Month: February 2018

Storm Waves Can Move Boulders We Thought Only Tsunamis Had The Power To Shift

It’s not just tsunamis that can change the landscape: storms shifted giant boulders four times the size of a house on the coast of Ireland in the winter of 2013-14, leading researchers to rethink the maximum energy storm waves can have — and the damage they can do.

In a new paper in Earth Science Reviews, researchers from Williams College in the US show that four years ago, storms moved huge boulders along the west coast of Ireland. The same storms shifted smaller ones as high as 26 meters above high water and 222 meters inland. Many of the boulders moved were heavier than 100 tons, and the largest moved was 620 tons — the equivalent of six blue whales or four single-storey houses.

It was previously assumed that only tsunamis could move boulders of the size seen displaced in Ireland, but the new paper provides direct evidence that storm waves can do this kind of work. According to the UN, about 40 percent of the world’s population live in coastal areas (within 100 meters of the sea), so millions of people are at risk from storms. Understanding how those waves behave, and how powerful they can be, is key for preparation. It is therefore important to know the upper limits of storm wave energy, even in areas where these kinds of extreme wave energies are not expected.

“The effect of the storms of winter 2013-14 was dramatic,” said Dr. Rónadh Cox, Professor and Chair of Geosciences at Williams College and lead author of the study. “We had been studying these sites for a number of years, and realised that this was an opportunity to measure the coastal response to very large storm events.”

In the summer after the storms, Prof. Cox and a team of seven undergraduate students from Williams College surveyed 100 sites in western Ireland, documenting with photos the displacement of 1,153 boulders. They measured the dimensions and calculated the mass of each boulder. They knew where 374 of the boulders had come from, so for those they also documented the distance travelled. The largest boulder, at 237-239 m3 was an estimated 620 tons; the second biggest, at 180-185 m3, was about 475 tons. These giant rocks were close to sea level (although above the high tide mark). At higher elevations, and at greater distances inland, smaller boulders moved upwards and inland.

Analysis of this information showed that the waves had most power at lower elevations and closer to the shore. While this may not be surprising, the sheer energy of the waves and their ability to move such large boulders was — and this evidence proves that not only tsunami but also storm waves can move such large objects.

“These data will be useful to engineers and coastal scientists working in other locations,” said Prof. Cox. “Now that we know what storm waves are capable of, we have much more information for policy makers who are responsible for preparing coastal communities for the impact of high-energy storms.”

Modern Volcanism Tied To Events Occurring Soon After Earth’s Birth

Plumes of hot magma from the volcanic hotspot that formed Réunion Island in the Indian Ocean rise from an unusually primitive source deep beneath Earth’s surface, according to new work in Nature from Carnegie’s Bradley Peters, Richard Carlson, and Mary Horan along with James Day of the Scripps Institution of Oceanography.

Réunion marks the present-day location of the hotspot that 66 million years ago erupted the Deccan Traps flood basalts, which cover most of India and may have contributed to the extinction of the dinosaurs. Flood basalts and other hotspot lavas are thought to originate from different portions of Earth’s deep interior than most volcanoes at Earth’s surface and studying this material may help scientists understand our home planet’s evolution.

The heat from Earth’s formation process caused extensive melting of the planet, leading Earth to separate into two layers when the denser iron metal sank inward toward the center, creating the core and leaving the silicate-rich mantle floating above.

Over the subsequent 4.5 billion years of Earth’s evolution, deep portions of the mantle would rise upwards, melt, and then separate once again by density, creating Earth’s crust and changing the chemical composition of Earth’s interior in the process. As crust sinks back into Earth’s interior — a phenomenon that’s occurring today along the boundary of the Pacific Ocean — the slow motion of Earth’s mantle works to stir these materials, along with their distinct chemistry, back into the deep Earth.

But not all of the mantle is as well-blended as this process would indicate. Some older patches still exist — like powdery pockets in a poorly mixed bowl of cake batter. Analysis of the chemical compositions of Réunion Island volcanic rocks indicate that their source material is different from other, better-mixed parts of the modern mantle.

