This morning, the sun erupted with the most powerful solar flare in a decade, blasting the Earth’s upper atmosphere with energetic X-ray and extreme ultraviolet (EUV) radiation.
The flare was triggered by intense magnetic activity over an active region called AR2673 that has been roiling with sunspot activity for days, threatening an uptick in space weather activity. As promised, that space weather brought an explosive event at 1202 UTC (8:02 a.m. PT) that ionized the Earth’s upper atmosphere and causing a shortwave radio blackout over Europe, Africa and the Atlantic Ocean, reports Spaceweather.com.
The powerful X9.3-class flare came after an earlier X2.2 blast from the same active region, a significant flare in itself. X-class flares are the most powerful type of solar flares.
The electromagnetic radiation emitted by flaring events affect the Earth’s ionosphere immediately, but now space weather forecasters are on the lookout for a more delayed impact of this eruption.
Solar flares can create magnetic instabilities that may launch coronal mass ejections (CMEs) — basically vast magnetized bubbles of energetic solar plasma — into interplanetary space. Depending on the conditions, these CMEs may take hours or days to reach Earth (if they are Earth-directed) and can generate geomagnetic storms should they collide and interact with our planet’s global magnetic field.
When the universe’s first black holes appeared is one of the biggest mysteries in astrophysics. Were they born immediately after the Big Bang 13.8 billion years ago? Or did they pop into existence after the first population of massive stars exploded as supernovas millions of years later?
The origin of primordial black holes isn’t a trivial matter. In our modern universe, the majority of galaxies have supermassive black holes in their cores and we’re having a hard time explaining how they came to be the monsters they are today. For them to grow so big, there must have been a lot of primordial black holes formed early in the universe’s history clumping together to form progressively more massive black holes.
Immediately after the Big Bang, the researchers suggest that a uniform energy field pervaded our baby universe. In all the superheated chaos, long before stars started to form, this energy field condensed as “Q balls” and clumped together. These clumps of quasi-matter collapsed under gravity and the first black holes came to be.
These primordial black holes have been singled out as possible dark matter candidates (classed as massive astrophysical compact halo objects, or “MACHOs”) and they may have coalesced to quickly seed the supermassive black holes. In short: if these things exist, they could explain a few universal mysteries.
It is thought that energetic events in the universe are responsible for the creation for approximately half of elements heavier than iron. Elements lighter than iron (except for hydrogen, helium and lithium) were formed by nuclear fusion inside the cores of stars. But the heavier elements formed via r-process nucleosynthesis are thought to have been sourced via supernova explosions and neutron star collisions. Basically, the neutron-rich debris left behind by these energetic events seeded regions where neutrons could readily fuse, creating heavy elements.
These mechanisms for heavy element production are far from being proven, however.
“Scientists know that these heavy elements exist, but they’re not sure where these elements are being formed,” Kusenko said in a statement. “This has been really embarrassing.”
A cosmic goldmine
So what have primordial black holes got to do with nucleosynthesis?
If we assume the universe is still populated with these ancient black holes, they may collide with spinning neutron stars. When this happens, the researchers suggest that the black holes will drop into the cores of the neutron stars.
Like a parasite eating its host from the inside, material from the neutron star will be consumed by the black hole in its core, causing the neutron star to shrink. As it loses mass, the neutron star will spin faster, causing neutron-rich debris to fling off into space, facilitating (you guessed it) r-process nucleosynthesis, creating the heavy elements we know and love — like gold. The whole process is expected to take about 10,000 years before the neutron star is no more.
So, where are they?
There’s little evidence that primordial black holes exist, so the researchers suggest further astronomical work to study the light of distant stars that may flicker by the passage of invisible foreground black holes. The black holes’ gravitational fields will warp spacetime, causing the starlight to dim and brighten.
It’s certainly a neat theory to think that ancient black holes are diving inside neutron stars to spin them up and create gold in the process, but now astronomers need to prove that primordial black holes are out there, possibly contributing to the dark matter budget of our universe.
