Some ‘water worlds’ like Jupiter’s moon Europa could potentially be habitable for life. NASA/JPL-Caltech/SETI InstituteDaniel Apai, University of Arizona The search for life beyond Earth is a key driver of modern astronomy and planetary science. The U.S. is building multiple major telescopes and planetary probes to advance this search. However, the signs of life – called biosignatures – that scientists may find will likely be difficult to interpret. Figuring out where exactly to look also remains challenging. I am an astrophysicist and astrobiologist with over 20 years of experience studying extrasolar planets – which are planets beyond our solar system. My colleagues and I have developed a new approach that will identify the most interesting planets or moons to search for life and help interpret potential biosignatures. We do this by modeling how different organisms may fare in different environments, informed by studies of limits of life on Earth.
New telescopes to search for life
Astronomers are developing plans and technology for increasingly powerful space telescopes. For instance, NASA is working on its proposed Habitable Worlds Observatory, which would take ultrasharp images that directly show the planets orbiting nearby stars. My colleagues and I are developing another concept, the Nautilus space telescope constellation, which is designed to study hundreds of potentially Earthlike planets as they pass in front of their host stars.Future telescopes, like the proposed Nautilus, could help search the skies for habitable planets.Katie Yung, Daniel Apai /University of Arizona and AllThingsSpace /SketchFab, CC BY-ND These and other future telescopes aim to provide more sensitive studies of more alien worlds. Their development prompts two important questions: “Where to look?” and “Are the environments where we think we see signs of life actually habitable?” The strongly disputed claims of potential signs of life in the exoplanet K2-18b, announced in April 2025, and previous similar claims in Venus, show how difficult it is to conclusively identify the presence of life from remote-sensing data.
When is an alien world habitable?
Oxford Languages defines “habitable” as “suitable or good enough to live in.” But how do scientists know what is “good enough to live in” for extraterrestrial organisms? Could alien microbes frolic in lakes of boiling acid or frigid liquid methane, or float in water droplets in Venus’ upper atmosphere? To keep it simple, NASA’s mantra has been “follow the water.” This makes sense – water is essential for all Earth life we know of. A planet with liquid water would also have a temperate environment. It wouldn’t be so cold that it slows down chemical reactions, nor would it be so hot that it destroys the complex molecules necessary for life. However, with astronomers’ rapidly growing capabilities for characterizing alien worlds, astrobiologists need an approach that is more quantitative and nuanced than the water or no-water classification.
A community effort
As part of the NASA-funded Alien Earths project that I lead, astrobiologist Rory Barnes and I worked on this problem with a group of experts – astrobiologists, planetary scientists, exoplanet experts, ecologists, biologists and chemists – drawn from the largest network of exoplanet and astrobiology researchers, NASA’s Nexus for Exoplanet System Science, or NExSS. Over a hundred colleagues provided us with ideas, and two questions came up often: First, how do we know what life needs, if we do not understand the full range of extraterrestrial life? Scientists know a lot about life on Earth, but most astrobiologists agree that more exotic types of life – perhaps based on different combinations of chemical elements and solvents – are possible. How do we determine what conditions those other types of life may require? Second, the approach has to work with incomplete data. Potential sites for life beyond Earth – “extrasolar habitats” – are very difficult to study directly, and often impossible to visit and sample. For example, the Martian subsurface remains mostly out of our reach. Places like Jupiter’s moon Europa’s and Saturn’s Moon Enceladus’ subsurface oceans and all extrasolar planets remain practically unreachable. Scientists study them indirectly, often only using remote observations. These measurements can’t tell you as much as actual samples would.Mars’ hot, dusty surface is hostile for life. But scientists haven’t been able to study whether some organisms could lurk beneath.NASA/JPL-Caltech/Malin Space Science Systems To make matters worse, measurements often have uncertainties. For example, we may be only 88% confident that water vapor is present in an exoplanet’s atmosphere. Our framework has to be able to work with small amounts of data and handle uncertainties. And, we need to accept that the answers will often not be black or white.
