Engineers from the SSAB steel-making company have unveiled the world’s first piece of steel cast without burning any coal or fossil fuel. Instead, they used hydrogen to power the process.
Metalworking and coal burning have been entwined for as long as humanity has been using metals. Coal is a very good source of energy, providing the heat necessary to refine and process most metals. But it is also a source of carbon, a critical chemical in the production of steel, and the compound that allows us to turn metal ores (usually oxides) into actual metals (by leaching out the oxygen).
For most of our history, this wasn’t that much of an issue. Coal smoke is definitely not healthy for you or anyone living near the smeltery or ye olde blacksmith, but overall production of metals was limited in scope — so the environment could absorb and process its emissions.
Today, however, the sheer scale at which we produce metals means that this process has a real impact on the health of the world around us. However, new technology could uncouple the process from coal, and pave the way towards ‘green’ metals. Engineers from the international, Sweden-based steel-making company SSAB have showcased the process, which relies on hydrogen instead of coal to produce the necessary temperatures.
“The first fossil-free steel in the world is not only a breakthrough for SSAB, it represents proof that it’s possible to make the transition and significantly reduce the global carbon footprint of the steel industry,” said Martin Lindqvist, SSAB’s president and CEO, for CNBC.
The “hybrid process” used by SSAB uses hydrogen as fuel to produce the required energy, instead of the traditional approach of burning coal. This process, called HYBRIT (Hydrogen Breakthrough Ironmaking Technology), uses electricity produced through renewable means to produce hydrogen, which is in turn burned to generate heat. Although there is burning involved, it doesn’t produce any pollution — in fact, the only end product is water.
HYBRIT can be used both for the production of iron pellets — the main raw material used by steel foundries — and in the carbon purification process, which is the step that transforms iron into steel. The first piece of HYBRIT steel was produced for the Volvo Group and is going to become a part of the company’s fleet of trucks. A candleholder was also machined from this steel as proof that its mechanical properties are the same as regular steel produced by SSAB.
“The candle holder, with its softly pleated rays beaming out from the candle, symbolizes the light at the end of the tunnel. It is a symbol of hope. It truly is a piece of the future,” says Lena Bergström, who designed the item.
The steel industry today accounts for roughly 9% of global carbon dioxide emissions, and demand for (as well as production of) steel is steadily increasing.
SSAB developed the process in the context of a joint venture with the government-owned utility Vattenfall and Swedish mining company LKAB. The steel was processed in a pilot plant in the north of Sweden, and full-scale production capability is not expected for another five years or so, according toReuters. The slab of metal produced so far marks the culmination of over 5 years of research and development of the HYBRIT process.
“The goal is to deliver fossil-free steel to the market and demonstrate the technology on an industrial scale as early as 2026,” a statement form SSAB explained.
Purple bacteria are poised to turn your toilet into a source of energy and useable organic material.
Dried sewage sludge. Image credits: Hannes Grobe.
Household sewage and industrial wastewater are very rich in organic compounds, and organic compounds can be very useful. But there’s a catch: we don’t know of any efficient way to extract them from the eww goo yet. So these resource-laden liquids get treated, and the material they contain is handled as a contaminant.
New research plans to address this problem — and by using an environmentally-friendly and cost-efficient solution to boot.
The future is purple (and bacterial)
“One of the most important problems of current wastewater treatment plants is high carbon emissions,” says co-author Dr. Daniel Puyol of King Juan Carlos University, Spain.
“Our light-based biorefinery process could provide a means to harvest green energy from wastewater, with zero carbon footprint.”
The study is the first effort to apply purple phototrophic bacteria — phototrophic means they absorb photons, i.e. light, as they’re feeding — together with electrical stimulation for organic waste recovery. The team showed that this approach can recover up to 100% of the carbon in any type of organic waste, supplying hydrogen gas in return — which is very nice, as hydrogen gas can be used to create power cells or energy directly.
Although green is the poster-color for photosynthesis, it’s far from the only one. Chlorophyll’s role is to absorb energy from light — we perceive this absorption as color. Green chlorophyll, for example, absorbs the wavelengths we perceive as red (which sits opposite green on the color wheel). If you’ve ever toyed around with the color-correction feature in graphical software (a la Photoshop, for example), you know that taking out the reds in a picture will make it look green. The same principle applies here.
Plants are generally green because red wavelengths carry the most energy — and plants need energy to create organic molecules. But the substance comes in all sorts of colors in a variety of different organisms. Phototrophic bacteria also capture energy from sunlight, but they use a different range of pigment — from orange, reds, and browns, to shades of purple — for the job. However, the color itself isn’t important here.
“Purple phototrophic bacteria make an ideal tool for resource recovery from organic waste, thanks to their highly diverse metabolism,” explains Puyol.
These bacteria use organic molecules and nitrogen gas in lieu of CO2 and water as food. This supplies all the carbon, electrons, and nitrogen they need for photosynthesis. The end result is that they tend to grow faster than other phototrophic bacteria or algae and generate hydrogen gas, proteins, and a biodegradable type of polyester as waste.
But what really sealed the deal for the team is that they can decide which of these waste products the bacteria churn out. Depending on environmental conditions such as light intensity, temperature, and the nutrients available, one of these products will predominate in the material they excrete.
The team doubled-down on this property by flooding the bacteria’s environment with electricity.
“Our group manipulates these conditions to tune the metabolism of purple bacteria to different applications, depending on the organic waste source and market requirements,” says co-author Professor Abraham Esteve-Núñez of University of Alcalá, Spain.
“But what is unique about our approach is the use of an external electric current to optimize the productive output of purple bacteria.”
This concept — a “bioelectrochemical system” — works because all of the purple bacteria’s metabolic pathways use electrons as energy carriers. They use up electrons when capturing light, for example. On the other hand, turning nitrogen into ammonia releases electrons, which the bacteria need to dissipate. By applying an electrical current to the bacteria (i.e. by pumping electrons into their environment) or by taking electrons out, the team can cause the bacteria to switch from one process to the other. It also helps improve the overall efficiency of both processes (see Le Chatelier’s principle).
The team included an analysis of the optimum conditions for hydrogen production in the paper (it relies on a mixture of purple bacteria species). They also tested the effect of a negative current (electrons supplied by metal electrodes in the growth medium) on the metabolic behavior of the bacteria.
Their first key finding was that the nutrient blend that fed the highest rate of hydrogen production also minimized the production of CO2 — this would allow the bacteria to recover biofuel from wastewater with a low carbon footprint, the team explains. The negative current experiment proved that these bacteria can use cathode electrons to perform photosynthesis.
Even more striking were the results using electrodes, which demonstrated for the first time that purple bacteria are capable of using electrons from a negative electrode, or “cathode“, to capture CO2 via photosynthesis.
“Recordings from our bioelectrochemical system showed a clear interaction between the purple bacteria and the electrodes: negative polarization of the electrode caused a detectable consumption of electrons, associated with a reduction in carbon dioxide production,” says Esteve-Núñez.
“This indicates that the purple bacteria were using electrons from the cathode to capture more carbon from organic compounds via photosynthesis, so less is released as CO2.”
The paper “Biological and Bioelectrochemical Systems for Hydrogen Production and Carbon Fixation Using Purple Phototrophic Bacteria” has been published in the journal Frontiers in Energy Research.
Blue hydrogen, an energy source that involves obtaining hydrogen by using methane in natural gas, is usually described as a low-carbon option for generating electricity, powering vehicles, and even heating buildings. But researchers believe it may actually cause more harm to the climate than conventional fossil fuels.
In a new study, a team from Stanford and Cornell universities found that the CO2 footprint of blue hydrogen is more than 20% greater than that generated by natural gas or coal and around 60% higher than burning diesel oil for heat. The finding comes at the time the Biden administration is funding a set of regional hydrogen hubs.
