come up with several possible explanations for what might be causing the signal. As Méndez indicated, there are three major possibilities that he and his colleagues are considering:
“[T]hey could be (1) emissions from Ross 128 similar to Type II solar flares, (2) emissions from another object in the field of view of Ross 128, or just (3) burst from a high orbit satellite since low orbit satellites are quick to move out of the field of view. The signals are probably too dim for other radio telescopes in the world and FAST is currently under calibration.”
Unfortunately, each of these possibilities have their own drawbacks. In the case of a Type II solar flare, these are known to occur at much lower frequencies, and the dispersion of this signal appears to be inconsistent with this kind of activity. In the case of it possibly coming from another object, no objects (planets or satellites) have been detected within Ross 128’s field of view to date, thus making this unlikely as well.
The stars currently being examined as part of the GJ 436 campaign. Credit: PHL/Abel Méndez
Hence, the team has something of a mystery on their hands, and hopes that further observations will allow them to place further constrains on what the cause of the signal could be. “[W]e might clarify soon the nature of its radio emissions, but there are no guarantees,” wrote Méndez. “Results from our observations will be presented later that week. I have a Piña Colada ready to celebrate if the signals result to be astronomical in nature.”
And just to be fair, Méndez also addressed the possibility that the signal could be artificial in nature – i.e. evidence of an alien civilization. “In case you are wondering,” he wrote, “the recurrent aliens hypothesis is at the bottom of many other better explanations.” Sorry, alien-hunters. Like the rest of us, you’ll just have to wait and see what can be made of this signal.
Stardust in the Perseus Molecular Cloud, a star-forming region in the Perseus constellation. Credit & Copyright: Lorand Fenyes
For us Earthlings, life under a single Sun is just the way it is. But with the development of modern astronomy, we’ve become aware of the fact that the Universe is filled with binary and even triple star systems. Hence, if life does exist on planets beyond our Solar System, much of it could be accustomed to growing up under two or even three suns. For centuries, astronomers have wondered why this difference exists and how star systems came to be.
Whereas some astronomers argue that individual stars formed and acquired companions over time, others have suggested that systems began with multiple stars and lost their companions over time. According to a new study by a team from UC Berkeley and the Harvard-Smithsonian Center for Astrophysics (CfA), it appears that the Solar System (and other Sun-like stars) may have started out as binary system billions of years ago.
This study, titled “Embedded Binaries and Their Dense Cores“, was recently accepted for publication in the Monthly Notices of the Royal Astronomical Society. In it, Sarah I. Sadavoy – a radio astronomer from the Max Planck Institute for Astronomy and the CfA – and Steven W. Stahler (a theoretical physicist from UC Berkeley) explain how a radio surveys of a star nursery led them to conclude that most Sun-like stars began as binaries.
The dark molecular cloud, Barnard 68, is a stellar nursery that can only be studied using radio astronomy. Credit: FORS Team, 8.2-meter VLT Antu, ESO
For several decades, astronomers have known that stars are born inside “stellar nurseries”, which are the dense cores that exist within immense clouds of dust and cold, molecular hydrogen. These clouds look like holes in the star field when viewed through an optical telescope, thanks to all the dust grains that obscure light coming from the stars forming within them and from background stars.
Radio surveys are the only way to probe these star-forming regions, since the dust grains emit radio transmissions and also do not block them. For years, Stahler has been attempting to get radio astronomers to examine molecular clouds in the hope of gathering information on the formation of young stars inside them. To this end, he approached Sarah Sadavoy – a member of the VANDAM team – and proposed a collaboration.
The two began their work together by conducting new observations of both single and binary stars within the dense core regions of the Perseus cloud. As Sadavoy explained in a Berkeley News press release, the duo were looking for clues as to whether young stars formed as individuals or in pairs:
“The idea that many stars form with a companion has been suggested before, but the question is: how many? Based on our simple model, we say that nearly all stars form with a companion. The Perseus cloud is generally considered a typical low-mass star-forming region, but our model needs to be checked in other clouds.”
