And now Cassini’s gone. Smashed up in the atmosphere of Saturn. But planetary scientists are going to be picking through all those pictures and data for decades. Let’s look back at some of the science gathered up by Cassini so far, and we can still learn from this epic journey.
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Hubble image of the Ring Nebula (aka. Messier 57). Credit: NASA/ESA/ Hubble Heritage (STScI/AURA) – ESA /Hubble Collaboration
Welcome back to Messier Monday! We continue our tribute to our dear friend, Tammy Plotner, by looking at the the Big Ring itself, the planetary nebula known as Messier 57. Enjoy!
In the 18th century, while searching the night sky for comets, French astronomer Charles Messier kept noting the presence of fixed, diffuse objects in the night sky. In time, he would come to compile a list of approximately 100 of these objects, with the purpose of making sure that astronomers did not mistake them for comets. However, this list – known as the Messier Catalog – would go on to serve a more important function.
One of these objects is known as Messier 57, a planetary nebula that is also known as the Ring Nebula. This object is located about 2,300 light years from Earth in the direction of the Lyra constellation. Because of its proximity to Vega, the brightest star in Lyra and one of the stars that form the Summer Triangle, the nebula is relatively easy to find using binoculars or a small telescope.
What You Are Looking At:
Here you see the remainders of a sun-like star… At one time in its life, it may have had twice the mass of Sol, but now all that’s left is a white dwarf that burns over 100,000 degrees kelvin. Surrounding it is an envelope about 2 to 3 light years in size of what once was its outer layers – blown away in a cylindrical shape some 6000 to 8000 years ago. Like looking down the barrel of a smoking gun, we’re looking back in time at the end of a Mira-like star’s evolutionary phase.
It’s called a planetary nebula, because once upon a time before telescopes could resolve them, they appeared almost planet-like. But, as for M57, the central star itself is no larger than a terrestrial planet! The tiny white dwarf star, although it could be as much as 2300 light years away, has an intrinsic brightness of about 50 to 100 times that of our Sun.
One of the most beautiful features of M57 is the structure in the ring itself, sometimes called braiding – but scientifically known as “knots” in the gaseous structure. As C.R. O’Dell (et al) indicated in their 2003 study:
“We have studied the closest bright planetary nebulae with the Hubble Space Telescope’s WFPC2 in order to characterize the dense knots already known to exist in NGC 7293. We find knots in all of the objects, arguing that knots are common, simply not always observed because of distance. The knots appear to form early in the life cycle of the nebula, probably being formed by an instability mechanism operating at the nebula’s ionization front. As the front passes through the knots they are exposed to the photoionizing radiation field of the central star, causing them to be modified in their appearance. This would then explain as evolution the difference of appearance like the lacy filaments seen only in extinction in IC 4406 on the one extreme and the highly symmetric “cometary” knots seen in NGC 7293. The intermediate form knots seen in NGC 2392, NGC 6720, and NGC 6853 would then represent intermediate phases of this evolution.”
However, examining things like planetaries nebulae in different wavelengths of light can tell us so much more about them. Behold the beauty when see through the Spitzer Space Telescope! As M.M. Roth explained in a 2007 study:
“Emission nebulae like H II regions, Planetary Nebulae, Novae, Herbig Haro objects etc. are found as extended objects in the Milky Way, but also as point sources in other galaxies, where they are sometimes observable out to very large distances due to the high contrast provided by some prominent emission lines. It is shown how 3D spectroscopy can be used as a powerful tool for observations of both large resolved emission nebulae and distant extragalactic objects, with special emphasis on faint detection limits.”
History of Observation:
This deep space object was first discovered in early January 1779 by Antoine Darquier who wrote in his notes:
“This nebula, to my knowledge, has not yet been noticed by any astronomer. One can only see it with a very good telescope, it is not resembling any of those [nebula] already known; it has the apparent dimension of Jupiter, is perfectly round and sharply limited; its dull glow resembles the dark part of the Moon before the first and after the last quarter. Meanwhile, the center appears a bit less pale than the remaining part of its surface.”
Although Darquier did not post a date, it is believed his observation preceded Messier’s independent recovery made on January 31, 1779 when he states that Darquier picked it up before him:
“A cluster of light between Gamma and Beta Lyrae, discovered when looking for the Comet of 1779, which has passed it very close: it seems that this patch of light, which is round, must be composed of very small stars: with the best telescopes it is impossible to distinguish them; there stays only a suspicion that they are there. M. Messier reported this patch of light on the Chart of the Comet of 1779. M. Darquier, at Toulouse, discovered it when observing the same comet, and he reports: ‘Nebula between gamma and beta Lyrae; it is very dull, but perfectly outlined; it is as large as Jupiter and resembles a planet which is fading’.”
A few years later, Sir William Herschel would also observe Messier Object 57 with his superior telescope and in his private notes he writes:
“Among the curiosities of the heavens should be placed a nebula, that has a regular, concentric, dark spot in the middle, and is probably a Ring of stars. It is of an oval shape, the shorter axis being to the longer as about 83 to 100; so that, if the stars form a circle, its inclination to a line drawn from the sun to the center of this nebula must be about 56 degrees. The light is of the resolvable kind [i.e., mottled], and in the northern side three very faint stars may be seen, as also one or two in the southern part. The vertices of the longer axis seem less bright and not so well defined as the rest. There are several small stars very bear, but none seems to belong to it.”
Admiral Smyth would go on in later years to add his own detailed observations to history’s records:
“This annular nebula, between Beta and Gamma on the cross-piece of the Lyre, forms the apex of a triangle which it makes with two stars of the 9th magnitude; and its form is that of an elliptic ring, the major axis of which trends sp to nf [SW to NE]. This wonderful object seems to have been noted by Darquier, in 1779; but neither he nor his contemporaries, Messier and Méchain, discerned its real form, seeing in this aureola of glory only “a mass of light in the form of a planetary disc, very dingy in colour.”