The ambitious $100 million Breakthrough Listen project aims to scan a million stars in our galaxy and dozens of nearby galaxies across radio frequencies and visible light in hopes of discovering a bona fide artificial signal that could be attributed to an advanced alien civilization. But in its quest, Breakthrough Listen has studied the signals emanating from FRB 121102 — and recorded 15 bursts — to better understand what might be causing it.
FRBs remain a mystery. First detected by the Parkes Radio Telescope in Australia, these very brief bursts of radio emissions seemed to erupt from random locations in the sky. But the same location never produced another FRB, making these bizarre events very difficult to understand and impossible to track.
Hypotheses ranged from powerful bursts of energy from supernovae to active galactic nuclei to (you guessed it) aliens, but until FRB 121102 repeated itself in 2015, several of these hypotheses could be ruled out. Supernovae, after all, only have to happen once — this FRB source is repeating, possibly hinting at a periodic energetic phenomenon we don’t yet understand. Also, because FRB 121102 is a repeater, in 2016 astronomers could trace back the location of its source to a dwarf galaxy 3 billion light-years from Earth.
Now we ponder the question: What in the universe generates powerful short bursts of radio emissions from inside a dwarf galaxy, repeatedly?
Using the Green Bank Telescope in the West Virginia, scientists of Breakthrough Listen recorded 400 TB of data over a five hour period on Aug. 26. In these data, 15 FRBs were recorded across the 4 to 8 GHz radio frequency band. The researchers noted the characteristic frequency dispersion of these FRBs, caused by the signal traveling through gas between us and the source.
Now that we have dedicated and extremely detailed measurements of this set of FRBs, astrophysicists can get to work trying to understand what natural phenomenon is generating these bursts. This is the story so far, but as we’re talking radio emissions, mysteries and a SETI project, aliens are never far away…
Probably Not Aliens
It may be exciting to talk about the possibility of aliens generating this signal — as a means of communication or, possibly, transportation via beamed energy — but that avenue of speculation is just that: speculation. But to speculate is understandable. FRBs are very mysterious and, so far, astrophysicists don’t have a solid answer.
But this mystery isn’t without precedent.
In 1967, astronomers Jocelyn Bell Burnell and Antony Hewish detected strange radio pulses emanating from a point in the sky during a quasar survey to study interplanetary scintillation (IPS). The mysterious pulses had an unnaturally precise period of 1.33 seconds. At the time, nothing like it had been recorded and the researchers were having a hard time explaining the observations. But in the back of their minds, they speculated that, however unlikely, the signal might be produced by an alien intelligence.
“We did not really believe that we had picked up signals from another civilization, but obviously the idea had crossed our minds and we had no proof that it was an entirely natural radio emission. It is an interesting problem – if one thinks one may have detected life elsewhere in the universe how does one announce the results responsibly? Who does one tell first? We did not solve the problem that afternoon, and I went home that evening very cross here was I trying to get a Ph.D. out of a new technique, and some silly lot of little green men had to choose my aerial and my frequency to communicate with us.”
This first source was nicknamed “LGM-1” (as in “Little Green Men-1”), but far from being an artificial source, the duo had actually identified the first pulsar — a rapidly-spinning, highly magnetized neutron star that generates powerful emissions from its precessing magnetic poles as it rotates.
This is how science works: An interesting signal is detected and theories are formulated as to how that signal could have been generated.
In the case of LGM-1, it was caused by an as-yet-to-be understood phenomenon involving a rapidly-spinning stellar corpse. In the case of FRB 121102, it is most likely an equally as compelling phenomenon, only vastly more powerful.
The least likely explanation of FRB 121102 makes a LOT of assumptions, namely: aliens that have become so incredibly technologically advanced (think type II or even type III on the Kardashev Scale) that they can fire a (presumably) narrow beam directly at us through intergalactic space over and over again (to explain the repeated FRB detections) — the odds of which would be vanishingly low — unless the signal is omnidirectional, so they’d need to access way more energy to make this happen. Another assumption could be that intelligent, technologically advanced civilizations are common, so it was only a matter of time before we saw a signal like FRB 121102.
Or it could be a supermassive black hole (say) doing something very energetic that science can’t yet explain.
Occam’s razor suggests the latter might be more reasonable.