Infrared image from the Hubble Space Telescope, showing a bright, fan-shaped object (lower right quadrant) thought to be a binary star that emits light pulses as the two stars interact. Credit: NASA/ESA/ J. Muzerolle (STScI)
Their observations of the Perseus cloud revealed a series of Class 0 and Class I stars – those that are <500,000 old and 500,000 to 1 million years old, respectively – that were surrounded by egg-shaped cocoons. These observations were then combined with the results from VANDAM and other surveys of star forming regions – including the Gould Belt Survey and data gathered by SCUBA-2 instrument on the James Clerk Maxwell Telescope in Hawaii.
From this, they created a census of stars within the Perseus cloud, which included 55 young stars in 24 multiple-star systems (all but five of them binary) and 45 single-star systems. What they observed was that all of the widely separated binary systems – separated by more than 500 AU – were very young systems containing two Class 0 stars that tended to be aligned with the long axis of their egg-shaped dense cores.
Meanwhile, the slightly older Class I binary stars were closer together (separated by about 200 AU) and did not have the same tendency as far as their alignment was concerned. From this, the study’s authors began mathematically modelling multiple scenarios to explain this distribution, and concluded that all stars with masses comparable to our Sun start off as wide Class 0 binaries. They further concluded that 60% of these split up over time while the rest shrink to form tight binaries.
“As the egg contracts, the densest part of the egg will be toward the middle, and that forms two concentrations of density along the middle axis,” said Stahler. “These centers of higher density at some point collapse in on themselves because of their self-gravity to form Class 0 stars. “Within our picture, single low-mass, sunlike stars are not primordial. They are the result of the breakup of binaries. ”
The two brightest stars of the Centaurus constellation, the binary star system of Alpha Centauri. Credit: Wikipedia Commons/Skatebiker
Findings of this nature have never before been seen or tested. They also imply that each dense core within a stellar nursery (i.e. the egg-shaped cocoons, which typically comprise a few solar masses) converts twice as much material into stars as was previously thought. As Stahler remarked:
“The key here is that no one looked before in a systematic way at the relation of real young stars to the clouds that spawn them. Our work is a step forward in understanding both how binaries form and also the role that binaries play in early stellar evolution. We now believe that most stars, which are quite similar to our own sun, form as binaries. I think we have the strongest evidence to date for such an assertion.”
This new data could also be the start of a new trend, where astronomers rely on radio telescopes to examine dense star-forming regions with the hopes of witnessing more in the way of stellar formations. With the recent upgrades to the VLA and the Atacama Large Millimeter/submillimeter Array (ALMA) in Chile, and the ongoing data provided by the SCUBA-2 survey in Hawaii, these studies may be coming sooner other than later.
Another interesting implication of the study has to do with something known as the “Nemesis hypothesis”. In the past, astronomers have conjectured that a companion star named “Nemesis” existed within our Solar System. This star was so-named because the theory held that it was responsible for kicking the asteroid which caused the extinction of the dinosaurs into Earth’s orbit. Alas, all attempts to find Nemesis ended in failure.
Artist’s impression of the binary star system of Sirius, a white dwarf star in orbit around Sirius (a white supergiant). Credit: NASA, ESA and G. Bacon (STScI)
As Steven Stahler indicated, these findings could be interpreted as a new take on the Nemesis theory:
“We are saying, yes, there probably was a Nemesis, a long time ago. We ran a series of statistical models to see if we could account for the relative populations of young single stars and binaries of all separations in the Perseus molecular cloud, and the only model that could reproduce the data was one in which all stars form initially as wide binaries. These systems then either shrink or break apart within a million years.”
So while their results do not point towards a star being around for the extinction of the dinosaurs, it is possible (and even highly plausible) that billions of years ago, the Solar planets orbited around two stars. One can only imagine what implications this could have for the early history of the Solar System and how it might have affected planetary formation. But that will be the subject of future studies, no doubt!