“Sir W. Herschel called it a perforated resolvable nebula, and justly ranked it among the curiosities of the heavens. He considered the vertices of the longer axis less bright and not so well defined as the rest; and he afterwards added: ‘By the observations of the 20-feet telescope, the profundity of the stars, of which it probably consists, must be of a higher than the 900th order, perhaps 950.'”
“This is a vast view of the ample and inconceivable dimensions of the spaces of the Universe; and if the oft-cited cannon-ball, flying with the uniform velocity of 500 miles an hour, would require millions of years to reach Sirius, what an incomprehensible time it would require to pass so overwhelming an interval as 950 times the distance! And yet, could we arrive there, by all analogy, no boundary would meet the eye, but thousands and ten thousands of other remote and crowded systems would still bewilder the imagination.
“In my refractor this nebula has a most singular appearance, the central vacuity being black, so as to countenance the trite remark of its having a hole through it. Under favourable circumstances, when the instrument obeys the smooth motion of the equatorial clock, it offers the curious phenomenon of a solid ring of light in the profundity of space. The annexed sketch affords a notion of it. Sir John Herschel, however, with the superior light of his instrument, found that the interior is far from absolutely dark. “It is filled,’ he says, ‘with a feeble but very evident nebulous light, which I do not remember to have been noticed by former observers.'”
Since Sir John’s observation, the powerful telescope of Lord Rosse has been directed to this subject, and under powers 600, 800, and 1000, it displayed very evident symptoms of resolvability at its minor axis. The fainter nebulous matter which fills it, was found to be irregularly distributed, having several stripes or wisps in it, and the regularity of the outline was broken by appendages branching into space, of which prolongations the brightest was in the direction of the major axis.
Locating Messier 57:
M57 is a breeze to locate because it is positioned between Beta and Gamma Lyrae (the westernmost pair of the lyre’s stars), at about one-third the distance from Beta to Gamma. While it is easily seen in binoculars, it is a little difficult to identify because of its small size, so binoculars must be very steady to distinguish it from the surrounding star field.
In even a small telescope at minimum power, you’ll quickly notice a very small, but perfect ring structure which takes very well to magnification. Despite low visual brightness, M57 actually takes well to urban lighting conditions and can even be spied during fairly well moonlit nights. Larger aperture telescopes will easily see braiding in the nebula structure and often glimpse the central star. May you also see the many faces of the “Ring”!
The location of Messier 57 in the Lyra Constellation. Credit: IAU and Sky & Telescope magazine (Roger Sinnott & Rick Fienberg)
And here are the quick facts on Messier 57 to help you get started:
Object Name: Messier 57 Alternative Designations: M57, NGC 6720, the “Ring Nebula” Object Type: Planetary Nebula Constellation: Lyra Right Ascension: 18 : 53.6 (h:m) Declination: +33 : 02 (deg:m) Distance: 2.3 (kly) Visual Brightness: 8.8 (mag) Apparent Dimension: 1.4×1.0 (arc min)
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.
Future missions could determine the presence of past life on Mars by looking for signs of extreme metal-metabolizing bacteria. Credit: NASA.
Over the past few decades, our ongoing studies of Mars have revealed some very fascinating things about the planet. In the 1960s and early 70s, the Mariner probes revealed that Mars was a dry, frigid planet that was most likely devoid of life. But as our understanding of the planet has deepened, it has come to be known that Mars once had a warmer, wetter environment that could have supported life.
This in turn has inspired multiple missions whose purpose it has been to find evidence of this past life. The key questions in this search, however, are where to look and what to look for? In a new study led by researchers from the University of Kansas, a team of international scientists recommended that future missions should look for vanadium. This rare element, they claim, could point the way towards fossilized evidence of life.
The microphone for the upcoming Mars mission will be attached to the SuperCam, seen here in this illustration zapping a rock with its laser. Credit: NASA/JPL-Caltech
To be clear, finding signs of life on a planet like Mars is no easy task. As Craig Marshall indicated in a University of Kansas press release:
“You’ve got your work cut out if you’re looking at ancient sedimentary rock for microfossils here on Earth – and even more so on Mars. On Earth, the rocks have been here for 3.5 billion years, and tectonic collisions and realignments have put a lot of stress and pressure on rocks. Also, these rocks can get buried, and temperature increases with depth.”
In their paper, Marshall and his colleagues recommend that missions like NASA’s Mars 2020 rover, the ESA’s ExoMars 2020 rover, and other proposed surface missions could combine Raman spectroscopy with the search for vanadium to find evidence of fossilized life. On Earth, this element has been found in crude oils, asphalts, and black shales that have been formed by the slow decay of biological organic material.
In addition, paleontologists and astrobiologists have used Raman spectroscopy – a technique that reveals the cellular compositions of samples – on Mars for some time to search for signs of life. In this respect, the addition of vanadium would provide material that would act as a biosignature to confirm the existence of organic life in samples under study. As Marshall explained:
“People say, ‘If it looks like life and has a Raman signal of carbon, then we have life. But, of course, we know there can be carbonaceous materials made in other processes — like in hydrothermal vents — consistent with looking like microfossils that also have some carbon signal. People also make wonderful carbon structures artificially that look like microfossils — exactly the same. So, we’re at a juncture now where it’s really hard to tell if there’s life only based on morphology and Raman spectroscopy.”
Artist’s impression of the Mars 2020 with its sky crane landing system deployed. Credit: NASA/JPL
This is not the first time that Marshall and his co-authors have advocated using vanadium to search for signs of life. Such was the subject of a presentation they made at the Astrobiology Science Conference in 2015. What’s more, Marshall and his team emphasize that it would be possible to perform this technique using instruments that are already part of NASA’s Mars 2020 mission.
Their proposed method also involves new technique known as X-ray fluorescence microscopy, which looks at elemental composition. To test this technique, the team examined thermally altered organic-walled microfossils which were once organic materials )called acritarchs). From their data, they confirmed that traces of vanadium are present within microfossils that were indisputably organic in origin.
