For centuries, the search for life beyond Earth has been soaked in one belief: water is essential. Now, MIT researchers are challenging this planetary doctrine—suggesting that the ingredients for life could thrive in liquids far different from water, and perhaps on worlds much harsher than our own.

In a study published this week in Proceedings of the National Academy of Sciences, the MIT-led team demonstrated that a special blend of chemicals—known as ionic liquids—can easily form on rocky planets and moons, potentially creating new havens for life in the cosmos.

Ionic liquids are a type of salt that stays liquid at temperatures below 100°C and, unlike water, can endure extremes of heat and pressure. In their experiments, the researchers mixed sulfuric acid (often produced by volcanoes) with simple nitrogen-rich organic compounds (found on asteroids and planetary atmospheres). The result: a persistent, stable liquid that doesn’t evaporate even when most of the acid is gone.

Ionic liquids, it turns out, can be friendly to rare biomolecules—like hardy proteins—that can resist breakdown in harsh conditions.

Expanding the habitability zone

“We consider water to be required for life because that is what’s needed for Earth life. But if we look at a more general definition, we see that what we need is a liquid in which metabolism for life can take place,” said Dr. Rachana Agrawal, who led the study at MIT’s Department of Earth, Atmospheric and Planetary Sciences. “Now if we include ionic liquid as a possibility, this can dramatically increase the habitability zone for all rocky worlds.”

The implications are staggering: even on planets that are too hot, or whose atmospheres are too thin for water to exist, stable ionic liquids could form and persist—potentially nurturing forms of alien life, though they may look nothing like Earth’s water-based organisms.

From Venus to beyond

The inspiration came when the team was working to solve a Venus mystery. Venus, shrouded in clouds of sulfuric acid, has long fascinated scientists seeking signs of life. When Dr. Agrawal and her colleagues tried to evaporate sulfuric acid from a solution to isolate organic molecules, a stubborn liquid layer wouldn’t go away. They realized they’d accidentally created an ionic liquid—a discovery that opened new doors in astrobiology.

Dr. Sara Seager, MIT’s Class of 1941 Professor of Planetary Sciences and co-leader of the study, described the breakthrough: “In high school, you learn that an acid wants to donate a proton. Oddly enough, we knew from our past work that sulfuric acid (the main component of Venus’ clouds) and nitrogen-containing compounds have this unique chemistry—one gives up a hydrogen, one takes it. It’s like one person’s trash is another person’s treasure.”

After testing over 30 nitrogen compounds with sulfuric acid, the scientists confirmed that ionic liquids reliably form under a wide range of conditions—even on basalt rocks similar to those on planetary surfaces.

“We were just astonished that the ionic liquid forms under so many different conditions,” Seager said. “If you put the sulfuric acid and the organic on a rock, the excess acid seeps into the pores, but you’re still left with a drop of ionic liquid. Whatever we tried, ionic liquid still formed.”

Their experiments showed that this process happens up to 180°C and at pressures far below Earth’s, broadening the realm of possible habitable worlds.

New oases in the universe

Imagine a rocky world, hotter than Earth, where volcanic sulfuric acid flows over pockets of organic matter—ingredients for life scattered across the solar system. According to Dr. Seager, these spots could become long-lived pools of ionic liquid, tiny oases for simple, exotic life forms.

“We’re envisioning a planet warmer than Earth, that doesn’t have water, and at some point in its past or currently, it has to have had sulfuric acid, formed from volcanic outgassing,” Seager explained. “This sulfuric acid has to flow over a little pocket of organics. And organic deposits are extremely common in the solar system.”

Just how far could this discovery go? The team says much more work lies ahead. They will now focus on what kinds of molecules—and what forms of life—could actually flourish in these unearthly environments.

“We just opened up a Pandora’s box of new research,” Seager said. “It’s been a real journey.”

Contributors to the study include: MIT scientists Sara Seager, Rachana Agrawal, Iaroslav Iakubivskyi, Weston Buchanan, Ana Glidden, Jingcheng Huang; Maxwell Seager (Worcester Polytechnic Institute); William Bains (Cardiff University); Janusz Petkowski (Wroclaw University of Science and Technology).

On July 30th, NISAR  — the NASA-ISRO joint space mission — launched to space aboard the GSLV Mark II rocket from Sriharikota, Andhra Pradesh. The satellite, now safely tucked into a sun-synchronous orbit around earth, will enter a commissioning phase over the next three months, to deploy all its instruments.

Perched at an altitude of 750 km, the three ton satellite will complete an orbit around the earth every 12 days, while studying the planet’s diverse geology with unprecedented detail.

NISAR, a portmanteau for the NASA-ISRO synthetic aperture radar mission, marks the culmination of a decade-long effort to build the most powerful earth observation satellite to date.

In 2007, NASA had begun actively exploring an ambitious undertaking to build a satellite, which could map the earth and the whole ecosystem. On the agenda were investigations into studying climate change and its role in exacerbating extreme weather events. These include surveillance over vulnerable hotspots, such as Greenland and Antarctica, where disappearing ice sheets have been linked to the global average increase in sea-levels over the years.

Remote sensing satellites traditionally used can’t capture the full picture, without uninterrupted sunlight exposure or obstructions namely cloud cover. But synthetic aperture radar is a fix to these problems. Clouds are transparent to radio and microwaves unlike visible light. As such, a synthetic aperture radar can work across any weather, whether sunlit or not alike.

That said, SAR technology isn’t new. They have been around for about seventy years, since the first proof of principle was proven in the 1950s. In 1978, the US launched the first SAR-equipped earth observation satellite, Seasat, to monitor oceans. Neither Seasat or for that matter any SAR-based successors, could bear resolutions as high as 1 cm, or map terrain across a swath area as wide as about 240 km, as NISAR can.

