New spacey stories: killer asteroids, stellar DNA, and rogue planets

I meant to post at least once a month, but I think you’ll understand that it’s hard to find the time while juggling new freelance science writing work with a 9-month-old kiddo at home. Anyway, here’s a couple pieces I’ve published over the past month. Enjoy! (See links below for the full articles.) As usual, thanks go to my helpful editors: Heather D’Angelo, Lisa Grossman, Lauren Morello and Jane Lee.


Maybe Dark Matter Didn’t Kill the Dinosaurs after All

Artist’s impression of the Chicxulub impact. Credit: Donald E. Davis, via Wikimedia Commons

A giant asteroid or comet the size of a city smashed into the Yucatán 66 million years ago, likely causing the demise of dinosaurs and many other species. Scientists have wondered: is that a random, unfortunate event, or has life on Earth been subjected to periodic impacts from outer space?

Some researchers proposed that, if the dinosaur extinction — the last of five mass extinctions — had an astronomical origin, rather than being driven by volcano eruptions or global warming, for example, then maybe others did too. And if impacts from huge boulders of rock and ice drove these extinctions, they had to come from somewhere. It’s possible that dark matter could periodically dislodge distant comets from their tenuous orbits beyond Pluto, sending a few of them dangerously in Earth’s direction — thus linking the fates of dark matter and dinosaurs.

But a new study by a team of physicists and geologists from Durham University and Lancaster University in the United Kingdom appears to shoot down that dark matter interpretation. If it were true, extinctions would have happened in cycles. But these scientists pored over the fossil record over the past 500 million years, looking for extinctions occurring periodically, but they didn’t find any significant patterns like that in the data.

“We needn’t search the heavens to find reasons for these extinction events. The vast majority of them are due to Earth processes, not astronomical ones,” says David Harper, lead author of the study.

The dark matter idea, popularized by Lisa Randall’s 2015 book, “Dark Matter and the Dinosaurs,” might sound far-fetched. But…

[Read the entire story in, published on 14 March 2017.]

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My new freelance writings: climate costs, light pollution, binary stars

I set out as a freelance science writer this month, and here’s a few excerpts from my latest pieces in Slate, New Scientist, and Inside Science. (See links below for the full articles.) As usual, thanks go to my insightful editors, Susan Matthews, Lisa Grossman, and Chris Gorski, and thanks to Abigail Malate, who provided illustrations for the light pollution article.


Here’s One Way Trump’s Team Could Manipulate Government Data

It has plans to recalculate the social cost of carbon, which has been called “the most important number you’ve never heard of.”



…Would Trump try to meddle with the government’s data-collection process? His transition team is interested in doing exactly that. One of the first things that might be under attack? A number known as the “social cost of carbon.”

Since 2008, the final year of the Bush administration, agencies like the Environmental Protection Agency, Department of Energy, and Department of Transportation have been required to take the social cost of carbon into account when assessing and enacting regulations. Everything from refrigerators to cars and trucks to power plants emits carbon, which then goes on to hurt our health, our lands, our long-term viability on this planet, etc. The social cost of carbon allows more than 70 federal regulations, and even some local and state ones, to meaningfully and uniformly account for these costs while regulating. It’s sort of like a carbon tax that only applies to government decisions and is never actually paid but still incentivizes long-term good behavior over short-term economic gains.

“It’s the most important number you’ve never heard of,” says Michael Greenstone, a University of Chicago economist.

It exists thanks to a 2007 federal court case that forced the Bush administration to account for the social cost of carbon when regulating the fuel economy of trucks and SUVs. The suit argued, among other things, that the Energy Policy and Conservation Act’s “calculation of the costs and benefits of alternative fuel economy standards assigns zero value to the benefit of carbon dioxide (CO2) emissions reduction” and that these benefits should be included. This was achieved by calculating and accounting for the social cost of carbon. Another court finding upheld and reinforced that decision just last year: A trade association of refrigerator companies had tried to argue that the cost of carbon estimate was just a guess and that the government didn’t have the authority to consider it. The court disagreed, upholding that the calculation “is supported by substantial evidence and is neither arbitrary nor capricious”…

[Read the entire story in Slate, published on 26 January 2017.]

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To combat climate change, incremental change is not enough

Some people, including Andrew Revkin in the New York Times, argue that we can effectively mitigate climate change and keep greenhouse gas emissions in check with small policy changes here and there. But I think we no longer have that option; the window for solving this massive problem with incremental changes closed years ago.