“Blue hydrogen provides no benefit,” the researchers wrote. “We suggest that blue hydrogen is best viewed as a distraction, something than may delay needed action to truly decarbonize the global energy economy, in the same way that has been described for shale gas as a bridge fuel and for carbon capture and storage in general.”
The role of hydrogen
Hydrogen is widely seen as an important fuel for a future energy transition. Currently, it’s used mostly by industry during oil-refining and synthetic nitrogen fertilizer production, and not so much for energy because it’s expensive relative to fossil fuels. However, hydrogen is increasingly being promoted as a way to address climate change
The vast majority of hydrogen (96%) is generated from fossil fuels, particularly from steam methane reforming (SMR) of natural gas but also from coal gasification. In SMR, heat, and pressure are used to convert the methane in natural gas to hydrogen and carbon dioxide. The hydrogen so produced is often referred to as “gray hydrogen ” — this type is responsible for 6% of all-natural gas consumption globally
That’s not the only “colored” type of hydrogen. There’s “brown hydrogen,” made from coal gasification. When such electricity is produced by a renewable source, such as wind or solar, the hydrogen is termed “green hydrogen.”
But blue hydrogen is different. It’s produced using the same reforming process that is used to create other types of hydrogen, but the CO2 that would ordinarily be released is captured and stored underground. As of 2021, there were only two blue-hydrogen facilities globally that used natural gas to produce hydrogen on a commercial scale.
The problems of blue hydrogen
In the study, the researchers found the production of blue hydrogen is energy-intensive, with emissions released during the heating and pressuring process and from the use of natural gas as a base fuel to generate the hydrogen. Energy is also needed in the carbon-capture process, leading to higher emissions compared to fossil fuels, particularly methane emissions.
They also warned that not all carbon dioxide emissions from blue hydrogen can be captured, which would make the situation even worse. Even in the best-case scenario, in which blue hydrogen would be produced with renewable electricity instead of natural gas, emissions would still be high and there would be a large consumption of renewable energy.
Instead, renewable electricity could be better used by society in other ways, replacing the use of fossil fuels, for example, they argued. Similarly, the researchers see no advantage in using blue hydrogen-powered by natural gas compared with simply using natural gas directly for heat. Blue hydrogen has emissions as large or larger than those of natural gas used for heat, as they showed.
“In the past, no effort was made to capture the carbon dioxide byproduct of gray hydrogen, and the greenhouse gas emissions have been huge,” Robert Howarth, co-author, said in a statement. “Now the industry promotes blue hydrogen as a solution, an approach that still uses the methane from natural gas, while attempting to capture the byproduct CO2.”
We’re all made of star dust — an often-quoted phrase referring to the fact that nearly all the elements in the human body were forged in a star. But what are stars, themselves, made of?
Actually, stars are made of the same chemical elements as planet Earth, though not nearly in the same proportions. The vast majority of stars are made almost entirely of hydrogen (about 90%) and helium (about 10%) — elements that are relatively rare on our planet, and the lightest on the periodic table — while all the other elements represent just 0.1%.
Among other elements, oxygen usually dominates, followed by carbon, neon, and nitrogen, with iron being the most common metal element. Still, there is only one atom of oxygen in the Sun for every 1200 hydrogen atoms and only one of iron for every 32 oxygen atoms.
It makes sense that hydrogen is the dominant element of the sun and other stars. In order to burn bright for billions of years, stars convert hydrogen into helium through a constant nuclear reaction similar to a hydrogen bomb. So, in a sense, the sun is in a state of constant nuclear explosion, and only appears as a solid sphere because it’s held together by its own massive gravity.
What’s more, as we’ll see, the composition and chemical makeup of stars can vary considerably depending on their states of aging or upon where they are in the galaxy.
Also, elements other than hydrogen or helium can be forged by stars, but only towards the end of their life cycle. Typically, in a star such as the Sun, the heavier elements were seeded by stars that existed before it. Some stars go out with a bang, producing a supernova — a powerful and luminous explosion — during their last evolutionary stages, which ejects heavy elements into space. So new stars can incorporate this material. Due to the laws of physics, the universe recycles everything.
Not all stars glitter the same, nor are they made of the same stuff
All stars are amazing in their own way, but some shine more brightly than others. Hot stars appear white or blue when observed from Earth, whereas cooler stars appear in orange or red hues. Astronomers plot a star’s luminosity and temperature onto a graph called the Hertzsprung-Russell diagram, which is useful to classify stars.
Although there are many types of stars, the most common are main sequence stars — about 90% of all known stars, including the Sun, are in this class.
Below main sequence stars are white dwarfs, the stellar core remnant after a star has exhausted all its fuel. These ancient stars are incredibly dense. A teaspoonful of their matter would weigh as much on Earth as an elephant.
Such densities are possible because white dwarf material is not composed of atoms joined by chemical bonds, but rather consists of a plasma of unbound nuclei and electrons. For this reason, nuclei can be placed closer than normally allowed by electron orbitals in normal matter.
Because white dwarfs are the remnant cores of normal stars, they are primarily made of the “waste” products of the nuclear fusion reactions that they used to support. These “waste” products are primarily carbon and oxygen, with traces of other elements. But that’s not to say there isn’t helium and hydrogen left. The outer part of a white dwarf contains the two elements. And due to the tremendous gravitational force associated with these dense stars, these elements are stratified with the heaviest elements residing at the deepest depths in the star.
Above main sequence stars are ‘giants’ and ‘supergiants’. Before stars reach the very end of their evolution — when they turn into dwarfs or explode into supernovae — they condense and compact, heating up further as the last of their hydrogen is burned. This causes the star’s outer layers to expand outward. At this stage, the star becomes a large red giant.
According to an old study published in the 1985 edition of the Astrophysical Journal, red giants are mainly made of helium and hydrogen, along with carbon, oxygen, nitrogen, and iron. Astrophysicists also recorded the presence of heavy s-process elements such as strontium, yttrium, zirconium, barium, and neodymium.
Supergiants are among the most massive and luminous stars in the universe. Stars that are ten times bigger than the sun (or larger) will turn into supergiants when they run out of fuel. They are similar to red giants in composition except that they are, you guessed it, much larger.
The Sun is expected to turn into a red giant once it exhausts its fuel. Luckily, that won’t happen for another five billion years.
Our understanding of Mars has been a true rollercoaster. Centuries ago, scholars thought Mars could host rivers and oceans like on Earth and maybe teeming with life. When the first observations came in from Galileo Galilei in 1610, astronomers discovered a planet with polar ice caps that was seemingly similar to Earth, so the hypothesis seemed to stand. But as we learned increasingly more, it became apparent that Mars isn’t exactly a lush planet.
Mars is barren nowadays, and while it may have been water-rich at some point in the past, that’s not really the case now. But there’s one more twist to the story: Mars really does have ice caps, and it does have some liquid water. Granted, that water is full of salts and buried beneath the surface, but it’s still liquid water.
According to a new study, this brine can be used to produce breathable air and fuel for Martian colonists — two valuable resources we would absolutely need on the Red Planet.
The rovers we’ve sent to Mars don’t really need oxygen. They do just fine in the ultra-thin atmosphere of the planet, wandering around and doing experiments in freezing temperatures. But if we want to establish a colony (or more likely, a research base), we can’t really manage without oxygen.
In 2008, NASA’s Phoenix Mars Lander came with some good news in that regard. It “tasted” the Martian water and upon analyzing it, found out how it manages to stay liquid on the freezing temperatures of Mars.
