John Crimaldi is a professor of civil, environmental and architectural engineering at the University of Colorado, Boulder.
Every time you flush a toilet, it releases plumes of tiny water droplets into the air around you. These droplets, called aerosol plumes, can spread pathogens from human waste and expose people in public restrooms to contagious diseases.
Scientific understanding of the spread of aerosol plumes – and public awareness of their existence – has been hampered by the fact that they are normally invisible. My colleagues Aaron True, Karl Linden, Mark Hernandez, Lars Larson and Anna Pauls and I were able to use high-power lasers to illuminate these plumes, enabling us to image and measure the location and motion of spreading aerosol plumes from flushing commercial toilets in vivid detail.
Aerosol plumes from commercial toilets can rise 5 feet above the bowl.
John Crimaldi/Scientific Reports, CC BY-NC-ND
Going up instead of down
Toilets are designed to efficiently empty the contents inside the bowl through a downward motion into the drain pipe. In the flush cycle, water comes into forceful contact with the contents inside the bowl and creates a fine spray of particles suspended in air.
We found that a typical commercial toilet generates a strong upward jet of air with velocities exceeding 6.6 feet per second (2 meters per second), rapidly carrying these particles up to 5 feet (1.5 meters) above the bowl within eight seconds of the start of the flush.
To visualize these plumes, we set up a typical lidless commercial toilet with a flushometer-style valve found throughout North America in our lab. Flushometer valves use pressure instead of gravity to direct water into the bowl. We used special optics to create a thin vertical sheet of laser light that illuminated the region from the top of the bowl to the ceiling. After flushing the toilet with a remote electrical trigger, the aerosol particles scatter enough laser light to become visible, allowing us to use cameras to image the plume of particles.
Even though we expected to see these particles, we were still surprised by the strength of the jet ejecting the particles from the bowl.
A related study used a computational model of an idealized toilet to predict the formation of aerosol plumes, with an upward transport of particles at speeds above the bowl approaching 3.3 feet per second (1 meter per second), which is about half of what we observed with a real toilet.
Using lasers to visualize invisible toilet plumes by
The Conversation on
YouTube
Why lasers?
Scientists have known for decades that flushing toilets can release aerosol particles into the air. However, experimental studies have largely relied on devices that sampled the air at fixed locations to determine the number and size of particles toilets produce.
Water streams forcefully into the toilet bowl during a flush cycle.
SouthHamsian/Wikimedia Commons, CC BY-NC-SA
While these earlier approaches can confirm the presence of aerosols, they provide little information about the physics of the plumes: what they look like, how they spread and how fast they move. This information is critical to develop strategies to mitigate the formation of aerosol plumes and reduce their capacity to transmit disease.
As an engineering professor whose research focuses on interactions between fluid physics and ecological or biological processes, my laboratory specializes in using lasers to determine how various things are transported by complex fluid flows. In many cases, these things are invisible until we illuminate them with lasers.
An advantage of using laser light to measure fluid flows is that, unlike a physical probe, light does not alter or disrupt the very thing you are trying to measure. Furthermore, using lasers to make invisible things visible helps people, as visual creatures, better understand complexities in the fluid environment they live in.
Aerosols and disease
Aerosol particles containing pathogens are important human disease vectors. Smaller particles that remain suspended in air for a period of time can expose people to respiratory diseases like influenza and COVID-19 through inhalation. Larger particles that settle quickly on surfaces can spread intestinal diseases like norovirus through contact with the hands and mouth.
Toilet bowl water contaminated by feces can have pathogen concentrations that persist after dozens of flushes. But it is still an open question as to whether toilet aerosol plumes present a transmission risk.
While we were able visually and quantitatively to describe how aerosol plumes move and disperse, our work does not directly address how toilet plumes transmit disease, and this remains an ongoing aspect of research.
Visualizing usually invisible toilet plumes in the lab with lasers by
The Conversation on
YouTube
Limiting toilet plume spread
Our experimental methodology provides a foundation for future work to test a range of strategies to minimize the risk of exposure to diseases from flushing toilets. This could include assessing changes to aerosol plumes emanating from new toilet bowl designs or flush valves that change the duration or intensity of the flush cycle.
Meanwhile, there are ways to reduce human exposure to toilet plumes. An obvious strategy is to close the lid prior to flushing. However, this does not completely eliminate aerosol plumes, and many toilets in public, commercial and health care settings do not have lids. Ventilation or UV disinfection systems could also mitigate exposure to aerosol plumes in the bathroom.
This article is republished from The Conversation under a Creative Commons license.
When the James Webb Space Telescope launched late last year, astronomers bestowed it with an infinite number of missions. I say infinite because the ultimate goal of this engineering marvel isn’t merely to answer every question we have about the universe. It’s to answer questions no mortal human would’ve thought to ask.
But before skipping to that mind-bending end goal, our brilliant new lens is dutifully strutting through the tasks we did give it, one of which is to pierce through veils of cosmic gas and dust and reveal secret star escapades within. Things standard optical telescopes, like Hubble, can’t always see.
Behold, on Tuesday, the JWST decoded a glimmering scene behind one of space’s dark curtains, a dusty canopy that enshrouds a pair of merging galaxies some 270 million light-years away from Earth.
The JWST caught a glimpse of a sparkly, sparkly cosmic scene.
ESA/Webb, NASA, CSA, L. Armus, A. Evans
What am I looking at?
We have two realms, dubbed IC 1623 A and B, stuck on a collision course through space and time. They’re located in the constellation Cetus, and have long been of interest to scientists for a few reasons.
Perhaps most strikingly, they might be in the process of forming a supermassive black hole — a gargantuan void with enough gravitational force to warp the fabric of our universe as we know it.
But that budding cavern of destruction is expected to be strung with a necklace of light.
The ultra-high intensity of galaxy merger IC 1623 also spurred the creation of a zippy star-forming region nearby. It’s called a starburst, and this one in particular, according to the European Space Agency, is creating new stars at a rate more than 20 times that of the Milky Way galaxy.
And this is what the JWST caught.
Hubble already gave us a preliminary view of IC 1623 A and B, but astronomy’s newest contract with space has pierced through the duo’s cosmic veil, just as scientists hoped it would since the beginning. By doing so, it’s shown us the luminous core of this merger and presented humanity with a full, mesmerizing image of IC 1623 rather than a concealed one with a central region left to our imagination.
Here’s Hubble’s view of merging galaxies IC 1623 A and B. It’s much less sparkly, because the central regions of these realms are obscured by dark dust.
ESA/Webb, NASA, CSA, L. Armus, A. Evans
Why can the JWST do what Hubble can’t?
Two words: infrared imaging.
All light emanating from deep space can be categorized on a sort of diagram known as the electromagnetic spectrum. Different wavelengths of light, which also translate to different colors in our eyes, are located on different parts. On one hand you have redder wavelengths, and on the other, bluer ones.
But if you go beyond the red side of the electromagnetic spectrum, as some light indeed does, you get to infrared light.
Infrared light, unlike regular red light, is essentially invisible to human eyes. That means it’s also invisible to instruments that act like human eyes, even if they’re really powerful versions like the Hubble Space Telescope.
But infrared light is precisely the kind of light emanating from stars within most clouds of thick cosmic dust, like the veil surrounding IC 1623. So to figure out what’s going on inside, we need an infrared-light-detecting telescope. And that’s JWST.