“We tested acritarchs to do a proof-of-concept on a microfossil where there’s no shadow of a doubt that we’re looking at preserved ancient biology,” Marshall said. “The age of this microfossil we think is Devonian. These guys are aquatic microorganisms — they’re thought to be microalgae, a eukaryotic cell, more advanced than bacterial. We found the vanadium content you’d expect in cyanobacterial material.”
These microfossilized bit of life, they argue, are probably not very distinct from the kinds of life that could have existed on Mars billions of years ago. Other scientific research has also indicated that vanadium is the result of organic compounds (like chlorophyll) from living organisms undergoing a transformation process caused by heat and pressure (i.e. diagenetic alteration).
Artist’s impression of ESA’s ExoMars rover (foreground) and Russia’s stationary surface science platform (background) on the surface of Mars. Credit: ESA/ATG medialab
In other words, after living creatures die and become buried in sediment, vanadium forms in their remains as a result of being buried under more and more layers of rock – i.e. fossilization. Or, as Marshall explained it:
“Vanadium gets complexed in the chlorophyll molecule. Chlorophylls typically have magnesium at the center — under burial, vanadium replaces the magnesium. The chlorophyll molecule gets entangled within the carbonaceous material, thus preserving the vanadium. It’s like if you have a rope stored in your garage and before you put it away you wrap it so you can unravel it the next time you need it. But over time on the garage floor it becomes tangled, things get caught in it. Even when you shake that rope hard, things don’t come out. It’s a tangled mess. Similarly, if you look at carbonaceous material there’s a tangled mess of sheets of carbon and you’ve got the vanadium mixed in.”
The work was supported by an ARC International Research Grant (IREX) – which sponsors research that seeks to find biosignatures for extracellular life – with additional support from the Australian Synchrotron and the Advanced Photon Source at the Argonne National Laboratory. Looking forward, Marshall and his colleagues hope to conduct further research that will involve using Raman spectroscopy to study carbonaceous materials.
At present, their research appears to have attracted the interesting of the European Space Agency. Howell Edwards, who also conducts research using Raman spectroscopy (and who’s work has been supported by an ARC grant), is part of the ESA’s Mars Explorer team, where he is responsible for instrumentation on the ExoMars 2020 rover. But, as Marshall indicated, the team also hopes that NASA will consider their study:
“Hopefully someone at NASA reads the paper. Interestingly enough, the scientist who is lead primary investigator for the X-ray spectrometer for the space probe, they call it the PIXL, was his first graduate student from Macquarie University, before his KU times. I think I’ll email her the paper and say, ‘This might be of interest.’”
The next decade is expected to be a very auspicious time for exploration missions to Mars. Multiple rovers will be exploring the surface, hoping to find the elusive evidence of life. These missions will also help pave the way for NASA’s crewed mission to Mars by the 2030s, which will see astronauts landing on the surface of the Red Planet for the first time in history.
If, in fact, these missions find evidence of life, it will have a profound effect on all future mission to Mars. It will also have an immeasurable impact on humanity’s perception of itself, knowing at long last that billions of years ago, life did not emerge on Earth alone!
Artist’s impression shows the binary asteroid 288P, located in the Main Asteroid Belt between the planets Mars and Jupiter. Credit: ESA/Hubble, L. Calçada.
In 1990, the NASA/ESA Hubble Space Telescope was deployed into Low Earth Orbit (LEO). As one of NASA’s Great Observatories – along with the Compton Gamma Ray Observatory, the Chandra X-ray Observatory, and the Spitzer Space Telescope – this instrument remains one of NASA’s larger and more versatile missions. Even after twenty-seven years of service, Hubble continues to make intriguing discoveries, both within our Solar System and beyond.
The latest discovery was made by a team of international astronomers led by the Max Planck Institute for Solar System Research. Using Hubble, they spotted a unique object in the Main Asteroid Belt – a binary asteroid known as 288P – which also behaves like a comet. According to the team’s study, this binary asteroid experiences sublimation as it nears the Sun, which causes comet-like tails to form.
Using the Hubble telescope, the team first observed 288P in September 2016, when it was making its closest approach to Earth. The images they took revealed that this object was not a single asteroid, but two asteroids of similar size and mass that orbit each other at a distance of about 100 km. Beyond that, the team also noted some ongoing activity in the binary system that was unexpected.
As Jessica Agarwal explained in a Hubble press statement, this makes 288P the first known binary asteroid that is also classified as a main-belt comet. “We detected strong indications of the sublimation of water ice due to the increased solar heating – similar to how the tail of a comet is created,” she said. In addition to being a pleasant surprise, these findings are also highly significant when it comes to the study of the Solar System.
Since only a few objects of this type are known, 288P is an extremely important target for future asteroid studies. The various features of 288P also make it unique among the few known wide asteroid binaries in the Solar System. Basically, other binary asteroids that have been observed orbited closer together, were different in size and mass, had less eccentric orbits, and did not form comet-like tails.
The observed activity of 288P also revealed a great deal about the binary asteroids past. From their observations, the team concluded that 288P has existed as a binary system for the past 5000 years and must have accumulated ice since the earliest periods of the Solar System. As Agarwal explained:
“Surface ice cannot survive in the asteroid belt for the age of the Solar System but can be protected for billions of years by a refractory dust mantle, only a few meters thick… The most probable formation scenario of 288P is a breakup due to fast rotation. After that, the two fragments may have been moved further apart by sublimation torques.”
Image depicting the two areas where most of the asteroids in the Solar System are found: the Main Asteroid Belt and the Trojans. Credit: ESA/Hubble, M. Kornmesser
Naturally, there are many unresolved questions about 288P, most of which stem from its unique behavior. Given that it is so different from other binary asteroids, scientists are forced to wonder if it merely coincidental that it presents such unique properties. And given that it was found largely by chance, it is unlikely that any other binaries that have similar properties will be found anytime soon.
