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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.

Veena M A

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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.

Image credit: Wikimedia Commons

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.

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Space & Physics

Researchers Uncover New Way to Measure Hidden Quantum Interactions in Materials

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Image credit: Pixabay

A team of MIT scientists has developed a theory-guided strategy to directly measure an elusive quantum property in semiconductors — the electron-phonon interaction — using an often-ignored effect in neutron scattering.

Their approach, published this week in Materials Today Physics, reinterprets an interference effect, typically considered a nuisance in experiments, as a valuable signal. This enables researchers to probe electron-phonon interactions — a key factor influencing a material’s thermal, electrical, and optical behaviour — which until now have been extremely difficult to measure directly.

“Rather than discovering new spectroscopy techniques by pure accident, we can use theory to justify and inform the design of our experiments and our physical equipment,” said Mingda Li, senior author and associate professor at MIT, in a media statement.

By engineering the interference between nuclear and magnetic interactions during neutron scattering, the team demonstrated that the resulting signal is directly proportional to the electron-phonon coupling strength.

“Being able to directly measure the electron-phonon interaction opens the door to many new possibilities,” said MIT graduate student Artittaya Boonkird.

While the current setup produced a weak signal, the findings lay the groundwork for next-generation experiments at more powerful facilities like Oak Ridge National Laboratory’s proposed Second Target Station. The team sees this as a shift in materials science — using theoretical insights to unlock previously “invisible” properties for a range of advanced technologies, from quantum computing to medical devices.

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Space & Physics

Dormant Black Holes Revealed in Dusty Galaxies Through Star-Shredding Events

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Image credit: NRAO/AUI/NSF/NASA

In a major discovery, astronomers at MIT, Columbia University, and other institutions have used NASA’s James Webb Space Telescope (JWST) to uncover hidden black holes in dusty galaxies that violently “wake up” only when an unsuspecting star wanders too close.

The new study, published in Astrophysical Journal Letters, marks the first time JWST has captured clear signatures of tidal disruption events (TDEs) — catastrophic episodes where a star is torn apart by a galaxy’s central black hole, emitting a dramatic burst of energy.

“These are the first JWST observations of tidal disruption events, and they look nothing like what we’ve ever seen before,” said lead author Megan Masterson, a graduate student at MIT’s Kavli Institute for Astrophysics and Space Research. “We’ve learned these are indeed powered by black hole accretion, and they don’t look like environments around normal active black holes.”

Until now, nearly all TDEs detected since the 1990s were found in relatively dust-free galaxies using X-ray or optical telescopes. However, researchers suspected many more events remained hidden behind thick clouds of galactic dust. JWST’s powerful infrared vision has finally confirmed their hunch.

By analyzing four galaxies previously flagged as likely TDE candidates, the team detected distinct infrared fingerprints of black hole accretion — the process of material spiraling into a black hole, producing intense radiation. These signatures, invisible to optical telescopes, revealed that all four events stemmed not from persistently active black holes but dormant ones, roused only when a passing star came too close.

“There’s nothing else in the universe that can excite this gas to these energies, except for black hole accretion,” Masterson noted.

Among the four signals studied was the closest TDE ever detected, located 130 million light-years away. Another showed an initial optical flash that scientists had earlier suspected to be a supernova. JWST’s readings helped clarify the true cause.

“These four signals were as close as we could get to a sure thing,” said Masterson. “But the JWST data helped us say definitively these are bonafide TDEs.”

To determine whether the central black holes were inherently active or momentarily triggered by a star’s disruption, the team also mapped the dust patterns around them. Unlike the thick, donut-shaped clouds typical of active galaxies, these dusty environments appeared markedly different — further confirming the black holes were usually dormant.

“Together, these observations say the only thing these flares could be are TDEs,” Masterson said in a media statement.

The findings not only validate JWST’s unprecedented ability to study hidden cosmic phenomena but also open new pathways for understanding black holes that lurk quietly in dusty galactic centers — until they strike.

With future observations planned using JWST, NEOWISE, and other infrared tools, the team hopes to catalog many more such events. These cosmic feeding frenzies, they say, could unlock key clues about black hole mass, spin, and the very nature of their environments.

“The actual process of a black hole gobbling down all that stellar material takes a long time,” Masterson added. “And hopefully we can start to probe how long that process takes and what that environment looks like. No one knows because we just started discovering and studying these events.”

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Space & Physics

MIT unveils an ultra-efficient 5G receiver that may supercharge future smart devices

A key innovation lies in the chip’s clever use of a phenomenon called the Miller effect, which allows small capacitors to perform like larger ones

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Image credit: Mohamed Hassan from Pixabay

A team of MIT researchers has developed a groundbreaking wireless receiver that could transform the future of Internet of Things (IoT) devices by dramatically improving energy efficiency and resilience to signal interference.

Designed for use in compact, battery-powered smart gadgets—like health monitors, environmental sensors, and industrial trackers—the new chip consumes less than a milliwatt of power and is roughly 30 times more resistant to certain types of interference than conventional receivers.

“This receiver could help expand the capabilities of IoT gadgets,” said Soroush Araei, an electrical engineering graduate student at MIT and lead author of the study, in a media statement. “Devices could become smaller, last longer on a battery, and work more reliably in crowded wireless environments like factory floors or smart cities.”

The chip, recently unveiled at the IEEE Radio Frequency Integrated Circuits Symposium, stands out for its novel use of passive filtering and ultra-small capacitors controlled by tiny switches. These switches require far less power than those typically found in existing IoT receivers.

A key innovation lies in the chip’s clever use of a phenomenon called the Miller effect, which allows small capacitors to perform like larger ones. This means the receiver achieves necessary filtering without relying on bulky components, keeping the circuit size under 0.05 square millimeters.

Credit: Courtesy of the researchers/MIT News

Traditional IoT receivers rely on fixed-frequency filters to block interference, but next-generation 5G-compatible devices need to operate across wider frequency ranges. The MIT design meets this demand using an innovative on-chip switch-capacitor network that blocks unwanted harmonic interference early in the signal chain—before it gets amplified and digitized.

Another critical breakthrough is a technique called bootstrap clocking, which ensures the miniature switches operate correctly even at a low power supply of just 0.6 volts. This helps maintain reliability without adding complex circuitry or draining battery life.

The chip’s minimalist design—using fewer and smaller components—also reduces signal leakage and manufacturing costs, making it well-suited for mass production.

Looking ahead, the MIT team is exploring ways to run the receiver without any dedicated power source—possibly by harvesting ambient energy from nearby Wi-Fi or Bluetooth signals.

The research was conducted by Araei alongside Mohammad Barzgari, Haibo Yang, and senior author Professor Negar Reiskarimian of MIT’s Microsystems Technology Laboratories.

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