INSIGHTS
Musings on Physics and Education
By Chiara Marletto
At birth, we set out on a journey to understand the Universe. As we orbit around the sun, we sense, feel, taste, and observe the vast collection of phenomena around us. In early childhood, this exploration is natural and immediate to us, like breathing, eating and sleeping. Along the way we gather many new tools — keys to access further levels of understanding. As new-borns, we can engage with the world to some extent, but still minimally: our senses have to develop further; our brain has to expand and generate novel connections; our language and thinking skills have yet to emerge. Then we go through several milestones, such as the first time we can smile back at our parents, the first words, the first steps, and so on. As toddlerhood sets in, we start speaking one (or more) languages. We learn to sing, play, amuse and be amused, yell, say ‘yes’ and ‘no’. We learn about how to tell that an object is larger than another; how to balance when we trip on an obstacle; how to stand back up after a fall, and go back to walking. At some later point, we learn about drawing and art, numbers and shapes.
It is remarkable that, especially in early childhood, we traverse this vast and far-reaching learning playfully. We seek delight by expanding the mind to appreciate more and more of the world. This process of intellectual growth is not without its problems: mistakes do occur along the way, but instead of being discouraged or ashamed by them, we quickly learn from them and move forward towards new concepts, new ideas, and new shores.
That seamless and effortless learning gradually becomes more laboured as the years go by. Learning eventually becomes a chore, not a delight; in fact, it has to be enforced via a set of rewards and punishments; fences and boundaries proliferate, making it scary and challenging to tackle the study of particular topics. For most children, this transition is marked by the start of formal education and entry into the school system. There are exceptions – some lucky pupils encounter extraordinary teachers, who are knowledgeable, inspirational, compassionate, and delightfully humane; this usually enhances their passion for learning. But such cases are rare.
While most subjects, as presented in traditional schooling, tend to appear unappealing or hard to learn, some subjects are notoriously considered harder to conquer than others. The sciences, in particular, have a terrible reputation. The fences erected around these subjects are particularly thorny and menacing. Students can almost sense the approaching of troubles as they hear the first few lessons on these topics. Even when the students are successful at solving problems and passing exams, they may be less fond of these subjects, particularly when compared to others, such as Literature, Arts, or Music.
What is the reason for this endemic lack of affection? Just like some musical instruments have a more immediate entry to the level at which one can be playful and enjoy oneself — think, for instance, of learning the piano versus learning the guitar, which requires many more mechanical skills; so in the case of science it is harder to learn its language (mathematics) to the degree that allows one to have fun. Instead, given that we naturally have access to hearing and vision, it is far easier to enjoy a good drawing, a beautiful painting or a piece of music. Likewise, children engage with learning at least one language in their early years, so they do not have to overcome an extra language barrier when they approach a good story or a piece of literature. With mathematics, one needs to overcome a much stronger language barrier.
There is, however, a more profound problem. You can easily see the magic when an artist, say, draws from scratch a beautiful tiger on a piece of canvas, almost bringing to life a piece of inanimate matter; you can also immediately sense the power of a beautifully executed piece of music; or be hooked in by a good story. But who gets drawn in when reading a chemical reaction, an equation, or a mathematical theorem? The issue here is the lack of emphasis on what makes the sciences fun. It is challenging to see why they are interesting and beautiful without a proper introduction; an introduction that, in fact, may never occur during childhood. When children first approach the sciences, they are typically suspicious or bored, so it is no surprise that many end up estranged from those subjects.
Physics, the subject I love the most, has one of the worst reputations. This comes to me as a surprise, because in fact physics is one of the most beautiful aspects of the human intellectual enterprise. In reality, physics is very different from how it is featured in traditional education.
The best way to understand the true essence of physics is to evoke how the ancient Greeks thought about it. With the word physics (‘Τά Φυσικά’) they intended the study of nature, of all things in the Universe, known and yet to be known.