(Credit: US Dept. of Energy)

(Credit: US Dept. of Energy)

Even while we brace ourselves for the incoming Trump administration, with numerous appointments on the transition team who deny basic scientific understanding about climate change and human activities driving it, we should not just defend current first steps in place, like the Clean Power Plan. If we are to combat climate change and if we are serious about avoiding worst-case scenarios, which would detrimentally affect millions of people worldwide, especially those living in coastal areas and low-lying islands, then we need to actively push for more.

In politics, people often talk of incremental changes, pushing for small reforms when the opportunity arises in the hopes that they somehow add up to bigger shifts over time. That might make sense for some policy goals, but as we reach so many “tipping points” with the climate, such as indicated by the horrible state of Arctic sea ice this year, we no longer have time for dilly-dallying. People and groups from very different political backgrounds have come together for big changes before—often for war—and now I hope that many will try to set aside their differences to try to realize a common goal.

The Clean Power Plan, developed under the Clean Air Act, goes after power plants, the country’s largest source of carbon dioxide emissions. It sets targets such that the national electricity sector’s emissions must drop by about 26-28% below 2005 levels by 2025. (Recall that 1990 was the original baseline, used by the UN’s Framework Convention on Climate Change, but the Obama administration shifted it, possibly to make it seem like its reductions are larger than they actually are.) The result will be less of an emphasis on coal-fired power plants and more renewable energy as well as energy efficiency gains. We may see more use of natural gas or even nuclear power.

But the Clean Power Plan is not enough even to meet the country’s Paris Agreement commitments. Other beneficial policies make a difference as well, including California’s climate regulations—which include generating 50% of the state’s electricity from renewables by 2030; reducing hydrofluorocarbons; and the EPA and Department of Transportation’s regulations on heavy-duty vehicles. If all of these things went according to plan, the US’s Paris pledges might be achievable.

Some people who should know better (such as the IPCC and US Democrats) include flawed or unproven technology, like carbon capture and storage in these policy frameworks. We should not depend on these or other so-called “negative-emission” technologies developing in the near future, as argued in this recent paper in Science by Kevin Anderson and Glen Peters.

Furthermore, even before Donald Trump takes office, the US is not on a path to meet its Paris Agreement pledges. This analysis in Nature Climate Change by Jeffery Greenblatt and Max Wei makes it clear that more has to be done. The Paris Agreement itself was supposed to be just a first step.

Even *if* the US and other major greenhouse gas-producing nations fulfill their Paris climate pledges, we’re still heading toward around 3 degrees of warming, far beyond what scientists warn is a safe threshold. When climate experts put together the Paris Agreement, they recommended 1.5 degrees warming as the threshold we should shoot for, but I don’t think it’s possible to achieve that economically or practically. But perhaps with major policy shifts in the US, Canada, Europe, Australia, China, India, Brazil and elsewhere, 2 degrees might be achievable. Even that, however, could mean losing some island nations, more extreme flooding and droughts, numerous losses of species, suffering coral reefs, dwindling of some agricultural crops and fisheries, and shifting of ecosystems and growing deserts, among other disruptive and destructive impacts. In the US as well, economists and climate scientists are trying to estimate the “social cost of carbon,” which could cost this country billions or more in damage (though Trump’s transition team has tried to downplay these numbers so far).

The fact is, to mitigate climate change, we can’t emit much more greenhouse gas. The US has already burned through most of its carbon budget. Shifts from fossil fuels to renewable sources of energy, especially solar and wind, are already happening, and this trend would be tough to reverse by the incoming administration. Instead, it could be framed as a business opportunity, and perhaps Trump would be keen to back it in some way.

Lastly, let’s remember that, across the political spectrum, many people are in favor of major infrastructure projects. Investing in wind farms and solar power plants while upgrading public transportation systems, for example, could create millions of jobs, stimulate the economy and put us on a better path toward reigning in our toxic greenhouse gases.

Trump Transition News in Nature: Budget Situation, Scientists Respond

Here’s a pair of stories I’ve worked on recently on the transition to the Trump era and what that means for science. The second one was written by Heidi Ledford, Sara Reardon and me. Thanks as usual to Lauren Morello for help editing. Thanks also go to my very informative sources. At the end of this post, I’ve also included links to a couple related stories by my Nature colleagues, and I recommend checking them out, too.


Stopgap spending bill leaves US scientists in limbo

Proposal would keep funding flat for most research agencies, but cuts could come early next year.

In what has become a year-end tradition in Washington DC, the US Congress is getting ready to approve a stopgap spending measure before it adjourns for the holidays.