A new study from the Center for Planetary Science claims that a comet may be responsible fr the famous Wow! Signal. Credit: NASA/JPL-Caltech
On August 15th, 1977, astronomers using the Big Ear radio telescope at Ohio State University detected a 72-second radio signal coming from space. This powerful signal, which quickly earned the nickname the “Wow! signal”, appeared to be coming from the direction of the Sagittarius Constellation, and some went so far as to suggest that it might be extra-terrestrial in origin.
Since then, the Wow! signal has been an ongoing source of controversy among SETI researchers and astronomers. While some have maintained that it is evidence of extra-terrestrial intelligence (ETI), others have sought to find a natural explanation for it. And thanks a team of researchers from the Center of Planetary Science (CPS), a natural explanation may finally have been found.
In the past, possible explanations have ranged from asteroids and exoplanets to stars and even signals from Earth – but these have all been ruled out. And then in 2016, the Center for Planetary Science – a Florida-based non-profit scientific and astronomical organization – proposed a hypothesis arguing that a comet and/or its hydrogen cloud could be the cause.
This was based on the fact that the Wow! signal was transmitting at a frequency of 1,420 MHz, which happens to be the same frequency as hydrogen. This explanation was also appealing because the movement of the comet served as a possible explanation for why the signal has not been detected since. To validate this hypothesis, the CPS team reportedly conducted 200 observations using a 10-meter radio telescope.
This telescope, they claim, was equipped with a spectrometer and a custom feed horn designed to collect a radio signal centered at 1420.25 MHz. Between Nov. 27th, 2016, and Feb. 24th, 2017, they monitored the area of space where the Wow! signal was detected, and found that a pair of Solar comets (which had not been discovered in 1977) happened to conform to their observations, and could therefore have been the source.
Spectra obtained from these comets – P/2008 Y2(Gibbs) and 266/P Christensen – indicated that they were emitting a radio frequency that was consistent with the Wow! signal. As Antonio Paris (a professor at the CPS), described in a recent paper that appeared in the Journal of the Washington Academy of Sciences:
“The investigation discovered that comet 266/P Christensen emitted a radio signal at 1420.25 MHz. All radio emissions detected were within 1° (60 arcminutes) of the known celestial coordinates of the comet as it transited the neighborhood of the ‘Wow!’ Signal. During observations of the comet, a series of experiments determined that known celestial sources at 1420 MHz (i.e., pulsars and/or active galactic nuclei) were not within 15° of comet 266/P Christensen.”
The Wow! signal represented as “6EQUJ5”. Credit: Big Ear Radio Observatory/NAAPO
The team also examined three other comets to see if they emitted similar radio signals. These comets – P/2013 EW90 (Tenagra), P/2016 J1-A (PANSTARRS), and 237P/LINEAR – were selected randomly from the JPL Small Bodies database, and were confirmed to emit a radio signal at 1420 MHz. Therefore, the results of this investigation conclude that the 1977 “Wow!” Signal was a natural phenomenon from a Solar System body.
However, not everyone is convinced. In response to the paper, Yvette Cendes – a PhD student with the Dunlap Institute at the University of Toronto – wrote a lengthy response on reddit as to why it fails to properly address the Wow! signal. For starters, she cites how the research team measured the signal strength in terms of decibels:
“I have never, ever, EVER used dB in a paper, nor have I ever read a paper in radio astronomy that measured signal strength in dB (except perhaps in the context of an instrumentation paper describing the systems of a radio telescope, i.e. not science but engineering.) We use a different unit in astronomy for flux density, the Jansky (Jy), where 1 Jy= ?230 dBm/(m2·Hz). (dB is a log scale, and Janskys are not.)”
Another point of criticism is the lack of detail in the paper, which would make reproducing the results very difficult – a central requirement where scientific research is concerned. Specifically, they do not indicate where the 10-meter radio telescope they used came from – i.e. which observatory of facility it belonged to, or even if it belonged to one at all – and are rather vague about its technical specification.
