Global Population Boom: Are People the Problem, the Solution, or Both?
Professor Joel Cohen first asks and answers the question, "How did humans grow from small populations on the African savannah to almost seven billion people?" After holding steady for thousands of years, the world population exploded after 1800, more than tripling in 200 years. And while the rate of population growth is slowing down, Cohen shows how high birth rates in poor countries are turning societies on their head and leading to explosive problems in the future. Can we prevent an outcome where rich western countries are in permanent population decline while cities in Africa, South America, and Asia swell into massively overcrowded slums with no access to education, healthcare, or hope? Cohen applies demography to this pressing question with fascinating results.
How We Speak Reveals What We Think, with Steven Pinker
How is it that human beings have come to acquire language? Steven Pinker's introduction to the field includes thoughts on the evolution of spoken language and the debate over the existence of an innate universal grammar, as well as an exploration of why language is such a fundamental part of social relationships, human biology, and human evolution. Finally, Pinker touches on the wide variety of applications for linguistics, from improving how we teach reading and writing to how we interpret law, politics, and literature.
How Societies Should Organize: Balancing Freedom and Community
Engagement with the the fundamentals of political philosophy is an essential step toward being able to think critically about the power structures in place and make your voice heard as a citizen. Professor Tamar Gendler begins with the question of why human beings should cooperate, then looks at the different answers that arise from two very different perspectives: Hobbes' theory of self-interest versus the social contract theory of Rousseau and Locke. Next, she shows how, with Marx's communism, political philosophy evolved to the point at which it had the power to overturn established hierarchies and dominate the international politics of the twentieth century.
A universe in a nutshell: The physics of everything, with Michio Kaku
In a profoundly informative and deeply optimistic discussion, Professor Michio Kaku delivers a glimpse of where science will take us in the next hundred years, as warp drives, teleportation, inter-dimensional wormholes, and even time travel converge with our scientific understanding of physical reality. While firing up our imaginations about the future, he also presents a succinct history of physics to the present.
Everyone Has Their Price: An Introduction to Economics
Levmore brings the future of economics into sharp focus by contrasting the approaches of the emerging global economic powers of India and China. From the basics of pricing, demand, and competition, to global politics and the future of government, Dr. Levmore makes it easy to see economics at work all around us. This may well be the only field in which thinking about the cost of a chocolate chip cookie or how airline ticket pricing works is expected to provide insights into the machinations of the entire world.
Psychology is the Study of Innate Human Compassion
Give Paul Bloom one hour, and he'll teach you "the psychology of everything." Through the case studies of compassion, racism, and sex, Dr. Bloom explores the intrinsic fundamentals of human nature, including some of our most intriguing tendencies, such as the kindness of babies, stereotyping (which can be both detrimental and beneficial), and our universal sense of beauty. Additional topics addressed in the lecture include: "What do studies suggest is the number one characteristic that males and females look for in a mate?", "How can I get someone to have compassion for causes I care about?", "Are we all unconscious racists?", and even, "What do the porn preferences of monkeys tells us about our own sexual choices?"
Social capital: If you want to succeed, start making friends
If you think you're in complete control of your destiny or even your own actions, you're wrong. Every choice you make, every behavior you exhibit, and even every desire you have finds its roots in the social universe. In his lecture, Nicholas Christakis explains why individual actions are inextricably linked to sociological pressures. Whether you’re absorbing altruism performed by someone you’ll never meet or deciding to jump off the Golden Gate Bridge, collective phenomena affect every aspect of your life.
Inside Every Human Cell May Lie the Fountain of Youth
Professor Douglas Melton begins with a look at the basis for regenerative medicine, the human body’s ability to divide, grow, and specialize cells. With a solid foothold in developmental biology, we see how this knowledge led to the breakthrough cloning experiments we’re all familiar with: Hello, Dolly! Next, we’re introduced to the science of stem cells and their greatest hope: new "man-made" stem cells that could soon be used to reverse incurable degenerative diseases like diabetes, heart disease, and Alzheimer’s. Lastly, Professor Melton tells how these same stem cells may be the keys that unlock an end to aging as we know it.
The Great Unexpected Utility of the Arts
Art is often dismissed as being purely subjective, but President Botstein argues that there are some commonalities among the diverse products that different people call art. He points out that art-making is uniquely a human activity, that it has its own semantic vocabulary that transcends the limitations of language, that its very existence is meaningless without viewer engagement and response. He argues that the most important thing about art is every person's capacity to make it, and that the body/mind discipline of cultivating your artistic abilities has collateral utility for every aspect of life. By the end of the lecture you will understand why you should actively make art part of your life-long education.
Strange Beauty: How Reading the Classics Will Change You
From "What's the best kind of life for a human?" to "How should governments be arranged?", the great classics tackle some of the most enduring questions that have resisted the attempts of science and the ages to solve. Brenzel will try to convince you that having intimate conversations with these great works will not only build your intellectual muscle but will also help you to grapple with the big questions in your own life and improve your judgment.
