Space & Physics
Could dark energy be a trick played by time?
David Wiltshire, a cosmologist at New Zealand’s University of Canterbury, proposed an alternate model that gets rid of dark energy entirely. But in doing so, it sacrifices an assumption cosmologists had held sacred for decades.
In 1924, American astronomer Edwin Hubble discovered that our universe expands in all directions. Powering this expansion was a Big Bang, an event that marked the birth of our current universe some 13.7 billion years ago. Back then, the finding came as a jolt to the astronomy community and the whole world. In 1998, there was even further shake-up when observations of type 1A supernovae from distant galaxies indicated the universe was expanding – at an accelerated rate. But the source of its driving force have remained in the dark.
Dark energy was born from efforts to explain the accelerated expansion. It remains a placeholder name for an undetected energy density contribution that offers a repulsive effect counterbalancing gravity’s attractive nature at long distances. Consensus emerged in support of this dark energy model thereafter. In 2011, astronomers behind the type 1A supernovae study went on to share the Nobel Prize in Physics.
More than two decades later, we are none the wiser to uncover what dark energy is. However, cosmologists have deemed it to be a constant of nature, one that does not evolve with time. So was the surprise when preliminary findings from the Dark Energy Spectroscopic Instrument (DESI) survey indicated dark energy was not just variable, but also weakening over time. The Lambda-Cold Dark Matter, more technically known as the standard model, has never stood on shakier grounds.
Fine-tuned to a Big Crunch ending
In cosmological models, the Greek letter “Lambda” fits as a placeholder for dark energy. It depicts a major chunk – some 70% of the universe’s energy density. But this figure holds only if it is a true cosmological constant. If dark energy is variable, then inevitable we end up fine-tuning the universe’s fate. A constant dark energy would yield a universe expanding forever.
But going by DESI’s preliminary findings, if dark energy is weakening over time, the the universe is set to collapse on itself in the far future. This is the Big Crunch hypothesis. It was amidst the caucus surrounding DESI’s latest findings, the cosmology community took interest in a paper published in the December edition of the Monthly Notices of the Royal Astronomical Society.
In 2007, David Wiltshire, a cosmologist at New Zealand’s University of Canterbury, and the paper’s co-author, had proposed an alternate model called timescape cosmology, to get rid of dark energy entirely. It requires a sacrifice over an assumption cosmologists have held so sacred in their models. Known as cosmological principle, it shares much in common with Aristotle and Ptolemy’s outdated viewpoint that the earth was at the center of the solar system.
A special place in the universe
The cosmological principle assumes matter in the universe is distributed uniformly everywhere on average, and in every direction that we look around. But cosmologists propose to adopt a pragmatic approach like the Polish Prussian astronomer, Nicholas Copernicus, had proposed in the 16th century. In the Copernican model of the solar system, the earth bore no special location in it. Likewise, timescape cosmology requires earth to not occupy a special location.
Saying that, the cosmological principle has a certain appeal among cosmologists. Theoretical calculations would appear complex to manipulate discarding uniformity. At the same time, cosmologists do contend that something has to give way, in light of astronomical observations that contend the cosmological principle is indeed outright wrong.
Inhabiting a time bubble
One of the hallmark phenomena in Einstein’s general theory of relativity is gravitational time dilation. Time passes slower under a gravitational field. Bizarre as though it may seem to be, experiments have proven this subtle, but measurable effect.
In 1959, two Harvard physicists Robert Pound and Glen Rebka Jr. used a pair of atomic clocks to demonstrate this effect – also known as gravitational time dilation. Two clocks were stationed in their office building – one atop the roof, and the other closer to earth. The clock stationed closer to earth, lagged in comparison to the one atop the roof. Here, time dilation occurs in response to earth’s gravity tugging weakly at the clock atop, compared to the one below.
The universe looks clumpier in certain directions at cosmic scales than others. Galaxies bind together under gravity to form strands like that of a vast, interconnected cosmic web. Voids of cosmic proportions occupy the space in between. These voids experience a faster time flow, since they’re subject to weaker gravity from the surrounding galaxies. But observers in these galaxies have a skewed perception of time, since they’re living embedded inside a bubble of strong gravity. Events outside their time bubble play out akin to a fast-forwarded YouTube video.