The key is something called perchlorate, a chemical compound containing chlorine and oxygen. Perchlorate is very stable in water, and its salts are very solluble — up to the point where they absorb and collect water vapor over time. As the perchlorate absorbs more water, it also dissolves into the water, substantially lowering its freezing temperature — this is how the water manages to remain liquid at temperatures way below the normal freezing point of water.
The European Space Agency’s Mars Express has found several such underground ponds of perchlorate brine and now, a new study reports that these pockets of liquid water could be used to produce valuable resources.
Of course, you can’t drink salty water. You also can’t use it for too many things. If you want to apply the electrolysis to break it down into oxygen (for breathing) and hydrogen (for fuel), you’d normally need to remove the salt — a very costly and complicated process in the harsh Martian environment. This is where the research team led by Vijay Ramani from the University of Connecticut comes in.
Typically, electrolysis requires purified water, but Ramani’s research team found a way to apply electrolysis efficiently to extract hydrogen and oxygen out of the brine simultaneously, without needing to also extract the perchlorate.
“Our Martian brine electrolyzer radically changes the logistical calculus of missions to Mars and beyond” said Ramani. “This technology is equally useful on Earth where it opens up the oceans as a viable oxygen and fuel source”
They built a modular electrolysis system and tested it at -33 Fahrenheit (-36 Celsius), showing that it really does work. The fact that it’s modular means you can start a small operation on Mars (say, a small research base) and then build on it. Ironically, they were also able to use the salt in their favor.
“Paradoxically, the dissolved perchlorate in the water, so-called impurities, actually help in an environment like that of Mars,” said Shrihari Sankarasubramanian, a research scientist in Ramani’s group and joint first author of the paper.
“They prevent the water from freezing,” he said, “and also improve the performance of the electrolyzer system by lowering the electrical resistance.”
The results are so promising, researchers say, that they’re even considering using a similar technology here on Earth. For instance, submarines or deep-sea could make great use of this technology, potentially enabling us to explore uncharted environments in the deep ocean.
“Having demonstrated these electrolyzers under demanding Martian conditions, we intend to also deploy them under much milder conditions on Earth to utilize brackish or salt water feeds to produce hydrogen and oxygen, for example through seawater electrolysis,” said Pralay Gayen, a postdoctoral research associate in Ramani’s group and also a joint first author on this study.
NASA’s Perseverance rover, currently en-route to Mars, is also carrying some instruments that will allow it to produce oxygen from the Martian brine — but no hydrogen. Perseverance’s equipment is also 25 times less efficient than that designed in Ramani’s lab, but it will be a test for the technology and could perhaps offer new insights on how to apply the technology.
While a Martian base is probably pretty distant possibility, a lunar outpost is almost in sight. NASA has concrete plans to send humans back to the moon in this decade, and it wants to lay down infrastructure for a permanent research base. If this is successful, a Martian base might not be that far off.
The study “Fuel and oxygen harvesting from Martian regolithic brine” was published in PNAS.
Some microbes can not only survive but also replicate in an atmosphere comprised entirely out of hydrogen. These important findings suggest that life might appear in a variety of extraplanetary environments that scientists previously discounted.
Life never ceases to surprise us
Billions of years ago, Earth had very small amounts of hydrogen in its primordial atmosphere, up to about 0.1%. The molecular hydrogen persisted in the atmosphere for hundreds of millions of years up to the Great Oxidation Event.
Today, what little hydrogen is produced is rapidly consumed by microorganisms, oxidized in the atmosphere, or lost to space.
Astrophysicists believe that many rocky exoplanets, super-Earth exoplanets (an extrasolar planet with a mass higher than Earth’s, but substantially below those of the Solar System’s ice giants), and even rogue rocky planets (planets outside a solar system) may have a hydrogen-abundant atmosphere under certain conditions.
Some examples of such planets include Trappist-1 d, e, f and g, and LHS 1132b.
Seeing as it seems likely that there are some hydrogen-dominated atmospheres beyond our solar system, and considering that such rocky planets are easier to detect than those with nitrogen or CO2-dominated atmospheres, researchers at MIT wanted to investigate the viability of life on such planets.
The research team conducted growth experiments in a bioreactor system on two species of microorganisms: Escherichia coli and the yeast Saccharomyces cerevisiae.
“We note that we chose a 100% H2 gas environment as a control. Actual atmospheres dominated by H2 will always have other gas components that are products of planetary geology or atmospheric photochemistry. Furthermore, rocky planets will have to be colder than Earth, have a more massive surface gravity than Earth and/or a replenishment mechanism to maintain an H2-dominated atmosphere,” the authors wrote in their study.
Remarkably, both organisms could reproduce normally in a 100% hydrogen atmosphere. However, they do so at slower rates than in oxygenated air.
E. coli reproduced two times slower, while the yeast was around 2.5 orders of magnitude slower. The authors argue that the lack of oxygen is responsible for the reduced rate of replication.
E. coli also synthesizes an impressive number of volatile molecules that can be detected on worlds light-years away from Earth.
“That such a simple organism as E. coli—and a single species at that—has a diverse enough metabolic machinery capable of producing a range of gases with useful spectral features is very promising for biosignature gas detection on exoplanets. While most of the gases are produced in small quantities on Earth there are exoplanet environments where the gases if produced in larger quantities could build up,” the authors wrote in their paper published today in the journal Nature Astronomy.
All life on Earth owes its existence to the Sun, whose rays have showered the planet with energy for billions of years. But, like all things, the Sun has its days numbered. Every star has a life cycle consisting of formation, main sequence, and ultimately death when it runs out of fuel — the Sun is no exception.
The good news is that before this will happen, our species should have evolved into something entirely different or long become extinct. According to scientists, the sun has enough fuel to keep it running for another 5 billion years. When that happens, the solar system will be transformed forever.
The life cycle of the Sun
The star is classed as a G-type main-sequence star, also known as a yellow dwarf. Like other G-type main-sequence stars, the Sun converts hydrogen to helium in its core through nuclear fusion. Each second, it fuses about 600 million tons of hydrogen to helium. The term yellow dwarf is a misnomer since G stars actually range in color from white to slightly yellow. The Sun is, in fact, white but appears yellow because of Rayleigh scattering caused by the Earth’s atmosphere.
The Sun and its planets have been around for about 4.57 billion years. They were all formed out of the same giant cloud of molecular gas and dust which, at some critical point, collapsed under gravity at the center of the nebula.
Due to a nonuniform distribution of mass, some pockets were denser, consequently attracting more and more matter. At the same time, these clumps of matter that were increasing in mass began to rotate due to the conservation of momentum. The increasing pressure also caused the dense regions of gas and dust to heat up.
Scientists’ models suggest that the initial cloud of dust and gas eventually settled into a huge ball of matter at the center, surrounded by a flat disk of matter. The ‘ball’ would eventually turn into the Sun once the temperature and pressure were high enough to trigger nuclear fusion, while the disk would go on to form the planets.
Scientists estimate that it took the Sun only 100,000 years to gather enough mass in order to begin fusing hydrogen into helium. For roughly a few million years, the Sun shone very brightly as a T Tauri star, before it eventually settled into its current G-type main-sequence configuration.
Like most other stars in the universe, the Sun is currently living through its ‘main sequence’ phase. Every second, 600 million tons of matter are converted into neutrinos and roughly 4 x 1027 Watts of energy.
What happens to Earth after the sun dies
There is only a finite amount of hydrogen in the Sun which means it must eventually run out. Since its formation, scientists estimate the Sun consumed as much hydrogen as about 100 times the mass of the Earth.
As the Sun loses hydrogen, its fuel-holding core shrinks, allowing the outer layers to contract towards the center. This puts more pressure on the core, which responds by increasing the rate at which it fuses hydrogen into helium. Naturally, this means the Sun will get brighter with time.