A new approach to habitability
The new approach, called the quantitative habitability framework, has two distinguishing features: First, we moved away from trying to answer the vague “habitable to life” question and narrowed it to a more specific and practically answerable question: Would the conditions in the habitat – as we know them – allow a specific (known or yet unknown) species or ecosystem to survive? Even on Earth, organisms require different conditions to survive – there are no camels in Antarctica. By talking about specific organisms, we made the question easier to answer. Second, the quantitative habitability framework does not insist on black-or-white answers. It compares computer models to calculate a probabilistic answer. Instead of assuming that liquid water is a key limiting factor, we compare our understanding of the conditions an organism requires (the “organism model”) with our understanding of the conditions present in the environment (the “habitat model”). Both have uncertainties. Our understanding of each can be incomplete. Yet, we can handle the uncertainties mathematically. By comparing the two models, we can determine the probability that an organism and a habitat are compatible. As a simplistic example, our habitat model for Antarctica may state that temperatures are often below freezing. And our organism model for a camel may state that it does not survive long in cold temperatures. Unsurprisingly, we would correctly predict a near-zero probability that Antarctica is a good habitat for camels.A hydrothermal vent deep in the Atlantic Ocean. These vents discharge incredibly hot plumes of water, but some host hearty microorganisms.P. Rona / OAR/National Undersea Research Program (NURP); NOAA We had a blast working on this project. To study the limits of life, we collected literature data on extreme organisms, from insects that live in the Himalayas at high altitudes and low temperatures to microorganisms that flourish in hydrothermal vents on the ocean floor and feed on chemical energy. We explored, via our models, whether they may survive in the Martian subsurface or in Europa’s oceans. We also investigated if marine bacteria that produce oxygen in Earth’s oceans could potentially survive on known extrasolar planets. Although comprehensive and detailed, this approach makes important simplifications. For example, it does not yet model how life may shape the planet, nor does it account for the full array of nutrients organisms may need. These simplifications are by design. In most of the environments we currently study, we know too little about the conditions to meaningfully attempt such models – except for some solar system bodies, such as Saturn’s Enceladus. The quantitative habitability framework allows my team to answer questions like whether astrobiologists might be interested in a subsurface location on Mars, given the available data, or whether astronomers should turn their telescopes to planet A or planet B while searching for life. Our framework is available as an open-source computer model, which astrobiologists can now readily use and further develop to help with current and future projects. If scientists do detect a potential signature of life, this approach can help assess if the environment where it is detected can actually support the type of life that leads to the signature detected. Our next steps will be to build a database of terrestrial organisms that live in extreme environments and represent the limits of life. To this data, we can also add models for hypothetical alien life. By integrating those into the quantitative habitability framework, we will be able to work out scenarios, interpret new data coming from other worlds and guide the search for signatures of life beyond Earth – in our solar system and beyond. Daniel Apai, Associate Dean for Research and Professor of Astronomy and Planetary Sciences, University of Arizona This article is republished from The Conversation under a Creative Commons license. Read the original article.
Hollywood Legend Rob Reiner and Wife Found Dead; Son in Custody
Renowned filmmaker Rob Reiner and his wife, Michele Singer Reiner, were found dead in their Los Angeles home in a reported homicide. Police have arrested their son in connection with the case, and tributes are pouring in.
Director Rob Reiner participates in a discussion following a screening of the film LBJ at the LBJ Presidential Library in Austin, Texas on Saturday October 22, 2016 On Saturday evening October 22, 2016, the LBJ Presidential Library held a sneak peek of Rob Reiner’s new filmÊLBJ, starring Woody Harrelson as the 36th president. The film, which premiered at the Toronto International Film Festival in September, chronicles the life and times of Lyndon Johnson who would inherit the presidency at one of the most fraught moments in American history. Following the screening, director Rob Reiner, actor Woody Harrelson, and writer Joey Hartstone joined LBJ Library Director Mark Updegrove on stage for a conversation about the film. LBJ Library photo by Jay Godwin 10/22/2016
Hollywood Legend Rob Reiner and Wife Found Dead; Son in Custody
December 15, 2025
Renowned filmmaker and actor Rob Reiner, 78, and his wife Michele Singer Reiner, 68, were found dead in their Brentwood, Los Angeles home on Sunday, authorities say. Emergency responders were called to the residence Sunday afternoon, where both were discovered with fatal wounds consistent with a stabbing. Police are treating the case as a double homicide.