This isn’t to say aliens don’t exist or that intelligent aliens aren’t transmitting radio signals, it just means the real cause of this particular FRB repeater is being generated by a known phenomenon doing something unexpected, or a new (and potentially more exciting) phenomenon that’s doing something exotic and new. It doesn’t always have to be aliens.
PSA: Things can go bump (or burst!) in the cosmos and be compelling/fascinating/intriguing without being ALIENS!
The U.S. media is currently saturated with hot takes, histories, weird facts, “how to’s” and weather reports around the Great American Eclipse that will glide across the continent on Monday (yes, THIS Monday, it’s finally here). But, today, one news report stood out from the crowd:
On reading the NBC News report (that was penned by an unknown Reuters writer), it is as tone deaf as the headline.
“American employers will see at least $694 million in missing output for the roughly 20 minutes that outplacement firm Challenger, Gray & Christmas estimates workers will take out of their workday on Monday to stretch their legs, head outside the office and gaze at the nearly two-and-a-half minute eclipse,” they write.
“Stretch their legs” for a “two-and-a-half minute eclipse,” — wow, what a waste of time. Worse than that, “[m]any people may take even longer to set up their telescopes or special viewing glasses, or simply take off for the day.” Unbelievable. Those skiving freeloaders.
How dare they take some time to step away from their computer screens to take a little time to gaze in awe at the most beautiful and rare natural celestial event to occur on our planet.
How dare they put pressure on the U.S. economy by bleeding hundreds of millions of dollars in lost revenue from the monstrous multi-trillion dollar consumerist machine.
How dare they be moved to tears as the moon completely blocks the sun, an event that has caused fear, suspicion, omen, wonderment, joy, inspiration, excitement and unadulterated passion throughout the history of our species.
How dare th— oh wait a minute. The lede appears to be buried:
“Compared to the amount of wages being paid to an employee over a course of a year, it is very small,” Challenger said. “It’s not going to show up in any type of macroeconomic data.”
So what you’re staying is, $700 million won’t even show up as a blip in economic analyses? Tell me more.
“It also pales when compared with the myriad other distractions in the modern workplace, such as March Madness, Cyber Monday, and the Monday after the Super Bowl,” they write. Well, whatdoyouknow, the Super Bowl is a distraction too? Those monsters.
So what you’re saying is, this isn’t really news. As a science news producer, I completely understand the pressures to keep up with the news cycle and finding fresh takes on tired stories (and let’s face it, 2017 has seen its fair share of eclipse articles). But for this particular angle, I think I would have most likely relegated the “lost” revenue to a footnote in a more informative and less clickbaity piece.
Monday’s eclipse will do untold good to this nation. The U.S. is going through a tumultuous stage in its young history, to put it mildly. This nation needs perspective to overcome the ineptitude, anti-science rhetoric and messages of segregation coming from its government; it needs an event that will be enjoyed by everyone, not just a fortunate subsection of society or the elite. The eclipse will inspire millions of people to look up (safely!) and ponder why is it that our planet’s only natural satellite can exactly fit into the disk of the sun.
Astronomy is an accessible gateway to the sciences and the eclipse will inspire, catalyzing many young minds to consider a future in STEM fields of study. This will enrich society in a myriad of ways and the economic gains from events such as Monday’s eclipse will make “$700 million” look like a piss in a swimming pool.
So, you know what? I’m glad this eclipse will “cost” the U.S. $700 million — I see it as an accidental investment in the future of this nation, a healthy nation that will hopefully put the antiscience stance of its current leaders behind it.
The funny thing about habitable zones is that they’re not necessarily habitable. In fact, depending on the star, some of them are likely downright horrible.
Take, for example, the “habitable zone exoplanet” orbiting our neighboring star Proxima Centauri. When the discovery of Proxima b was announced last year, the world erupted with excitement. After all, astronomers had detected an Earth-sized world right on our galactic doorstep, a mere four light-years away.
Immediately there was discussion about Proxima b’s habitable potential (could there be aliens?) and the possibility of the world becoming an interstellar target (might we one day go there on vacation?).