This infographic illustrates the spectrum of electromagnetic energy, specifically highlighting the portions detected by NASA’s Hubble, Spitzer and Webb space telescopes. Spitzer is now retired, and wasn’t as high tech as the JWST is.
NASA and J. Olmsted [STScI]
As a side note, light from stars and other phenomena located really, really far away from Earth arrive at our planet as infrared light, too. That’s why the JWST is prepped to bring us information about the distant universe as it was near the beginning of time, information invisible to us and to the Hubble Space Telescope. More on that here.
Returning to IC 1623, ESA explains that “Webb’s infrared sensitivity and its impressive resolution at those wavelengths allows it to see past the dust and has resulted in the spectacular image above, a combination of MIRI and NIRCam imagery,” in reference to two of the JWST’s high-tech instruments.
Another Easter egg in this image, as with all JWST pics, is the eight-pronged diffraction spikes you see at the very center. (It looks like six spikes, but there are two mini-spikes traveling horizontally through the midpoint. They’re just hard to see). All JWST images have this signature, in contrast to Hubble’s four-pronged version.
Here’s an outline of what the JWST’s diffraction spikes look like. You’ll see these in every JWST image!
NASA, ESA, CSA, Leah Hustak (STScI), Joseph DePasquale (STScI)
In general, these spikes are super prominent when lots of light is present in an image, explaining why the telescope’s latest image of two galactic cores boasts its bright central snowflake.
Hopefully, the next time JWST focuses its lens, it’ll be on one of those sights with evidence of something we never thought to ask about.
The discovery is a step towards much more accessible superconductivity.
It may be possible to develop superconductors that operate at room temperature with further knowledge of the relationship between spin liquids and superconductivity, which would transform our daily lives.
Superconductors offer enormous technical and economic promise for applications such as high-speed hovertrains, MRI machines, efficient power lines,
The electrical resistance of a superconductor has a specific critical temperature beyond which it drops suddenly to zero, unlike an ordinary metallic conductor, whose resistance declines gradually as temperature is reduced, even down to near
Scientists were taken aback when high-temperature superconductors were initially uncovered. Scientists had assumed that good superconductivity would be found in metals. Contrary to predictions, it was found that insulating ceramic materials are the best superconductors.
Finding properties that are common to these ceramic materials may help identify where their superconductivity originated from and improve control over the critical temperature. One such property is that the electrons in these materials resist each other strongly. They are thus unable to move freely. They are instead trapped inside a periodic lattice structure.
Electrons have two defining properties: their charge (a moving charge results in an electric current) and their spin. Spin is the quantum property of electrons responsible for their magnetic properties. It is as if a tiny bar magnet is attached to each electron. In ordinary materials, the charge and spin are “built-in” to the electrons and cannot be separated.
However, in special quantum materials called “quantum spin liquids”, interactions between the electrons enable a unique phenomenon whereby each electron is broken into two particles, one with charge (but no spin) and one with spin (and no charge). Such quantum spin liquids may exist in high-temperature superconductors and, in fact, their existence could explain why the superconductivity in these materials is so good.
The challenge is that these spin liquids are “invisible” to conventional measurements. Even when we suspect a material may be a spin liquid, there is no experiment that could verify it or probe its nature. This is similar to dark matter which doesn’t interact with light and is therefore very difficult to detect.
The current study, conducted by Professor Beena Kalisky and doctoral student Eylon Persky from the Physics Department at Bar-Ilan University and their collaborators, is a significant step towards the development of a method to study spin liquids. The researchers examined the properties of a spin liquid by making it interact with a superconductor. They used an engineered material made of alternating atomic layers of the superconductor and the candidate spin liquid.
“Unlike spin liquids which do not generate any signals, superconductors have clear magnetic signatures that are easy to measure. We were, therefore, able to study the properties of the spin liquid by measuring the small changes it generated in the superconductor,” says Persky. The researchers used a scanning SQUID – an extremely sensitive magnetic sensor capable of detecting both magnetism and superconductivity – to investigate the properties of the heterostructure.
“We’ve observed vortices created in the superconductor. These vortices are circulating electric currents, each holding one quantum of magnetic flux. The only way to create such vortices is by applying a magnetic field, but in our case, the vortices were created spontaneously,” explains Kalisky. This observation showed that the material itself generated a magnetic field. The biggest surprise came when this field did not show itself in a direct measurement. “Surprisingly, we found that the magnetic field created by the material was invisible to a direct magnetic measurement,” adds Kalisky.
The results pointed to a “hidden” magnetic phase, which was exposed in the experiment through the interaction with the superconducting layer. Collaborating with groups from Bar-Ilan University, the Technion, the Weizmann Institute, the University of California, Berkeley, and the Georgia Institute of Technology, the researchers concluded that this magnetic phase was probably a direct result of the relationship between the spin liquid layer and the superconducting layer. The hidden magnetism is a result of the spin-charge separation in the spin liquid. The superconductor reacts to this magnetism and this generates vortices without the need for a “real” magnetic field.
This is, in fact, the first direct observation of the link between these two phases of matter. These results provide access to the properties of the elusive spin liquids, such as the interactions between the electrons. The results also open the door to engineering additional layered materials, through which the relationship between superconductivity and other electronic phases could be studied. Further studies of the relationship between spin liquids and superconductivity may enable designing superconductors that work at room temperature, and this, in turn, would change our daily lives.
Reference: “Magnetic memory and spontaneous vortices in a van der Waals superconductor” by Eylon Persky, Anders V. Bjørlig, Irena Feldman, Avior Almoalem, Ehud Altman, Erez Berg, Itamar Kimchi, Jonathan Ruhman, Amit Kanigel and Beena Kalisky, 27 July 2022, Nature. DOI: 10.1038/s41586-022-04855-2
Researchers have unpacked a major cybersecurity find—a malicious UEFI-based rootkit used in the wild since 2016 to ensure computers remained infected even if an operating system is reinstalled or a hard drive is completely replaced.
The firmware compromises the UEFI, the low-level and highly opaque chain of firmware required to boot up nearly every modern computer. As the software that bridges a PC’s device firmware with its operating system, the UEFI—short for Unified Extensible Firmware Interface—is an OS in its own right. It’s located in an SPI-connected flash storage chip soldered onto the computer motherboard, making it difficult to inspect or patch the code. Because it’s the first thing to run when a computer is turned on, it influences the OS, security apps, and all other software that follows.
Exotic, yes. Rare, no.
On Monday, researchers from Kaspersky profiled CosmicStrand, the security firm’s name for a sophisticated UEFI rootkit that the company detected and obtained through its antivirus software. The find is among only a handful of such UEFI threats known to have been used in the wild. Until recently, researchers assumed that the technical demands required to develop UEFI malware of this caliber put it out of reach of most threat actors. Now, with Kaspersky attributing CosmicStrand to an unknown Chinese-speaking hacking group with possible ties to cryptominer malware, this type of malware may not be so rare after all.
“The most striking aspect of this report is that this UEFI implant seems to have been used in the wild since the end of 2016—long before UEFI attacks started being publicly described,” Kaspersky researchers wrote. “This discovery begs a final question: If this is what the attackers were using back then, what are they using today?”