This meaning still gets very close to the spirit of the modern physics enterprise. Physics aims to understand how the Universe works. What makes it tick. It is the most subtle and refined tool to dissect reality and make it understandable. I am not just talking about explaining the so-called microscopic world, which consists of elementary particles, interactions, and spacetime. Physics explains much of the stuff existing at our (macroscopic) scale: from computers to smartphones, to the Internet, to the workings of our brains when we think. It does so by finding the unifying explanations for those phenomena and then expressing them as laws. The laws of physics are the basic rules that tell matter, space, and time how to behave. They govern everything, from the elementary particles to the chemistry fuelling life and our thinking. Without knowledge of the physical laws, the world looks one way. Once you know the laws of physics, you can see much more. Knowing the physical laws makes you reach a much deeper level of engagement with the world — like a higher state of enlightenment.
The physicist R. Feynman wrote a remarkable passage about how the worldview provided by the laws of physics gives us a deeper appreciation of the Universe. He insists that physics does not subtract from the enjoyment but adds to it. Feynman uses a flower as an example, but one can use any other object of beauty in our surroundings. The sea waves, a grain of sand, the light beaming through a prism, the rainbow, a waterfall. Zooming in into their workings, down to the size of an atom and beyond, and finding how they are all connected by unifying laws, is an experience that resembles an epiphany. Imagine looking at a mechanical clock, one of those metal clocks made of cogs and gears all working together to produce a neat ticking sound while the hands advance rhythmically round and round, keeping time. One way to enjoy the clock is to notice the beauty of the manufacturing – for instance, the shape of the hands and the numbers painted around the clock. Then, if we pay more attention to the detail, we may be struck by the complexity of the design — how all cogs fit into one another, producing a seamless motion that propels the hands of the clock. Then, we can appreciate the regularity of the ticking sound. And so on. Each of these levels gives us a fuller experience of the clock. Physics indeed adds to this: it tells us how the ticking sound propagates from the clock to our ears, how the motion of the cogs and hands must unfold in time, and how much energy is required to wind up the clock once it has run out of charge; how it’s all made by atomic particles strung together by microscopic, invisible interactions.
If physics really provides such powerful and far-reaching account about the Universe and how we fit in it, why is it rarely presented as such in school? The answer is complex. A considerable part of the reason is that school aims to optimise certain parameters (the ability to pass standardised texts, covering pre-defined curricula, etc.) that have nothing to do with presenting a given subject in its best form. So, unless a teacher happens to be particularly enlightened, the most beautiful features of the subject rarely shine through, and they are kept as secrets. This is a tragedy because, in this way, people of all ages keep missing out on some true beauty. Conventional wisdom tells us that physics is far from anything that can be interesting or useful to understand the Universe. In textbook presentations, physics appears like a set of mechanical rules to solve parochial problems about, say, inclined planes and falling bodies. There seems to be little creativity involved in it: it all looks like a repetitive exercise. It is paradoxical that people who do physics as their profession, like me, think that the opposite is true. Physics is dazzling and enchanting; it also has a deep, intimate connection with the fabric of reality. By the study of it, you can, in fact, move much closer to understanding the Universe and our place within it.
This leads us to the two main reasons why we should care about physics in the first place — which is my final thought for this piece. One reason is that physics is fun. Simply put, it adds much delight to our lives. There are many forms of enjoyment and pleasure in the world; the joy that comes through the mind is the most durable, portable, and resilient. It does not depend on the state of your body — you can enjoy a song, a work of art, or a novel, whether or not you are in good health, irrespective of your age and physical form. It is portable – once you have savoured it, you have it in you for as long as you live. It is resilient because you can learn how to cultivate it irrespective of your surroundings — even in the darkest corners of one’s life, the mind’s delight carries the light through. It is, therefore, a huge advantage to know that physics is an intellectual delight which is often hidden away from most. The sooner we realise this, the richer our life experience can be. This particular form of intellectual delight also constitutes a potent remedy against terror, fear, and angst. For physics (like the rest of the sciences) dispels fear (which stems from ignorance) and infuses reality with brightness, clarity of understanding, and wonder. The other reason is that understanding the cosmos is essential to our species’ perpetuation. We live in a universe that is not tailor-made for us — we need to be continuously focused to find and solve problems that may become existential threats to humanity. Understanding the laws of physics gives us access to technologies and insights that have made, and may make, the difference between good and bad quality of life, between life and death, and between our species’ extinction and survival.
