Space & Physics
Fusion Energy: The quest for unlimited power
The potential benefits of fusion energy are enormous. It could provide a nearly limitless supply of energy, reduce our reliance on fossil fuels, and help combat climate change

Imagine a world with a virtually unlimited source of clean energy that could power our cities, industries, and homes without the harmful emissions and environmental impacts of fossil fuels. This isn’t science fiction—it’s the promise of fusion energy. But what exactly is fusion energy, and how close are we to making it a reality?
Nuclear fusion involves combining light elements, such as hydrogen, to form heavier elements, releasing a significant burst of energy in the process. This process, which powers the heat and light of the Sun and other stars, is praised for its potential as a sustainable, low-carbon energy source.
This process contrasts with the nuclear fission process used in nuclear power plants, where heavy atomic nuclei are split into lighter ones. But this is fraught with radioactive waste and safety concerns.
The road to practical fusion energy is steep and fraught with challenges. The foremost obstacle is achieving and maintaining the extremely high temperatures and pressures required for fusion. Similar to those at the Sun’s core, these conditions are necessary to overcome the electrostatic forces that repel the positively charged atomic nuclei. For decades, scientists have experimented with different methods to achieve these conditions. The two primary approaches are magnetic confinement and inertial confinement.
Magnetic confinement, as seen in the tokamak design, employs powerful magnetic fields to contain hot plasma within a doughnut-shaped chamber. Inertial confinement, on the other hand, involves compressing a small pellet of fusion fuel with intense laser beams to achieve the conditions for fusion. Both methods have seen significant advancements but are yet to reach the break-even point, where the energy output from fusion equals the energy input required to sustain the reaction. However, recent breakthroughs have brought us closer than ever to this elusive goal.
The primary fuel for nuclear fusion is deuterium and tritium. Deuterium and tritium are isotopes of hydrogen, the universe’s most abundant element. Isotopes are members of a family of elements that all have the same number of protons but different numbers of neutrons. While all isotopes of hydrogen have one proton, deuterium has one neutron, and tritium has two, so their ion masses are heavier than those of protium, the isotope of hydrogen with no neutrons. Deuterium can be extracted from seawater, while tritium can be bred from lithium. When deuterium and tritium fuse, they form a helium atom, which has two protons and two neutrons, and release an energetic neutron. These energetic neutrons could serve as the foundation for generating energy in future fusion power plants.
Power plants today generate electricity using fossil fuels, nuclear fission, or renewable sources like wind or water. Regardless of the energy source, these plants convert mechanical power, such as the rotation of a turbine, into electrical power. In a coal-fired steam station, coal combustion turns water into steam, which then drives turbine generators to produce electricity.
The tokamak is an experimental machine designed to harness fusion energy. Inside a tokamak, the energy produced through atomic fusion is absorbed as heat by the vessel’s walls. Similar to conventional power plants, a fusion power plant will use this heat to produce steam, which then generates electricity via turbines and generators.
The international ITER project in France is the largest and most ambitious tokamak experiment to date. ITER aims to demonstrate the feasibility of fusion as a large-scale and carbon-free source of energy
At the core of a tokamak is a doughnut-shaped vacuum chamber. Under extreme heat and pressure inside this chamber, gaseous hydrogen fuel becomes plasma, creating an environment where hydrogen atoms can fuse and release energy. The plasma’s charged particles are controlled and shaped by large magnetic coils surrounding the vessel. This property allows physicists to confine the hot plasma away from the vessel walls. The term “tokamak” is derived from a Russian acronym for “toroidal chamber with magnetic coils.”

Fusion energy scientists consider tokamaks to be the leading plasma confinement design for future fusion power plants. In a tokamak, magnetic field coils confine plasma particles, enabling the plasma to reach the conditions necessary for fusion.
The international ITER project in France is the largest and most ambitious tokamak experiment to date. ITER aims to demonstrate the feasibility of fusion as a large-scale and carbon-free source of energy. It’s a collaboration involving 35 countries, including India, and is expected to produce first plasma in the coming years.