“We need more theoretical and observational work, as well as more objects similar to 288P, to find an answer to this question,” said Agarwal. In the meantime, this unique binary asteroid is sure to provide astronomers with many interesting opportunities to study the origin and evolution of asteroids orbiting between Mars and Jupiter.
In particular, the study of those asteroids that show comet-like activity (aka. main-belt comets) is crucial to our understanding of how the Solar System formed and evolved. According to contrasting theories of its formation, the Asteroid Belt is either populated by planetesimals that failed to become a planet, or began empty and gradually filled with planetesimals over time.
In either case, studying its current population can tell us much about how the planets formed billions of years ago, and how water was distributed throughout the Solar System afterwards. This, in turn, is crucial to determining how and where life began to emerge on Earth, and perhaps elsewhere!
Be sure to check out this animation of the 288P binary asteroid too, courtesy of the ESA and Hubble:
I don’t have to tell you that the vision of human space exploration in the Solar System has kind of stalled. Half a century ago, humans set foot on the Moon, and we haven’t been back since. Instead, we’ve thoroughly explored every cubic meter of low Earth orbit, going around and around the Earth. In fact, back in 2016, the International Space Station celebrated 100,000 orbits around the Earth.
The space shuttle was the last US vehicle capable of taking humans up into orbit, and it was retired back in 2011. So things look pretty bleak for sending humans out to explore the Solar System.
Earlier this year, however, NASA announced their next great step in their human space exploration efforts: the Deep Space Gateway. And if all goes well, we’ll see humans living and working farther from Earth, and for longer periods than ever before.
After the space shuttle program was wrapped up, NASA had a bunch of challenges facing it. Perhaps the greatest of these, was what to do with the enormous workforce that built and maintained the space shuttle fleet. Thousands were laid off, and moved to other aerospace jobs and other industries, but the space agency worked to develop the next big launch system after the shuttle.
Originally there were the Ares rockets, as part of the Constellation Program, but these were canceled and replaced with the Space Launch System. We’ve done a whole episode on the SLS, but the short version is that this new rocket will be capable of lifting more cargo into orbit than any rocket ever.
The first version, known as the Block 1 will be capable of lofting 70,000 kg into low-Earth orbit, while the upcoming Block 2 will be able to carry 130,000 kg into LEO – more than the mighty Saturn V rocket.
What are you going to do with a rocket this powerful? Launch new space telescopes, robotic missions to the outer Solar System, and put humans into space, of course.
In addition to the SLS, NASA is also working on a new capsule, known as the Orion Crew Module. This Apollo-esque capsule will be capable of carrying a crew of 4 astronauts out beyond low-Earth orbit, and returning them safely back to Earth.
But if you can send astronauts out beyond low-Earth orbit, where will they go? Artist’s impression of the Deep Space Gateway, currently under development by Lockheed Martin. Credit: NASA The Deep Space Gateway.
The plan is to put a brand new space station into a cis-lunar orbit. Specifically, it’s known as a near-rectilinear halo orbit. It won’t actually be orbiting the Moon, but it’ll be on an orbit that allows it to serve as a stepping stone to the Moon. Sort of a bridge between Lagrange points. This station will range in distance from 1,500 to 70,000 km from the Moon in a way that keeps it relatively easy to reach.
From the outside, it’ll look like a smaller version of the International Space Station, with a group of 4 pressurized modules connected together: a power module, habitation module, cargo logistics pod, and an EVA module.
Space inside the Gateway will be cramped, with astronauts needing to share their living quarters, reconfiguring the space as necessary. Seriously, the ISS is going to feel like a luxury hotel after spending time in the Gateway. Artist illustration of Habitation Module. Credit: Lockheed Martin
The station will be solar powered, with arrays providing 40 kW of energy. It’ll also have 12 kW ion thrusters which will be used for station keeping, as well as traditional hydrazine thrusters. The first habitation module will be capable of supplying the astronauts for 30-60 days, but a later cargo logistics pod will extend the length of missions.
Right now, there are a group of contractors being considered to build the Deep Space Gateway. The designs I’m showing you come from Lockheed Martin, but things could change.
The goal of the Deep Space Gateway will be to keep humans alive in space outside the Earth’s protective magnetosphere for at least a year, studying the effects of deep space on the human body.
But in the long term, the Gateway will serve as a stepping stone to Mars. The astronauts will assemble the future Deep Space Transport, a spacecraft that will carry humans to the Red Planet. But more on that later.
On the International Space Station, astronauts are protected by the Earth’s magnetosphere from solar radiation and cosmic rays. But on board the Deep Space Gateway, there’ll be no such protection. Instead, the station will need to be reinforced with radiation protection. At the same time, the region actually has less space junk, so it won’t need to same kind of micrometeorite protection.
In addition to being a science platform, the DSG will serve as a base of operations for exploring the Moon. In the near term, NASA is planning new lander and rover missions to the Moon. The Gateway could serve as a dock for missions blasting off from the Moon, where astronauts could unload science samples, and refurbish a rover for another mission down on the lunar surface.
Another intriguing idea is that the Deep Space Gateway could be used as a place to study samples from Mars without a risk of contaminating Earth. Under the current planetary contamination guidelines, samples from Mars need to be sterilized before they can be brought to Earth.
It’s hard to search for life in your samples, when you need to kill all life in your samples. But I’m sure the astronauts would be willing to take the risk of catching Martian flu for a chance to discover there’s life on Mars.
When will we actually see the Deep Space Gateway?
Not for a few years, sadly. Building the Gateway is going to require a few launches of the SLS, and there are already a bunch of missions queued up to use this new launcher. SLS Block 1 Expanded View. Credit: NASA
The first launch of SLS will be an uncrewed test with an Orion capsule, sometime in 2019, known as EM-1. This will be followed by the launch of the Europa Clipper mission, also in 2019.