Spectra obtained from an area in the direction of the Sagittarius constellation. Credit: The Center for Planetary Science
Last, but not least, there is the matter of the environment in which the observations took place, which are not specified. This is also very important for radio astronomy, as it raised the issue of interference. As Cendes put it:
“This might sound pedantic, but this is insanely important in radio astronomy, where most signals we ever search for are a tiny fraction of the man-made ones, which can be millions of times brighter than an astronomical signal. (A cell phone on the moon would be one of the brighter radio astronomy sources in the sky, to give you an idea!) Radio Frequency Interference (RFI) is super important for the field, so much that people can spend their careers on it (I’ve written a chapter on my thesis on this myself), and the “radio environment” of an observatory can be worth a paper in itself.”
Beyond these apparent incongruities, Cendes also states that the hypothesis for the experiment was flawed. Essentially, the Big Ear searched for the same signal for a period of 22 years, but found nothing. If the comet hypothesis held true, there should be an explanation as to why no trace of the signal was found until this time. Alas, one is lacking, as far as this most recent study is concerned.
“And now you likely have an idea on why one-off events are so hard to prove in science,” she claims. “But then, this is really the major reason the Wow! signal is unsolved to this day- without a plausible explanation, [without] additional data, we just will never know.”
Though it may be hard to accept, it is entirely possible that we may never know what the Wow! signal truly was – whether it was a one-off event, a naturally-occurring phenomena, or something else entirely. And if the comet hypothesis should prove to be unverifiable, then that is certainly good news for the SETI enthusiasts!
While the elimination of natural explanations doesn’t prove that things like Wow! signal are proof of alien civilizations, it at least indicates that this possibility cannot be ruled out just yet. And for those hopeful that evidence of intelligent life will be someday found, that’s really the best we can hope for… for now!
Artist’s impression shows three bright red flashes depicting fast radio bursts far beyond the Milky Way, appearing in the constellations Puppis and Hydra, above the Mongolo radio telescope in Australia. Credit: James Josephides/Mike Dalley.
Fast Radio Bursts (FRBs) have puzzled astronomers since they were first detected in 2007. These mysterious milliseconds-long blasts of radio waves appear to be coming from long distances, and have been attributed to various things such as alien signals or extraterrestrial propulsion systems, and more ‘mundane’ objects such as extragalactic neutron stars. Some scientists even suggested they were some type of ‘local’ source, such as atmospheric phenomena on Earth, tricking astronomers about their possible distant origins.
So far, less than two dozen FRBs have been detected in a decade. But now researchers from the Australian National University and Swinburne University of Technology have detected three of these mystery bursts in just six months using the interferometry capabilities of the Molonglo Observatory Synthesis Telescope (MOST) in Canberra, Australia. In doing so, they were able to confirm that these FRBs really do come from outer space.
“Figuring out where the bursts come from is the key to understanding what makes them,” said Manisha Caleb, a PhD candidate at ANU, and lead author of a new paper. “While only one burst has been linked to a specific galaxy we expect Molonglo will do this for many more bursts.”
The unique long and narrow configuration of MOST provides a huge collecting area of about 18,000 square meters for a very large field of view, about 8 square degrees of the sky. In an effort to boost the capabilities of this telescope for hunting for the elusive FRBs, MOST has been upgraded and reconfigured, with the ultimate goal of localizing the bursts down to an individual galaxy.
Caleb produced software to sift through the 1,000 terabytes of data produced by MOST each day, and that allowed her and her team to make the three new FRB discoveries.
They determined the three new FRBs really were from space because the events were well beyond the 10,000 km near-field limit of the telescope, which ruled out local (terrestrial) sources of interference as a possible origin.
Caleb and her team wrote in their paper that they also demonstrated with pulsars that a repeating FRB seen with MOST has the potential to be localized quite precisely, which is “an exciting prospect for identifying the host,” they wrote.
Gemini composite image of the field around FRB 121102, the only repeating FRB discovered so far. Credit: Gemini Observatory/AURA/NSF/NRC.