Using new isotope data, the research team revealed that Réunion lavas originate from regions of the mantle that were isolated from the broader, well-blended mantle. These isolated pockets were formed within the first ten percent of Earth’s history.

Isotopes are elements that have the same number of protons, but a different number of neutrons. Sometimes, the number of neutrons present in the nucleus make an isotope unstable; to gain stability, the isotope will release energetic particles in the process of radioactive decay. This process alters its number of protons and neutrons and transforms it into a different element. This new study harnesses this process to provide a fingerprint for the age and history of distinct mantle pockets.

Samarium-146 is one such unstable, or radioactive, isotope with a half-life of only 103 million years. It decays to the isotope neodymium-142. Although samarium-146 was present when Earth formed, it became extinct very early in Earth’s infancy, meaning neodymium-142 provides a good record of Earth’s earliest history, but no record of Earth from the period after all the samarium-146 transformed into neodymium-142. Differences in the abundances of neodymium-142 in comparison to other isotopes of neodymium could only have been generated by changes in the chemical composition of the mantle that occurred in the first 500 million years of Earth’s 4.5 billion-year history.

The ratio of neodymium-142 to neodymium-144 in Réunion volcanic rocks, together with the results of lab-based mimicry and modeling studies, indicate that despite billions of years of mantle mixing, Réunion plume magma likely originates from a preserved pocket of the mantle that experienced a compositional change caused by large-scale melting of Earth’s earliest mantle.

The team’s findings could also help explain the origin of dense regions right at the boundary of the core and mantle called large low shear velocity provinces (LLSVPs) and ultralow velocity zones (ULVZs), reflecting the unusually slow speed of seismic waves as they travel through these regions of the deep mantle. Such regions may be relics of early melting events.

“The mantle differentiation event preserved in these hotspot plumes can both teach us about early Earth geochemical processes and explain the mysterious seismic signatures created by these dense deep-mantle zones,” said lead author Peters.

Search For First Stars Uncovers ‘Dark Matter’

A team of astronomers led by Prof. Judd Bowman of Arizona State University unexpectedly stumbled upon “dark matter,” the most mysterious building block of outer space, while attempting to detect the earliest stars in the universe through radio wave signals, according to a study published this week in Nature.

The idea that these signals implicate dark matter is based on a second Nature paper published this week, by Prof. Rennan Barkana of Tel Aviv University, which suggests that the signal is proof of interactions between normal matter and dark matter in the early universe. According to Prof. Barkana, the discovery offers the first direct proof that dark matter exists and that it is composed of low-mass particles.

The signal, recorded by a novel radio telescope called EDGES, dates to 180 million years after the Big Bang.

What the universe is made of

“Dark matter is the key to unlocking the mystery of what the universe is made of,” says Prof. Barkana, Head of the Department of Astrophysics at TAU’s School of Physics and Astronomy. “We know quite a bit about the chemical elements that make up the earth, the sun and other stars, but most of the matter in the universe is invisible and known as ‘dark matter.’ The existence of dark matter is inferred from its strong gravity, but we have no idea what kind of substance it is. Hence, dark matter remains one of the greatest mysteries in physics.

“To solve it, we must travel back in time. Astronomers can see back in time, since it takes light time to reach us. We see the sun as it was eight minutes ago, while the immensely distant first stars in the universe appear to us on earth as they were billions of years in the past.”

Prof. Bowman and colleagues reported the detection of a radio wave signal at a frequency of 78 megahertz. The width of the observed profile is largely consistent with expectations, but they also found it had a larger amplitude (corresponding to deeper absorption) than predicted, indicating that the primordial gas was colder than expected.

Prof. Barkana suggests that the gas cooled through the interaction of hydrogen with cold, dark matter.