The primary objective of ITER is to investigate and demonstrate burning plasmas—plasmas where the energy from helium nuclei produced by fusion reactions is sufficient to maintain the plasma’s temperature, reducing or eliminating the need for external heating. ITER will also test the feasibility and integration of essential fusion reactor technologies, such as superconducting magnets, remote maintenance, and systems for exhausting power from the plasma. Additionally, it will validate tritium breeding module concepts that could enable tritium self-sufficiency in future reactors.
ITER made headlines just last year when it achieved a major milestone: the successful installation of its first-of-a-kind superconducting magnet system. This system is crucial for creating the powerful magnetic fields needed to contain the superheated plasma. This achievement brings us one step closer to achieving sustained fusion reactions.
On October 3, 2023, the Joint European Torus (JET) project in Oxford produced power for five seconds, resulting in a “ground-breaking record” of 69 megajoules of power. That energy was generated using only 0.2 milligrams of fuel.
An alternative method is inertial confinement fusion, where a compact fusion fuel pellet is compressed by high-powered lasers. The National Ignition Facility (NIF) in the United States is leading the way in this research. On December 5, 2022, the National Ignition Facility (NIF), located at the Lawrence Livermore National Laboratory in California, directed a series of lasers to emit 2.05 megajoules of energy towards a small cylinder containing a frozen pellet of deuterium and tritium, which are denser variants of hydrogen. The pellet underwent compression, resulting in the generation of temperatures and pressures of sufficient magnitude to induce fusion of the hydrogen contained inside it. During an extremely brief ignition, the merging atomic nuclei discharged 3.15 megajoules of energy, surpassing the amount of energy necessary to heat the pellet by approximately 50 percent. This stage is crucial in the journey towards the practical realisation of fusion energy production.
On October 3, 2023, the Joint European Torus (JET) project in Oxford produced power for five seconds, resulting in a “ground-breaking record” of 69 megajoules of power. That energy was generated using only 0.2 milligrams of fuel. In addition, many private companies are making waves in the fusion energy scene.
While these achievements are remarkable, there are still many technical hurdles to overcome. We need to improve the efficiency and durability of fusion reactors, develop materials that can withstand the extreme conditions inside them, and create systems for safely handling and breeding tritium.
Despite these challenges, the potential benefits of fusion energy are enormous. It could provide a nearly limitless supply of energy, reduce our reliance on fossil fuels, and help combat climate change. Imagine a world where energy is abundant, clean, and available to all—fusion energy could make this vision a reality. As we look to the future, the quest for fusion energy represents one of the greatest scientific and engineering challenges of our time. It’s a testament to human ingenuity and our unwavering determination to solve the world’s most pressing problems.
Space & Physics
This Sodium-Fuelled Clean Energy Breakthrough Could Electrify Aviation and Shipping
The innovation offers more than triple the energy density of today’s lithium-ion batteries — potentially clearing a major hurdle for electric-powered aviation, rail, and maritime travel

A new type of fuel cell developed by MIT researchers could represent a pivotal breakthrough in the race to decarbonize heavy transportation. Designed around liquid sodium metal, the innovation offers more than triple the energy density of today’s lithium-ion batteries — potentially clearing a major hurdle for electric-powered aviation, rail, and maritime travel.
Unlike traditional batteries that require time-consuming recharging, this system operates like a fuel cell that can be refueled quickly using liquid sodium — a cheap, abundant substance derived from salt. The technology, which uses air as a reactant and a solid ceramic electrolyte to facilitate the reaction, was tested in lab prototypes and demonstrated energy densities exceeding 1,500 watt-hours per kilogram — a level that could enable regional electric flight and clean shipping.
“We expect people to think that this is a totally crazy idea,” said Professor Yet-Ming Chiang, lead author and Kyocera Professor of Ceramics, in a media statement. “If they didn’t, I’d be a bit disappointed because if people don’t think something is totally crazy at first, it probably isn’t going to be that revolutionary.”
Chiang explained that current lithium-ion batteries top out at around 300 watt-hours per kilogram — far short of the 1,000 watt-hours needed for electric aircraft to become viable at scale. The new sodium-based cell meets that benchmark, which could enable 80% of domestic flights and drastically reduce aviation’s carbon footprint.