The legislation introduced yesterday in the House of Representatives would hold spending flat at most science agencies, with some limited increases. These include an extra US$872 million to implement provisions of the 21st Century Cures Act, a bill that would reform drug development and biomedical research. The money would be split between the National Institutes of Health, the Food and Drug Administration and state governments…

The stopgap funding bill, which would expire on 28 April, also allows for extra funding to keep a handful of major multiyear space programmes on track. These include the National Oceanic and Atmospheric Administration’s Joint Polar Satellite System, a series of probes designed to monitor Earth’s weather and climate, as well as NASA efforts to explore deep space and develop a replacement for the retired space shuttle.

But for most science programmes, funding would remain at roughly the same level as in the past fiscal year. And continuing to operate under a temporary funding measure means that agencies cannot start new programmes or end old ones without explicit permission from Congress.

“Every time you delay a [final] spending bill, it prevents the science agencies from doing the planning they need, and it keeps them in limbo,” says Lexi Shultz, director of public affairs for the American Geophysical Union in Washington DC…

Many researchers are more worried about what might come after this temporary funding extension, if it is approved. When president-elect Donald Trump takes office on 20 January 2017, Republicans will control the White House and both houses of Congress — and their science priorities are very different from those of outgoing President Barack Obama, a Democrat…

[For more, read the entire story in Nature, published on 7 December 2016.]

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Is Trump betraying his base?

Many Trump voters hope their man in the White House will be a brave outsider who will shake things up in Washington and improve their economic and job situations. But his platform, landing team and appointments so far indicate that they’ll be sorely disappointed.

(Credit: Mike Segar/Reuters)

(Credit: Mike Segar/Reuters)

President-Elect Trump won 62 million votes, and the way I see it, many of those came from people who felt disillusioned and disenfranchised by a system in which the political establishment ignored their concerns and struggles. Many from Midwestern states also saw local industries erode and jobs remain hard to come by—the rate of unemployment plus underemployment is stuck at 10%, higher than when Obama took office in 2008—at odds with talk by commentators of an improving economy. (Racism, sexism, and xenophobia disturbingly factored into Trump’s campaign as well; these are very important issues, but I’ll write about them more later.)

However, it’s hard to see how Trump would change business-as-usual when lobbyists and Washington insiders make up so many of his appointees and transition team. These include Wilbur Ross, founder of a private equity firm, to lead the Commerce Department. He previously owned a coal company whose Sago mine in West Virginia had been cited for hundreds of safety and health violations and in which 12 miners lost their lives following an (avoidable) explosion. Betsy DeVos, a prominent donor to head Education, would likely push for more access to private schools which would lead to decreased funding to public ones, including those that many Trump voters’ families depend on. Trump also has numerous advisers and potential appointees from Washington think tanks and lobbying firms, including Myron Ebell, Michael McKenna and Michael Catanzaro.

None of these people have experience with or a record of supporting working-class people, whom Trump won more votes from than Mitt Romney, the 2012 Republican candidate, according to exit polls. He also won more men and more people with less than a university education, according to a Pew survey, and his supporters primarily came from rural areas and suburbs. (And yes, there was a big racial divide, but it looks similar to previous elections, in spite of the role racial issues and immigration played in Trump’s campaign.)

Furthermore, the tax code Trump has proposed would raise taxes on the poorest while cutting them for the richest people. Nearly 8 million families, most of them single-parent ones, would see higher taxes, too. The biggest tax changes would be to the richest 1 percent, who would benefit from windfalls of 13.5% on average, the Tax Policy Center finds. The richest of the top 1 percent (multi-millionaires) would also benefit from him repealing the estate tax (and possibly the gift and generation-skipping taxes). If all these tax cuts passed, the deficit would balloon over Trump’s term and it could be tough for his administration to continue the federal government’s support for the welfare system that some of his voters and many other people rely on, including Social Security, Medicare and Medicaid.

Trump voters are concerned about what they perceive as inequality in job opportunities, according to a Pew survey conducted right before the election. (But they’re not worried about economic inequality, presumably hoping that the “American Dream” will one day come true for them.) It’s not clear where the needed jobs would come from during Trump’s term though. Infrastructure projects often create many jobs, but Trump’s proposal seems to depend on huge tax credits, which won’t necessarily have the intended results.

Nevertheless, if Italy’s experience with Berlusconi is any guide, I suspect that most Trump voters won’t simply turn against him just because he broke some campaign promises or because his economic policies don’t benefit them. People want to feel like they have someone, anyone, who listens to them and represents their interests. If no one else provides a clear and credible alternative, I think many people will stick with Trump through his term.