“Tuning in” to the early universe

“I realized that this surprising signal indicates the presence of two actors: the first stars, and dark matter,” says Prof. Barkana. “The first stars in the universe turned on the radio signal, while the dark matter collided with the ordinary matter and cooled it down. Extra-cold material naturally explains the strong radio signal.”

Physicists expected that any such dark matter particles would be heavy, but the discovery indicates low-mass particles. Based on the radio signal, Prof. Barkana argues that the dark-matter particle is no heavier than several proton masses. “This insight alone has the potential to reorient the search for dark matter,” says Prof. Barkana.

Once stars formed in the early universe, their light was predicted to have penetrated the primordial hydrogen gas, altering its internal structure. This would cause the hydrogen gas to absorb photons from the cosmic microwave background, at the specific wavelength of 21 cm, imprinting a signature in the radio spectrum that should be observable today at radio frequencies below 200 megahertz. The observation matches this prediction except for the unexpected depth of the absorption.

Prof. Barkana predicts that the dark matter produced a very specific pattern of radio waves that can be detected with a large array of radio antennas. One such array is the SKA, the largest radio telescope in the world, now under construction. “Such an observation with the SKA would confirm that the first stars indeed revealed dark matter,” concludes Prof. Barkana.

Black Holes From Small Galaxies Might Emit Gamma Rays

As a general rule of thumb, if there is a puzzling phenomenon occurring somewhere deep in outer space, a black hole is often the culprit behind it.

This is according to postdoctoral researcher Vaidehi Paliya in the department of physics and astronomy, whose January 2018 publication in The Astrophysical Journal Letters details the discovery of seven galaxies that could potentially shake up what astrophysicists thought they knew about how the size of a galaxy — and the black hole at its center — can affect its behavior.

It has been widely believed that only massive galaxies contain enough energy to become blazars, which are stupendous jets of radiation powerful enough to stretch thousands of light years. But Paliya’s latest research might indicate that smaller galaxies can also do this, if the conditions are right.

There are three main types of galaxies: oval-shaped ellipticals, disk-like spirals and irregulars that don’t quite fit in with either of the former classes.

“Elliptical galaxies are the oldest, most massive galaxies in the universe,” Paliya said. “People propose that elliptical galaxies form when two smaller galaxies collide, merging into one big elliptical. Typically, ellipticals are found to host a black hole that is more than a billion times the mass of our sun.”

Through their inherent, inescapable gravitational force, black holes at the center of galaxies will grow larger by drawing in and “eating” the surrounding matter through a process called accretion.

“It’s like when you pour water in the kitchen sink, you see it forms a spiral, then it goes down the drain. In a similar way, matter forms an accretion disk around the black hole,” Paliya said. “The black hole then grows rapidly and becomes a monster.”

But when the accretion disk surrounding the black hole begins emitting extreme bursts of energy — in radio, infrared or X-ray bands — the galaxy is said to be “active,” opening the door to another galaxy classifier beyond shape.

“Blazars are one type of active galaxy,” said Marco Ajello, a professor of physics and astronomy and Paliya’s advisor. “These are galaxies that host a supermassive black hole, and this black hole — in some way — is able to accelerate particles to near the speed of light and keep them collimated in narrow beams, called jets, which become very bright sources of light when they are pointing toward us.”

These jets are some of the most extreme sources of gamma-ray radiation in outer space.

“These blazars have jets that are like fountains. If you wanted a huge fountain, you’d need to have a very powerful engine at the base. Blazars need to have very massive black holes at their centers to be able to launch jets,” Paliya said. “Generally, we don’t expect these powerful jets from sources that are small, like our galaxy.”

The Milky Way is a spiral galaxy with pinwheel-like arms made up of gas and dust that contain a bright center of older stars. Typically, spiral galaxies are less massive and much less active than their elliptical counterparts.

When the Fermi Gamma-Ray Space Telescope, launched in 2008 by NASA, detected gamma ray emission from four spiral galaxies in its first year of orbit, physicists were perplexed.