While researchers from fellow security firm Qihoo360 reported on an earlier variant of the rootkit in 2017, Kaspersky and most other Western-based security firms didn’t take notice. Kaspersky’s newer research describes in detail how the rootkit—found in firmware images of some Gigabyte or Asus motherboards—is able to hijack the boot process of infected machines. The technical underpinnings attest to the sophistication of the malware.
A rootkit is a piece of malware that runs in the deepest regions of the operating system it infects. It leverages this strategic position to hide information about its presence from the operating system itself. A bootkit, meanwhile, is malware that infects the boot process of a machine in order to persist on the system. The successor to legacy BIOS, UEFI is a technical standard defining how components can participate in the startup of an OS. It’s the most “recent” one, as it was introduced around 2006. Today, almost all devices support UEFI when it comes to the boot process. The key point here is that when we say something takes place at the UEFI level, it means that it happens when the computer is starting up, before the operating system has even been loaded. Whatever standard is being used during that process is only an implementation detail, and in 2022, it will almost always be UEFI anyway.
In an email, Kaspersky researcher Ivan Kwiatkowski wrote:
So a rootkit may or may not be a bootkit, depending on where it is installed on the victim’s machine. A bootkit may or may not be a rootkit, as long as it infected a component used for the system startup (but considering how low-level these usually are, bootkits will usually be rootkits). And firmware is one of the components which can be infected by bootkits, but there are others, too. CosmicStrand happens to be all of these at the same time: It has the stealthy rootkit capabilities and infects the boot process through malicious patching of the firmware image of motherboards.
The workflow of CosmicStrand consists of setting “hooks” at carefully selected points in the boot process. Hooks are modifications to the normal execution flow. They usually come in the form of additional code developed by the attacker, but in some cases, a legitimate user may inject code before or after a particular function to bring about new functionality.
The CosmicStrand workflow looks like this:
The initial infected firmware bootstraps the whole chain.
The malware sets up a malicious hook in the boot manager, allowing it to modify Windows’ kernel loader before it is executed.
By tampering with the OS loader, the attackers are able to set up another hook in a function of the Windows kernel.
When that function is later called during the normal startup procedure of the OS, the malware takes control of the execution flow one last time.
It deploys a shellcode in memory and contacts the C2 server to retrieve the actual malicious payload to run on the victim’s machine.
It is a rare delight for a sequel to be as good as the original, but on July 12, the James Webb Space Telescope’s second set of images certainly lived up to expectations set by its extraordinary deep field reveal the prior evening. As a matter of fact, it surpassed it by leaps and bounds.
The unveiling of that first image by President Joe Biden wasn’t exactly impressive, but the image itself? Magnificent. Known as “Webb’s First Deep Field,” it gives astronomers a look at galaxy cluster SMACS 0723.
JWST’s First Deep Field was revealed on July 11.
NASA, ESA, CSA, and STScI
What you’re looking at is a minuscule patch of the Southern Hemisphere sky — equivalent to a grain of sand held up to the heavens — yet replete with thousands of galaxies, from spirals and ellipticals to simple pinpricks of light only a few pixels wide. And thanks to a phenomenon known as gravitational lensing, it provides us with the deepest, and oldest, view of the cosmos yet — as well as concrete proof of Albert Einstein’s general relativity. That’s a lot to live up to, right?
Well, even though the images released Tuesday don’t reach quite so far back in space and time, they are undoubtedly profound, equal to the First Deep Field in beauty and delicately woven with exquisite cosmic detail.
Three major images make up the JWST’s first full-color set.
Two focus on nebulas, huge clouds of dust and gas within which stars are sometimes born, and the other analyzes a region known as Stephan’s Quintet, a frightening corner of the cosmos where five galaxies are locked in an ultimately fatal dance.
Then there’s the spectral data of WASP-96 b — a really hot, giant, gassy exoplanet — which reveals the composition of its atmosphere in unprecedented detail. This one isn’t an image like you’d expect, but arguably something even more valuable. It’s a spectral dataset that helps us understand not what a spaceborne object aesthetically looks like but rather what it’d be like to stand on it. And, as they say, the book is often better than the film.
Let’s break down each one and explain why the JWST’s second batch of cosmic goodies is just as groundbreaking as its first peek.
The nebulas
Nebulas are immense clouds of dust and gas that exist at either end of a star’s life. Some are home to fledgling baby stars, while others are created by their explosive deaths. But in both cases, nebulas are responsible for some of the most stunning visuals we have of our cosmos — and through the JWST’s lens, the most powerful infrared imager we’ve ever worked with, their marvel is only enhanced.
You can read exactly how the JWST’s infrared imaging works here, but the basic principle is it can access light — emanating across the cosmos from stars, galaxies and other luminescent objects — that’s stuck in a region of the electromagnetic spectrum invisible to our eyes. And more specifically to nebulas, that “hidden” light, so to speak, happens to be the main kind shooting through their dust clouds from whatever lies inside.
That means our pupils, and even massive telescopes like the Hubble Space Telescope, can’t penetrate nebular curtains of gaseousness. They’re veils that typically obscure our view of the flashy features within — namely, stars just bursting to life or those in the process of dying. The JWST’s instruments, however, easily get past them via infrared imaging to check out what’s going on backstage. Plus, NASA’s next-gen scope offers a much (much) better resolution than a telescope such as Hubble — in effect, catching the internal nebula show as well as external structure with a sophisticated clarity novel to human eyes.
Now that we know what we’re about to look at, let’s get into it.
For its first nebula science discoveries, the JWST focused on two separate stardust clouds: The Carina Nebula, located about 8,500 light-years from Earth, and the Eight Burst Nebula, which is much closer at around 2,000 light-years away.
Starting off strong, behold: the Eight Burst Nebula. It’s also known as the Southern Ring Nebula.
On the left is a version of the Southern Ring Nebula taken by JWST’s Nircam and on the right, by MIRI.
NASA
“This is a planetary nebula,” NASA astronomer Karl Gordon said. “It’s caused by a dying star that spilled a large fraction of its mass over in successive waves.” These shockwaves can be clearly seen in the image, they’re the pond-like ripples floating around the center that resembles a biological cell.
On the left, you’ll see them a bit more clearly. That’s because this side is a version of the nebular image taken by the JWST’s Near-Infrared Camera, or Nircam. It’s often considered the telescope’s holy grail imager because it leads the charge in finding pieces of the invisible universe. In this case, Nircam helps illustrate the layers of light that connect to make up this complex system. Like a mixed-media painting, it offers a good deal of texture to showcase different facets of the Southern Ring, including those shockwaves.
And on the right is a version of the image drawn by the JWST’s Mid-Infrared Instrument, or MIRI. Like it’s name, MIRI’s specialty is catching light from the mid-infrared region of the electromagnetic spectrum. Thanks to MIRI, we also get an exciting Easter egg in this photo.
Right in the center of the cosmic eye, there are clearly two stars present. Next to the brighter one, we can see the dying one that caused the nebula — the dot that looks redder on the left. This star duo had been theorized to exist in the past… dancing around one another in an intergalactic waltz. But we hadn’t ever been seen both together before. This is the first time.
MIRI captured both stars present in this nebula for the first time ever.
Screenshot by Monisha Ravisetti/NASA
According to NASA, the brighter star will probably eject its own planetary nebula in the future — but until then, will continue to influence the nebula’s appearance, thus giving us the vivid spectacle we see today. “As the pair continues to orbit one another,” NASA says, “they ‘stir the pot’ of gas and dust, causing asymmetrical patterns.”