Alas, for the moment, these exo-dreams are pure fantasy as the only things we know about this world are its mass and its orbital period around the star. We have no clue about the composition of this exoplanet’s atmosphere — or even if it has an atmosphere at all. And, according to new research published in The Astrophysical Journal Letters, Proxima b would probably be a very unlikely place to find extraterrestrial life and you’d be ill advised to invest in a vacation home there.
Like TRAPPIST-1 — that other star system that contains “habitable, but probably not so habitable” exoplanets — Proxima Centauri is a red dwarf star. By their nature, red dwarfs are small and cooler than our sun. Their habitable zones are therefore very compact; to receive enough heating energy to keep water in a liquid state on their surfaces, any “habitable” red dwarf exoplanets would need to snuggle up really close to their star. Liquid water (as we all know) is essential for life. So, if you want to find life as we know it (not that weird Titan life), studying habitable zone planets would be a good place to start. And as red dwarfs are abundant in our galaxy, seeking out habitable zone planets in red dwarf star systems would, at first, seem like an even better place to start.
Except, probably not.
Red dwarfs are angry. They erupt with powerful flares, have powerful stellar winds and their habitable zones are awash with intense ultraviolet radiation. And, like TRAPPIST-1, Proxima Centauri probably wouldn’t be a great place to live.
But the researchers decided to test this hypothesis by throwing Earth in at the deep end.
“We decided to take the only habitable planet we know of so far — Earth — and put it where Proxima b is,” said Katherine Garcia-Sage, a space scientist at NASA’s Goddard Space Flight Center in Greenbelt, Md., and lead author of the study.
The big advantage for Earth is that it possesses a powerful global magnetic field that can deflect our sun’s solar wind and coronal mass ejections with a minimum of effort. But put Earth in a habitable zone orbit around Proxima Centauri and bad stuff starts to happen, fast.
At this location, the intensity of extreme ultraviolet radiation becomes a problem. Using data from NASA’s Chandra X-ray Observatory, the researchers could gauge the star’s activity and how much radiation would hit Proxima b. According to their calculations, the exoplanet receives hundreds of times more extreme ultraviolet radiation than Earth receives from our sun and, even if we assume Proxima b has an “Earth-like” magnetosphere, it will lose its atmosphere very quickly.
As ultraviolet radiation will ionize the exoplanet’s atmosphere, electrons (that are negatively charged) will be readily stripped from light atoms (hydrogen) and eventually the heavier atoms too (like oxygen and nitrogen). As the electrons are lost to space, a powerful “charge separation” is created and the positively charged ions that are left behind in the atmosphere will be dragged with the electrons, causing them to also be lost to space. Granted, the global magnetic field will have an effect on the rate of atmosphere loss, but the researchers estimate that this process will drain an atmosphere from Proxima b 10,000 times faster than what happens on Earth.
“This was a simple calculation based on average activity from the host star,” added Garcia-Sage. “It doesn’t consider variations like extreme heating in the star’s atmosphere or violent stellar disturbances to the exoplanet’s magnetic field — things we’d expect provide even more ionizing radiation and atmospheric escape.”
In the worst-case scenario, where the outer atmospheric temperatures are highest and the planet exhibits an “open” field line configuration, Proxima b would lose the equivalent of the whole of Earth’s atmosphere in just 100 million years. If the atmospheric temperatures are cool and a “closed” magnetic field line configuration is assumed, it will take 2 billion years for the atmosphere to be completely lost to space. Either way you look at it, unless the atmosphere is being continuously replaced (perhaps by very active volcanism), Proxima b will have very little chance to see life evolve.
“Things can get interesting if an exoplanet holds on to its atmosphere, but Proxima b’s atmospheric loss rates here are so high that habitability is implausible,” said Jeremy Drake, of the Harvard-Smithsonian Center for Astrophysics and study co-author. “This questions the habitability of planets around such red dwarfs in general.”
The Earth and Mars are currently on exact opposite sides of the sun — a celestial situation known as “Mars solar conjunction” — a time when we have no way of directly communicating with satellites and rovers at the Red Planet. So, when the Solar and Heliospheric Observatory (SoHO) spotted a huge (and I mean HUGE) bubble of superheated plasma expand from the solar disk earlier today (July 23), it either meant our nearest star had launched a vast coronal mass ejection directly at Earth or it had sent a CME in the exact opposite direction.