“It was unexpected — we have only seen that kind of gamma ray emission from blazars,” said Dieter Hartmann, a professor of physics and astronomy and co-author of the study. “When these four sources were discovered, people speculated that they could be blazars. But since there were so few sources, nobody was certain about it. Then the question became: are these really a new type of source, or are they just exceptions to the standard?”

The question was left up in the air, until Paliya’s collaborators in India released a catalog of active spiral galaxies in 2017. Known as Seyfert galaxies, these are another type of active galaxy with relatively low mass black holes residing at their centers. However, rather than emitting violent bursts of gamma-ray radiation, like blazars, Seyfert galaxies are known for their strong ultra-violet emissions.

The catalog provided the first chance for astrophysicists to address the question of the Fermi telescope’s 2008 discovery. Is it possible for a spiral galaxy to emit jetted gamma-ray radiation?

“I took this catalog of 11,101 Seyfert galaxies, and I studied them in the gamma ray band using the data from the Large Area Telescope onboard Fermi satellite,” Paliya said. “From that, I found four new gamma ray sources and three that were earlier known as blazars but we believe are actually Seyfert galaxies.”

This breakthrough is an indication that even smaller sources are capable of launching powerful gamma ray jets — a potential paradigm shift in the field of astrophysics.

“If the jet is similar to that of blazars, but its black hole is small, you can imagine it like a car. Say a smaller car is going the same speed as another car that has a much bigger engine. The engine in the smaller car would then need to be much more efficient,” Ajello said. “So, it could be that the black hole is working more efficiently in smaller, spiral systems than it is in larger objects like blazars.”

To understand the elliptical/spiral nature of the host galaxies of these seven gamma-ray detected sources, Ajello and Paliya intend to obtain deep images with the highest resolution — a challenge for ground-based optical telescopes due to the blurring effects of the atmosphere.

“The light-collecting power of a telescope is proportional to the square of its diameter. This means that with bigger telescopes, we can collect a lot more photons. More photons mean more information,” Paliya said.

The Gran Telescopio Canarias, or the “Great Canary Telescope,” is a 10.4-meter reflecting telescope that began gathering observations in 2007. Currently holding the title of the “world’s largest single-aperture optical telescope,” the Gran Telescopio Canarias is slated to be surpassed in the next decade with the unveiling of the Thirty Meter Telescope (TMT). When finished, TMT will have a 30-meter primary mirror and will allow researchers to see outer space with unprecedented clarity — at least 10 times better than the Hubble Space Telescope.

Ajello and Paliya intend to use the Hubble Space Telescope, and potentially upcoming facilities like TMT, to peer beyond the bright centers of the seven sources they uncovered to distinguish with certainty whether the galaxies are elliptical or spiral.

“If it is an elliptical, then it’s true that we are just looking at a normal blazar. It’s probably a smaller elliptical and a smaller black hole,” Ajello said. “But if it’s a spiral, then the jets can happen in any environment that is a black hole, within some newfound conditions.”

“It is of great importance to better understand the environments of super-massive black holes that are able to launch jets in which particle acceleration takes place under extreme astrophysical conditions,” Hartmann added.

Paliya also intends to study whether the differences observed in gamma rays translate across the electromagnetic spectrum.

“This is all about optics,” Paliya said. “How do blazars behave at, say, radio frequencies? Then, how do these Seyferts compare? This discovery has indicated that yes, something different is occurring.”

The researchers said that discoveries such as these are important in helping us understand the evolution of the universe. These discoveries could represent some of the missing pieces of the puzzle of how galaxies and black holes have grown together throughout history.

Mineralogy Of Potential Lunar Exploration Site

A detailed study of a giant impact crater on the Moon’s far side could provide a roadmap for future lunar explorers.

The study, by planetary scientists from Brown University, maps the mineralogy of the South Pole-Aitken (SPA) basin, a gash in the lunar surface with a diameter of approximately 2,500 kilometers (1,550 miles). SPA is thought to be the oldest and largest impact basin on the Moon, and scientists have long had their eyes on it as a target for future lunar landers.