Also, on that right-hand image, if you glance toward the top left, you’ll see a mysterious blueish line that appears to have been flung out from the nebula. This little line has its own grand story.
See that blueish streak?
Screenshot by Monisha Ravisetti/NASA
“I made a bet that said ‘It’s part of the nebula,'” Gordon said. “I lost the bet, because then we looked more carefully at both Nircam and MIRI images, and it’s very clearly an edge-on galaxy.” Yep, there’s an entire faraway galaxy lurking in this picture. The JWST has some tricks up its sleeve.
Next up is the Carina Nebula — once again, courtesy of the JWST’s Nircam and MIRI.
NASA
“Honestly, it took me a while to figure out what to call out in this image,” NASA astrophysicist Amber Straughn said. “There’s just so much going on here. It’s so beautiful.”
This astonishing image is technically the edge of a giant cavity within a nebula called NGC 3324, known as the Carina Nebula. It boasts an incredible wealth of emerging stellar nurseries, cosmic cliffs and individual stars that call this nebula their abode. Until now, all those cosmic sparkles and details were completely hidden from our view due to the thick dust and gas surrounding them — but, remember, the JWST infrared cameras can literally pierce that veil of intergalactic secrets and access valuable sights within.
Decoding this image could very well shed light on how stars are formed, what kind of star-making material goes into that formation and even dissect the mechanism of violent, starry winds that affect surrounding space.
And if you’re curious about all those hills, valleys and spikes? So are NASA scientists. They’re kind of puzzles yet to be solved. Or as Straughn puts it, “we see examples of structures that, honestly, we don’t even know what they are.”
Something we do know, though, is the JWST also just gave us a groundbreaking view of an alien world. An exoplanet.
WASP-96 b
The hot, gaseous, giant exoplanet WASP-96 b is a scientific curiosity. Its parent star, WASP-96, lies about 1,120 light-years from Earth, making it the closest object in Webb’s first batch of images. Here it is.
NASA
OK, though this image isn’t what you’d normally think of when hoping for a planetary portrait, it’s incredibly important for the field of astronomy. What you’re looking at is direct spectral data of an exoplanet in a solar system beyond our own.
While we don’t get a view of the planet hanging out in space by its star, this “spectra” clues us in to the ingredients that make up this alien world. What astronomers detected is striking.
The JWST’s spectral analysis of WASP-96 b indicates a telltale signature of water vapor in the planet’s atmosphere as well as evidence of clouds and hazes, which are tiny solid particles that sort of act like pseudo-clouds. And yes, I said water. But before you get too excited about packing up to move to WASP-96 b, a world decked-out in H2O, note this exoplanet is closer to its star than Mercury is to the sun. That means its deathly hot and all its water is not liquid. Oh, and it orbits that star every three and a half Earth days.
This is probably (definitely) not habitable for us Earthlings.
A hypothetical visualization of WASP-96b from NASA’s exoplanet catalog.
Screenshot by Monisha Ravisetti/NASA
Regardless, it’s an intriguing finding because while astronomers have, so far, located over 5,000 worlds outside of our solar system — and studied many of them with Hubble and other space telescopes — WASP-96 b always stood out for its potentially unusual atmosphere. But until now, we didn’t have a good look at that planetary shield, making WASP-96 b a hot topic for debate.
“Most close-in exoplanets that have been studied with Hubble have flat, white spectra, which is taken as evidence that they are very cloudy,” Benjamin Pope, a planetary scientist at the University of Queensland in Australia, said. But such clouds are a nuisance because they prevent astronomers from getting a good feel for the composition of an exoplanet’s atmosphere. That’s not a problem with WASP-96b, so previous data suggested it was basically free of clouds. “It has the clearest skies of any exoplanet we know of,” said Coel Hellier, an astrophysicist at Keele University who was a member of the team that first discovered the planet, prior to the release of the spectra.
Webb’s shown that, with better data, we’ve been able to resolve some of the questions around WASP-96b. Like… maybe it does have clouds!
But in the grand scheme of things, this spectral data can be thought of as proof of concept that the JWST works as we hoped. Which means it will be able to assess the composition of many planets’ atmospheres in the future. “[WASP-96 b] is nothing like our solar system planets,” Knicole Colon, an astrophysicist at NASA said. “But that’s okay because what we’re seeing is, again, the first exoplanet data from Webb. This is just the beginning.”
While astronomers have long used Hubble, and other telescopes, to gather data about exoplanets and their atmospheres, there’s just nothing like the James Webb Space Telescope. “JWST is just going to be so much better for this,” notes Pope.
Only time will tell what comes next.
Moving on — what can Webb teach us about galaxies? As it turns out, quite a bit. Say hello to your new galactic muses.
Stephan’s Quintet
Last but absolutely not least for NASA’s Tuesday JWST image release is the breathtaking glimpse we got of Stephan’s Quintet.
This dramatic grouping of five individual galaxies was discovered in the 19th century, long before the first space telescopes — well, even the first satellites — made it to orbit. It’s a bright region of space, made up of five galaxies and home to a huge shockwave, courtesy of two galaxies colliding at extreme speed.
Of today’s image releases, the Quintet is the farthest from Earth, with the galaxies located between 39 and 340 million light-years from our planet (one of the galaxies, NGC 7320, is much closer than the other four). We’ve been observing it from the ground for almost 150 years, and Hubble has also captured striking images of the grouping. But we’ve never seen it like this.
NASA
In this gigantic scene, the JWST revealed the Quintet with so much detail that we can literally see individual stars speckling the galaxies. The one on the left, in particular, is a starry spectacle fit for a fairytale universe.
But perhaps the most incredible aspect of this photo has to do with the top-most galaxy that appears violent, yet awfully serene. This duality is because it turns out to hold one of the most terrifying, yet majestic, features of the universe. A black hole.
The JWST confirmed that this galaxy has an active galactic nucleus — that is, a supermassive black hole 24 million times the mass of our sun, sitting at its center. It’s a void that’s simultaneously pulling in material and spitting out light energy equivalent to the burn of 40 billion suns.
A close-up of a star-spotted galaxy, courtesy of NASA’s JWST.
Screenshot by Monisha Ravisetti/NASA
The JWST’s Nirspec and MIRI teamed up to dissect the features of this abyss, offering proof of matter swirling around it.
The composition of gas around the black hole in Stephan’s Quintet.
Screenshot by Monisha Ravisetti/NASA
And if you zoom out and peruse the background of the JWST’s depiction of Stephan’s Quintet, you’ll catch sight of throngs of other galaxies dotting the dark canvas of space. Believe it or not, that’s kind of a happy accident — one we might want to get used to.
The JWST is so powerful and precise it’s nearly impossible for it to take an image of what we’d consider “blank space.” It can’t help but serendipitously capture cosmic treasures. Every time.
It’s just… too good.
It’s also extremely efficient, which is why we can expect an unending influx of images and spectral data as incredible as the JWST’s first full set, on a regular basis. “This is just the beginning,” was a sentiment repeatedly brought up during NASA’s Tuesday broadcast, and for good reason. This is the first page of astronomy’s next grand chapter.