NASA engaged in a cost-effective strategy, opening doors for international partners to pool resources, and co-develop the satellite and the scientific campaigns.

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(A) Melt pond in Greenland | Photo Credit: Michael Studinger (2008) (B) NASA administrator Charles Bolden and ISRO chairman K. Radhakrishnan sign documents, which included a charter on NISAR, in Toronto | Photo Credit: NASA (2014)

NASA and ISRO share expertise

NASA found an interested party in ISRO, which at the time was developing the Radar Imaging Satellite (RISAT), which had a smaller scope to study India’s geology. India, being especially vulnerable to floods, landslides and cyclones, couldn’t overlook the incentives an extra eye in the sky could provide.

NISAR can track and relay even the minutest of changes on the surface in near real-time. In principle, the satellite should detect a flooded area hidden from view to rescuers on-ground, or even traditional remote sensing satellites which use passive receivers. The satellite can serve a key role in an integrated multi-hazard early warning system.

In 2014, ISRO inked the NISAR agreement with NASA. The mission would only be their latest collaboration between the two space agencies. Previously, they had collaborated on 2008’s Chandrayaan-1. Back then, NASA’s Moon Mineralogy Mapper (M3) instrument and miniSAR radar onboard the Chandrayaan orbiter, led the famous detection of water ice on the moon. 

Although NISAR was originally slated for launch in 2020, innumerable delays followed as they sorted technical challenges, and the abrupt global lockdown amid COVID pandemic.

Upon project completion last year, NISAR had become the most expensive satellite built, with NASA and ISRO pouring some $1.5 billion into development. The costs were unevenly split between them; with NASA spending some $1.3 billion, and ISRO bearing a modest amount at $91 million.

But a white paper details ISRO had contributed an equal value in engineering various components, re-establishing parity. ISRO engineered the spacecraft body, readied tracking stations on-ground, and developed the short wavelength S-band radar. The S-band (at 12 cm) complements NASA’s longer wavelength L-band (24 cm) radar.

The L-band can track changes under thick foliage or leaves, under forests. It can even measure land deformation rates as tiny as 4 mm/year. While the L-band serves as NISAR’s primary means of acquiring radar data, ISRO’s S-band radar will help provide details that concern Indian earth scientists, monitoring coastal erosion for example. Both radars work in tandem with NASA-designed radar receiver and reflector – a 12-meter wide meshed net, resembling a canopy attached to the spacecraft body via a boom. 

Three months from now, once the commissioning phase is complete, NISAR will begin its observational runs, and beam radar data back to earth continuously. The National Remote Sensing Centre in Hyderabad, and Goddard Space Flight Centre in Maryland, will process the respective L & S-band data independently, and archive them online for the world to see, all in a matter of few hours.

• MIT physicists perform the most idealized double-slit experiment to date, using individual atoms as slits.
• Experiment confirms the quantum duality of light: light behaves as both a particle and a wave, but both behaviors can’t be observed simultaneously.
• Findings disprove Albert Einstein’s century-old prediction regarding detecting a photon’s path alongside its wave nature.

In a study published in Physical Reviews Letters on July 22, researchers at MIT have realized an idealized version of the famous double-slit experiment in quantum physics yet.

The double-slit experiment—first devised in 1801 by the British physicist Thomas Young—remains a perplexing aspect of reality. Light waves passing through two slits, form interference patterns on a wall placed behind. But this phenomenon is at odds with the fact light also behaves as particles. The contradiction has lent itself to a paradox, which sits at the foundation of quantum mechanics. It has sparked a historic scientific duel nearly a century ago, between physics heavyweights Albert Einstein and Niels Bohr. The study’s findings have now settled the decades-old debate, showing Einstein’s predictions were off the mark.

Einstein had suggested that by detecting the force exerted when a photon passes through a slit—a nudge akin to a bird brushing past a leaf—scientists could witness both light’s wave and particle properties at once. Bohr countered with the argument that observing a photon’s path would inevitably erase its wave-like interference pattern, a tenet since embraced by quantum theory.

The MIT team stripped the experiment to its purest quantum elements. Using arrays of ultracold atoms as their slits and weak light beams to ensure only one photon scattered per atom, they tuned the quantum states of each atom to control the information gained about a photon’s journey. Every increase in “which-path” information reduced the visibility of the light’s interference pattern, flawlessly matching quantum theory and further debunking Einstein’s proposal.

“Einstein and Bohr would have never thought that this is possible, to perform such an experiment with single atoms and single photons,” study senior author and Nobel laureate, Wolfgang Ketterle, stated in a press release. “What we have done is an idealized Gedanken (thought) experiment.”

In a particularly stunning twist, Ketterle’s group also disproved the necessity of a physical “spring”—a fixture in Einstein’s original analogy—by holding their atomic lattice not with springs, but with light. When they briefly released the atoms, effectively making the slits “float” in space, the same quantum results persisted. “In many descriptions, the springs play a major role. But we show, no, the springs do not matter here; what matters is only the fuzziness of the atoms,” commented MIT researcher Vitaly Fedoseev in a media statement. “Therefore, one has to use a more profound description, which uses quantum correlations between photons and atoms.”

The paper arrives as the world prepares for 2025’s International Year of Quantum Science and Technology — marking 100 years since the birth of quantum mechanics. Yoo Kyung Lee, a fellow co-author, noted in a media statement, “It’s a wonderful coincidence that we could help clarify this historic controversy in the same year we celebrate quantum physics.”