Not the end of dark energy
Distant galaxies appears to recede accelerated in the reference frame of our time bubble. That appearance is a mere temporal illusion; an effect David Wiltshire says we falsely assume to be dark energy. So far, timescape cosmology has only occupied a niche interest in cosmology circles. There is far too little evidence to support a claim that dark energy affects arise truly from us inhabiting a time bubble.
Cosmologists had taken to social media to critique Wiltshire’s use of type 1A supernovae datasets used in his analysis. Saying that, none of the critiques themselves are conclusive. As observations pile up in the future, there may come a definitive closure. Until then it’s a waiting game for more data and refined analysis. Meanwhile on the contrary, it is too early to abdicate dark energy as a concept altogether. Lambda-CDM model would be the first to undergo a major rehaul, should DESI’s preliminary findings hold in successive observational runs. Until then, we can only speculate the universe’s fate.
Space & Physics
India’s New Satellite Will Be Tested During Disasters
India’s latest Earth-observation satellite, EOS-05, could give disaster agencies a broader and more frequent view of floods, landslides and other hazards. But its real value will depend on how quickly satellite data can be turned into information that helps authorities act on the ground.
When a flood spreads or a landslide cuts off a village, one of the first things authorities need is a clear picture of what has happened. India’s newest Earth-observation satellite could help close part of that information gap. Which areas are under water? Which roads are still open? Where are people stranded? Ground teams may be unable to reach affected areas, while conditions can change faster than assessments can be completed.
On September 4, the Indian Space Research Organisation (ISRO) successfully launched GSLV-F17 carrying EOS-05, which ISRO describes as India’s first imaging satellite designed for geosynchronous orbit. The satellite was placed into a sub-geosynchronous transfer orbit before its subsequent orbital operations.
The launch is a technological milestone. But its larger significance may be in how India uses the satellite once it is in operation.
Seeing a Disaster From Above
Earth-observation data already play a role in India’s disaster management. ISRO’s systems are used for applications including flood mapping, damage assessment and emergency management, while the National Database for Emergency Management brings together geospatial information for disaster agencies.
EOS-05 adds a different capability because of its orbit. A geosynchronous satellite can repeatedly observe a broad region as the Earth rotates. That makes it possible to monitor large areas without relying entirely on a satellite making another pass over the location.
During a flood, that could help authorities understand the extent of inundation. After a landslide, imagery could contribute to assessing affected terrain. The same Earth-observation infrastructure has applications in agriculture, water resources, forestry and urban planning. But the satellite itself is not the solution.
The Real Test is Speed
There is a long distance between an image captured in space and a decision made in a district control room. Data have to be received, processed and interpreted. The resulting information has to reach officials and emergency teams quickly enough to matter. That is particularly important when disasters are unfolding by the hour.
A satellite cannot rescue people or reopen a blocked road. What it can do is help authorities decide where those efforts are most urgently needed.
That distinction is important. The value of space technology in disaster management is not simply that it produces better images. It is that those images can potentially reduce the time needed to understand what is happening on the ground.
From Mapping Damage to Managing Risk
India’s disaster landscape makes that capability increasingly relevant. Floods can spread across districts, while landslides can isolate mountain communities with little warning. Cyclones, forest fires and extreme rainfall can also leave authorities trying to assess large areas at once.
Satellite observation cannot predict every such event. But combined with weather forecasts, river-level data, ground reports and geographic information, it can provide a fuller picture of how a disaster is unfolding. That is where EOS-05 could become more than another addition to India’s satellite fleet.
The real measure of its success will not be the launch itself, or even the quality of the images it produces. It will be whether those images reach the right people quickly enough to change what happens on the ground. Because in a disaster, seeing more is useful only if it helps authorities act faster and act in the right place.
Space & Physics
India’s Moonshot Moment: Can New Delhi Turn Orbit Into Influence
India’s space mission is entering a new era, from Gaganyaan and space stations to private startups, space diplomacy and national security.
Gaganyaan is only the beginning. India’s space mission faces new opportunities and challenges as human spaceflight, diplomacy, private industry and security reshape its ambitions beyond Earth.