“Hubble’s extreme deep field was two weeks of continuous work,” Bill Nelson, NASA administrator said of probably the most famous image taken by the JWST’s predecessor. “Imaging with Webb, we took that image before breakfast. The amazing thing about Webb is the speed at which we can churn out discoveries”
What this means is that even though Tuesday’s release of JWST images was encapsulated in pomp and announced to the sound of champagne glasses clinking, everything we’ve seen took something like a week to put together. “We’re going to be doing discoveries like this every week,” Nelson said.
Hubble and James Webb Space Telescope Images Compared: See the Difference
It’s not often that the sequel is as good as the original, but the second image release from the James Webb Space Telescope certainly lived up to expectations set by Monday evening’s jaw-dropping deep field reveal. In fact, it surpassed it by leaps and bounds.
The unveiling of that first image by President Joe Biden wasn’t exactly impressive, but the image itself? Magnificent. Known as “Webb’s First Deep Field,” it gives astronomers a look at galaxy cluster SMACS 0723.
JWST’s First Deep Field was revealed on July 11.
NASA, ESA, CSA, and STScI
What you’re looking at is a minuscule patch of the Southern Hemisphere sky — equivalent to a grain of sand held up to the heavens — yet replete with thousands of galaxies, from spirals and ellipticals to simple pinpricks of light only a few pixels wide. And thanks to a phenomenon known as gravitational lensing, it provides us with the deepest, and oldest, view of the cosmos yet — as well as concrete proof of Albert Einstein’s general relativity. That’s a lot to live up to, right?
Well, even though the images released Tuesday don’t reach quite so far back in space and time, they are undoubtedly profound, equal to the First Deep Field in beauty and delicately woven with exquisite cosmic detail.
Three major images make up the JWST’s first full-color set.
Two focus on nebulas, huge clouds of dust and gas within which stars are sometimes born, and the other analyzes a region known as Stephan’s Quintet, a frightening corner of the cosmos where five galaxies are locked in an ultimately fatal dance.
Then there’s the spectral data of WASP-96 b — a really hot, giant, gassy exoplanet — which reveals the composition of its atmosphere in unprecedented detail. This one isn’t an image like you’d expect, but arguably something even more valuable. It’s a spectral dataset that helps us understand not what a spaceborne object aesthetically looks like but rather what it’d be like to stand on it. And, as they say, the book is often better than the film.
Let’s break down each one and explain why the JWST’s second batch of cosmic goodies is just as groundbreaking as its first peek.
The nebulas
Nebulas are immense clouds of dust and gas that exist at either end of a star’s life. Some are home to fledgling baby stars, while others are created by their explosive deaths. But in both cases, nebulas are responsible for some of the most stunning visuals we have of our cosmos — and through the JWST’s lens, the most powerful infrared imager we’ve ever worked with, their marvel is only enhanced.
You can read exactly how the JWST’s infrared imaging works here, but the basic principle is it can access light — emanating across the cosmos from stars, galaxies and other luminescent objects — that’s stuck in a region of the electromagnetic spectrum invisible to our eyes. And more specifically to nebulas, that “hidden” light, so to speak, happens to be the main kind shooting through their dust clouds from whatever lies inside.
That means our pupils, and even massive telescopes like the Hubble Space Telescope, can’t penetrate nebular curtains of gaseousness. They’re veils that typically obscure our view of the flashy features within — namely, stars just bursting to life or those in the process of dying. The JWST’s instruments, however, easily get past them via infrared imaging to check out what’s going on backstage. Plus, NASA’s next-gen scope offers a much (much) better resolution than a telescope such as Hubble — in effect, catching the internal nebula show as well as external structure with a sophisticated clarity novel to human eyes.
Now that we know what we’re about to look at, let’s get into it.
For its first nebula science discoveries, the JWST focused on two separate stardust clouds: The Carina Nebula, located about 8,500 light-years from Earth, and the Eight Burst Nebula, which is much closer at around 2,000 light-years away.
Starting off strong, behold: the Eight Burst Nebula. It’s also known as the Southern Ring Nebula.
On the left is a version of the Southern Ring Nebula taken by JWST’s Nircam and on the right, by MIRI.
NASA
“This is a planetary nebula,” NASA astronomer Karl Gordon said. “It’s caused by a dying star that spilled a large fraction of its mass over in successive waves.” These shockwaves can be clearly seen in the image, they’re the pond-like ripples floating around the center that resembles a biological cell.
On the left, you’ll see them a bit more clearly. That’s because this side is a version of the nebular image taken by the JWST’s Near-Infrared Camera, or Nircam. It’s often considered the telescope’s holy grail imager because it leads the charge in finding pieces of the invisible universe. In this case, Nircam helps illustrate the layers of light that connect to make up this complex system. Like a mixed-media painting, it offers a good deal of texture to showcase different facets of the Southern Ring, including those shockwaves.
And on the right is a version of the image drawn by the JWST’s Mid-Infrared Instrument, or MIRI. Like it’s name, MIRI’s specialty is catching light from the mid-infrared region of the electromagnetic spectrum. Thanks to MIRI, we also get an exciting Easter egg in this photo.
Right in the center of the cosmic eye, there are clearly two stars present — not just the dying one, which is the one that looks redder on the left. The brighter, second star had been theorized to exist in the past… but hadn’t ever been seen before. This is the first time we’ve laid eyes on it.
MIRI captured both stars present in this nebula for the first time ever.
Screenshot by Monisha Ravisetti/NASA
According to NASA, it will probably eject its own planetary nebula in the future — but until then, that star will continue to influence the nebula’s appearance, giving us the vivid spectacle we see today. “As the pair continues to orbit one another,” NASA says, “they ‘stir the pot’ of gas and dust, causing asymmetrical patterns.”
Also, on that right-hand image, if you glance toward the top left, you’ll see a mysterious blueish line that appears to have been flung out from the nebula. This little line has its own grand story.
See that blueish streak?
Screenshot by Monisha Ravisetti/NASA
“I made a bet that said ‘It’s part of the nebula,'” Gordon said. “I lost the bet, because then we looked more carefully at both Nircam and MIRI images, and it’s very clearly an edge-on galaxy.” Yep, there’s an entire faraway galaxy lurking in this picture. The JWST has some tricks up its sleeve.
Next up is the Carina Nebula — once again, courtesy of the JWST’s Nircam and MIRI.
NASA
“Honestly, it took me a while to figure out what to call out in this image,” NASA astrophysicist Amber Straughn said. “There’s just so much going on here. It’s so beautiful.”
This astonishing image is technically the edge of a giant cavity within a nebula called NGC 3324, known as the Carina Nebula. It boasts an incredible wealth of emerging stellar nurseries, cosmic cliffs and individual stars that call this nebula their abode. Until now, all those cosmic sparkles and details were completely hidden from our view due to the thick dust and gas surrounding them — but, remember, the JWST infrared cameras can literally pierce that veil of intergalactic secrets and access valuable sights within.
Decoding this image could very well shed light on how stars are formed, what kind of star-making material goes into that formation and even dissect the mechanism of violent, starry winds that affect surrounding space.
And if you’re curious about all those hills, valleys and spikes? So are NASA scientists. They’re kind of puzzles yet to be solved. Or as Straughn puts it, “we see examples of structures that, honestly, we don’t even know what they are.”
Something we do know, though, is the JWST also just gave us a groundbreaking view of an alien world. An exoplanet.