Moreover, the sodium-fueled system offers environmental benefits beyond zero emissions. Its chemical byproduct, sodium oxide, reacts spontaneously in the atmosphere to capture carbon dioxide and convert it into sodium bicarbonate — better known as baking soda — which may help counteract ocean acidification if it ends up in marine environments.
“There’s this natural cascade of reactions that happens when you start with sodium metal,” Chiang said. “It’s all spontaneous. We don’t have to do anything to make it happen, we just have to fly the airplane.”
The team has already created two functioning lab-scale prototypes: one vertical and one horizontal model. In both, sodium gradually reacts with oxygen from air to generate electricity, and a moist air stream improves the process by allowing liquid byproducts to be expelled more easily.
Karen Sugano, one of the MIT doctoral students on the project, noted, “The key was that we can form this liquid discharge product and remove it easily, as opposed to the solid discharge that would form in dry conditions,” she said in a media statement.
The researchers have founded a startup, Propel Aero, housed in MIT’s startup incubator The Engine, to scale the technology. Their first commercial goal: a brick-sized fuel cell capable of powering a large agricultural drone — expected to be ready within a year.
Chiang emphasized the economic and safety benefits of using sodium, which melts just below 100°C and was once mass-produced in the U.S. for leaded gasoline production. “It reminds us that sodium metal was once produced at large scale and safely handled and distributed around the U.S.,” he said.
Critically, the fuel cell design also avoids many safety concerns of high-energy batteries by physically separating the fuel and oxidizer. “If you’re pushing for really, really high energy density, you’d rather have a fuel cell than a battery for safety reasons,” Chiang said.
By reviving and reimagining sodium-metal chemistry in a practical, scalable form, the MIT team may have lit the path toward clean, electrified transportation systems — from the skies above to the oceans below.
Space & Physics
Is Time Travel Possible? Exploring the Science Behind the Concept
Subtle forms of time travel — such as time dilation — do occur and have practical implications in science and technology.

Everyone is, in a way, a time traveller. Whether we like it or not, we are constantly moving through time — one second per second. From one birthday to the next, we travel through time at a steady pace, just like walking one foot per footstep. However, when we talk about “time travel,” we often imagine something much more dramatic — traveling faster (or even backward) through time, as seen in science fiction movies and novels. But is such a thing truly possible?
From Fiction to Science
The concept of time travel first gained widespread attention through literature, particularly with H.G. Wells’ 1895 novel The Time Machine. In it, time is described as the fourth dimension, akin to space, and the protagonist travels forward and backward in time using a specially built machine. Interestingly, this idea predates Albert Einstein’s theory of relativity, which would later reshape how we understand space and time.

Einstein’s Contribution: Relativity and Time Dilation
In the early 20th century, Albert Einstein introduced a revolutionary idea through his theory of relativity. He proposed that space and time are interconnected, forming a four-dimensional continuum called space-time. According to his theory, the speed of light (186,000 miles per second) is the ultimate speed limit in the universe. But how does this relate to time travel?
Einstein’s theory states that as you move faster — especially at speeds approaching the speed of light — time slows down relative to someone who is stationary. This phenomenon, known as time dilation, has been proven through various experiments. One famous example involved two synchronized atomic clocks — one placed on Earth and the other onboard a high-speed jet. When the plane returned, the onboard clock showed slightly less time had passed compared to the one on the ground. This demonstrates that, at very high speeds, time passes more slowly.
Astronaut Twins and Time
A notable example of time dilation involved twin astronauts Scott and Mark Kelly. Scott spent 520 days aboard the International Space Station, while Mark spent only 54 days in space. Due to the effects of time dilation, Scott aged slightly less than Mark — by about 5 milliseconds. Though this difference is minuscule, it is real and measurable, showing that time can indeed “bend” under certain conditions.