Scientists estimate that the Sun’s luminosity increases by 1% every 100 million years. Compared to when it turned into a G-type main-sequence star 4.5 billion years ago, the Sun is now 30% more luminous.
All of this means that the Sun will slowly turn the heat up on Earth. About 1.1 billion years from now, the Sun will be 10% brighter, triggering a greenhouse effect on Earth similar to the warming that made Venus into a hellish planet.
The heat transfer with Earth’s atmosphere would be huge by this point in time, causing the oceans to boil and the ice caps to melt. As the atmosphere becomes saturated with water, high energy radiation from the Sun will split apart the molecules, allowing water to escape into space as hydrogen and oxygen until the whole planet becomes a barren wasteland.
Life would stand no chance, permanently sealing Earth’s fate as the next Venus or Mars. Speaking of which, at this point into the future, Mars’ orbit would move into the habitable zone, which might become a second Earth for a short while before it too would become unsalvageable.
Some 3.5 billion years from now, the Sun will be 40% brighter than today.
And, in about 5.4 billion years, the Sun will run out of hydrogen fuel, marking the end of its main sequence phase. What will inevitably happen next is that the built-up helium in the core will become unstable and collapse under its own weight. Since the Sun first started fusing hydrogen, all of the helium it has produced has accumulated in the core with no way to get rid of it.
At this point, the Sun will be ready to enter its “Red Giant” phase, characterized by an enormous swelling in size due to gravitational forces that compress the core and allow the rest of the sun to expand. The Sun will grow so large that it will encompass the orbits of Venus and Mercury, and quite possibly even Earth. Some astronomers estimate it might grow to 100 times its current size.
What this means is that even if life on Earth somehow miraculously survives the tail-end of the Sun’s main sequence, it will most certainly be destroyed by a Red Sun so large it will touch our planet.
Don’t be blue, even stars have to die
The Sun will remain in a Red Giant phase for about 120 million years. At this point, the core of the Sun, when it reaches the right temperature and pressure, will start fusing helium into carbon, then carbon and helium into oxygen, neon and helium into magnesium, and so on all the way up to iron. This reaction is triggered when the last remaining shell of hydrogen that envelops the core is burned.
The Sun will then eventually expel its outer layers and then contract into a white dwarf. Meanwhile, all the Sun’s outer material will dissipate, leaving behind a planetary nebula.
“When a star dies it ejects a mass of gas and dust – known as its envelope – into space. The envelope can be as much as half the star’s mass. This reveals the star’s core, which by this point in the star’s life is running out of fuel, eventually turning off and before finally dying,” explained astrophysicist Albert Zijlstra from the University of Manchester in the UK.
“It is only then the hot core makes the ejected envelope shine brightly for around 10,000 years – a brief period in astronomy. This is what makes the planetary nebula visible. Some are so bright that they can be seen from extremely large distances measuring tens of millions of light years, where the star itself would have been much too faint to see.”
If it were much more massive, the Sun’s final fate would have been much more spectacular exploding into a supernova and perhaps forming a black hole. Due to its relatively small size, however, the Sun will likely live as a white dwarf for trillions of years before finally fading away entirely leaving the solar system in pitch-black darkness. The Sun has now become a black dwarf.
In summary: the sun has about 5-7 billion years left of its main sequence phase — the most stable part of its life. However, life on Earth might become extinct as early as 1 billion years from now due to the Sun becoming hot enough to boil the oceans.
We now have an accurate measurement of how large protons are.
Back in 2010, a team of physicists set their field (figuratively) on fire. They measured the radius of a proton and found it to be 4% smaller than expected. Physicists are very passionate about this kind of stuff and it sparked a huge debate. Now, researchers from York University have put the debate to rest by taking a precise measurement of the size of the proton.
How big is something very small?
“The level of precision required to determine the proton size made this the most difficult measurement our laboratory has ever attempted,” said Distinguished Research Professor Eric Hessels, Department of Physics & Astronomy, who led the study.
The exact size of the proton is an important unsolved problem in fundamental physics today, one which the present study addresses. The team reports that protons measure 0.833 femtometers in diameter (a femtometer is one-trillionth of a millimeter). This measurement is roughly 5% percent smaller than the previously-accepted radius value.
“After eight years of working on this experiment, we are pleased to record such a high-precision measurement that helps to solve the elusive proton-radius puzzle,” said Hessels.
The exact measurement of the proton’s radius would have significant consequences for the understanding of the laws of physics, such as the theory of quantum electrodynamics, which describes how light and matter interact. Hessels says that the study didn’t exist in a vacuum — three previous studies were pivotal in attempting to resolve the discrepancy between electron-based and muon-based determinations of the proton size.
The 2010 study was the first to use muonic hydrogen to determine the proton size (whereas previous experiments used regular hydrogen). Hydrogen atoms are made up of one proton and one electron In the 2010 experiment, the team replaced the electron with a muon, a related (but heavier) particle.
While a 2017 study using simple hydrogen agreed with the 2010 muon-based result, a 2018 experiment, also using hydrogen, supported the pre-2010 value. Hessels and his team spent the last eight years trying to get to the bottom of the issue and understand why researchers were getting different results when measuring with muons rather than electrons.
The team carried out a high-precision measurement using a technique they developed for this purpose, the frequency-offset separated oscillatory fields technique (FOSOF). In essence, they used a fast beam of hydrogen atoms created by shooting protons through hydrogen molecules. Their result agrees with the value found in the 2010 study.
The paper “A measurement of the atomic hydrogen Lamb shift and the proton charge radius” has been published in the journal Science.
A small six-seat airplane that is entirely powered by hydrogen rather than fossil fuels is the largest zero-emissions aircraft in the world. For the last year, the plane designed by ZeroAvia, a California-based startup, has been in tests and only recently surfaced to the public’s attention. It allegedly has a 500-mile range which might lead to massive reductions in aircraft emissions if the technology is applied at scale.
The air travel industry is thought to be responsible for 900 million metric tons of CO2 emissions a year. The industry has pledged to reduce aircraft emissions in half by 2050 compared to 2005 levels but how could that realistically ever happen considering how the rate of air travel is surging? Around the world, airlines carried 4.3 billion passengers in 2018, an increase of 38 million compared to the year before.
Our only chance of drastically reducing air travel emissions isn’t to fly less but to radically alter how aircraft are powered.
There are various entrepreneurs and companies who are looking to disrupt the industry. Eviation, for instance, is a startup that designing 100% battery-electric planes.
ZeroAvia, on the other hand, has eyed hydrogen. Researchers at ZeroAvia argue that it is difficult to fly battery-electric aircraft over long ranges, whereas hydrogen fuel cells are nearly four times as energy dense as the most advanced battery currently available on the market. What’s more, high-density batteries have to be frequently replaced which translates into more cost for airlines.
Meanwhile, aircraft with a drive train powered by hydrogen might actually save airlines money — at least for short flights, which are quite a few. The industry estimates that nearly half of global flights are 500 miles or less.
Theoretically, there is no physical constraint on the hydrogen power train. However, larger planes with longer range would require more safety tests. At the moment, ZeroAvia is employing liquid hydrogen stored in carbon fiber cylinders.
In the future, ZeroAvia plans on demonstrating a 20-seat model. It is already in talks with several airlines, which have expressed interest in the technology.
A group of researchers representing several institutions in Denmark, with colleagues from Sintex and Haldor Topsoe, has developed an electrified methane reformer that produces far less CO2 than conventional steam-methane reformers. The method could allow us to produce hydrogen and hydrogen fuel much more cleanly in reformers, and could also be used in tandem with other recent research to help us mitigate global warming.