Finally, how will journalists grapple with the Trump era? Many have different thoughts on this (see this, this, and this), and I’m still trying to figure it out for myself as well. I don’t really have an answer yet, but stay tuned.

My election polling coverage for Nature

Here’s a few stories I’ve been working on lately for Nature. If you’re interested in them, you can read the whole thing on Nature‘s website. (And if you quote or cite any of them, please give proper credit.) Special thanks go to my editors, Lauren Morello and Richard Monastersky. At the bottom of this, I’ve also posted a few other election-related articles from my colleagues.


Pollsters struggle to explain failures of US presidential forecasts

Most surveys did not predict Donald Trump’s victory over Hillary Clinton.

What went wrong? That’s the question that many political pollsters in the United States are asking themselves in the aftermath of the 8 November presidential election. Republican Donald Trump won in an electoral landslide, but for months most polls forecast a victory for his Democratic opponent, Hillary Clinton.

Many types of polls, including randomized telephone polls and online polls that people opt into, tightened in the weeks leading up to the election — but still pointed to a Clinton win.

“The industry is definitely going to be spending a lot of time doing some soul-searching about what happened and where do we go from here,” says Chris Jackson, head of US public polling at Ipsos, a global market-research and polling firm based in Paris.

(Credit: Reuters/Danny Moloshok)

(Credit: Reuters/Danny Moloshok)

The most recent national polls — including those conducted by ABC/Washington Post, Ipsos, YouGov, and Fox News — all estimated a Clinton lead of 3 to 4% over Trump. Minor-party candidates, such as Gary Johnson of the Liberal Party and Jill Stein of the Green Party, were forecast to win single-digit support. Yet as this article went to press, as the last votes were being counted, Clinton leads the popular vote by a razor-thin margin: just 0.2%. The majority of states have tipped for Trump, awarding him their valuable electoral-college votes and ensuring his victory.

Poll aggregators such as FiveThirtyEight and New York Times nonetheless forecast Clinton’s chances of victory at 71% or higher, while the Huffington Post predicted a Clinton landslide. This dramatic polling failure could have been due to factors such as poorly assessed likely voters, people misreporting their voting intentions, or pollsters poorly surveying some segments of the population.

“It’s a big surprise that such a wide variety of polls using such a wide variety of methodologies have all the errors fall in the same direction,”says Claudia Deane, vice president of research at the Pew Research Center in Washington DC…

[For more, read the entire story in Nature, published on 9 November 2016.]

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Counting the uncounted in the US election

Following disturbing allegations of sexual harassment and assault by Donald Trump, and in spite of embarrassing leaked emails among Hillary Clinton’s staffers, Clinton seems to be on her way to victory with some 46% of the popular vote, according to recent national polls, such as Ipsos and Pew. But as I wrote in the current issue of Nature (my first feature story for the magazine!), pollsters disagree about how estimate “likely voters”—people who will actually turnout to vote on Election Day. What no one disputes, however, is that only half of voting-age Americans will vote that day.

Only half, maybe a bit more. That means that Clinton will have actually earned less than a quarter of everyone’s votes, and 76% of Americans will not have voted for the new president. That’s at least 180 million people. Since this typical of US elections, an important question we should ask is, what does it mean for democracy in this country?

(Credit: Reuters/Danny Moloshok)

(Credit: Reuters/Danny Moloshok)

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California’s poised to become the first state to ban plastic bags

On the 8th of November, if California voters pass a referendum on the ballot known as Proposition 67, the state will become the first in the country to ban single-use plastic bags at groceries, pharmacies, and convenience stores. Considering that Californians go through some 10 to 20 billion plastic bags per year, each one in use for an average of 15 minutes, this could make a big difference.

(Credit: Nicram Sabad/Shutterstock)

(Credit: Nicram Sabad/Shutterstock)

I get it. Plastic bags are useful and convenient. But so were polystyrene-foam products, and we managed to abandon them in the 1990s because they were damaging the ozone layer. It’s time for us to adapt to the 21st century and be less wasteful with plastic. You can still pay 10 cents for a paper bag if you really need it.

Plastic bags pollute our oceans, coastlines and streets. A recent study found that one-fourth of fish sampled in California markets had plastic debris in them, and shellfish had even more. If we were to continue with business as usual, we could have more plastic than fish in the ocean, by weight, by 2050, according to a study last year. Another study found that 90% of seabirds worldwide swallow plastic, and sea turtles get tangled in or eat the bags too, unfortunately mistaking them for jellyfish.