The GPS Example
Surprisingly, even GPS satellites experience time differently than we do on Earth. These satellites orbit at altitudes of about 20,200 kilometers and travel at speeds of roughly 14,000 km/h. Due to both their speed (special relativity) and weaker gravitational pull at high altitudes (general relativity), time ticks slightly faster for the satellites than for devices on Earth. This discrepancy is corrected using Einstein’s equations to ensure precise positioning. Without these adjustments, GPS systems could be off by several miles each day.
Science Fiction vs. Scientific Reality
Science fiction has long explored imaginative time travel — characters jumping into machines and traveling decades into the future or past. Stories often depict them altering historical events or witnessing the far future. However, there is no scientific evidence that anyone has travelled backward or forward in time in such a dramatic way.
Renowned physicist Stephen Hawking addressed this idea humorously in 2009. He hosted a party for time travellers — but only announced it afterward, reasoning that if time travel were possible, people from the future would show up. No one came. Hawking took this as a tongue-in-cheek sign that backward time travel may not be feasible.
Could Wormholes Be the Key?
Theoretical physics does suggest possibilities like wormholes — shortcuts through space-time. According to Einstein’s equations, these could, in theory, connect distant places and times. A wormhole might allow someone to enter at one point in space and exit at another, potentially in a different time. However, this remains purely speculative. The extreme gravitational forces within black holes or wormholes could destroy anything attempting to pass through.
Moreover, the idea of backward time travel introduces major paradoxes — such as the classic “grandfather paradox,” where someone goes back in time and prevents their own existence. Such contradictions challenge our understanding of causality and logic.
The Limitations of Current Science
At present, building a time machine capable of transporting people backward or forward in time by centuries remains outside the realm of scientific possibility. It’s a concept best enjoyed in novels and films for now. However, subtle forms of time travel — such as time dilation — do occur and have practical implications in science and technology.
While we may not have DeLoreans or TARDISes at our disposal, time travel — at least in small, measurable ways — is a part of our reality. The interplay of speed, gravity, and time demonstrates that our universe is far more flexible than it appears. And who knows? In some distant corner of the cosmos, nature might already be bending time in ways we are only beginning to imagine.
Until then, we’ll keep moving forward — one second per second.
Space & Physics
MIT Physicists Capture First-Ever Images of Freely Interacting Atoms in Space
The new technique allows scientists to visualize real-time quantum behavior by momentarily freezing atoms in motion and illuminating them with precisely tuned lasers

In an intriguing advancement for quantum physics, MIT researchers have captured the first images of individual atoms freely interacting in space — a feat that until now was only predicted theoretically.
The new imaging technique, developed by a team led by Professor Martin Zwierlein, allows scientists to visualize real-time quantum behavior by momentarily freezing atoms in motion and illuminating them with precisely tuned lasers. Their results, published in Physical Review Letters, reveal how bosons bunch together and fermions pair up in free space — phenomena crucial to understanding superconductivity and other quantum states of matter.
“We are able to see single atoms in these interesting clouds of atoms and what they are doing in relation to each other, which is beautiful,” said Zwierlein in a press statement.
Using their method — called “atom-resolved microscopy” — the team was able to trap atom clouds with a loose laser, briefly immobilize them with a lattice of light, and then image their positions via fluorescence. This approach allowed the researchers to observe quantum behaviors at the level of individual atoms for the first time.
The MIT group directly visualized sodium atoms (bosons) bunching together in a shared quantum wave — a vivid confirmation of the de Broglie wave theory — and lithium atoms (fermions) pairing up despite their natural repulsion, a key mechanism underlying superconductivity.
“This kind of pairing is the basis of a mathematical construction people came up with to explain experiments. But when you see pictures like these, it’s showing in a photograph, an object that was discovered in the mathematical world,” said co-author Richard Fletcher in a press statement.
Two other research teams — one led by Nobel laureate Wolfgang Ketterle at MIT, and another by Tarik Yefsah at École Normale Supérieure — also reported similar quantum imaging breakthroughs in the same journal issue, marking a significant moment in the experimental visualization of quantum mechanics.
The MIT team plans to expand the technique to probe more exotic quantum behaviors, including quantum Hall states. “Now we can verify whether these cartoons of quantum Hall states are actually real,” Zwierlein added. “Because they are pretty bizarre states.”
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