“This is a highly detailed look at the compositional structure of this huge impact basin using modern, cutting-edge data,” said Dan Moriarty, a postdoctoral researcher at NASA’s Goddard Space Flight Center who led the research while a doctoral student at Brown. “Given that it’s such an important target for future exploration and perhaps returning a sample to Earth, we hope this will serve as a framework for more detailed study and landing site selection.”

The study will be published in the Journal of Geophysical Research: Planets.

The impact that created SPA is thought to have blasted all the way through the Moon’s crust and into the mantle, which is part of the reason that scientists are so interested in it. Visiting SPA and grabbing a sample of that exposed mantle material could provide critical clues about the Moon’s origin and evolution. A sample could also help scientists put a firm date on the impact. SPA is thought to be the Moon’s oldest basin, so a firm date would be a key milestone in the timeline of lunar history as well as events affecting early Earth.

But in order to get the right samples, it’s important to know the best spots to find them. That’s what Moriarty and co-author Carlé Pieters, a professor in Brown’s Department of Earth, Environmental and Planetary Sciences, had in mind for this study. They used detailed data from Moon Mineralogy Mapper, a spectrometer that flew aboard India’s Chandrayaan-1 spacecraft for which Pieters is principal investigator.

“Having global access with modern imaging spectrometers from lunar orbit is the next best thing to having a geologist with a rock hammer doing the field work across the surface.” Pieters said. “Ideally, in the future we’ll have both working together.”

The research identified four distinct mineralogical regions that form a bullseye pattern within and around the basin. At the bulleye’s center is a region of what appears to be deposits of volcanic material, a sign that the center of the basin may have been covered by a volcanic flow sometime soon after the SPA impact. That central region is surrounded by a ring of material dominated by magnesium-rich pyroxene, a mineral thought to be plentiful in the lunar mantle. Outside of that is a ring in which pyroxene mixes with the standard crustal rocks of the lunar highlands. Outside of that ring is the basin exterior, where the signatures of impact-related material disappear.

The findings have some interesting implications for SPA exploration, the researchers say. The research suggests, for example, that finding pristine mantle material in the middle of the basin might be a bit tricky because of the large volcanic deposit.

“That’s a little bit counterintuitive,” Moriarty said. “Typically the deepest excavation would be in the middle of the crater. But we show that the middle of SPA has been covered over by what looks like a volcanic flow.”

So if you’re looking for mantle, it might be wise to land in the ring surrounding the center, where what appears to be mantle material is highly concentrated.

But an ideal landing site, Moriarty says, might be a spot that has both mantle and volcanic material, because those volcanics are interesting in their own right. Their composition is a little different than that of other volcanic rocks found on the Moon, which suggests they have a unique origin.

“If these rocks are indeed volcanic, it means that there was a really interesting kind of volcanism happening at SPA,” Moriarty said. “It could be related to the extreme geophysical environment that would have been in place during the formation of the basin. That would be really interesting to look at in more depth.”

With that in mind, Moriarty says a good spot to land might be near the border of the volcanic center and the pyroxene ring. Another strategy could be to look for a spot where the volcanic material has been pierced by a subsequent impact. Moriarty and Pieters found several such craters in the volcanic patch where the pyroxene material has been re-excavated.

“We think going after both mantle and volcanics would make for a richer science return,” Moriarty said.

Moriarty is hopeful that these findings will give mission planners something to think about. China is currently in the process of planning for a mission to SPA. The region has appeared repeatedly on NASA’s “decadal survey” of planetary scientists, which is used to inform the agency’s mission priorities.

“Impacts are the dominant process that drove solar system creation and evolution, and SPA is the largest confirmed impact structure on the Moon, if not the entire solar system,” Moriarty said. “That makes it an important end member in understanding impact processes. We think this work could provide a roadmap for exploring SPA in more detail.”