Los Angeles police arrested the couple’s 32-year-old son, Nick Reiner, in connection with the deaths. He is being held in custody as investigators continue to piece together the circumstances surrounding the incident.
2016 SAMHSA Voice Awards
Reiner was one of Hollywood’s most influential figures, known for his work as a director, producer and actor. His career spanned decades, from early television fame to directing beloved films that shaped American cinema.
Friends, colleagues and public figures have begun sharing tributes and reactions to the news as the investigation is ongoing.
More details will be updated as they become available.
FDA’s COVID-19 Vaccine Safety Claims Lack Solid Evidence—Why Overreaction Could Harm Public Health
COVID-19 vaccine safety: The FDA’s claims about COVID-19 vaccine deaths in children lack strong evidence and could restrict vaccine access. Learn why experts say VAERS reports aren’t proof, and how overreacting may harm public health and trust in vaccines.
The death of children due to an unsafe vaccine is a serious allegation. I am a pediatric cardiologist who has studied the link between COVID-19 vaccines and heart-related side effects such as myocarditis in children. To my knowledge, studies to date have shown such side effects are rare, and severe outcomes even more so. However, I am open to new evidence that could change my mind. But without sufficient justification and solid evidence, restricting access to an approved vaccine and changing well-established procedures for testing vaccines would carry serious consequences. These moves would limit access for patients, create roadblocks for companies and worsen distrust in vaccines and public health. In my view, it’s important for people reading about these FDA actions to understand how the evidence on a vaccine’s safety is generally assessed.
Determining cause of death
The FDA memo claims that the deaths of these children were directly related to receiving a COVID-19 immunization. From my perspective as a clinician, it is awful that any child should die from a routine vaccination. However, health professionals like me owe it to the public to uphold the highest possible standards in investigating why these deaths occurred. If the FDA has evidence demonstrating something that national health agencies worldwide have missed – widespread child deaths due to myocarditis caused by the COVID-19 vaccine – I don’t doubt that even the most pro-vaccine physician will listen. So far, however, no such evidence has been presented. While a death logged in VAERS is a starting point, on its own it is insufficient to conclude whether a vaccine caused the death or other medical causes were to blame. To demonstrate a causal link, FDA staff and physicians must align the VAERS report with physicians’ assessments of the patient, as well as data from other sources for monitoring vaccine safety. These include PRISM, which logs insurance claims data, and the Vaccine Safety Datalink, which tracks safety signals in electronic medical records. It’s known that most deaths logged only in VAERS of children who recently received vaccines have been incorrectly attributed to the vaccines – either by accident or in some cases on purpose by anti-vaccine activists.
Heart-related side effects of COVID-19 vaccines
In his Substack and Twitter accounts, Prasad has said that he believes the rate of severe cardiac side effects after COVID-19 vaccination is severely underestimated and that the vaccines should be restricted far more than they currently are. In a July 2025 presentation, Prasad quoted a risk of 27 cases per million of myocarditis in young men who received the COVID-19 vaccine. A 2024 review suggested that number was a bit lower – about 20 cases out of 1 million people. But that same study found that unvaccinated people had greater risk of heart problems after a COVID-19 infection than vaccinated people. In a different study, people who got myocarditis after a COVID-19 vaccination developed fewer complications than people who got myocarditis after a COVID-19 infection. Existing vaccine safety infrastructure in the U.S. successfully identifies dangers posed by vaccines – and did so during the COVID-19 pandemic. Today, most COVID-19 vaccines in the U.S. rely on mRNA technology. But as vaccines were first emerging during the COVID-19 pandemic, two pharmaceutical companies, Janssen and AstraZeneca, rolled out a vaccine that used a different technology, called a viral vector. This type of vaccine had a very rare but genuine safety problem that was detected.A report in VAERS is at most a first step to determining whether a vaccine caused harm. VAERS, the Vaccine Safety Datalink, clinical investigators in the U.S. and their European counterparts detected that these vaccines did turn out to cause blood clotting. In April 2021, the FDA formally recommended pausing their use, and they were later pulled from the market. Death due to myocarditis from COVID-19 vaccination is exceedingly rare. Demonstrating that it occurred requires proof that the person had myocarditis, evidence that no other reasonable cause of death was present, and the absence of any additional cause of myocarditis. These factors cannot be determined from VAERS data, however – and to date, the FDA has presented no other relevant data.