So far, however, just one FRB has repeated, and although Caleb and her team were able to observe the area of each of the new FRBs for several hours, (105 hours following FRB 160317, 43 hours on FRB 160410 and 35 hours on FRB 160608) they found that “no repeat pulses were found from any of the FRB positions.”
But with the nature and source of these FRBs still being highly debated, the capabilities of MOST and an Australian collaboration called BURST provides the most promising hope for determining what FRBs truly are. The BURST project will perform deep FRB searches with MOSTS’s wide field-of-view and nearly constant single pulse searches of the radio sky. You can read more about the project here.
An artist's illustration of a light-sail powered by a radio beam (red) generated on the surface of a planet. Could the part of the beam that misses the sail be our mysterious Fast Radio Bursts? Image Credit: M. Weiss/CfA
The extremely energetic events that we see out there in the Universe are usually caused by cataclysmic astrophysical events and activities of one sort or another. But what about Fast Radio Bursts? A pair of astrophysicists at Harvard say that the seldom seen phenomena could, maybe, possibly, be evidence of an advanced alien technology.
Fast radio bursts (FRBs) are short-lived radio pulses that last only a few milliseconds. It’s been assumed that they have some astrophysical cause. Fewer than 2 dozen of them have been detected since their discovery in 2007. They’re detected by our huge radio telescopes like the Arecibo Observatory in Puerto Rico, and the Parkes Observatory in Australia. They’re extremely energetic, and their source is a great distance from us.
The NSF’s Arecibo Observatory, which is located in Puerto Rico, is the world largest radio telescope. Arecibo detected 11 FRBs over the course of 2 months. Credit: NAIC
The two astrophysicists, Avi Loeb at the Harvard-Smithsonian Center for Astrophysics, and Manasvi Lingam at Harvard University, decided to investigate the possibility that FRBs have an alien technological origin.
“Fast radio bursts are exceedingly bright given their short duration and origin at great distances, and we haven’t identified a possible natural source with any confidence. An artificial origin is worth contemplating and checking.” – Avi Loeb, Harvard-Smithsonian Center for Astrophysics
I’ll Take ‘Alien Signals’ For $200 Alex
Loeb and Lingam began by calculating how much energy would be needed to send a signal that strong across such an enormous distance. They found that doing so with solar energy requires a solar array with an area twice the surface area of Earth. That would be enough energy, if the alien civilization was as close as we are to a star similar to our Sun.
Obviously, such a massive construction project is well beyond us. But however unlikely it sounds, it can’t be ruled out.
The pair also asked themselves questions about the viability of such a project. Would the heat and energy involved in such a solar array melt the structure itself? Their answer is that water-cooling would be sufficient to keep an array like this operating.
Their next question was, “Why build something like this in the first place?”
I’ll Take ‘Alien Spacecraft Propulsion Systems’ For $400 Alex”
The thinking behind their idea is based on an idea that we ourselves have had: Could we power a spacecraft by pushing on it with lasers? Or Microwaves? If we’ve thought of it, why wouldn’t other existing civilizations? If another civilization were doing it, what would the technology look like?
Their investigation shows that the engineering they’re talking about could power a spacecraft with a payload of a million tons. That would be about 20 times bigger than our largest cruise ship. According to Lingam, “That’s big enough to carry living passengers across interstellar or even intergalactic distances.”
If FRBs are indeed the result of an alien propulsion system, here’s how it would work: Earth is rotating and orbiting, which means the alien star and galaxy are moving relative to us. That’s why we would only see a brief flash. The beam sweeps across the sky and only hits us for a moment. The repeated appearance of the FRB could be a clue to its alien, technological origin.
The authors of the study outlining this thinking know that it’s speculative. But it’s their job to speculate within scientific constraints, which they have done. As they say in the conclusion of their paper, “Although the possibility that FRBs are produced by extragalactic civilizations is more speculative than an astrophysical origin, quantifying the requirements necessary for an artificial origin serves, at the very least, the important purpose of enabling astronomers to rule it out with future data.”