Learn to Invest and Start a Business in Under an Hour
We all want to be financially stable and enjoy a well-funded retirement, but we don't want to squander our hard-earned money on poor investments. In this powerful lecture, Ackman navigates the complex landscape of how businesses work and how to make smart investments following a simple business model we can all relate to: a lemonade stand. From balance sheets and growth assumptions to the difference between debt and equity, by the end of the hour you will have a working vocabulary of financial terms.
Ideas Rule the World, not Kings or Corporations
How many people remember who ruled England when Chaucer wrote or when Milton wrote or when Shakespeare wrote or even when Dickens wrote? Lawrence Summers makes the compelling case that history is shaped by ideas and the spread of knowledge rather than empire and conquest. Every innovative policy, maverick action, and upset of the status quo is rooted in an idea, a small pebble that starts a wave that eventually reaches all shores.
- In some fundamental ways, humans haven't changed all that much since the days when we were sitting around communal fires, telling tales.
- Although we don't always recognize them as such, stories, symbols, and rituals still have tremendous, primal power to move us and shape our lives.
- This is no less true in the workplace than it is in our personal lives.
- The word "creative" is sometimes waved around like a badge of honor. We speak of creativity in hushed tones, as the special province of the "talented". In reality, the creative process is messy, open, and vulnerable.
- For this reason, creativity is often at its best in a group setting like brainstorming. But in order to work, the group creative process needs to be led by someone who understands it.
- This sense of deep trust—that no idea is too silly, that every creative impulse is worth voicing and considering—is essential to producing great work.
- Climate scientists say that Greenland is experiencing ice losses that are unusually early and heavy.
- Two main weather factors are fueling the losses: a high-pressure system and the resulting low cloud cover.
- Greenland is a major contributor to sea-level rise.
Four trillion pounds of ice melted in Greenland on June 13 due to unusually warm and sunny weather, scientists report. Although it's normal for ice to melt during Greenland's "melt season," the ice this year is melting earlier than expected and at an alarmingly fast rate.
"It's very unusual to have this much melt so early in the season," William Colgan, senior researcher at the Geological Survey of Denmark and Greenland, told the BBC. "It takes very rare conditions but they're becoming increasingly common."
Greenland's current ice loss is on track to break records. In 2012, the island nation saw similarly severe losses, which, like current melting, was fueled by two main weather factors: a high-pressure system that carried warm air from the Central Atlantic to the skies over Greenland, causing warmer temperatures, and the resulting low cloud cover and snowfall, which allowed sunlight to hit the vast ice sheets.
Frozen white ice reflects most sunlight back into the sky. But melting ice turns into darker colors, which absorb more light and heat. This creates a positive feedback loop that speeds up melting.
"You've experienced this if you've walked down the road barefoot on a hot summer day," geologist Trevor Nace wrote for Forbes.
"The black asphalt is much hotter than the white concrete sidewalk. This is due to the difference in how much solar radiation white versus black reflects. Hence, as Greenland melts more of its ice, the surface is converted from a high albedo white to darker colors. This, in turn, causes more melting and adds to the positive feedback loop."
Arctic Monitoring and Assessment Programme/https://amap.no
This figure depicts how radiation from the sun is reflected or absorbed by different terrains. More radiation is reflected by white snow and ice, while more radiation is absorbed by dark surfaces, such as water.
Steffen Olsen, a scientist with the Danish Meteorological Institute, got an eerie up-close look at the changing ice sheets last week. Olsen was on a routine mission to pick up weather monitoring tools on sea ice in northwest Greenland when he saw meltwater pooled up on the sheet's surface, making it look like his sled dogs were walking on water.
Greenland's rapidly melting ice could raise global sea levels.
"Greenland has been an increasing contributor to global sea level rise over the past two decades," Thomas Mote, a research scientist at the University of Georgia who studies Greenland's climate, told CNN. "And surface melting and runoff is a large portion of that."
- A team of researchers discovered that permafrost in Northern Canada is melting at unusually fast rates.
- This could causes dangerous and costly erosion, and it's likely speeding up climate change because thawing permafrost releases heat-trapping gasses into the atmosphere.
- This week, Canada's House of Commons declared a national climate emergency.
A new study shows that permafrost in the Canadian Arctic is melting 70 years earlier than predicted. The melting was triggered by a series of unusually hot summers, said researchers from the University of Alaska Fairbanks, who measured the thawing while visiting remote outposts in Northern Canada. "What we saw was amazing," Prof. Vladimir E. Romanovsky told Reuters. "It's an indication that the climate is now warmer than at any time in the last 5,000 or more years."
Permafrost is ground that's been frozen for two or more consecutive years. This frozen soil helps to structurally support mountain ranges and slopes. "Think of permafrost as sort of the glue that holds the northern landscape together," permafrost scientist Steve Kokelj told CBC.
When permafrost thaws quickly, it not only causes landscapes to erode, but also releases tons of heat-trapping gasses into the atmosphere. This could start a dangerous feedback loop that speeds up climate change and threatens the ability to maintain and build new infrastructure.