As another solar observatory — the STEREO-A spacecraft — currently has a partial view of the other side of the sun (it orbits ahead of Earth’s orbit, so it can see regions of the sun that are out of view from our perspective), we know that this CME didn’t emanate from the sun’s near side, it was actually launched away from us and Mars will be in for some choppy space weather very soon.
It appears the CME emanated from active region (AR) 2665, a region of intense magnetic activity exhibiting a large sunspot.
CMEs are magnetic bubbles of solar plasma that are ejected at high speed into interplanetary space following a magnetic eruption in the lower corona (the sun’s lower atmosphere). From STEREO-A’s unique vantage point, it appears the CME detected by SoHO was triggered by a powerful solar flare that generated a flash of extreme-ultraviolet radiation (possibly even generating X-rays):
When CMEs encounter Earth’s global magnetic field, the radiation environment surrounding our planet increases, posing a hazard for satellites and unprotected astronauts. In addition, if the conditions are right, geomagnetic storms may commence, creating bright aurorae at high latitudes. These storms can overload power grids on the ground, triggering mass blackouts. Predicting when these storms will occur is of paramount importance, so spacecraft such as SoHO, STEREO and others are constantly monitoring our star’s magnetic activity deep inside the corona and throughout the heliosphere.
Mars, however, is a very different beast to Earth in that it doesn’t have a strong global magnetosphere to shield against incoming energetic particles from the sun, which the incoming CME will be delivering very soon. As it lacks a magnetic field, this CME will continue to erode the planet’s thin atmosphere, stripping some of the gases into space. Eons of space weather erosion has removed most of the Martian atmosphere, whereas Earth’s magnetism keeps our atmospheric gases nicely contained.
When NASA and other space agencies check in with their Mars robots after Mars solar conjunction, it will be interesting to see if any recorded the space weather impacts of this particular CME.
There are few places that elicit such vivid thoughts of exotic habitable exoplanets than TRAPPIST-1 — a star system located less than 40 light-years from Earth. Alas, according to two recent studies, the planetary system surrounding the tiny red dwarf star may actually be horrible.
For anyone who knows a thing or two about red dwarfs, this may not come as a surprise. Although they are much smaller than our sun, red dwarfs can pack a powerful space weather punch for any world that orbits too close. And, by their nature, any habitable zone surrounding a red dwarf would have to be really compact, a small detail that would bury any “habitable” exoplanet in a terrible onslaught of ultraviolet radiation and a blowtorch of stellar winds. These factors would make the space weather environment around TRAPPIST-1 extreme to say the least.
“The concept of a habitable zone is based on planets being in orbits where liquid water could exist,” said Manasvi Lingam, a Harvard University researcher who led a Center for Astrophysics (CfA) study, published in the International Journal of Astrobiology. “This is only one factor, however, in determining whether a planet is hospitable for life.”
The habitable zone around any star is the distance at which a small rocky world can orbit and receive just the right amount of heating to maintain liquid water on its hypothetical surface. Orbit too close and the water vaporizes; too far and it freezes. As life needs liquid water to evolve, seeking out exoplanets in their star’s habitable zone is a good place to start.
For the sun-Earth system, we live in the middle of the habitable zone, at a distance of one astronomical unit (1 AU). For a world orbiting a red dwarf like TRAPPIST-1, its orbital distance would be a fraction of that — i.e. three worlds orbit TRAPPIST-1 in the star’s habitable zone at between 2.8% and 4.5% the distance the Earth orbits the sun. This is because red dwarfs are very dim and produce meager heating — for a world to receive the same degree of heating that our planet enjoys, a red dwarf world would need to snuggle up really close to its star.
But just because TRAPPIST-1 is dim, it doesn’t mean it holds back on ultraviolet radiation. And, according to this study, the three “habitable” exoplanets in the TRAPPIST-1 system are likely anything but — they would receive disproportionate quantities of damaging ultraviolet radiation.