Once those missions are out of the way, the first crewed launch with SLS blasts off some time between 2021 and 2023. Designated as EM-2, this is when the construction of the Deep Space Gateway begins. 4 astronauts will spend 3 weeks beyond low Earth orbit, delivering the first module to the Deep Space Gateway: the Solar Power Electric Bus.
In 2024, EM-3 will have another crew of 4 blast off with the Deep Space Gateway’s Habitation Module. EM-4 should lift off by 2025 with the Logistics module. Finally, some time around 2026, mission EM-5 will deliver the station’s Airlock module. SLS Block 2. Credit: NASA
What comes next? After the Deep Space Gateway, there’ll be the Deep Space Transport. If you’ve seen The Martian, think of the Hermes spacecraft that ferries the crew to and from Mars. The details are thin right now, but if all goes well, the pieces of the Transport will launch to the Gateway by 2027.
The various components will be assembled by the astronauts over the course of several launches, and once completed, the Deep Space Transport would make a series of 1-3 year missions to and from Mars. It’ll carry a crew of a six astronauts in a large habitation module and keep them alive for the journey.
The first mission could head out in 2033, with a human flyby of Mars. Side note, wouldn’t it be heartbreaking to get that close to Mars, and not actually be able to set foot on the surface? Anyway, future missions to Mars will include landings, and perhaps a visit to the SpaceX luxury Martian hotel where the astronauts can relax and apologize to each other for what they did when they all got space madness.
But this is so far in the future, it’s pretty hard to even wrap my mind around it yet.
Of course, these are all long term plans. And as I’ve mentioned in previous episodes, long term plans have a tendency of getting canceled. Who knows if the Deep Space Gateway actually get constructed, or if NASA will shift its support to private missions to Mars.
An artist's rendering of a hyperloop on a track leading to downtown Toronto. A pitch for a hyperloop linking Toronto and Montreal via Ottawa is among 10 winners of a global challenge. Credit: transpodhyperloop.com
In 2012, SpaceX founder Elon Musk unveiled his idea for what he called the “fifth mode of transportation”. Known as the Hyperloop, his proposal called for the creation of a high-speed mass transit system where aluminum pod cars traveled through a low-pressure steel tube. This system, he claimed, would be able to whisk passengers from San Francisco to Los Angeles in just 35 minutes.
Since that time, many companies have emerged that are dedicated to making this proposal a reality, which include the Los Angeles-based company known as Hyperloop One. Back in 2016, this company launched the Hyperloop One Global Challenge to determine where Hyperloop routes should be built. Earlier this month, the winners of this competition were announced, which included the team recommending a route from Toronto to Montreal.
The Toronto-Montreal team (aka. team HyperCan) was just one of over 2600 teams that registered for the competition, a combination of private companies, engineers, and urban planners. After the field was narrowed down to the 35 strongest proposals, ten finalists were selected. These included team HyperCan, as well as teams from India, Mexico, the UK and the US.
The Toronto-to-Montreal route, one of ten winning proposals submitted to the Hyperloop One Global Challenge. Credit: hyperloop-one.com
As Rob Lloyd, the CEO of Hyperloop One, said about the competition in a company statement:
“The results of the Hyperloop One Global Challenge far exceeded our expectations. These 10 teams each had their unique strengths in showcasing how they will alleviate serious transportation issues in their regions… Studies like this bring us closer to our goal of implementing three full-scale systems operating by 2021.”
Team HyperCAN was led by AECOM Canada, the Canadian-subsidiary of the multinational engineering firm. For their proposal, they considered how a Hyperloop system would address the transportation needs of Canada’s largest megacity region. This region is part of what is sometimes referred to as the Quebec City-Windsor corridor, which has remained the most densely-populated region in modern Canadian history.
The region that extends from Montreal to Toronto, and includes the nation’s capitol of Ottawa, is by the far the most populated part of this corridor. It is the fourth most populous region in North America, with roughly 1 in 4 Canadians – over 13 million people – living in a region that measures 640 km (400 mi) long. Between the density, urban sprawl, and sheer of volume of business that goes on in this area, traffic congestion is a natural problem.
In fact, traveling from Montreal to Ottawa to Toronto can take a minimum of five hours by car, and the highway connections between them – Highway 417 (the “Queensway”) and Highway 401 – are the busiest in all of Canada. Within the greater metropolitan area of Toronto alone, the average daily traffic on the 401 is about 450,000 vehicles, and this never drops below 20,000 vehicles between urban centers.
In Montreal, the situation is much the same. In an average year, commuters spend an estimated 52 hours stuck in peak hour traffic, which earned the city the dubious distinction of having the worst commute in the country. To make matters worse, it is anticipated that population and urban growth are going to make congestion grow by about 6% in the next few years (by 2020).
Hence why team HyperCAN thinks a Hyperloop network would be ideally suited for this corridor. Not only would it offer commuters an alternative to driving on busy highways, it would also address the current lack of rapid and on-demand mass transport in this region. According to AECOM Canada’s proposal:
“No mode of transportation has existing or planned capacity to accommodate the growth in traffic along this corridor. By moving higher volumes of people in less time, Hyperloop could generate greater returns socially and provide much-needed capacity to accommodate the forecasted growth in demand for travel in the corridor.”
The benefits of such a high-speed transit system are also quite clear. Based on its top projected speeds, a Hyperloop trip between Ottawa and Toronto – which ideally takes about 3 hours by car – could be reduced to 27 minutes. A trip from Montreal to Ottawa could be done in 12 minutes instead of 2 hours, and a trip between Toronto and Montreal could be done in just 39 minutes.
And since the Hyperloop would make its transit from city-center to city-center, it offers something that high-speed rail and air travel do not – on-demand connections between cities. The existence of such a system could therefore attract business, investment, workers and skilled professionals to the region and allow the Toronto-Montreal corridor to gain an advantage in the global economy.