Less gas for your buck
Global production of hydrogen is around 60 million tons per year. The gas is vital for the production of methanol and ammonia for fertilizer (which is its primary use so far), and could become the bedrock of a hydrogen-fuel economy. However, it’s also a pretty dirty business: some estimates place around 3% of the world’s current CO2 emissions on the back of steam-methane reformers, our primary source of hydrogen.
A steam-methane reformer is a very large implement, think of it as a simplified and scaled-down oil refinery, which is used to extract hydrogen from methane gas. The process involves burning natural gas to heat up a methane-water mixture, under pressure, ‘cooking’ it into syngas — a mix of carbon monoxide and hydrogen. Needless to say, this produces quite a lot of CO2, which is released into the atmosphere. Additional CO2 is also produced inside the reformer as an incomplete reaction product.
The team aimed to reduce the hydrogen industry’s carbon footprint by devising an electricity-based methane reformer. This device, they report, is significantly smaller (one hundred times smaller, in fact) than a traditional reformer and far cleaner. It uses electricity to heat up the water-methane mixture, which removes CO2 emissions associated with the burning of natural gas. The approach also results in a much more even and easily-controlled heating of the water-methane mix, slashing the amount of CO2 produced inside the reforming chamber.
If powered by electricity generated from a renewable resource, the team points out, the electric reformer would reduce the footprint of hydrogen production dramatically. If all the steam-methane reformers in the world were replaced by electrified systems, they add, the world would see a 1% drop in CO2 emissions.
We’ve also talked recently about a somewhat unorthodox idea to help us fight climate warming: replacing anthropic methane in the atmosphere with CO2. The authors of that study already propose degrading methane through heat into CO2. Coupled with the new electric reformer, we could also generate hydrogen for use as fuel or fertilizers.
The paper “Electrified methane reforming: A compact approach to greener industrial hydrogen production” has been published in the journal Science.
Illustration of planetary nebula NGC 7027 and helium hydride molecules. Credit: NASA.
About 100,000 years after the Big Bang, a blink of an eye on the universe’s timescale, the primordial atoms helium and hydrogen combined to form the first molecule, helium hydride. Physicists believe that this molecule’s formation helped the young universe cool down, allowing stars to form. Helium hydride should still be present in some parts of the modern universe but it has never been detected in space — until now.
“The lack of evidence of the very existence of helium hydride in interstellar space was a dilemma for astronomy for decades,” said Rolf Guesten of the Max Planck Institute for Radio Astronomy, in Bonn, Germany, and lead author of the study published in the journal Nature this week.
The discovery was made by NASA’s Stratospheric Observatory for Infrared Astronomy, or SOFIA, the world’s largest airborne observatory. Flying up to 13,700 meters (45,000 feet), SOFIA makes observations above the interfering layers of Earth’s atmosphere, taking off and landing for each observation. Inside a modified Boeing 747SP jetliner, scientists fitted state-of-the-art instruments such as the German Receiver at Terahertz Frequencies (GREAT) instrument that can be tuned to the frequency of helium hydride, similar to tuning an FM radio to the right station, and search for it in space.
NASA researchers pointed SOFIA’s instruments onto a planetary nebula located 3,000 light-years away called NGC 7027. Since the 1970s, scientists had suspected that this is one of the best places to look for helium hydride but until now they were lacking the proper tools.
“This molecule was lurking out there, but we needed the right instruments making observations in the right position — and SOFIA was able to do that perfectly,” said Harold Yorke, director of the SOFIA Science Center, in California’s Silicon Valley.
Finding evidence of the primordial molecule validates our current models of how the universe came to existence. According to the theory, after the universe started to cool down, hydrogen atoms interacted with helium hydride, leading to the creation of molecular hydrogen — the substance primarily responsible for the formation of the first stars. Once the first stars appear, they could forge heavier elements that would eventually disperse into the universe forming asteroids, planetoids, and planets.
“It was so exciting to be there, seeing helium hydride for the first time in the data,” said Guesten. “This brings a long search to a happy ending and eliminates doubts about our understanding of the underlying chemistry of the early universe.
Researchers from Stanford University have developed a process to make hydrogen fuel using only electrodes, solar power, and saltwater from the San Francisco Bay.
A prototype device used solar energy to create hydrogen fuel from seawater. Image credits Yun Kuang et al., (2019), PNAS.
Hydrogen fuel holds a lot of promise as the energy source of the future. It’s clean, doesn’t emit anything, it’s energy-dense, and it’s beyond abundant — if only we were able to develop a way of retrieving the element from its chemical constraints. A new paper describes a way to do just that, starting from saltwater.
Salt of the water
Why is this news? Well, it simply comes down to quantities — the Earth has a lot of saltwater, but not very much fresh water. Methods of producing hydrogen fuel from the latter have already been developed, but the fact of the matter is that fresh water is valuable. We need it to drink, we need it to wash, we need it to grow our crops and, as our planet’s population increases, we run a very real risk of not having enough water for everyone. So it doesn’t make sense to use it for energy — we need it elsewhere.
“You need so much hydrogen [to power our cities and economies that] it is not conceivable to use purified water,” said Hongjie Dai, J.G. Jackson and C.J. Wood professor in chemistry at Stanford and co-senior author on the paper. “We barely have enough water for our current needs in California.”
Salty water, in contrast, is plentiful — which also means cheap. There’s enough of it that we can turn it into hydrogen without upsetting the natural balance of Earth’s ecosystems too much. Hydrogen fuel also doesn’t emit carbon dioxide as it ‘burns’, only water. Given our current troubles with man-made climate change and habitat destruction, both are very appealing qualities.
Saltwater does, however, come with a major drawback. It’s not that hard to split water into hydrogen and oxygen, and we’ve known how to do it for a long time now. Just take a power source, connect two wires to and place their other end (or some electrodes if you want to be fancy about it) in water. Turn the power on, and you’ll get hydrogen bubbles at the negative end (cathode), and oxygen bubbles at the positive end (anode). This process is called electrolysis.
So far so good. But, if you try the same thing with saltwater, the chloride ions in salt (salt is a mix of chloride and sodium atoms) will corrode the anode and break down the system pretty quickly. Dai and his team wanted to find a way to stop those components from breaking down in the process.
Their approach was to coat the anode in several layers of negatively-charged material, which would repeal chloride, thus prolonging the useable life of the electrolysis rig. They layered nickel-iron hydroxide on top of nickel sulfide, over a nickel foam core. The nickel foam acts as a conductor, carrying electricity from the power source, while the nickel-iron hydroxide performs the electrolysis proper, separating water into oxygen and hydrogen.
As this happens, the nickel sulfide becomes negatively charged, protecting the anode. Just as the negative ends of two magnets push against one another, the negatively charged layer repels chloride and prevents it from reaching the core metal. Without the coating, the anode only works for around 12 hours in seawater, according to Michael Kenney, a graduate student in the Dai lab and co-lead author on the paper.
“The whole electrode falls apart into a crumble,” Kenney said. “But with this layer, it is able to go more than a thousand hours.”
Another bonus this coating brings to the table is that it allows for electrolysis to be performed at much higher currents. Previous efforts to split seawater had to use low current, as higher values promote corrosion. The team was able to conduct up to 10 times more electricity through their multi-layer device, which helps it generate hydrogen faster. Dai says they likely “set a record on the current to split seawater.” By eliminating the corrosive effect of salt, the team was able to use the same currents as those in devices that use purified water.
The team conducted most of their tests in controlled laboratory conditions, where they could regulate the amount of electricity entering the system. But, they also designed a solar-powered demonstration machine that produced hydrogen and oxygen gas from seawater collected from San Francisco Bay. Dai says the team pointed the way forward but will leave it up to manufacturers to scale and mass produce the design.