There are other interpretations when it comes to FRBs, of course. The others of another paper say that for at least one group of FRBs, known as FRB 121102, the source is likely astrophysical. According to them, FRBs likely come from “a young, highly magnetized, extragalactic neutron star.”
Lurking behind these papers are some intriguing questions that are also fun to ponder.
If the system required a solar array twice the size of Earth, where would the materials come from? If the system required water-cooling to avoid melting, where would all the water come from? It’s impossible to know, or to even begin speculating. But a civilization able to do something like this would have to be master engineers and resource exploiters. That goes without saying.
Why they might do it is another question. Probably the same reasons we would: curiosity and exploration, or maybe to escape a dying world.
NASA's Spitzer Space Telescope captured this stunning infrared image of the center of the Milky Way Galaxy, where the black hole Sagitarrius A resides. Credit: NASA/JPL-Caltech
It might sound trite to say that the Universe is full of mysteries. But it’s true.
Chief among them are things like Dark Matter, Dark Energy, and of course, our old friends the Black Holes. Black Holes may be the most interesting of them all, and the effort to understand them—and observe them—is ongoing.
That effort will be ramped up in April, when the Event Horizon Telescope (EHT) attempts to capture our first image of a Black Hole and its event horizon. The target of the EHT is none other than Sagittarius A, the monster black hole that lies in the center of our Milky Way Galaxy. Though the EHT will spend 10 days gathering the data, the actual image won’t be finished processing and available until 2018.
The EHT is not a single telescope, but a number of radio telescopes around the world all linked together. The EHT includes super-stars of the astronomy world like the Atacama Large Millimeter Array (ALMA) as well as lesser known ‘scopes like the South Pole Telescope (SPT.) Advances in very-long-baseline-interferometry (VLBI) have made it possible to connect all these telescopes together so that they act like one big ‘scope the size of Earth.
The ALMA array in Chile. Once ALMA was added to the Event Horizon Telescope, it increased the EHT’s power by a factor of 10. Image: ALMA (ESO/NAOJ/NRAO), O. Dessibourg
The combined power of all these telescopes is essential because even though the EHT’s target, Sagittarius A, has over 4 million times the mass of our Sun, it’s 26,000 light years away from Earth. It’s also only about 20 million km across. Huge but tiny.
The EHT is impressive for a number of reasons. In order to function, each of the component telescopes is calibrated with an atomic clock. These clocks keep time to an accuracy of about a trillionth of a second per second. The effort requires an army of hard drives, all of which will be transported via jet-liner to the Haystack Observatory at MIT for processing. That processing requires what’s called a grid computer, which is a sort of virtual super-computer comprised of 800 CPUs.
But once the EHT has done its thing, what will we see? What we might see when we finally get this image is based on the work of three big names in physics: Einstein, Schwarzschild, and Hawking.
A simulation of what the EHT might show us. Image: Event Horizon Telescope Organization
As gas and dust approach the black hole, they speed up. They don’t just speed up a little, they speed up a lot, and that makes them emit energy, which we can see. That would be the crescent of light in the image above. The black blob would be a shadow cast over the light by the hole itself.
Einstein didn’t exactly predict the existence of Black Holes, but his theory of general relativity did. It was the work of one of his contemporaries, Karl Schwarzschild, that actually nailed down how a black hole might work. Fast forward to the 1970s and the work of Stephen Hawking, who predicted what’s known as Hawking Radiation.
Taken together, the three give us an idea of what we might see when the EHT finally captures and processes its data.
Einstein’s general relativity predicted that super massive stars would warp space-time enough that not even light could escape them. Schwarzschild’s work was based on Einstein’s equations and revealed that black holes will have event horizons. No light emitted from inside the event horizon can reach an outside observer. And Hawking Radiation is the theorized black body radiation that is predicted to be released by black holes.
The power of the EHT will help us clarify our understanding of black holes enormously. If we see what we think we’ll see, it confirms Einstein’s Theory of General Relativity, a theory which has been confirmed observationally over and over. If EHT sees something else, something we didn’t expect at all, then that means Einstein’s General Relativity got it wrong. Not only that, but it means we don’t really understand gravity.