Originally published here.
Why is the Trump Administration trying to kill a small space science institute in New York City? Explanation begins with Galileo’s method of scientific inquiry and ends with the role of special interest money in the United States government.
By James Hansen
Galileo improved the telescope, allowing clearer observations of the planets and the Sun. Galileo differed from his peers, as he was unafraid to challenge authority. He claimed that the world should be understood based on observations, and he spoke directly to the public. He obtained philanthropic support for his observations and openly described the conclusion that Earth was not the center of the solar system – Earth revolved around the Sun.
Implications of Galileo’s approach rattled the establishment. Galileo was opposed not only by the Catholic Church, but by many professors who did not fully understand Galileo’s work and were reluctant to support a heretical viewpoint. At his Inquisition, Galileo recanted his views, to save his life. He could wait for history to vindicate him; the Scientific Revolution was beginning.
Science research and the primacy of observations were well advanced by October 1957 when the Soviet Union launched Sputnik 1, the first human-made Earth satellite. The United States responded by forming NASA in 1958 and supporting universities to develop space scientists. I benefitted from that support and, as a 25-year-old post-doc in February 1967, drove with great expectations from Iowa City to New York City, pulling over only once for a few hours of sleep, my destination being the NASA Goddard Institute for Space Studies (GISS) on the edge of the Columbia University campus.
GISS attracted scientists from around the world to carry out space science research, as described in The Universe on a Scratch Pad.[1] Patrick Thaddeus built a microwave telescope on the roof of GISS, which he used to discover numerous molecules in space, survey the molecular Milky Way, and help revolutionize understanding of the interstellar medium and star formation. In this citadel of research, I worked with Henk van de Hulst, the world-leading expert on light scattering, and led a team that developed an instrument for the Pioneer mission to Venus to investigate the veil of Venus, which shrouds Earth’s nearest neighbor. We measured the properties of Venus aerosols – fine airborne particles that turned out to be sulfuric acid – more precisely in the 1970s than aerosols on Earth are measured today.
What is the justification for such a small laboratory? Robert Jastrow, the first GISS director, described the “GISS formula” for research in cooperation with nearby universities, including Columbia, New York University, and the City University of New York. The formula put equal emphasis on observations – the foundation of science – and theory. The small added cost of location in an urban setting was justified by the gain from working with top-notch academia, as well as the proximity of national media to help promulgate scientific progress. Indeed, the GISS formula actually limited costs by employing only a small number of government scientists, along with students, post-docs, and university research associates.
The GISS formula has other merits: independent thinking and ability to rapidly change research focus. For example, as changes of Earth’s ozone layer emerged in the 1970s, it became clear that our home planet was more interesting and important than other planets. I began compiling Earth observations, including global temperature, and focused my research group on development of a global model for computer simulation of climate change on Earth.
In 1982, soon after I was appointed to succeed Jastrow as GISS director, I was instructed to move GISS to the main Goddard center, which housed about 10,000 employees in suburban Maryland. The GISS formula would have been lost. Thus, we refused to go, but we survived in New York with reduced government funding. In this setting, we investigated climate change with equal emphasis on (1) paleoclimate, the history of climate change, (2) global climate modeling, and (3) observations of ongoing climate change. Based on this multi-faceted research approach, I could testify to Congress in 1988 with a high degree of confidence that the world had entered a period of global warming driven by human-made changes of Earth’s atmosphere.
In 1989, Congress approved a multi-billion-dollar NASA “Mission to Planet Earth” to study global change. We GISS scientists proposed that the mission include small satellites for crucial climate measurements, especially of atmospheric aerosols and their effect on clouds. Aerosols increase reflection of sunlight to space, thus causing global cooling that partly offsets warming from increasing carbon dioxide and other greenhouse gases. Unfortunately, our proposal was viewed by NASA management as a threat to their larger satellites,[2] rather than a complement.