Of course, whenever major projects come up, it’s only a matter of time before the all-important aspect of cost rears its head. However, as Hyperloop One indicated, such a project could benefit from existing infrastructure spending in Canada. Recently, the Trudeau administration created an infrastructure bank that pledged $81.2 billion CAD ($60.8 billion USD) in spending over the next 12 years for public transit, transport/trade corridors, and green infrastructure.
A Hyperloop that connects three of Canada’s largest and most dynamic cities together certainly meets all these criteria. In fact, according to team HyperCAN, green infrastructure would be yet another benefit of a Toronto-Montreal Hyperloop system. As they argued in their proposal, the Hyperloop can be powered by hydro or other renewables and would be 100% emissions-free.
This would be consistent with the Canadian government commitment to reducing carbon emissions by 30% by 2030 (from their 2005 levels). According to figures compiled by Environment and Climate Change Canada, in 2015:
“Canada’s total greenhouse gas (GHG) emissions were 722 megatonnes (Mt) of carbon dioxide equivalent (CO2 eq). The oil and gas sector was the largest GHG emitter in Canada, accounting for 189 Mt CO2 eq (26% of total emissions), followed closely by the transportation sector, which emitted 173 Mt CO2 eq (24%).”
By allowing commuters to switch to a mass transit system that would reduce the volume of cars traveling between cities, and produces no emissions itself, a Hyperloop would help Canadians meet their reduced-emission goals. Last, but certainly not least, there is the way that such a system would create opportunities for economic growth and cooperation between Canada and the US.
On the other side of the border from the Quebec City-Windsor Corridor, there is the extended urban landscape that includes the cities of Chicago, Detroit, Cincinnati, Cleveland, Columbus, Indianaopli, Pittsburgh, and St. Louis. This transnational mega-region, which has over 55 million people living within it, is sometimes referred to as the Great Lakes Megalopolis.
Not only would a Hyperloop connection between two of its northernmost urban centers offer opportunities for cross-border commerce, it would also present the possibility of extending this line down into the US. With a criss-cross pattern of Hyperloops that can whisk people from St. Louis and Pittsburgh to Montreal, business would move at a speed never before seen!
Given the litany of reasons for building a Hyperloop along this corridor, it should come as no surprise that AECOM and team HyperCAN are not alone in proposing that it be built. TransPod Inc, a Toronto-based Hyperloop company, is also interested in constructing Hyperloop lines in countries where aging infrastructure, high-density populations, and a need for new transportation networks coincide.
As Sebastien Gendron, the CEO of TransPod, recently indicated in an interview with Huffington Post Canada, his company hopes to have a Hyperloop up and running in Canada by 2025. He also expressed high-hopes that the public will embrace this new form of transit once its available. “We already travel at that speed with an aircraft and the main difference with our system is we are on the ground,” he said. “And it’s safer to be on the ground than in the air.”
According to Gendron, TransPod is currently engaged in talks with the federal transportation department to ensure safety regulations are in place for when the technology is ready to be implemented. In addition, his company is also bidding for provincial and city support to build a 4 to 10 km (2.5 to 6 mi) track between the cities of Calgary-Edmonton in Alberta, which would connect the roughly 3 million people living there.
When Musk first unveiled his vision for the Hyperloop, he indicted that he was too busy with other projects to pursue it, but others were free to take a crack at it. In the five years that have followed, several companies have emerged that have been more than happy to oblige him. And Musk, to his credit, has offered support by holding events like Pod Design Competitions and offering the use of his company’s own test track.
And despite misgivings by those who claimed that such a system posed too many technical and engineering challenges – not to mention that the cost would be prohibitive – those who are committing to building Hyperloops remain undeterred. With every passing year, the challenges seem that much more surmountable, and support from the public and private sector is growing.
By the 2020s and 2030s, we could very well be seeing Hyperloops running between major cities in every mega-region in the world. These could include Toronto and Montreal, Boston and New York, Los Angeles and San Fransisco, Moscow and St. Petersburg, Tokyo to Nagoya, Mumbai to New Delhi, Shanghai to Beijing, and London to Edinburgh.
A computer generated handout image released by the European Space Agency shows the impact of the DART (Double Asteroid Redirection Test) projectile on the binary asteroid system (65803) Didymos. Credit: ESA/AFP
For decades, scientists have known that in near-Earth space there are thousands of comets and asteroids that periodically cross Earth’s orbit. These Near-Earth Objects (NEOs) are routinely tracked by NASA’s Center for Near Earth Object Studies (CNEOS) to make sure that none pose a risk of collision with our planet. Various programs and missions have also been proposed to divert or destroy any asteroids that might pass too closely to Earth in the future.
One such mission is the Asteroid Impact & Deflection Assessment (AIDA), a collaborative effort between NASA and the European Space Agency (ESA). Recently, the ESA announced that it would be withdrawing from this mission due to budget constraints. But this past Wednesday (Sept. 20th), during the European Planetary Science Conference in Riga, a group of international scientists urged them to reconsider.
In addition to NASA and the ESA, AIDA was designed with assistance from the Observatoire de la Côte d´Azur (OCA), and the Johns Hopkins University Applied Physics Laboratory (JHUAPL). To test possible asteroid deflection techniques, the mission intends to send a spacecraft to crash into the tiny moon of the distant asteroid named Didymos (nicknamed “Didymoon”) by 2022 to alter its trajectory.
Artist’s impression of the path DART will take to reach the asteroid Didymos. Credit: NASA
This mission would be a first for scientists, and would test the capabilities of space agencies to divert rocks away from Earth’s orbit. NASA’s contribution to this mission is known as the Double Asteroid Redirection Test (DART), the spacecraft which would be responsible for crashing into Didymoon. Plans for this spacecraft recently entered Phase B, having met with approval, but still in need of further development.
The plan was to mount DART on an already planned commercial or military launch, and would then be placed in geosynchronous orbit between December 2020 and May 2021. It would then rely on a NEXT-C ion engine to push itself beyond the Moon and reach an escape point to depart the Earth-Moon system, eventually making its way to Didymos and Didymoon.