A problematic vision for future vaccine approvals
Currently, vaccines are tested both by seeing how well they prevent disease and by how well they generate antibodies, which are the molecules that help your body fight viruses and bacteria. Some vaccines, such as the COVID-19 vaccine and the influenza vaccine, need to be updated based on new strains. The FDA generally approves these updates based on how well the new versions generate antibodies. Since the previous generation of vaccines was already shown to prevent infection, if the new version can generate antibodies like the previous one, researchers assume its ability to prevent infection is comparable too. Later studies can then test how well the vaccines prevent severe disease and hospitalization. The FDA memo says this approach is insufficient and instead argues for replacing such studies with many more placebo-controlled trials – not just for COVID-19 vaccines but also for widely used influenza and pneumonia vaccines. That may seem reasonable theoretically. In practice, however, it is not realistic. Today’s influenza vaccines must be changed every season to reflect mutations to the virus. If the FDA were to require new placebo-controlled trials every year, the vaccine being tested would become obsolete by the time it is approved. This would be a massive waste of time and resources.Influenza vaccines must be updated for every flu season.Jacob Wackerhausen/iStock via Getty Images Plus Also, detecting vaccine-related myocarditis at the low rate at which it occurs would have required clinical trials many times larger than the ones that were done to approve COVID-19 mRNA vaccines. This would have cost at least millions of dollars more, and the delay in rolling out vaccines would have also cost lives. Placebo-controlled trials would require comparing people who receive the updated vaccine with people who remain unvaccinated. When an older version of the vaccine is already available, this means purposefully asking people to forgo that vaccine and risk infection for the sake of the trial, a practice that is widely considered unethical. Current scientific practice is that only a brand-new vaccine may be compared against placebo. While suspected vaccine deaths should absolutely be investigated, stopping a vaccine for insufficient reasons can lead to a significant drop in public confidence. That’s why it’s essential to thoroughly and transparently investigate any claims that a vaccine causes harm.
Tariffs 101: What they are, who pays them, and why they matter now
Learn what tariffs are, who pays them, and why they matter for the U.S. economy. Explore how import taxes impact prices, trade policy, and everyday consumers as the Supreme Court reviews Trump’s global tariffs.
Tariffs 101: What they are, who pays them, and why they matter now
Kent Jones, Babson College The U.S. Supreme Court is currently reviewing a case to determine whether President Donald Trump’s global tariffs are legal. Until recently, tariffs rarely made headlines. Yet today, they play a major role in U.S. economic policy, affecting the prices of everything from groceriesto autosto holiday gifts, as well as the outlook for unemployment, inflation and even recession. I’m an economist who studies trade policy, and I’ve found that many people have questions about tariffs. This primer explains what they are, what effects they have, and why governments impose them.
What are tariffs, and who pays them?
Tariffs are taxes on imports of goods, usually for purposes of protecting particular domestic industries from import competition. When an American business imports goods, U.S. Customs and Border Protection sends it a tariff bill that the company must pay before the merchandise can enter the country. Because tariffs raise costs for U.S. importers, those companies usually pass the expense on to their customers by raising prices. Sometimes, importers choose to absorb part of the tariff’s cost so consumers don’t switch to more affordable competing products. However, firms with low profit margins may risk going out of business if they do that for very long. In general, the longer tariffs are in place, the more likely companies are to pass the costs on to customers. Importers can also ask foreign suppliers to absorb some of the tariff cost by lowering their export price. But exporters don’t have an incentive to do that if they can sell to other countries at a higher price. Studies of Trump’s 2025 tariffs suggest that U.S. consumers and importers are already paying the price, with little evidence that foreign suppliers have borne any of the burden. After six months of the tariffs, importers are absorbing as much as 80% of the cost, which suggests that they believe the tariffs will be temporary. If the Supreme Court allows the Trump tariffs to continue, the burden on consumers will likely increase. While tariffs apply only to imports, they tend to indirectly boost the prices of domestically produced goods, too. That’s because tariffs reduce demand for imports, which in turn increases the demand for substitutes. This allows domestic producers to raise their prices as well.