We persisted in advocacy of small satellites for decades, which resulted in renewed efforts to move GISS to Maryland. Again, GISS survived with further reduction of support, but with our perspective and intellectual integrity intact. Finally, after we had carried out additional research and aircraft measurements, we proposed a small satellite aerosol mission in cooperation with Pete Wordon, director of NASA Ames Research Center. When this proposal was blocked by the director of Goddard Space Flight Center, I retired from NASA.
In 2013, I initiated a broad research program, Climate Science, Awareness and Solutions, based entirely on public and philanthropic support, with cooperation of Prof. Jeff Sachs and Columbia University. Our research, based on paleoclimate, climate modeling, and modern observations, has produced results that challenge the climate dogma promulgated by the United Nations. The UN climate assessment (by IPCC, the Intergovernmental Panel on Climate Change) and the UN policy approach (defined by the Kyoto Protocol and Paris Agreement) are each so seriously flawed that they pose a threat to the future of young people and future generations.
The crucial science issue is climate sensitivity, which is a measure of global climate change in response to an imposed climate “forcing” such as a change of atmospheric greenhouse gases or aerosols. The common measure of climate sensitivity is the equilibrium (eventual) global warming in response to doubled atmospheric CO2 (carbon dioxide). IPCC’s best estimate of climate sensitivity (3 degrees Celsius, which is 5.4 degrees Fahrenheit) is based mainly on climate models, which have many uncertainties. Clouds are especially difficult to model because even a small cloud change affects Earth’s reflectivity and energy balance. Thus, climate models, by themselves, cannot define climate sensitivity accurately.
Recent paleoclimate studies, especially improved data on global temperature during the last ice age[3] and on longer time scales,[4] show with more than 99 percent confidence that climate sensitivity is greater than IPCC’s best estimate. Another, independent, indication of climate sensitivity is provided by satellite observations of a change in the amount of sunlight reflected by Earth. Earth has become darker during the past 25 years, as reflection of sunlight by clouds diminished. This cloud change provides an empirical measure of cloud feedback, that is, the response of clouds to global warming. This amplifying cloud feedback confirms the high climate sensitivity derived from paleoclimate studies.
Explanation[5] of how IPCC underestimated climate sensitivity involves their reliance on climate models and their assumption that climate forcing by aerosols changed little in 1970-2005, as global temperature rose. However, even though global emissions of sulfur dioxide gas – the main cause of aerosol formation – were nearly constant in 1970-2005, emissions spread globally into more pristine air where emissions cause a larger climate forcing. Thus, aerosols had a cooling effect during 1970-2005. The upshot is that the average of climate models used by IPCC understated aerosol cooling and required a climate sensitivity of only 3 degrees Celsius to match observed warming. With more realistic aerosol cooling, larger climate sensitivity is required.
Thus, all three methods of analysis – paleoclimate, satellite observations, and climate modeling – indicate a climate sensitivity substantially higher than IPCC’s best estimate of 3 degrees Celsius; our best estimate is 4.5 degrees Celsius.[5] The practical impact of this high climate sensitivity and aerosol forcing will be enormous. Aerosol cooling constrained global warming in 1970-2005, but since 2005 aerosols have been on decline globally, especially in China, Europe and the United States and since 2020 aerosols from ships have decreased due to regulations on the sulfur content of ship fuel. The result is acceleration of global warming. The global warming rate in the past two decades is nearly double the rate in 1970-2005.
Confirmation of our analysis is provided by precise monitoring of Earth’s energy imbalance – the difference between absorbed solar radiation and heat radiation emitted to space. Because of the change from increasing aerosols in 1970-2005 to decreasing aerosols, Earth’s energy imbalance – which is the drive for global warming – has doubled since 2005, from 0.6 to 1.2 watts per square meter averaged over Earth’s surface. The latter value is equal to the energy in 800,000 Hiroshima atomic bombs per day (220 per second), with 90 percent of this excess energy going into the ocean. Because of the massive size of the ocean, warming is gradual but relentless. In the absence of effective policy intervention, regional climate extremes will grow in coming decades, and there will be effects that are practically irreversible, such as rising sea level.