Europe’s contribution to the mission was known as the Asteroid Impact Mission (AIM), which would involve sending a small craft close to Didymos to observe the crash and conduct research on the asteroid’s moon. Unfortunately, this aspect of the mission suffered a setback when space ministers from the ESA’s 22 member states rejected a €250 million ($300 million USD) request for funding last December.
However, during the European Planetary Science Congress – which will be taking place from September 17th to 22nd in the Latvian capital of Riga – scientists took the opportunity to advise the mission’s European partners to get back on board. As they emphasized, this mission – which is a dry-run for future asteroid redirect missions – is crucial if space agencies hope to develop the capacity to protect Earth from hazardous NEOs.
ESA’s Asteroid Impact Mission, a candidate mission due for launch in 2020, will map the smaller body of the Didymos binary asteroid system down to 1 m resolution following its arrival in 2022. Credit: ESA
Andrew Cheng from JHUAPL is the project scientist for the DART mission. As he told the AFP at the European Planetary Science Congress, “This is the kind of disaster that could be a tremendous catastrophe.” He also stressed that unlike other natural disasters, an asteroid strike “is something that the world is able to defend. We can do something.”
But before that can happen, the methods need to be further developed, tested and refined. Hence why Didymoon was selected as the target for the AIDA mission. Whereas the meteor that exploded over the Russian town of Chelyabinsk in 2013 was just 20 meters across (65 feet), but still injured 1600 people, Didymoon measures about 160 meters (525 feet) in diameter.
It is estimated that if this asteroid struck Earth, the resulting impact would be as powerful as a 400 megatonne blast. To put that in perspective, the most powerful thermonuclear device ever built – the Soviet Tsar Bomba – had a yield of 50 megatonnes. Hence, the smaller companion of this binary asteroid, if it struck Earth, would have an impact 80 times greater than the most powerful bomb ever built by humans.
In addition to advocating that the ESA remain committed to the mission, European scientists at the conference also proposed an altered, more cost-effective alternative for AIM. This alternative called for a miniaturized version of the AIM craft that would be equipped with just a camera, forgoing a lander and radars designed to probe Didymoon’s internal structure.
Simulated image of the Didymos system, derived from photometric lightcurve and radar data. Credits: Naidu et al./AIDA Workshop (2016)
According to Patrick Michel, the science lead for the AIM mission, this revised mission would cost about €210 million ($250 million USD). But as he also noted, this would require that the AIM part of the mission be delayed. While it would still conduct crucial measurements of Didymoon, it would not be part of the AIDA mission if NASA decides to stick with its original timeline.
“The main point of the mission was to measure the mass of the object, because this is how you really measure the deflection,” he said. “Two or three years (after impact), these things won’t change. Of course it’s better… that we have the two at the same time. But we found something I think that still works and allows to relax the very tight schedule.”
In the meantime, Jan Woerner – the head of the European Space Agency – indicated that the ESA would be moving forward with the new proposal when the next ministerial meeting takes place in 2019. As he told the AFP via email:
“It is important for humanity, as a species we have the means today to deflect an asteroid. We know it will happen, one day sooner or later. It’s not a question of if, but when. We have never tested asteroid deflection and there is no way we can test in (the) laboratory. We need to know if our models are correct, (whether) our simulations work as expected.”
In the end, it remains to be seen if the AIDA mission will see one or two missions traveling to Didymoon by 2022. Obviously, it would be better if both mission happened simultaneously, as the AIM mission will be capable of obtaining information DART will not. Much of that information has to do with with studying the effects of the collision up close and as they happen.
But regardless of how this mission unfolds, it is clear that space agencies from around the world are dedicated to developing techniques for protecting Earth from asteroids that pose a collision hazard. Between NASA, the ESA, and their many institutional partners and private contractors, multiple methods are being developed to divert or destroy oncoming space rocks before they hit us.
However, I’m pretty sure not one of them involves sending a bunch of miners with minimal training into space to plant a nuke inside an asteroid. That would just be silly on its face!
And be sure to check out this video that details the AIDA and Asteroid Impact Mission, courtesy of ESA:
As it swings by Earth NASA’s first ever asteroid sample return mission, OSIRIS-REx (Origins, Spectral Interpretation, Resource Identification, and Security – Regolith Explorer), will pass only 11,000 miles (17,000 kilometers) above Earth just before 12:52 p.m. EDT on Friday.
And NASA is asking the public to try and ‘Catch It If You Can’ – by waving hello and/or taking snapshots during and after the probes high speed flyby.
OSIRIS-REx will be approaching Earth at a velocity of about 19,000 mph on Friday as it begins flying over Australia during the Earth Gravity Assist (EGA) maneuver.
Since blastoff from the Florida Space Coast on Sept. 8, 2016 the probe has already racked up almost 600 million miles on its round trip journey from Earth and back to set up Friday’s critical gravity assist maneuver to Bennu and back.
As OSIRIS-REx continues along its flight path the spacecraft will reach its closest point to Earth over Antarctica, just south of Cape Horn, Chile. It will gain a velocity boost of about 8400 mph.
The spacecraft will also conduct a post flyby science campaign by collecting images and science observations of Earth and the Moon four hours after closest approach to calibrate its five science instruments.
NASA’s OSIRIS-REx asteroid sampling spacecraft, return capsule and payload fairings inside the Payloads Hazardous Servicing Facility high bay at NASA’s Kennedy Space Center is being processed for Sep. 8, 2016 launch to asteroid Bennu from Cape Canaveral, FL. Credit: Ken Kremer/kenkremer.com
The allure of Bennu is that it is a carbon rich asteroid – thus OSIRIS-REx could potentially bring back samples infused with the organic chemicals like amino acids that are the building blocks of life as we know it.
“We are interested in that material because it is a time capsule from the earliest stages of solar system formation,” OSIRIS-Rex Principal Investigator Dante Lauretta told Universe Today in a prelaunch interview with the spacecraft in the cleanroom at NASA’s Kennedy Space Center.