“Because of the onslaught by the star’s radiation, our results suggest the atmosphere on planets in the TRAPPIST-1 system would largely be destroyed,” said co-author Avi Loeb, who also works at Harvard. “This would hurt the chances of life forming or persisting.”
Life as we know it needs an atmosphere, so the erosion by UV radiation seems like a significant downer for the possible evolution of complex life.
That’s not the only bad news for our extraterrestrial life dreams around TRAPPIST-1, however. Another study carried out by the CfA and the University of Massachusetts in Lowell (and published in The Astrophysical Journal Letters) found more problems. Like the sun, TRAPPIST-1 generates stellar winds that blast energetic particles into space. As these worlds orbit the star so close, they would be sitting right next to the proverbial nozzle of a stellar blowtorch — models suggest they experience 1,000 to 100,000 times stellar wind pressure than the solar wind exerts on Earth.
And, again, that’s not good news if a planet wants to hold onto its atmosphere.
“The Earth’s magnetic field acts like a shield against the potentially damaging effects of the solar wind,” said Cecilia Garraffo of the CfA and study lead. “If Earth were much closer to the sun and subjected to the onslaught of particles like the TRAPPIST-1 star delivers, our planetary shield would fail pretty quickly.”
So it looks like TRAPPIST-1 e, f and g really take a pounding from their angry little star, but the researchers point out that it doesn’t mean we should forget red dwarfs as potential life-giving places. It’s just that life would have many more challenges to endure than we do on our comparatively peaceful place in the galaxy.
“We’re definitely not saying people should give up searching for life around red dwarf stars,” said co-author Jeremy Drake, also from CfA. “But our work and the work of our colleagues shows we should also target as many stars as possible that are more like the sun.”
From crashing black holes to wobbling neutron stars, these cosmic phenomena generate ripples in spacetime and not necessarily emissions in the electromagnetic spectrum. So when the Laser Interferometer Gravitational-wave Observatory (LIGO) made its first gravitational wave detection in September 2015, the science world became very excited about the reality of “gravitational wave astronomy” and the prospect of detecting some of the most massive collisions that happen in the dark, billions of light-years away.
Like waves rippling over the surface of the ocean, gravitational waves travel through spacetime, a prediction that was made by Albert Einstein over a century ago. And like those ocean waves, gravitational waves might reveal something about the nature of spacetime.
We’re talking extra-dimensions and a new study suggests that gravitational waves may carry an awful lot more information with them beyond the characteristics of what generated them in the first place.
Our 4-D Playing Field
First things first, remember that we interact only with four-dimensional spacetime: three dimensions of space and one dimension of time. This is our playing field; we couldn’t care less whether there are more dimensions out there.
Unless you’re a physicist, that is.
And physicists are having a hard job describing gravity, to put it mildly. This might seem weird considering how essential gravity is for, well, everything. Without gravity, no stars would form, planets wouldn’t coalesce and the cosmos would be an exceedingly boring place. But gravity doesn’t seem to “fit” with the Standard Model of physics. The “recipe” for the universe is perfect, except it’s missing one vital ingredient: Gravity. (It’s as if a perfect cake recipe is missing one crucial ingredient, like flour.)
There’s another weird thing about gravity: Although it’s very important in our universe (yes, there might be more than one universe, but I’ll get to that later), it is actually the weakest of all forces.
String theory (and, by extension, superstring theory) predicts that the universe is composed of strings that vibrate at different frequencies. These strings form something like a vast, superfine noodle soup and these strings thread through many dimensions (many more than our four-dimensions) creating all the particles and forces that we know and love.
Now, the possible reason why gravity is so weak when compared with the other fundamental forces could be that gravity is interacting with many more dimensions that are invisible to us 4-D beings. Although string theory is a wonderful mathematical tool to describe this possibility, there is little physical evidence to back up this superfine noodly mess, however.
But as already mentioned, if string theory holds true, it would mean that our universe contains many more dimensions than we regularly experience. (The unifying superstring theory, called “M-theory”, predicts a total of 11 dimensions and may provide the framework that unifies the fundamental forces and could be the diving board that launches us into the vast ocean that is the multiverse… but I’ll stop there, I’ve said too much.)