The Moon Formed Inside A Vaporized Earth Synestia

A new explanation for the Moon’s origin has it forming inside the Earth when our planet was a seething, spinning cloud of vaporized rock, called a synestia. The new model led by researchers at the University of California, Davis and Harvard University resolves several problems in lunar formation and is published Feb. 28 in the Journal of Geophysical Research — Planets.

“The new work explains features of the Moon that are hard to resolve with current ideas,” said Sarah Stewart, professor of Earth and Planetary Sciences at UC Davis. “The Moon is chemically almost the same as the Earth, but with some differences,” she said. “This is the first model that can match the pattern of the Moon’s composition.”

Current models of lunar formation suggest that the Moon formed as a result of a glancing blow between the early Earth and a Mars-size body, commonly called Theia. According to the model, the collision between Earth and Theia threw molten rock and metal into orbit that collided together to make the Moon.

The new theory relies instead on a synestia, a new type of planetary object proposed by Stewart and Simon Lock, graduate student at Harvard and visiting student at UC Davis, in 2017. A synestia forms when a collision between planet-sized objects results in a rapidly spinning mass of molten and vaporized rock with part of the body in orbit around itself. The whole object puffs out into a giant donut of vaporized rock.

Synestias likely don’t last long — perhaps only hundreds of years. They shrink rapidly as they radiate heat, causing rock vapor to condense into liquid, finally collapsing into a molten planet.

“Our model starts with a collision that forms a synestia,” Lock said. “The Moon forms inside the vaporized Earth at temperatures of four to six thousand degrees Fahrenheit and pressures of tens of atmospheres.”

An advantage of the new model, Lock said, is that there are multiple ways to form a suitable synestia — it doesn’t have to rely on a collision with the right sized object happening in exactly the right way.

Once the Earth-synestia formed, chunks of molten rock injected into orbit during the impact formed the seed for the Moon. Vaporized silicate rock condensed at the surface of the synestia and rained onto the proto-Moon, while the Earth-synestia itself gradually shrank. Eventually, the Moon would have emerged from the clouds of the synestia trailing its own atmosphere of rock vapor. The Moon inherited its composition from the Earth, but because it formed at high temperatures it lost the easily vaporized elements, explaining the Moon’s distinct composition.

Additional authors on the paper are Michail Petaev and Stein Jacobsen at Harvard University, Zoe Leinhardt and Mia Mace at the University of Bristol, England and Matija Cuk, SETI Institute, Mountain View, Calif. The work was supported by grants from NASA, the U.S. Department of Energy and the UK’s Natural Environment Research Council.

Within 180 Million Years Of The Big Bang, Stars Were Born

Long ago, about 400,000 years after the beginning of the universe (the Big Bang), the universe was dark. There were no stars or galaxies, and the universe was filled primarily with neutral hydrogen gas.

Then, for the next 50-100 million years, gravity slowly pulled the densest regions of gas together until ultimately the gas collapsed in some places to form the first stars.

What were those first stars like and when did they form? How did they affect the rest of the universe? These are questions astronomers and astrophysicists have long pondered.

Now, after 12 years of experimental effort, a team of scientists, led by ASU School of Earth and Space Exploration astronomer Judd Bowman, has detected the fingerprints of the earliest stars in the universe. Using radio signals, the detection provides the first evidence for the oldest ancestors in our cosmic family tree, born by a mere 180 million years after the universe began.

“There was a great technical challenge to making this detection, as sources of noise can be a thousand times brighter than the signal — it’s like being in the middle of a hurricane and trying to hear the flap of a hummingbird’s wing.” says Peter Kurczynski, the National Science Foundation program officer who supported this study. “These researchers with a small radio antenna in the desert have seen farther than the most powerful space telescopes, opening a new window on the early universe.”

Radio Astronomy

To find these fingerprints, Bowman’s team used a ground-based instrument called a radio spectrometer, located at the Australia’s national science agency (CSIRO) Murchison Radio-astronomy Observatory (MRO) in Western Australia. Through their Experiment to Detect the Global EoR Signature (EDGES), the team measured the average radio spectrum of all the astronomical signals received across most of the southern-hemisphere sky and looked for small changes in power as a function of wavelength (or frequency).