The do or die gravity assist plunge is absolutely essential to set OSIRIS-REx on course to match the asteroid’s path and speed when it reaches the vicinity of asteroid Bennu a year from now in October 2018.
“The Earth Gravity Assist is a clever way to move the spacecraft onto Bennu’s orbital plane using Earth’s own gravity instead of expending fuel,” says Lauretta, of the University of Arizona, Tucson.
Just how close to Earth will OSIRIS-REx be during its flyby on Friday? The spacecraft will come within 11,000 miles (17,000 km) of the Earth’s surface as it passes over Antarctica at 12:52 a.m. EDT. on Sept. 22, 2017. Credits: NASA’s Goddard Space Flight Center/University of Arizona
Bennu’s orbit around the Sun is tilted at a six-degree inclination with respect to Earth’s orbital plane.
The asteroid is 1,614-foot (500 m) in diameter and crosses Earth’s orbit around the sun every six years.
Numerous NASA spacecraft – including NASA’s just completed Cassini mission to Saturn – utilize gravity assists around a variety of celestial bodies to gain speed and change course to save vast amounts of propellant and time in order to accomplish science missions and visit additional target objects that would otherwise be impossible.
The flyby will be a nail-biting time for NASA and the science team because right afterwards the refrigerator sized probe will be out of contact with engineers – unable to receive telemetry for about an hour.
“For about an hour, NASA will be out of contact with the spacecraft as it passes over Antarctica,” said Mike Moreau, the flight dynamics system lead at Goddard, in a statement.
“OSIRIS-REx uses the Deep Space Network to communicate with Earth, and the spacecraft will be too low relative to the southern horizon to be in view with either the Deep Space tracking station at Canberra, Australia, or Goldstone, California.”
NASA says the team will regain communication with OSIRIS-REx roughly 50 minutes after closest approach over Antarctica at about 1:40 p.m. EDT.
The post flyby science campaign is set to begin at 4:52 p.m. EDT, Friday, Sept. 22.
United Launch Alliance Atlas V rocket lifts off from Space Launch Complex 41 at Cape Canaveral Air Force Station carrying NASA’s Origins, Spectral Interpretation, Resource Identification, Security-Regolith Explorer, or OSIRIS-REx spacecraft on the first U.S. mission to sample an asteroid, retrieve at least two ounces of surface material and return it to Earth for study. Liftoff was at 7:05 p.m. EDT on September 8, 2016 in this remote camera view taken from inside the launch pad perimeter. Note the newly install crew access arm and white room for astronaut flights atop Atlas starting in early 2018. Credit: Ken Kremer/kenkremer.com
The OSIRIS-Rex spacecraft originally departed Earth atop a United Launch Alliance Atlas V rocket under crystal clear skies on September 8, 2016 at 7:05 p.m. EDT from Space Launch Complex 41 at Cape Canaveral Air Force Station, Florida.
Everything with the launch went exactly according to plan for the daring mission boldly seeking to gather rocks and soil from carbon rich Bennu.
View of science instrument suite and TAGSAM robotic sample return arm on NASA’s OSIRIS-REx asteroid sampling spacecraft inside the Payloads Hazardous Servicing Facility at NASA’s Kennedy Space Center. Probe is slated for Sep. 8, 2016 launch to asteroid Bennu from Cape Canaveral Air Force Station, FL. Credit: Ken Kremer/kenkremer.com
OSIRIS-Rex is equipped with an ingenious robotic arm named TAGSAM designed to collect at least a 60-gram (2.1-ounce) sample and bring it back to Earth in 2023 for study by scientists using the world’s most advanced research instruments.
“The primary objective of the OSIRIS-Rex mission is to bring back pristine material from the surface of the carbonaceous asteroid Bennu,” OSIRIS-Rex Principal Investigator Dante Lauretta told me in the prelaunch interview in the KSC cleanroom with the spacecraft as the probe was undergoing final launch preparations.
“We are interested in that material because it is a time capsule from the earliest stages of solar system formation.”
“It records the very first material that formed from the earliest stages of solar system formation. And we are really interested in the evolution of carbon during that phase. Particularly the key prebiotic molecules like amino acids, nucleic acids, phosphates and sugars that build up. These are basically the biomolecules for all of life.”
1 day to Earth flyby for OSIRIS-Rex
NASA and the mission team is also inviting the public to get engaged by participating in the Wave to OSIRIS-REx social media campaign.
“Individuals and groups from anywhere in the world are encouraged to take photos of themselves waving to OSIRIS-REx, share them using the hashtag #HelloOSIRISREx and tag the mission account in their posts on Twitter (@OSIRISREx) or Instagram (@OSIRIS_REx).
Participants may begin taking and sharing photos at any time—or wait until the OSIRIS-REx spacecraft makes its closest approach to Earth at 12:52p.m. EDT on Friday, Sept. 22.”
The probe’s flight path during the flyby will pass through the ring of numerous satellites orbiting in geosynchronous orbit, but none are expected to be within close range.
Members of the OSIRIS-REx mission team celebrate the successful spacecraft launch on Sept. 8, 2016 atop ULA Atlas V at the post-launch briefing at the Kennedy Space Center, FL. Principal Investigator Dante Lauretta is 4th from right, NASA Planetary Science Director Jim Green is center, 5th from left. Credit: Ken Kremer/kenkremer.com
Watch for Ken’s continuing onsite NASA mission and launch reports direct from the Kennedy Space Center and Cape Canaveral Air Force Station, Florida.
Stay tuned here for Ken’s continuing Earth and Planetary science and human spaceflight news.
Dr Dante Lauretta, principal investigator for OSIRIS-REx at the University of Arizona, Tucson, and Dr. Ken Kremer, Universe Today point to NASA’s OSIRIS-REx asteroid sampling spacecraft inside the Payloads Hazardous Servicing Facility at the Kennedy Space Center on Aug. 20, 2016. Credit: Ken Kremer/kenkremer.com
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.