Groovy. But what the heck has this got to do with gravitational waves? As gravitational waves travel through spacetime, they might be imprinted with information about these extra dimensions. Like our wave analogy, as the sea washes over a beach, the frequency of the waves increase as the water becomes shallower — the ocean waves are imprinted with information about how deep the water is. Could gravitational waves washing over (or, more accurately, through) spacetime also create some kind of signature that would reveal the presence of very, very tiny extra-dimensions as predicted by superstring theory?
Possibly, say researchers at the Max Planck Institute for Gravitational Physics (Albert Einstein Institute/AEI) in Potsdam, Germany.
“Physicists have been looking for extra dimensions at the Large Hadron Collider at CERN but up to now this search has yielded no results,” says Gustavo Lucena Gómez, second author of a new study published in the Journal of Cosmology and Astroparticle Physics. “But gravitational wave detectors might be able to provide experimental evidence.”
The researchers suggest that these extra-dimensions might modify the signal of gravitational waves received by detectors like LIGO and leave a very high-frequency “fingerprint.” But as this frequency would be exceedingly high — of the order of 1000 Hz — it’s not conceivable that the current (and near-future) ground-based gravitational wave detectors will be sensitive enough to even hope to detect these frequencies.
However, extra-dimensions might modify the gravitational waves in a different way. As gravitational waves propagate, they stretch and shrink the spacetime they travel through, like this:
The amount of spacetime warping might therefore be detected as more gravitational wave detectors are added to the global network. Currently, LIGO has two operating observing stations (one in Washington and one in Louisiana) and next year, the European Virgo detector will start taking data.
More detectors are planned elsewhere, so it’s possible that we may, one day, use gravitational waves to not only “see” black holes go bump in the night, we might also “see” the extra-dimensions that form the minuscule tapestry of the fabric beyond spacetime. And if we can do this, perhaps we’ll finally understand why gravity is so weak and how it really fits in with the Standard Model of physics.
Want to know more about gravitational waves? Well, here’s an Astroengine YouTube video on the topic:
Conventional wisdom would have us believe that stars form in extremely powerful and ordered magnetic fields. But “conventional,” our universe is not (as Yoda might say).
In a new and fascinating study published in Astrophysical Journal Letters and carried out by astronomers using the Atacama Large Millimeter/submillimeter Array (ALMA) in Chile, a star some 1,400 light-years away in the Serpens star-forming region had its magnetic field gauged.
The star, called Ser-emb 8, is embedded inside the magnetic field passing through the molecular cloud it was born in. As the surrounding dust aligns itself with the direction of these magnetic field lines, ALMA is able to make precise measurements of the polarization of the emissions produced by this dust. From these incredibly sensitive measurements, a map of the polarization of light could be created, providing a view of the magnetic nest the star was born in.
And this nest is an unexpected one; it’s a turbulent region lacking the strong and ordered magnetism that would normally be predicted to be in the immediate vicinity of Ser-emb 8. Previous studies have shown newborn stars to possess powerful magnetic fields that take on an “hourglass” shape, extending from the protostar and reaching light-years into space. Ser-emb 8, however, is different.
“Before now, we didn’t know if all stars formed in regions that were controlled by strong magnetic fields. Using ALMA, we found our answer,” said astronomer Charles L. H. “Chat” Hull, at the Harvard-Smithsonian Center for Astrophysics (CfA) in Cambridge, Mass. “We can now study magnetic fields in star-forming clouds from the broadest of scales all the way down to the forming star itself. This is exciting because it may mean stars can emerge from a wider range of conditions than we once thought.”
By comparing these observations with computer simulations, an insightful view of the earliest magnetic environment surrounding a young star has been created.
“Our observations show that the importance of the magnetic field in star formation can vary widely from star to star,” added Hull in a statement. “This protostar seems to have formed in a weakly magnetized environment dominated by turbulence, while previous observations show sources that clearly formed in strongly magnetized environments. Future studies will reveal how common each scenario is.”
Hull and his team think that ALMA has witnessed a phase of star formation before powerful magnetic fields are generated by the young star, wiping out any trace of this pristine magnetic environment passing through the star forming region.