WASP-96 b
The hot, gaseous, giant exoplanet WASP-96 b is a scientific curiosity. Its parent star, WASP-96, lies about 1,120 light-years from Earth, making it the closest object in Webb’s first batch of images. Here it is.
NASA
OK, though this image isn’t what you’d normally think of when hoping for a planetary portrait, it’s incredibly important for the field of astronomy. What you’re looking at is direct spectral data of an exoplanet in a solar system beyond our own.
While we don’t get a view of the planet hanging out in space by its star, this “spectra” clues us in to the ingredients that make up this alien world. What astronomers detected is striking.
The JWST’s spectral analysis of WASP-96 b indicates a telltale signature of water vapor in the planet’s atmosphere as well as evidence of clouds and hazes, which are tiny solid particles that sort of act like pseudo-clouds. And yes, I said water. But before you get too excited about packing up to move to WASP-96 b, a world decked-out in H2O, note this exoplanet is closer to its star than Mercury is to the sun. That means its deathly hot and all its water is not liquid. Oh, and it orbits that star every three and a half Earth days.
This is probably (definitely) not habitable for us Earthlings.
A hypothetical visualization of WASP-96b from NASA’s exoplanet catalog.
Screenshot by Monisha Ravisetti/NASA
Regardless, it’s an intriguing finding because while astronomers have, so far, located over 5,000 worlds outside of our solar system — and studied many of them with Hubble and other space telescopes — WASP-96 b always stood out for its potentially unusual atmosphere. But until now, we didn’t have a good look at that planetary shield, making WASP-96 b a hot topic for debate.
“Most close-in exoplanets that have been studied with Hubble have flat, white spectra, which is taken as evidence that they are very cloudy,” Benjamin Pope, a planetary scientist at the University of Queensland in Australia, said. But such clouds are a nuisance because they prevent astronomers from getting a good feel for the composition of an exoplanet’s atmosphere. That’s not a problem with WASP-96b, so previous data suggested it was basically free of clouds. “It has the clearest skies of any exoplanet we know of,” said Coel Hellier, an astrophysicist at Keele University who was a member of the team that first discovered the planet, prior to the release of the spectra.
Webb’s shown that, with better data, we’ve been able to resolve some of the questions around WASP-96b. Like… maybe it does have clouds!
But in the grand scheme of things, this spectral data can be thought of as proof of concept that the JWST works as we hoped. Which means it will be able to assess the composition of many planets’ atmospheres in the future. “[WASP-96 b] is nothing like our solar system planets,” Knicole Colon, an astrophysicist at NASA said. “But that’s okay because what we’re seeing is, again, the first exoplanet data from Webb. This is just the beginning.”
While astronomers have long used Hubble, and other telescopes, to gather data about exoplanets and their atmospheres, there’s just nothing like the James Webb Space Telescope. “JWST is just going to be so much better for this,” notes Pope.
Only time will tell what comes next.
Moving on — what can Webb teach us about galaxies? As it turns out, quite a bit. Say hello to your new galactic muses.
Stephan’s Quintet
Last but absolutely not least for NASA’s Tuesday JWST image release is the breathtaking glimpse we got of Stephan’s Quintet.
This dramatic grouping of five individual galaxies was discovered in the 19th century, long before the first space telescopes — well, even the first satellites — made it to orbit. It’s a bright region of space, made up of five galaxies and home to a huge shockwave, courtesy of two galaxies colliding at extreme speed.
Of today’s image releases, the Quintet is the farthest from Earth, with the galaxies located between 39 and 340 million light-years from our planet (one of the galaxies, NGC 7320, is much closer than the other four). We’ve been observing it from the ground for almost 150 years, and Hubble has also captured striking images of the grouping. But we’ve never seen it like this.
NASA
In this gigantic scene, the JWST revealed the Quintet with so much detail that we can literally see individual stars speckling the galaxies. The one on the left, in particular, is a starry spectacle fit for a fairytale universe.
But perhaps the most incredible aspect of this photo has to do with the top-most galaxy that appears violent, yet awfully serene. This duality is because it turns out to hold one of the most terrifying, yet majestic, features of the universe. A black hole.
The JWST confirmed that this galaxy has an active galactic nucleus — that is, a supermassive black hole 24 million times the mass of our sun, sitting at its center. It’s a void that’s simultaneously pulling in material and spitting out light energy equivalent to the burn of 40 billion suns.
A close-up of a star-spotted galaxy, courtesy of NASA’s JWST.
Screenshot by Monisha Ravisetti/NASA
The JWST’s Nirspec and MIRI teamed up to dissect the features of this abyss, offering proof of matter swirling around it.
The composition of gas around the black hole in Stephan’s Quintet.
Screenshot by Monisha Ravisetti/NASA
And if you zoom out and peruse the background of the JWST’s depiction of Stephan’s Quintet, you’ll catch sight of throngs of other galaxies dotting the dark canvas of space. Believe it or not, that’s kind of a happy accident — one we might want to get used to.
The JWST is so powerful and precise it’s nearly impossible for it to take an image of what we’d consider “blank space.” It can’t help but serendipitously capture cosmic treasures. Every time.
It’s just… too good.
It’s also extremely efficient, which is why we can expect an unending influx of images and spectral data as incredible as the JWST’s first full set, on a regular basis. “This is just the beginning,” was a sentiment repeatedly brought up during NASA’s Tuesday broadcast, and for good reason. This is the first page of astronomy’s next grand chapter.
“Hubble’s extreme deep field was two weeks of continuous work,” Bill Nelson, NASA administrator said of probably the most famous image taken by the JWST’s predecessor. “Imaging with Webb, we took that image before breakfast. The amazing thing about Webb is the speed at which we can churn out discoveries”
What this means is that even though Tuesday’s release of JWST images was encapsulated in pomp and announced to the sound of champagne glasses clinking, everything we’ve seen took something like a week to put together. “We’re going to be doing discoveries like this every week,” Nelson said.
Hubble and James Webb Space Telescope Images Compared: See the Difference
In a former gold mine a mile underground, inside a titanium tank filled with a rare liquified gas, scientists have begun the search for what so far has been unfindable: dark matter.
Scientists are pretty sure the invisible stuff makes up most of the universe’s mass and say we wouldn’t be here without it – but they don’t know what it is. The race to solve this enormous mystery has brought one team to the depths under Lead, South Dakota.
The question for scientists is basic, said Kevin Lesko, a physicist at Lawrence Berkeley National Laboratory. “What is this great place I live in? Right now, 95% of it is a mystery.”
The idea is that a mile of dirt and rock, a giant tank, a second tank and the purest titanium in the world will block nearly all the cosmic rays and particles that zip around and through all of us every day. But dark matter particles, scientists think, can avoid all those obstacles. They hope one will fly into the vat of liquid xenon in the inner tank and smash into a xenon nucleus like two balls in a game of pool, revealing its existence in a flash of light seen by a device called “the time projection chamber”.
Scientists announced Thursday that the five-year, $60m search finally got underway two months ago after a delay caused by the pandemic. So far the device has found … nothing. At least no dark matter.
Scientists hope that a particle of dark matter will fly into a vat of liquid xenon and smash into a nucleus to prove its existence. Photograph: Matthew Kapust/AP
That’s OK, they say. The equipment appears to be working to filter out most of the background radiation they hoped to block. “To search for this very rare type of interaction, job number one is to first get rid of all of the ordinary sources of radiation, which would overwhelm the experiment,” said University of Maryland physicist Carter Hall.