A brief history of tariffs
The U.S. Constitution assigns all tariff- and tax-making power to Congress. Early in U.S. history, tariffs were used to finance the federal government. Especially after the Civil War, when U.S. manufacturing was growing rapidly, tariffs were used to shield U.S. industries from foreign competition. The introduction of the individual income tax in 1913 displaced tariffs as the main source of U.S. tax revenue. The last major U.S. tariff law was the Smoot-Hawley Tariff Act of 1930, which established an average tariff rate of 20% on all imports by 1933. Those tariffs sparked foreign retaliation and a global trade war during the Great Depression. After World War II, the U.S. led the formation of the General Agreement on Tariffs and Trade, or GATT, which promoted tariff reduction policies as the key to economic stability and growth. As a result, global average tariff rates dropped from around 40% in 1947 to 3.5% in 2024. The U.S. average tariff rate fell to 2.5% that year, while about 60% of all U.S. imports entered duty-free. While Congress is officially responsible for tariffs, it can delegate emergency tariff power to the president for quick action as long as constitutional boundaries are followed. The current Supreme Court case involves Trump’s use of the International Emergency Economic Powers Act, or IEEPA, to unilaterally change all U.S. general tariff rates and duration, country by country, by executive order. The controversy stems from the claim that Trump has overstepped his constitutional authority granted by that act, which does not mention tariffs or specifically authorize the president to impose them.
The pros and cons of tariffs
In my view, though, the bigger question is whether tariffs are good or bad policy. The disastrous experience of the tariff war during the Great Depression led to a broad global consensus favoring freer trade and lower tariffs. Research in economics and political science tends to back up this view, although tariffs have never disappeared as a policy tool, particularly for developing countries with limited sources of tax revenue and the desire to protect their fledgling industries from imports. Yet Trump has resurrected tariffs not only as a protectionist device, but also as a source of government revenue for the world’s largest economy. In fact, Trump insists that tariffs can replace individual income taxes, a view contested by most economists. Most of Trump’s tariffs have a protectionist purpose: to favor domestic industries by raising import prices and shifting demand to domestically produced goods. The aim is to increase domestic output and employment in tariff-protected industries, whose success is presumably more valuable to the economy than the open market allows. The success of this approach depends on labor, capital and long-term investment flowing into protected sectors in ways that improve their efficiency, growth and employment. Critics argue that tariffs come with trade-offs: Favoring one set of industries necessarily disfavors others, and it raises prices for consumers. Manipulating prices and demand results in market inefficiency, as the U.S. economy produces more goods that are less efficiently made and fewer that are more efficiently made. In addition, U.S. tariffs have already resulted in foreign retaliatory trade actions, damaging U.S. exporters. Trump’s tariffs also carry an uncertainty cost because he is constantly threatening, changing, canceling and reinstating them. Companies and financiers tend to invest in protected industries only if tariff levels are predictable. But Trump’s negotiating strategy has involved numerous reversals and new threats, making it difficult for investors to calculate the value of those commitments. One study estimates that such uncertainty has actually reduced U.S. investment by 4.4% in 2025. A major, if underappreciated, cost of Trump’s tariffs is that they have violated U.S. global trade agreements and GATT rules on nondiscrimination and tariff-binding. This has made the U.S. a less reliable trading partner. The U.S. had previously championed this system, which brought stability and cooperation to global trade relations. Now that the U.S. is conducting trade policy through unilateral tariff hikes and antagonistic rhetoric, its trading partners are already beginning to look for new, more stable and growing trade relationships. So what’s next? Trump has vowed to use other emergency tariff measures if the Supreme Court strikes down his IEEPA tariffs. So as long as Congress is unwilling to step in, it’s likely that an aggressive U.S. tariff regime will continue, regardless of the court’s judgment. That means public awareness of tariffs – and of who pays them and what they change – will remain crucial for understanding the direction of the U.S. economy. Kent Jones, Professor Emeritus, Economics, Babson College This article is republished from The Conversation under a Creative Commons license. Read the original article.
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