In physics circles they say that it’s never smart to bet against Einstein. He’s been proven right time and time again. To find out if he was right again, we’ll have to wait until 2018.
Comet 45P is seen here on Feb. 8, 2017. The comet appears very spread out and diffuse. While its overall brightness is about magnitude +8.5, the comet appears diffuse and faint. Credit: Chris Schur
This animation of comet 45P/H-M-P is composed of thirteen delay-Doppler images made during 2 hours of observation using the Arecibo Observatory on Feb. 12. Credit: USRA
Comets hide their central engines well. From Earth, we see a bright, fuzzy coma and a tail or two. But the nucleus, the source of all the hubbub, remains deeply camouflaged by dust, at best appearing like a blurry star.
To see one up close, you need to send a spacecraft right into the comet’s coma and risk getting. Or you can do the job much more cheaply by bouncing radio waves off the nucleus and studying the returning echoes to create a shadowy image.
Although crude compared to optical photos of moons and planets, radar images reveal much about an asteroid including surface details like mountains, craters, shape and rotation rate. They’re also far superior to what optical telescopes can resolve when it comes to asteroids, which, as their name implies, appear star-like or nearly so in even large professional telescopes.
On Feb. 11, green-glowing comet 45P/Honda-Mrkos-Pajdusakova, made an unusually close pass of Earth, zipping just 7.7 million miles away. Astronomers made the most of the encounter by pressing the huge 1,000-foot-wide (305 meters) Arecibo radio dish into service to image the comet’s nucleus during and after closest approach.
Arecibo Observatory, the world’s biggest single dish radio telescope, was and is still being used to image comet 45P/H-M-P. Courtesy of the NAIC – Arecibo Observatory, a facility of the NSF
“The Arecibo Observatory planetary radar system can pierce through the comet’s coma and allows us to study the surface properties, size, shape, rotation, and geology of the comet nucleus”, said Dr. Patrick Taylor, USRA Scientist and Group Lead for Planetary Radar at Arecibo.
The two lobes of comet 67P/C-G stand out clearly in this photo taken by ESA’s Rosetta spacecraft while in orbit about the comet on March 6, 2015. Credit: ESA/Rosetta
Does the shape ring a bell? Remember Rubber Ducky? It doesn’t take a rocket scientist to see that the comet’s heart resembles the twin-lobed comet 67P/Churyumov-Gerasimenko orbited by ESA’s Rosetta spacecraft. Using the dish, astronomers have seen bright regions and structures on the comet; they also discovered that the nucleus is a little larger than expected with a diameter of 0.8 mile (1.3 km) and rotates about once every 7.6 hours. Go to bed at 10 and wake up at 6 and the comet will have made one complete turn.
Comet 45P is seen here on Feb. 8, 2017. While its overall brightness is about magnitude +8.5, the comet appears diffuse and rather faint. From dark skies, it remains a binocular object at least for a little while. Credit: Chris Schur
Radio observations of 45P/H-M-P will continue through Feb. 17. Right now, the comet is happily back in the evening sky and still visible with 10×50 or larger binoculars around 10-11 p.m. local time in the east. I spotted it low in Bootes last night about 15 minutes before moonrise under excellent, dark sky conditions. It looked like a faint, smoky ball nearly as big as the full moon or about 30 arc minutes across.
This week, the pale green blob (the green’s from fluorescing carbon), vaults upward from Bootes, crosses Canes Venatici and zooms into Coma Berenices. For maps to help you track and find it night by night, please click here. I suggest larger binoculars 50mm and up or a 6-inch or larger telescope. Be sure to use low power — the comet’s so big, you need a wide field of view to get dark sky around it in order to see it more clearly.
Very few comets pass near Earth compared to the number of asteroids that routinely do. That’s one reason 45P is only the seventh imaged using radar; rarely are we treated to such detailed views!