The climate threat is no reason to despair. However, to keep favorable climate we must account for world energy needs. Fossil fuels, the main source of gases that cause global warming, are an amazing energy source: a gallon of gasoline contains energy equal to that in 400 hours of labor by an adult. Fossil fuels have raised living standards in much of the world and provide 80 percent of the world’s energy today. And energy demand is rising. Billions of people still strive to escape poverty. Fossil fuels are convenient and they will remain affordable as long as they are not required to pay their cost to society caused by their effects on human health and climate change.
Economists agree[6] that the main policy needed to phase down fossil fuel emissions is a gradually rising carbon fee.[7] With these funds distributed uniformly to the public, most low- and middle-income people receive more in the carbon dividend than they pay in increased energy prices, thus tending to lock in the policy. Governments also need to support modern nuclear power, which is available 24/7 to complement intermittent renewable energy. However, these policies, despite their low cost, are not well pursued in the United States by either major political party.
Our government’s failure to address climate change effectively and the present administration’s desire to exterminate a small science laboratory in New York City have a common explanation. I describe in Sophie’s Planet[8] interactions with the government that expose a decades-long, confounding, failure to take sensible, inexpensive, actions that would address energy needs and climate change. The problem is traced to special financial interests, especially the fossil fuel industry and the military-industrial complex, in affecting policies.
Corruption was recognized as a threat by our nation’s founders, who provided us tools to fight it. Fossil fuel executives fund both parties to assure that a simple, honest, carbon fee is avoided, and they chortle at environmentalists who believe that subsidizing renewable energies will lead to phase out of fossil fuels. Militarism[9] tends to create permanent enemies and inhibit the global cooperation needed to address climate change. Soft power emanating from a democracy that functions as it is intended would be far more effective. It is possible to fix our democracy, I argue in Sophie’s Planet, whether via a third party that takes no money from special interests or via bi-partisan legislation that constrains special interests, as Senator John McCain once advocated.
However, President Trump’s attempt to close climate laboratories and halt collection of climate data is a new threat that warrants special attention. No executive order can destroy knowledge of the scientific method; in the worst case, institutes using the GISS formula can be reconstructed later. The greater threat is to science data, the essential fuel to keep the science flame burning. Even the Pope did not stop Vatican astronomers from observing the planets and thinking about their motions. Especially important are satellite data[10] for Earth’s radiation balance and ocean measurements by deep-diving Argo floats,[11] with continuous measurements of both data sources required for absolute calibration of Earth’s energy imbalance.[12]
Science itself is under threat today, in a way that I thought was no longer possible. Scientists who see and understand the threat must speak out. The next 5-10 years are crucial for policy decisions to define a course that provides energy to raise global living standards, while allowing climate policies that cool the planet enough to avoid locking in irreversible effects such as shutdown of the ocean’s overturning circulation and large sea level rise.[13] These objectives require knowledge of ongoing climate change and the drives that cause change. We scientists must stand up against the forces of ignorance, fight for the collection of data, and work with young people to help them find a path to a healthy climate that benefits all humanity.
[1] The Universe on a Scratchpad, NASA film of the early 1960s.
[2] Hansen J Battlestar Galactica, Chapter 31 in Sophie’s Planet, 10 draft chapters
[3] Seltzer AM et al. Widespread six degrees Celsius cooling on land during the Last Glacial Maximum. Nature 593, 228-32, 2021
[4] Hansen J, Sato M, Simon L et al. “Global warming in the pipeline,” Oxford Open Clim. Chan. 3(1), 2023, doi.org/10.1093/oxfclm/kgad008
[5] Hansen JE, Kharecha P, Sato M et al. Global warming has accelerated: are the United Nations and the public well-informed? Environ.: Sci. Pol. Sustain. Devel. 67(1), 6–44, 2025, https://doi.org/10.1080/00139157.2025.2434494
[6] Discussion of the Economists’ Statement is at Hansen J Student leadership on climate solutions, 31 July 2020
[7] Hansen JE The eyes of climate change history are on Biden, Boston Globe, 8 August 2022
[8] Hansen J Sophie’s Planet, preface and several draft chapters of book to be published by Bloomsbury.