Indian human space programme Gaganyaan is mooted by Indian Space Research Organisation. This ambitious space mission aims to send Indian astronauts in Outer Space indigenously by the proactive leadership of the Indian government. India as a leading space power of the world aims to demonstrate her space capabilities and research in the final frontier. The Gaganyaan mission is the dream of 1.4 billion Indians. The programme will be initiated in 2027 creating a historic mark in the collective space exploration journeys. This is a stepping stone as NASA is envisioning to make Moon as the next base for active space programmes by 2030.
According to NASA this spectacular feat will be achieved soon within 3 years. NASA has asked India’s ISRO to join for the permanent Lunar base in the south pole of Moon. Here comes the significance of Indo-US space partnership and how India will navigate through the space diplomacy keeping in mind of Indian dream of Bharatiya Antariksh Station and the long lasting commitment to strategic autonomy and an independent foreign policy. India already signed the Artemis accords in June 2023. If India is ready to be part of this initiative, it will mark the beginning of a new era in India-United States space cooperation. The question is how India will navigate this process, protecting its sovereignty and national interest while engaging with NASA to help build a new civilisation of space travellers on the lunar surface. According to media reports India’s spectacular success with the Chandrayaan missions has led the United States to choose India as a natural partner, inviting it to join space exploration programmes on the Moon.
India’s Space Mission: The Next Frontier of Global Power
The Gaganyaan mission is significant for strengthening Indian space station’s vision. The Bharatiya Antariksh Station is an Indian space station which is a symbol of Indian space nationalism and a centre for joint research with friendly nations. India is actively pushing for space diplomacy and it is evident from the trainings received by Gaganyaan crew members. They have trained in Russia and the United States, continuing India’s commitment to strong bilateral ties with both Cold War-era rivals. Space exploration and travel are combined with diplomacy, as Indian foreign policy in a multipolar world order pushes for strong partnerships with both Russia and the United States.
Indian Air Force veteran Wing Commander Rakesh Sharma was the first Indian cosmonaut to reach the final frontier, in a Soviet space mission. Following this historic feat, Kalpana Chawla and Sunita Williams travelled to outer space on American missions. Recently, Group Captain Shubhanshu Shukla represented India in the Axiom mission successfully travelling to International Space Station and returned safely as a national hero. He is also part of the Gaganyaan mission. Colonel Anil Menon, who is part of the US Space Force, is also now in outer space. He has strong Indian connections, making him the first astronaut with roots in Kerala to explore the domain of outer space.
With privatisation in outer space in India, Skyroot Aerospace, a private company based in Hyderabad, successfully launched Vikram-1 rocket to low Earth orbit. Thus India is taking leverage of the infinite possibilities chasing stars and galaxies. Indian space ambitions are at a historic juncture now, with over 400 private Space startups. Another mission is aiming for a reusable re-entry vehicle, targeted for launch in 2027, building on ISRO’s success with the Pushpak mission, the Reusable Launch Vehicle Landing Experiment, in 2024.
However, there are concerns in India’s space sector, with many ISRO scientists seeking early retirement. The efficiency of major projects like Aditya and Gaganyaan should not be affected by this. Former ISRO Chairman G Madhavan Nair shared his concerns with the media about bureaucratisation within the organisation. ISRO is a symbol of India’s space story which is filled with resilience and strength of great visionary leaders like Dr Vikram Sarabhai and Dr APJ Abdul Kalam. Unfortunately, there have been budgetary cuts to major ISRO space projects. The government’s focus on Viksit Bharat, a holistically developed India, is only possible with investment in science and technology, and in-depth research in the domain of outer space.
Outer space is militarised, and the race for resource nationalism is a reality. For India to emerge as a global power, investment in space exploration is inevitable. Nations are increasingly aware of the strategic use of outer space for securing national interests. Satellites with civilian and national security purposes are critical assets of any nation. India too has many civilian and strategic assets in outer space, and protecting these is the responsibility of the government. The anti-satellite test Mission Shakti is a milestone demonstrating India’s hard-power capabilities in outer space. Some nations have capabilities such as laser-guided weapons, which can disable or destroy an enemy’s assets during conflict. Space is a key domain for ensuring seamless communication and intelligence-sharing during both war and peace.
Intelligence and surveillance are key factors in winning the wars of the present and future. The dominance in space technology and information superiority will determine the victories of nations fighting for their national interest.