“One could just use these elements in existing electrolyzer systems and that could be pretty quick,” he adds. “It’s not like starting from zero — it’s more like starting from 80 or 90 percent.”
In the future, the technology could be used to generate breathable oxygen for divers or submarines while also providing power. And, perhaps, it could also be used in space exploration to limit the need for water purification systems — at least as far as power and oxygen are concerned.
The paper ” Solar-driven, highly sustained splitting of seawater into hydrogen and oxygen fuels” has been published in the journal Proceedings of the National Academy of Sciences.
Germany can boast running the first hydrogen-powered trains in the world.
Image credits Frank Paukstat / Flickr.
As of this Monday, passengers from the towns of Cuxhaven, Bremerhaven, Bremervoerde, and Buxtehude (all of them just west of Hamburg) can embark on a unique experience — on a train. Two Coradia iLint locomotives — designed and built by Alstom, the same company behind the bullet train — will ‘burn’ through hydrogen fuel cells to take these passengers for a ride.
People like fast trains. At the time of their unveiling, trains such as Japan’s bullet train and the French TGV made headlines, set records, and captured the public’s imagination. But going fast isn’t the only desirable quality in a train. For example, the TGV imposed itself, along with its electric transmission, during the 1973 oil crisis in France.
As Europe works to decouple its economy from fossil fuels, French company Alstom wants to provide them with trains made to measure. The company is now working to replace Germany’s old diesel-powered trains with hydrogen ones. Alstom CEO Henri Poupart-Lafarge inaugurated the first pair of such trains — christened Coradia iLint — at a ceremony in Bremervoerde, where the trains will undergo hydrogen refueling.
“The world’s first hydrogen train is entering into commercial service and is ready for serial production,” he said during the event.
The trains, painted bright blue, will run along a 100-kilometer (62-mile) long stretch of track. However, they can travel up to 1,000 kilometers (600 miles) on a single tank of hydrogen, the company reports.
Hydrogen engines draw on fuel cells to produce electricity. Hydrogen in these cells is combined with oxygen in the atmosphere to generate power, and their only exhaust product is pure water and steam. The engines in the Coradia iLints are very efficient, so the vehicles come equipped with banks of ion-lithium to make sure no charge is wasted.
They’re much quieter than their diesel-fueled counterparts, more eco-friendly, and have the upper hand on electric trains as they can run on any stretch of track, electrified or not. Their only down-side is a higher initial cost.
“Sure, buying a hydrogen train is somewhat more expensive than a diesel train, but it is cheaper to run,” says Stefan Schrank, Alstom’s project manager.
For their part, Germans seem to really dig the trains. Alstom reported that it has already signed a contract to deliver 14 trains in the Lower Saxony (northern Germany) region by 2021. The trains will be delivered to the local transport authority of Lower Saxony (LNVG), which will, in turn, lease them to a contracted train operator, the Eisenbahnen und Verkehrsbetriebe Elbe-Weser GmbH (EVB).
France is also working to acquire hydrogen-powered trains, which it plans to have ready by 2022. Other European countries, including the U.K, Netherlands, Norway, Denmark, and Italy, have also expressed an interest in such vehicles, as did Canada.
The Coradia iLint was first showcased at the rail industry trade fair InnoTrans in 2016, where the company boldly named it “train of the future”; we can only hope that their boast proves true.
Researchers from the University of Cambridge look to plants for a new energy revolution.
Oxygen, hydrogen (left) and water molecules (right). Image credits Luis Romero / Flickr.
Looking for new and more efficient ways of harvesting solar energy, a team of researchers from St John’s College has turned plants to the job. The team has successfully split water molecules into hydrogen and oxygen by altering and improving on natural photosynthetic processes. Photosynthesis is the process plants use to convert sunlight into energy.
Lettuce make fuel
Photosynthesis is arguably the most important process for life on Earth. The process — which uses energy in sunlight to break down water and carbon dioxide — provides the energy and building blocks that plants need to grow. In turn, plants act as primary producers: they form the first link of virtually every trophic network on the planet, essentially feeding the rest of the planet. Moreover, photosynthesis is the source of nearly all the oxygen in the atmosphere today. In its absence, oxygen (a very reactive gas) would bind with chemical compounds or would be used up in biological respiration pretty quickly, and we’d all choke to death. Which would be sad.
Not content to let the process drive just our biology, the team — led by St John’s College PhD student Katarzyna Sokół — worked on turning it into a power source.
Hydrogen has long been considered a viable — and powerful — alternative to fossil fuels. In fact, the first internal combustion engine ever built used a mixture of hydrogen and oxygen, not fossil fuels, to generate energy. It was designed by Francois Isaac de Rivaz, a Swiss inventor, all the way back in 1806. However, it never really caught on, as we didn’t know of any fast and cheap way of mass-producing the gas.
Artificial photosynthesis has yet to reach a point where it can supply enough hydrogen for wide-scale use, mostly because it relies on the use of catalysts, which are often expensive and toxic. On the other hand:
“Natural photosynthesis is not efficient because it has evolved merely to survive so it makes the bare minimum amount of energy needed — around 1-2 per cent of what it could potentially convert and store,” says Katarzyna Sokół, who is also the paper’s first author.
This means that neither can support an industrial-level economy based on hydrogen.
Experimental two-electrode setup showing the photoelectrochemical cell illuminated with simulated solar light. Image credits Katarzyna Sokół.
The team’s new paper details their efforts to change this state of affairs. Using a combination of biological components and manmade technologies, they managed to convert water into hydrogen and oxygen at high efficiency using only sunlight — a process known as semi-artificial photosynthesis. As part of their research, the team had to remove genetic limitations on photosynthesis that had been imposed millennia ago.
“Hydrogenase is an enzyme present in algae that is capable of reducing protons into hydrogen. During evolution this process has been deactivated because it wasn’t necessary for survival,” Sokół explains, “but we successfully managed to bypass the inactivity to achieve the reaction we wanted — splitting water into hydrogen and oxygen.”
The team is the first to successfully create semi-artificial photosynthesis driven solely by sunlight. Their method was over 80% more efficient than natural photosynthesis.
The groundwork they laid down in integrating organic and inorganic materials into semi-artificial devices also provides new avenues of research into other systems for solar energy capture, they add.
“It’s exciting that we can selectively choose the processes we want, and achieve the reaction we want which is inaccessible in nature,” Sokół explains.
“This could be a great platform for developing solar technologies. The approach could be used to couple other reactions together to see what can be done, learn from these reactions and then build synthetic, more robust pieces of solar energy technology.”
The paper has been published in the journal Nature.
People have effectively been able to acquire fuel and, consequently, energy from human urine. This capability has been known for a number of years. In late 2012, a small group of teenage girls from Nigeria made the news by presenting a generator that ran on urine at the Maker Faire Africa. In their generator, the pee is poured into an electrolytic cell where the hydrogen is isolated from other components in the liquid.
The hydrogen is then purified by passing through a filter. From there, it’s sent to a gas cylinder from which it is further pumped into a cylinder containing liquid borax. The borax aids in separating the hydrogen gas from any remaining moisture. The final step is for this gas to be sent to the generator. The girls’ machine was able to supply six hours’ worth of electricity by using a mere liter of liquid waste.
Of course, this was a rather simple apparatus primarily for display, but the important thing is it worked! Urine’s use for producing gas and/or syngas (synthesis gas) has the potential to be quite revolutionary.
Waste as a Water Source in Space
Credit: Wikimedia Commons.
Recycling everything possible in extraterrestrial day-to-day life and travel saves both space and money. For a while now, astronauts on the International Space Station have been recycling their own perspiration and pee. The purified output is clean water, which is drunk a second time over. This cycle can be repeated over and over.