Plastic bags are made from polyethylene, using the fossil fuels natural gas and petroleum. Only a few kinds are recyclable, and the others don’t decay. Well they do break down very very slowly, over hundreds or thousands of years, during which time they may kill or poison untold numbers of seabirds and turtles.

San Diego, my home town, became the 150th municipality in the state with a ban. The majority of Californians have begun to adapt to the ban. But when the state legislature passed it in 2014 (Senate Bill 270), people opposed to it—including the plastic industry, libertarians, and a few others—collected petition signatures opposed to it. The governor, other leading policy-makers, Democrats and Greens, and numerous environmental groups support the bill.

Now the plastic bag ban is on the ballot, for everyone to decide. A “yes” vote on Prop 67 would make uphold the legislation, while a “no” would overturn it. Two years ago, a USC Dornsife/Los Angeles Times poll showed broad support for a plastic ban, with nearly sixty percent of people supporting it and about a third opposed. A new poll may reveal a shift in public opinion, though I suspect that my fellow Californians will stick with the plastic bag ban.

And then we could see other states, like Massachusetts, follow suit. A few other state governments, in contrast, are trying to ban plastic bag bans, but if California is successful with their ban, maybe they’ll reconsider. Then a decade down the road…who knows, maybe the whole country will abandon plastic bags!

News from Nature: Gender Bias in Geoscience, Psychological Disputes, and Mining Asteroids

Here’s a few intriguing and nuanced stories I’ve been working on lately for Nature in Washington, D.C. If you’re interested in them, you can read the whole thing on Nature‘s website. (And if you quote or cite any of them, please give proper credit.) Special thanks go to my editors, Lauren Morello and Jane Lee.


Women postdocs less likely than men to get a glowing reference

Women and men applying for geoscience postdocs receive very different letters of support from their mentors.

Gender bias in scientific fields is no secret, and it is pervasive. It even creeps into the all-important recommendation letter, in which mentors typically bolster the credentials of their protégés.

Globally, female applicants are about 10% less likely than their male counterparts to receive ‘excellent’ letters for postdoctoral positions in the Earth sciences, according to a study published in Nature Geoscience on 3 October. The finding holds regardless of the gender of their recommenders or what part of the world the applicant works in.

“These results uncover a real problem in the geosciences, just like other disciplines,” says Kuheli Dutt, a social scientist at Columbia University in New York City and lead author of the paper. Women start off at a disadvantage, she adds, because they’re perceived as less competent than their male counterparts.

For example, in the US, women in science, technology, engineering and mathematics earn 41% of doctoral degrees, yet in 2012–13 they accounted for only 24% of postdoctoral positions at US federally funded research centres and labs, according to the National Science Foundation. In the geosciences, less than 10% of full professors are women, indicating that the postdoctoral stage — the usual gateway into faculty jobs — is the point at which many women leave the field.

[For more, read the entire story in Nature, published on 3 October 2016.]

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Book review: “Dark Matter and the Dinosaurs” by Lisa Randall

On the one hand, we have the elusive dark matter particles, dispersed throughout the universe across billions of light-years; on the other, we have the sorely missed dinosaurs, who lived in our own proverbial backyard but were driven extinct by a mysterious impactor 66 million years ago. What if these fascinating yet disparate phenomena, separated by so much space and time, were somehow related?


That, in essence, is the premise of Lisa Randall’s book, “Dark Matter and the Dinosaurs.” Maybe the “vanilla” cold dark matter model we have isn’t the only possible explanation of observations of the expanding universe and the cosmic web of millions of surveyed galaxies, she argues. It’s more fun to consider other more exotic models, even if they turn out to be wrong.

Dark matter particles don’t interact with each other the way our familiar atoms do. In fact, they hardly interact at all. They mostly just move apart with the growing universe and then clump together as they feel the effects of gravity over time. As a result, we end up with nearly spherical dark matter clumps throughout the universe, and we and the rest of the Milky Way are living inside one of those clumps. But if some dark matter interacts like normal matter, it could form a dense and thin disk—even thinner than the disk of our own galaxy. (Picture a compact disk hidden inside a bagel. Here’s a good composite image of our galaxy, on edge, which would be the bagel.)

If that’s the case, then as our solar system moves up and down through the disk, we’ll experience an extra little gravitational nudge each time we go through. This could periodically dislodge comets traveling in tenuous orbits in the Oort cloud in the distant realms of our solar system, flinging one comet away forever and sending another in an unfortunate Earthbound direction, where the consequences of its destructive impact in the Yucatan kills off the dinosaurs some 66 million years ago, thus finally linking dinosaurs to dark matter.

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