For example, there were 87 landslides in one night in Canada's Northwest Territories. Nobody was injured in those remote areas, but Canadian climate scientists have a saying: "What happens in the North doesn't stay in the North."
"It's a canary in the coalmine," Louise Farquharson, a post-doctoral researcher and co-author of the study, told Reuters. "It's very likely that this phenomenon is affecting a much more extensive region and that's what we're going to look at next."
Thawing permafrost might already be limiting where new buildings and infrastructure can be built.
"We have to figure out what we're going to do in the future," Aurora Research Institute professor Chris Burn told CBC. "Because otherwise, when we make an investment in a building [or road] which is meant to last 50 years, if in 15 years it's no good we've wasted a huge amount of resources."
A 'climate emergency' in Canada
Canada is especially vulnerable to climate change. A report issued in April from the Environment and Climate Change Canada said that Canada is warming twice as quickly as the rest of the world, but that the warming is "effectively irreversible." This week, Canada's House of Commons voted to declare a national climate emergency.
"This is a national security issue, it is time we started treating it as one," wrote Green Party Leader Elizabeth May on Twitter.
Jennifer Morgan, Executive Director of Greenpeace International, echoed a similar sense of urgency to Reuters. "Thawing permafrost is one of the tipping points for climate breakdown and it's happening before our very eyes," she said. "This premature thawing is another clear signal that we must decarbonize our economies, and immediately."
- Earth's orbital space is getting more crowded by the day.
- The more satellites and space junk we put into orbit, the greater a risk that there could be a collision.
- Not all materials burn up during reentry; that's why scientists need to stress test satellite parts to ensure that they won't become deadly falling objects.
It's a simple fact that where there are humans, there's trash. Earth's orbit is no exception. The Space Surveillance Network keeps track of 22,300 bits of space junk orbiting the Earth, but there's almost certainly more than this. Statistical models estimate that there are 34,000 objects larger than 10 centimeters; 900,000 from 1 cm to 10 cm; and 128,000,000 objects between 1mm and 1cm in space. And this is a significant problem.
If some of this space debris strikes a satellite, it could destroy that satellite, creating more bits of space debris that may strike other satellites in a chain reaction of catastrophe called the Kessler syndrome. To avoid this, it's important that we design satellites so that they can fall back to Earth and burn up in the atmosphere. This represents part of the mission of the European Space Agency's (ESA's) CleanSat initiative. This initiative is focused on keeping our use of space sustainable so that we can continue to enjoy the benefits of GPS, weather modeling and other satellite-based services.
It's also the reason why researchers blasted a magnetotorquer, a piece of satellite technology, in a plasma wind tunnel, heating it to several thousands of degrees Celsius within the hypersonic plasma until it was mostly vaporized. You can watch it happen in the video above. And here's a picture of the aftermath.
"Satellite reentry is not a single event but rather a process," explains Tiago Soares of CleanSat. "From observations, we see the main body break apart typically at 70–80 km altitude, after which the insides are scattered. The kind of objects that can survive down to the surface are propellant tanks made from materials with high melting points, such as titanium or stainless steel, along with dense items such as optical instruments and large mechanisms."
One such dense item is a magnetotorquer. This device helps satellites interact with Earth's magnetic field to orient the satellite, and it's made of some sturdy stuff. The outside is composed of a carbon fiber–reinforced polymer, while the inside is made of copper coils and an iron-cobalt core.
What is D4D? Design for demise.
The magnetotorquer prior to being melted.
Generally, parts of spacecraft and satellites burn up in reentry, but some sturdy pieces can survive the reentry process, or are instead only broken up into potentially deadlier fragments. In 1997, for example, a woman in Tulsa, Oklahoma, was struck by a small fragment from a Delta rocket, though she wasn't injured. She could have been, however: hundreds of miles away, two Texans were woken up in the middle of the night when the 250kg fuel tank from that same rocket fell just 50m from their farmhouse.
Avoiding incidents like these is why researchers wanted to observe the magnetotorquer as it was subjected to the high heat from the kind of plasma it would generate on reentry. Modern spacecraft are built according to the design-for-demise concept, or D4D. D4D is the idea that satellites should be designed so that as few of their parts as possible can survive reentry or so that they can be safely pushed off into quieter parts of space after their lifespan ends.
Thanks to D4D and modern regulations, there's a 1 in 10,000 chance that a dead satellite in an uncontrolled reentry could hurt anyone on the ground. But some components of a spacecraft are too sturdy to burn up during reentry, such as optical instruments, propellant and pressure tanks, reaction wheels (which are gyroscopes that change a satellite's direction), and magnetotorquers.
"As part of CleanSat," said Soares, "we are looking into making such objects more destructible. Perhaps through new aluminum alloys for tanks, for example. However, even redesigned parts will not melt if they are not exposed to the searing heat early enough. This shows the need to adopt an overall approach to D4D, such as opening up the satellite body as early as possible during reentry." That's why ESA blasted the magnetotorquer in a plasma wind tunnel. Doing so provides insights into the dynamics of satellite reentry, which will in turn enable us to make a cleaner, safer orbital space.