You’ve heard of twice-baked potatoes? Well, twice-expelled waste is starting to catch up in its popularity. Human urine and condensate (including breath moisture, human sweat, shower runoff, and animal pee) are all distilled and reverted to clean drinking water. As of 2015, about 6,000 extra liters of water are recycled each year.
Waste Empowering Yeast
One of the molecules which makes up our urine is called urea. Furthermore, urea is composed of nitrogen and carbon. Both of these chemicals are needed to feed a yeast, Yarrowia lipolytica, which when genetically tweaked properly can take a variety of forms such as bioplastics and even fatty acids. One particular fatty acid necessary for human health and functionality is Omega-3. The brain requires this nutrient.
Thus, Yarrowia lipolytica is being tested to hopefully be able to produce Omega-3’s efficiently in the future. This would be a great aid to humanity in the occasion of a manned mission to Mars or elsewhere. In addition, future astronauts will use 3D printers onboard their spacecraft to generate tools and other needed objects made of plastic. Yet again, the yeast can be altered to produce a certain type of polyester which could be employed for this purpose.
Feces and Urine for Future Food
The sheer quantity of food needed to sustain a manned mission to Mars remains a big problem. However, a clever party of researchers from Pennsylvania State University believes to have found an efficiently ingenious answer. The concept was discussed in a paper published in late 2017. Their space-saving device, a bioreactor, uses the urine as well as the feces of astronauts to feed a non-harmful bacteria that, in turn, is capable of sustaining the human space travelers.
Within the bioreactor, the solid and liquid waste become condensed leaving salts and methane gas in its place. It’s the methane which is used to grow the microbial mush, an edible element with a texture similar to that of Vegemite, a thick Australian spread made up of leftover brewers’ yeast extract along with an assortment of additives.
As you have seen, our astronauts’ waste will not be wasted. Scientists will surely engineer more ways for bodily waste to be put to beneficial use.
New research from Caltech could bring an economically-viable solar fuel to the market in the next few years.
Image credits Zero Emission Resource Organisation / Flickr.
One of the holy grails of renewable energy researchers which they have been pursuing for decades, is the brewing of economically-viable solar fuel. It sounds like something you drill out of the core of a star, but in reality, it’s both much more useful and less dramatic than that: “solar fuels” are chemical compounds which can be used to store solar energy.
Most of the recent research performed in this field focused on splitting water into its constituent parts (hydrogen and oxygen) using only sunlight. It’s easy to see why — hydrogen produced this way would be a clean, cheap, easy-to-produce and generally widely-available fuel. It could be used to power solar cells, motor vehicles, or even spin the turbines of power plants. One of it’s most attractive qualities is that it would be virtually endless and produces zero emissions: the only reactionary product of a hydrogen engine (which burns the gas, i.e. combines it back with oxygen) would be plain old water.
We’re actually pretty close to having the solar fuels we so desire, the only thing we’re missing is the “cheap” part. Back in 2014, a team of Caltech researchers led by Professor Harry developed a water-splitting catalyst from layers of nickel and iron. It worked pretty well for a prototype, showing that it has potential and could be scaled-up. However, while the catalyst clearly worked, nobody knew exactly how it did so. The working theory was that the nickel layers were somehow responsible for the material’s water-splitting ability.
Ball-and-stick model of the catalyst’s molecular structure. Iron atoms are blue, nickel is green, oxygen is shown in red and hydrogen in white. Image credits Caltech.
To get to the bottom of things, a team led by Bryan Hunter from Caltech’s Resnick Institute created an experiment during which the catalyst was starved of water, and observed how it behaved.
“When you take away some of the water, the reaction slows down, and you are able to take a picture of what’s happening during the reaction,” Bryan says.
The experiment revealed that the spot where water gets broken down on the catalyst — called its “active site” — wasn’t nickel, but iron atoms. The results are “very different” from what researchers expected to find, Hunter says. However, that isn’t a bad thing. Our initial hypothesis was a dud, but now that we know exactly how the alloy works — meaning we won’t waste time researching the wrong avenues.
“Now we can start making changes to this material to improve it.”
Gray believes the discovery will be a “game changer” in the field of solar fuels, alerting people that iron is “particularly good” for this type of applications. As we now know what we should look for, we can go on to the next step — which is finding out how to make such processes unfold faster and more efficient, which translates to lower costs of the final fuel.
“I wouldn’t be at all shocked if people start using these catalysts in commercial applications in four or five years.”
The paper “Trapping an Iron(VI) Water Splitting Intermediate in Nonaqueous Media” has been published in the journal Joule.
Viable fusion may be just around the corner, powered on by immensely powerful lasers. Even better, a newly technique requires no radioactive fuel and produces no toxic or radioactive waste.
The hydrogen bomb is the only man-made device to date that successfully maintained fusion. Image credits National Nuclear Security Administration / Nevada Site Office.
One of the brightest burning dreams of sci-fi enthusiasts the world over is closer to reality than we’ve ever dared hope: sustainable fusion on Earth. Drawing on advances in high-power, high-intensity lasers, an international research team led by Heinrich Hora, Emeritus Professor of Theoretical Physics at UNSW Sydney, is close to bringing hydrogen-boron reactions to a reactor near you.
Energy from scratch
In a recent paper, Hora argues that the path to hydrogen-boron fusion is now viable and closer to implementation that other types of fusion we’re toying with — such as the deuterium-tritium fusion system being developed by the US National Ignition Facility (NIF) and the International Thermonuclear Experimental Reactor under construction in France.
Hydrogen-boron fusion has several very appealing properties which Hora believes puts it at a distinct advantage compared to other systems. For one, it relies on precise, rapid bursts from immensely powerful lasers to squish atoms together. This dramatically simplifies reactor construction and reaction maintenance. For comparison, its ‘competitors’ have to heat fuel to the temperatures of the Sun and then power massive magnets to contain this superhot plasma inside torus-shaped (doughnut-like) chambers.
Furthermore, hydrogen-boron fusion doesn’t release any neutrinos in its primary reaction — in other words, it’s not radioactive. It requires no radioactive fuel and produces no radioactive waste. And, unlike most other energy-generation methods which heat water as an intermediary media to spin turbines — such as fossil-fuel or nuclear — hydrogen-boron fusion releases energy directly into electricity.
All of this goody goodness comes at a price, however, which always kept them beyond our grasp. Hydrogen-boron fusion reactions require immense pressures and temperatures — they’re only comfortable upwards of 3 billion degrees Celsius or so, some 200 times hotter than the Sun’s core.
Back in the 1970s, Hora predicted that this fusion reaction should be feasible without the need for thermal equilibrium, i.e. in temperature conditions we can actually reach and maintain. We had nowhere near the technological basis needed to prove his theory back then, however.
Why not blast it with a laser?
Image credits Hora et al., 2017, Lasers and Particles.
The dramatic advances we’ve made in laser technology over the last few decades are making the two-laser approach to the reaction Hora developed back then tangibly possible today.
Experiments recently performed around the world suggest that an ‘avalanche’ fusion reaction could be generated starting with bursts of a petawatt-scale laser pulse packing a quadrillion watts of power. If scientists could exploit this avalanche, Hora said, a breakthrough in proton-boron fusion was imminent.
“It is a most exciting thing to see these reactions confirmed in recent experiments and simulations,” he said.
“Not just because it proves some of my earlier theoretical work, but they have also measured the laser-initiated chain reaction to create one billion-fold higher energy output than predicted under thermal equilibrium conditions.”
Working together with 10 colleagues spread over six countries of the globe, Hora created a roadmap for the development of hydrogen-boron fusion based on his design. The document takes into account recent breakthroughs and points to the areas we still have to work on developing a functional reactor. The patent to the process belongs to HB11 Energy, an Australian-based spin-off company, which means it’s not open for everyone to experiment.