In India, the share of higher education in the annual budgetary allocation remains low. A young generation passionate to explore arenas of space science is to be inculcated with the right mindset. Allocation of funds in education sector is a key requirement for building a strong India with educated and skilled youth. ISRO’s active collaboration with 100 Atal Tinkering Labs is a positive step in inculcating the spirit of scientific enquiry at the grassroots level. Support and encouragement for students in the creative arts and sciences is the need of the hour. Atal Tinkering Labs and India’s startup ecosystem can achieve greater synergy, ensuring a seamless transition from school life to entrepreneurship, from plan to execution.
Human activity has actively degraded the ecosystem, impacting life on both land and water. Now, with active competition in the arena of outer space, space debris is a serious global security challenge. This debris travels swiftly in outer space, damaging active space assets including civilian and defence satellites. The young budding scientists of India need to re-invent and discover practical solutions to the pressing global challenge of space debris and work with relentless passion for making a strong and stable India.
Space & Physics
Meteorite Dust Reveals Evidence of Magnetic Field in the Young Solar System
A magnetic field in the early solar system has been detected in ancient meteorite grains, offering evidence that magnetism helped shape the young sun.
Ancient grains in an Antarctic meteorite reveal evidence of a magnetic field in early solar system, suggesting magnetism helped shape the young sun
Tiny mineral grains preserved inside an ancient meteorite have recorded evidence of a magnetic field that existed during the earliest stages of the solar system, suggesting that magnetism, alongside gravity, helped shape the young sun and its surrounding disk of gas and dust.
Ancient Meteorite Records Reveal a Magnetic Field in the Early Solar System
Scientists at the Massachusetts Institute of Technology (MIT) examined microscopic grains in a meteorite recovered from Antarctica and found traces of ancient magnetism dating to the first 200,000 years of solar system history. The findings provide what researchers describe as the earliest known evidence of a magnetic field in the infant solar system.
The study, published in the Proceedings of the National Academy of Sciences, challenges the view that gravity alone drove the transformation of the early solar system from a cloud of gas and dust into a flattened disk that eventually produced the sun and planets.
“This transition, from a spherical cloud to a protoplanetary disk, is one of the most significant events in all of solar system history,” said Benjamin Weiss, professor of Earth and Planetary Sciences at MIT, in a statement issued. Measurements from the study, he said, indicate that magnetism likely played a role.
Magnetic records preserved in meteorite grains
The researchers studied DOM 08006, a primitive meteorite discovered in 2008 in the Dominion Range of Antarctica. The meteorite contains calcium-aluminum-rich inclusions, or CAIs, which formed during the earliest period of solar system development.
CAIs are among the oldest known solid materials from the solar system. Some of the grains contain magnetic minerals that can preserve the imprint of a magnetic field present when they formed.
The team isolated tiny grains from the meteorite and subjected them to a series of tests to determine whether they retained remanent magnetisation — a lasting record of an earlier magnetic field.
The researchers found evidence of a magnetic field with an estimated strength of about 150 to 600 microteslas. That is roughly three to 12 times stronger than Earth’s magnetic field today.
The preservation of these records was possible because DOM 08006 appears to have undergone relatively little alteration during its long history.
“Other meteorites went through many different processes over this 4.5 billion year history,” Weiss said. “But somehow, DOM has experienced less alteration than any other meteorite.”
Magnetism before the planets
Scientists already had evidence of magnetic fields in the solar system several million years after its formation, when the sun had formed and the planets were beginning to take shape.
The new measurements push that evidence much further back — to a period when the solar system was still a collapsing cloud of gas and dust and the sun itself was beginning to form.
In the early solar system, electrically charged particles moving through the developing disk could have generated a magnetic field. That field may then have influenced the movement of gas and material towards the central star.
The researchers argue that magnetism therefore needs to be considered alongside gravity when reconstructing how the early solar system evolved.
“We think these kinds of magnetic fields were helping to move gas from the protoplanetary disk, in toward this central star, the sun,” said Cauê Borlina, the study’s first author and now an assistant professor at Purdue University.
The findings do not replace gravity as the main force shaping the early solar system. Instead, they suggest that magnetic fields were another important part of the physical processes that brought material together and helped the young sun grow.
The study was led by Borlina, with Weiss, Elias Mansbach and Nilanjan Chatterjee of MIT, along with researchers from Tsinghua University, the University of Cambridge, Caltech and the University of California, Los Angeles
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