As radio waves enter the ground-based antenna, they are amplified by a receiver, and then digitized and recorded by computer, similar to how FM radio receivers and TV receivers work. The difference is that the instrument is very precisely calibrated and designed to perform as uniformly as possible across many radio wavelengths.

The signals detected by the radio spectrometer in this study came from primordial hydrogen gas that filled the young universe and existed between all the stars and galaxies. These signals hold a wealth of information that opens a new window on how early stars — and later, black holes, and galaxies — formed and evolved.

“It is unlikely that we’ll be able to see any earlier into the history of stars in our lifetimes,” says Bowman. “This project shows that a promising new technique can work and has paved the way for decades of new astrophysical discoveries.”

This detection highlights the exceptional radio quietness of the MRO, particularly as the feature found by EDGES overlaps the frequency range used by FM radio stations. Australian national legislation limits the use of radio transmitters within 161.5 miles (260 km) of the site, substantially reducing interference which could otherwise drown out sensitive astronomy observations.

The results of this study have been recently published in Nature by Bowman, with co-authors Alan Rogers of the Massachusetts Institute of Technology’s Haystack Observatory, Raul Monsalve of the University of Colorado, and Thomas Mozdzen and Nivedita Mahesh also of ASU’s School of Earth and Space Exploration.

Unexpected results

The results of this experiment confirm the general theoretical expectations of when the first stars formed and the most basic properties of early stars.

“What’s happening in this period,” says co-author Rogers of MIT’s Haystack Observatory, “is that some of the radiation from the very first stars is starting to allow hydrogen to be seen. It’s causing hydrogen to start absorbing the background radiation, so you start seeing it in silhouette, at particular radio frequencies. This is the first real signal that stars are starting to form, and starting to affect the medium around them.”

The team originally tuned their instrument to look later in cosmic time, but in 2015 decided to extend their search. “As soon as we switched our system to this lower range, we started seeing things that we felt might be a real signature,” Rogers says. “We see this dip most strongly at about 78 megahertz, and that frequency corresponds to roughly 180 million years after the Big Bang,” Rogers says. “In terms of a direct detection of a signal from the hydrogen gas itself, this has got to be the earliest.”

The study also revealed that gas in the universe was probably much colder than expected (less than half the expected temperature). This suggests that either astrophysicists’ theoretical efforts have overlooked something significant or that this may be the first evidence of non-standard physics: Specifically, that baryons (normal matter) may have interacted with dark matter and slowly lost energy to dark matter in the early universe, a concept that was originally proposed by Rennan Barkana of Tel Aviv University.

“If Barkana’s idea is confirmed,” says Bowman, “then we’ve learned something new and fundamental about the mysterious dark matter that makes up 85 percent of the matter in the universe, providing the first glimpse of physics beyond the standard model.”

The next steps in this line of research are for another instrument to confirm this team’s detection and to keep improving the performance of the instruments, so that more can be learned about the properties of early stars. “We worked very hard over the last two years to validate the detection,” says Bowman, “but having another group confirm it independently is a critical part of the scientific process.”

Bowman would also like to see an acceleration of efforts to bring on new radio telescopes like the Hydrogen Epoch of Reionization Array (HERA) and the Owens Valley Long Wavelength Array (OVRO-LWA).

“Now that we know this signal exists,” says Bowman, “we need to rapidly bring online new radio telescopes that will be able to mine the signal much more deeply.”

The antennas and portions of the receiver used in this experiment were designed and constructed by Rogers and the MIT Haystack Observatory team. The ASU team and Monsalve added the automated antenna reflection measurement system to the receiver, outfitted the control hut with the electronics, constructed the ground plane and conducted the field work for the project. The current version of EDGES is the result of years of design iteration and ongoing detailed technical refinement of the calibration instrumentation to reach the levels of precision necessary for successfully achieving this difficult measurement.