“If the next few years of research don’t uncover any major engineering hurdles, we could have a prototype reactor within a decade,” said Warren McKenzie, managing director of HB11.
“From an engineering perspective, our approach will be a much simpler project because the fuels and waste are safe, the reactor won’t need a heat exchanger and steam turbine generator, and the lasers we need can be bought off the shelf,” he added.
The paper “Road map to clean energy using laser beam ignition of boron-hydrogen fusion” has been published in the journal Laser and Particle Beams.
An international research team has found the largest brown dwarf we’ve ever seen, and it has ‘the purest’ composition to boot. Known as SDSS J0104+1535, the dwarf trails at the edges of the Milky Way.
An artists’ representation of a brown dwarf with polar auroras. Image credits NASA / JPL.
Brown dwarfs — they’re like stars, but without the spark of love. They’re much too big to be planets but they’re too small to ignite and sustain fusion, so they’re not (that) bright and warm and so on. Your coffee is probably warmer than some Y-class brown dwarfs, which sit on the lower end of their energy spectrum. The coldest such body we know of, a Y2 class known as WISE 0855−0714, is actually so cold (−48 to −13 degrees C / −55 to 8 degrees F) your tongue would stick to it if you could lick it.
But they can still become really massive, as an international team of researchers recently discovered: nestled among the oldest of stars in the galaxy at the halo of our Milky Way, some 750 light years away from the constellation Pisces, they have found a brown dwarf which seems to be 90 times more massive than Jupiter — making it the biggest, most massive brown dwarf we’ve ever seen.
Named SDSS J0104+1535, the body is also surprisingly homogeneous as far as chemistry is concerned. Starting from its optical and near-infrared spectrum measured using the European Southern Observatory’s Very Large Telescope, the team says that this star is “the most metal-poor and highest mass substellar object known to-date”, made up of an estimated 99.99% hydrogen and helium. This would make the 10-billion-year-old star some 250 times purer than the Sun.
Y u so cold? Image credits NASA / JPL-Caltech.
“We really didn’t expect to see brown dwarfs that are this pure,” said Dr Zeng Hua Zhang of the Institute of Astrophysics in the Canary Islands, who led the team.
“Having found one though often suggests a much larger hitherto undiscovered population — I’d be very surprised if there aren’t many more similar objects out there waiting to be found.”
From its optical and infrared spectrum, measured using the Very Large Telescope, SDSS J0104+1535 has been classified as an L-type ultra-cool subdwarf — based on a classification scheme established by Dr Zhang.
The paper “Primeval very low-mass stars and brown dwarfs – II. The most metal-poor substellar object” has been published in the journal Monthly Notices of the Royal Astronomical Society.
This week, the German Aerospace Center (DLR) Institute for Solar Research turned on the Synlight project, an array of 149 huge spotlights. Together, these spotlights converge on a single 20-by-20 centimeter (8×8 inch) spot onto which it projects 10,000 times the amount of solar radiation that would have normally shined on the surface. The researchers call it the largest ‘artificial sun’, though we shouldn’t confuse it with fusion energy projects which would be more deserving of the title.
A huge lightbulb
The setup is comprised of xenon short-arc lamps, which you’d typically find in a modern cinema, arranged in a honeycomb structure in Juelich, just 30 kilometers (19 miles) west of Cologne. When the lights are turned on, an immense amount of power is concentrated on a small surface, just enough to heat it in excess of 3,000 degrees Celsius.
Unlike the sun, however, this project doesn’t create it energy. Rather, it eats it with a voracious appetite. Turning on the lights for four hours consumers as much electricity as a four-person household does in a whole year. It might help generate energy, though.
The goal of the project is to better understand solar radiation dynamics to find out how to maximally exploit solar energy. For instance, a setup similar to Synlight only comprised of mirrors could be used to generate renewable liquid hydrogen, a fuel which emits zero emissions when combusted. Right now, 99% of all man-made hydrogen is derived from fossil fuels through an energy and carbon intensive process called methane reforming.
Of course, hydrogen by itself is not without problems. Storing it can be a hassle because it’s the lightest and smallest molecule and just escapes most containers. It’s density is very small which can also be problematic. However, combining it with carbon monoxide results in eco-friendly kerosene for the aviation industry.
Once scientists master hydrogen production with Synlight, they can scale the system tenfold — all powered by the sun, not electricity, this time.
The DLR labs are busy with other interesting projects. One of them involves creating artificial comets made of water, rock dust, and soot, all locked in a vacuum chamber that, of course, contains an artificial sun.
Image of diamond anvils compressing molecular hydrogen. At higher pressures, the sample converts to atomic hydrogen, as shown on the right. Credit: R. Dias and I.F. Silvera.
By subjecting molecular hydrogen, a gas, to ungodly pressures higher than those found at the Earth’s core, Harvard researchers have accomplished the impossible: they’ve turned the lightest element into a metal. This is now the rarest and possibly the most expensive material on the planet. This may soon change as metal hydrogen moves from the stuff of alchemy to a critical resource in mankind’s quest of becoming an interstellar species.
The new material was created by Isaac Silvera, the Thomas D. Cabot Professor of the Natural Sciences, and post-doctoral fellow Ranga Dias. For over a hundred years scientists knew that it was theoretically possible to turn hydrogen into a metal if you compress it under the right condition but no one was able to prove it until recently.
“This is the holy grail of high-pressure physics,” Silvera said. “It’s the first-ever sample of metallic hydrogen on Earth, so when you’re looking at it, you’re looking at something that’s never existed before.
A tiny hydrogen sample was squeezed with a pressure of 495 gigapascals, or more than 71.7 million pounds-per-square-inch. The sample was also chilled to just above absolute zero. At such a tremendous strain, the molecular hydrogen breaks down and the dissociative elements turn into atomic hydrogen, which is a metal. When the researchers stopped the experiment, everyone was dumbstruck when they saw their sample was shining!
‘It’s a very fundamental and transformative discovery’ — Professor Silvera
What makes metallic hydrogen so interesting is the fact that it may be meta-stable, as reported by some models. In other words, once you lift the immense pressure that went into birthing the metal, the hydrogen will stay a metal. It’s akin to how graphite under immense heat and pressure turns into a diamond and remains in this configuration even after said heat and pressure is removed.
Compressed hydrogen going from transparent molecular to black molecular to atomic metallic hydrogen. Credit: R. Dias and I.F. Silvera
This feature has excited a lot of people, both in science and industry. That’s because metallic hydrogen has a couple of very appealing features. It’s predicted that metallic hydrogen could act as a superconductor at room temperatures, allowing electricity to flow through it with zero loss. Right now, as much as 15 percent of all the electricity we generate is lost down power lines.
It’s in transportation, however, that metallic hydrogen could be revolutionary. Its superconductive properties could make high-speed trains that use magnetic levitation a common sight. If used as a fuel, metallic hydrogen would be four times more powerful than the best propellant at our disposal today.
“It takes a tremendous amount of energy to make metallic hydrogen,” Professor Silvera said.
“And if you convert it back to molecular hydrogen, all that energy is released, so it would make it the most powerful rocket propellant known to man, and could revolutionize rocketry.
“That would easily allow you to explore the outer planets.”
Now, the researchers need to find out if the metal hydrogen is indeed stable at the surface and doesn’t decay in time. Already, there are voices who have criticized the discovery. Speaking to Nature News, five experts claim the evidence presented so far is unconvincing.
“If they want to be convincing, they have to redo the measurement, really measuring the evolution of pressure,” says Paul Loubeyre, a physicist at France’s Atomic Energy Commission in Bruyères-le-Châtel. “Then they have to show that, in this pressure range, the alumina is not becoming metallic.”