And if all their calculations and theories are right, they figure they’ll see only a couple fleeting signs of dark matter a year. The team of 250 scientists estimates they’ll get 20 times more data over the next couple of years.
By the time the experiment finishes, the chance of finding dark matter with this device is “probably less than 50% but more than 10%”, said Hugh Lippincott, a physicist and spokesman for the experiment in a Thursday news conference.
While that’s far from a sure thing, “you need a little enthusiasm”, Lesko said. “You don’t go into rare search physics without some hope of finding something.”
Lab workers take care to avoid contaminating the dark matter detector in the Sanford Underground Research Facility in Lead, South Dakota. Photograph: Stephen Groves/AP
Two hulking Depression-era hoists run an elevator that brings scientists to what’s called the Lux-Zeplin experiment in the Sanford Underground Research Facility. A 10-minute descent ends in a tunnel with cool-to-the-touch walls lined with netting. But the old, musty mine soon leads to a high-tech lab where dirt and contamination is the enemy. Helmets are exchanged for new cleaner ones and a double layer of baby blue booties go over steel-toed safety boots.
The heart of the experiment is the giant tank called the cryostat, lead engineer Jeff Cherwinka said in a December 2019 tour before the device was closed and filled. He described it as “like a Thermos” made of “perhaps the purest titanium in the world” designed to keep the liquid xenon cold and keep background radiation at a minimum.
Xenon is special, explained experiment physics coordinator Aaron Manalaysay, because it allows researchers to see if a collision is with one of its electrons or with its nucleus. If something hits the nucleus, it is more likely to be the dark matter that everyone is looking for, he said.
These scientists tried a similar, smaller experiment here years ago. After coming up empty, they figured they had to go much bigger. Another large-scale experiment is underway in Italy run by a rival team, but no results have been announced so far.
The scientists are trying to understand why the universe is not what it seems.
The research team stands next to the giant tank called the cryostat, which one scientist likened to a Thermos. Photograph: Matthew Kapust/AP
One part of the mystery is dark matter, which has by far most of the mass in the cosmos. Astronomers know it’s there because when they measure the stars and other regular matter in galaxies, they find that there is not nearly enough gravity to hold these clusters together. If nothing else was out there, galaxies would be “quickly flying apart”, Manalaysay said.
“It is essentially impossible to understand our observation of history, of the evolutionary cosmos without dark matter,” Manalaysay said.
Lippincott, a University of California, Santa Barbara, physicist, said, “We would not be here without dark matter.”
So while there’s little doubt that dark matter exists, there’s lots of doubt about what it is. The leading theory is that it involves things called Wimps – weakly interacting massive particles.
If that’s the case, Lux-Zeplin could be able to detect them. We want to find “where the wimps can be hiding”, Lippincott said.
The Curiosity rover has found an outstanding rock formation piercing the alien landscape of Mars. Amongst the shallow sands and boulders of the Gale Crater rise several twisting towers of rock – the spikes of sediment look almost like frozen streams of water poured from an invisible jug in the sky.
In reality, experts say the columns were probably created from cement-like substances that once filled ancient cracks of bedrock. As the softer rock gradually eroded away, the snaking streams of compact material remained standing.
Rock formations found on Mars. (NASA, JPL-Caltech, MSSS)
The rock formations were snapped by a camera on board the Curiosity rover on May 17, but the image was only shared last week by NASA and experts at the SETI institute (which stands for the Search for Extraterrestrial Intelligence), as part of SETI’s planetary picture of the day initiative.
#PPOD: Here is another cool rock at Gale crater on Mars! The spikes are most likely the cemented fillings of ancient fractures in a sedimentary rock. The rest of the rock was made of softer material and was eroded away. 📷: @NASA @NASAJPL @Caltech #MSSS fredk, acquired on May 17. pic.twitter.com/RGfjmRBfI7
— The SETI Institute (@SETIInstitute) May 26, 2022
As alien as the structures might look, they aren’t without precedent.
In Earthly geology, a ‘hoodoo’ is a tall and thin spire of rock formed by erosion. It can also be called a tent rock, fairy chimney, or earth pyramid.
Hoodoos are usually found in dry environments, like the canyons of Utah or southern Serbia, and the columns can sometimes tower as high as ten-story buildings.
A hoodoo in Bryce Canyon, Utah. (Don Graham/Flickr/CC BY SA 2.0)
The natural structures are formed by hard rock layers that build up within softer sedimentary rock. As the rest of the rock erodes away from rain, wind or frost, you’re left with a magnificent mould of an ancient fracture in the bedrock.
Hoodoos East Coulee, Alberta, Canada. (Darren Kirby/CC BY SA 2.0)
The two towers of rock on Mars look like they are about to topple over compared to the ones we see on Earth, but clearly they are solid enough to withstand the lighter surface gravity experienced on the red planet.
Another strange rock formation found by Curiosity earlier this year might have been created in a similar way, albeit with very different results.
This other, smaller rock looks sort of like a piece of coral or a flower with numerous little petals stretching up towards the sun.
“One theory that has emerged is that the rock is a type of concretion created by minerals deposited by water in cracks or divisions in existing rock,” a press release from NASA explained at the time.
“These concretions can be compacted together, can be harder and denser than surrounding rock, and can remain even after the surrounding rock erodes away.”
A flower-shaped rock found on Mars. (NASA, JPL-Caltech, MSSS)
The Gale crater isn’t wholly flat, but the alien spires discovered by Curiosity stand out from the rest of their environment, although no height measurements accompany the image.
The towering tombstones of rock might look lifeless now, but their formation speaks volumes about ancient conditions on Mars and whether life could have once thrived there billions of years ago.
The Gale crater itself is thought to be a dried-up lake bed, though possibly shallower and more transitory than experts once assumed.
Rock formations in and around the ancient lake are helping to reveal the region’s true history.
Induced transparency: The precise control of the energy flow (indicated by glowing particles in the fog) makes the artificial material become entirely transparent for the optical signal. Credit: Andrea Steinfurth / University of Rostock
Space, the final frontier. The starship Enterprise pursues its mission to explore the galaxy, when all communication channels are suddenly cut off by an impenetrable nebula. In many episodes of the iconic TV series, the valiant crew must “tech the tech” and “science the science” within just 45 minutes of airtime in order to facilitate their escape from this or a similar predicament before the end credits roll. Despite spending a significantly longer time in their laboratories, a team of scientists from the University of Rostock has succeeded in developing an entirely new approach for the design of artificial materials that can transmit light signals without any distortions by means of precisely tuned flows of energy. They have published their results in Science Advances.
“When light spreads in an inhomogeneous medium, it undergoes scattering. This effect quickly transforms a compact, directed beam into a diffuse glow, and is familiar to all of us from summer clouds and autumn fog alike,” Professor Alexander Szameit of the Institute for Physics at the University of Rostock describes the starting point of his team’s considerations. Notably, it is the microscopic density distribution of a material that dictates the specifics of scattering. Szameit continues, “The fundamental idea of induced transparency is to take advantage of a much lesser-known optical property to clear a path for the beam, so to speak.”