[9] Wertheim S. How Many Wars Is America Fighting? The Gravel Institute, last access 6 July 2025
[10] Loeb NG et al. Satellite and ocean data reveal marked increase in Earth’s heating rate, Geophys Res Lett 48 e2021GL093047, 2021
[11] von Schuckmann K et al., Heat stored in the Earth system: where does the energy go? Earth System Science Data 12, 2013-41, 2020
[12] Mauritsen T, Tsushima Y, Meyssignac B et al. Earth’s energy imbalance more than doubled in recent decades. AGU Advances 6, e2024AV001636, 2025
[13] Hansen J, Sato M, Hearty P et al. Ice melt, sea level rise and superstorms: evidence from paleoclimate data, climate modeling, and modern observations that 2 C global warming is highly dangerous. Atmos Chem Phys 16, 3761-812, 2016
About James Hansen
James Edward Hansen (born March 29, 1941) is an American climatologist. He is an adjunct professor directing the Program on Climate Science, Awareness and Solutions of the Earth Institute at Columbia University. He is best known for his research in climatology, his 1988 Congressional testimony on climate change that helped raise broad awareness of global warming, and his advocacy of action to avoid dangerous climate change. In recent years, he has become a climate activist to mitigate the effects of global warming, on a few occasions leading to his arrest.
Hansen also proposed an alternative approach of global warming, where the 0.7°C global mean temperature increase of the last 100 years can essentially be explained by the effect of greenhouse gases other than carbon dioxide (such as methane).
By 2045, there will be virtually nothing a human can do that a machine cannot to better for a tiny fraction of the cost. A robot that has a lifetime cost of $10,000, works 22 hours per day, and lasts 5 years would have an hourly marginal cost of just 25 cents. And when robots are building all the robots, they will cost a lot less than $10,000.
The marginal cost of labor will plummet toward zero as adoption of humanoid robots powered by increasingly capable AI explodes across every virtually industry worldwide. Humans simply will not be able to compete.
Join Adam Dorr, RethinkX Director of Research as he relays his latest insight on the inevitable and painful truth of the coming disruption of the human labor engine by AI and humanoid robots…
Visit the RethinkX Website for more groundbreaking insights: https://www.rethinkx.com
Courtesy of Pressenza
To confront the barrage of executive orders and undiplomatic policies from the U.S. government, the opposition is focusing on restoring institutions to their pre-Trump state—without recognizing that it was precisely those institutions that created the conditions for the current crisis.
The democracy they claim to defend was largely formal: it worked for some while leaving millions marginalized. For decades, no serious action was taken to stop the relentless concentration of wealth, the decline in living standards, or the dehumanizing effects of unchecked technological development. These issues remain unaddressed.
Now, the new administration is threatening to cut federal funding for public radio and television, accusing these outlets of being too “leftist” or “woke.”
But perhaps even more revealing than the threat itself is the reaction of public media institutions. WNYC in New York, for example, has leveraged this threat primarily as a fundraising opportunity, urging listeners to donate out of fear rather than conviction.
This response exposes a fundamental contradiction. These institutions speak of “democracy” and “public service,” yet they are unable—or unwilling—to mount a truly democratic response. Why aren’t they calling on people to stand up for public goods? Why not organize a large-scale campaign, like a concert in Central Park, to advocate for a federal public funding system that remains independent of presidential politics? New York has plenty of artists ready to contribute and stand up for others.
The question becomes clear:
Will institutions like WNYC and NPR help advance genuine democracy, or will they gradually transform into privatized versions of non-profit entities? If we want democracy, we need active public participation. If we accept privatization, we merely need people’s money.
Today, there is no visible leadership in our so-called democratic institutions that is mobilizing the population to build a new democratic system—one that addresses economic redistribution and real public participation. This isn’t just about public broadcasting. What future awaits Social Security, Medicare, the U.S. Postal Service, public libraries, and other essential public services?
These institutions cannot be privatized. No modern society can develop without deepening democracy, improving standards of living, and ensuring collective well-being. A society governed primarily by self-interest ultimately undermines itself.
So today, my call is to WNYC and NPR: Please stop trying to merely save yourselves in a collapsing system. Instead, help move the country forward. Mobilize people. Inspire engagement. Become a force in building a new, inclusive society for all.