This second property, known in the field of photonics under the arcane title of non-Hermiticity, describes the flow of energy, or, more precisely, the amplification and attenuation of light. Intuitively, the associated effects may seem undesirable—particularly the fading of a light beam due to absorption would seem highly counterproductive to the task of improving signal transmission. Nevertheless, non-Hermitian effects have become a key aspect of modern optics, and an entire field of research strives to harness the sophisticated interplay of losses and amplification for advanced functionalities.
“This approach opens up entirely new possibilities,” reports doctoral student Andrea Steinfurth, first author of the paper. In regard to a beam of light, it becomes possible to selectively amplify or dampen specific parts of a beam at the microscopic level to counteract any onset of degradation. To stay in the picture of the nebula, its light-scattering properties could be completely suppressed. “We are actively modifying a material to tailor it for the best possible transmission of a specific light signal,” Steinfurth explains. “To this end, the energy flow must be precisely controlled, so it can fit together with the material and the signal like pieces of a puzzle.” In close collaboration with partners from the Vienna University of Technology, the researchers in Rostock successfully tackled this challenge. In their experiments, they were able to recreate and observe the microscopic interactions of light signals with their newly developed active materials in networks of kilometer-long optical fibers.
In fact, induced transparency is just one of the fascinating possibilities that arise from these findings. If an object is truly to be made to vanish, the prevention of scattering is not enough. Instead, light waves must emerge behind it completely undisturbed. Yet, even in the vacuum of space, diffraction alone ensures that any signal will inevitably change its shape. “Our research provides the recipe for structuring a material in such a way that light beams pass as if neither the material, nor the very region of space it occupies, existed. Not even the fictitious cloaking devices of the Romulans can do that,” says co-author Dr. Matthias Heinrich, circling back to the final frontier of Star Trek.
The findings presented in this work represent a breakthrough in fundamental research on non-Hermitian photonics and provide new approaches for the active fine-tuning of sensitive optical systems, for example, sensors for medical use. Other potential applications include optical encryption and secure data transmission, as well as the synthesis of versatile artificial materials with tailored properties.
Reconfigurable silicon nanoantennas controlled by vectorial light field
More information:
Andrea Steinfurth et al, Observation of photonic constant-intensity waves and induced transparency in tailored non-Hermitian lattices, Science Advances (2022). DOI: 10.1126/sciadv.abl7412
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A new warp speed experiment could finally offer an indirect test of famed physicist Stephen Hawking’s most famous prediction about black holes.
The new proposal suggests that, by nudging an atom to become invisible, scientists could catch a glimpse of the ethereal quantum glow that envelops objects traveling at close to the speed of light.
The glow effect, called the Unruh (or Fulling-Davies-Unruh) effect, causes the space around rapidly accelerating objects to seemingly be filled by a swarm of virtual particles, bathing those objects in a warm glow. As the effect is closely related to the Hawking effect — in which virtual particles known as Hawking radiation spontaneously pop up at the edges of black holes — scientists have long been eager to spot one as a hint of the other’s existence.
Related: ‘X particle’ from the dawn of time detected inside the Large Hadron Collider
But spotting either effect is incredibly hard. Hawking radiation only occurs around the terrifying precipice of a black hole, and achieving the acceleration needed for the Unruh effect would probably need a warp drive. Now, a groundbreaking new proposal, published in an April 26 study in the journal Physical Review Letters, could change that. Its authors say they have uncovered a mechanism to dramatically boost the strength of the Unruh effect through a technique that can effectively turn matter invisible.
“Now at least we know there is a chance in our lifetimes where we might actually see this effect,” co-author Vivishek Sudhir, an assistant professor of mechanical engineering at MIT and a designer of the new experiment, said in a statement. “It’s a hard experiment, and there’s no guarantee that we’d be able to do it, but this idea is our nearest hope.”
First proposed by scientists in the 1970s, the Unruh effect is one of many predictions to come out of quantum field theory. According to this theory, there is no such thing as an empty vacuum. In fact, any pocket of space is crammed with endless quantum-scale vibrations that, if given sufficient energy, can spontaneously erupt into particle-antiparticle pairs that almost immediately annihilate each other. And any particle — be it matter or light — is simply a localized excitation of this quantum field.
In 1974, Stephen Hawking predicted that the extreme gravitational force felt at the edges of black holes — their event horizons — would also create virtual particles.
Gravity, according to Einstein’s theory of general relativity, distorts space-time, so that quantum fields get more warped the closer they get to the immense gravitational tug of a black hole’s singularity. Because of the uncertainty and weirdness of quantum mechanics, this warps the quantum field, creating uneven pockets of differently moving time and subsequent spikes of energy across the field. It is these energy mismatches that make virtual particles emerge from what appears to be nothing at the fringes of black holes.
“Black holes are believed to be not entirely black,” lead author Barbara Šoda, a doctoral student in physics at the University of Waterloo in Canada, said in a statement. “Instead, as Stephen Hawking discovered, black holes should emit radiation.”
Much like the Hawking effect, the Unruh effect also creates virtual particles through the weird melding of quantum mechanics and the relativistic effects predicted by Einstein. But this time, instead of the distortions being caused by black holes and the theory of general relativity, they come from near light-speeds and special relativity, which dictates that time runs slower the closer an object gets to the speed of light.
According to quantum theory, a stationary atom can only increase its energy by waiting for a real photon to excite one of its electrons. To an accelerating atom, however, fluctuations in the quantum field can add up to look like real photons. From an accelerating atom’s perspective, it will be moving through a crowd of warm light particles, all of which heat it up. This heat would be a telltale sign of the Unruh effect.
But the accelerations required to produce the effect are far beyond the power of any existing particle accelerator. An atom would need to accelerate to the speed of light in less than a millionth of a second — experiencing a g force of a quadrillion meters per second squared — to produce a glow hot enough for current detectors to spot.
“To see this effect in a short amount of time, you’d have to have some incredible acceleration,” Sudhir said. “If you instead had some reasonable acceleration, you’d have to wait a ginormous amount of time — longer than the age of the universe — to see a measurable effect.”
To make the effect realizable, the researchers proposed an ingenious alternative. Quantum fluctuations are made denser by photons, which means that an atom made to move through a vacuum while being hit by light from a high-intensity laser could, in theory, produce the Unruh effect, even at fairly small accelerations. The problem, however, is that the atom could also interact with the laser light, absorbing it to raise the atom’s energy level, producing heat that would drown out the heat generated by the Unruh effect.
But the researchers found yet another workaround: a technique they call acceleration-induced transparency. If the atom is forced to follow a very specific path through a field of photons, the atom will not be able to “see” the photons of a certain frequency, making them essentially invisible to the atom. So by daisy-chaining all these workarounds, the team would then be able to test for the Unruh effect at this specific frequency of light.
Making that plan a reality will be a tough task. The scientists plan to build a lab-size particle accelerator that will accelerate an electron to light speeds while hitting it with a microwave beam. If they’re able to detect the effect, they plan to conduct experiments with it, especially those that will enable them to explore the possible connections between Einstein’s theory of relativity and quantum mechanics.
“The theory of general relativity and the theory of quantum mechanics are currently still somewhat at odds, but there has to be a unifying theory that describes how things function in the universe,” co-author Achim Kempf, a professor of applied mathematics at the University of Waterloo, said in a statement. “We’ve been looking for a way to unite these two big theories, and this work is helping to move us closer by opening up opportunities for testing new theories against experiments.”
