A new network of dedicated antennas in Africa will lend insight into the havoc that storms of charged particles from the sun wreak on satellite and radio communications. Zambia set up its first such sensor in March—one of eight multifrequency receivers being deployed around the continent, in addition to four already operating in South Africa. Kenya and Nigeria will install their receivers by the end of the year.
Feeding into an upgraded space weather center scheduled to open in South Africa in 2022, the network will provide real-time data on how solar storms distort the ionosphere, the charged outer layer of Earth’s atmosphere. This distortion can have dangerous consequences, says Mpho Tshisaphungo, a space weather researcher at the South African National Space Agency (SANSA). Signals between crucial satellites and the ground pass through this region, where charged particles can cause interference. Also, high-frequency radio signals (often used in defense and emergency services communications) have to bounce off the ionosphere; Tshisaphungo notes that when solar storms alter the layer, “the radio signal may either be attenuated, delayed or absorbed by the ionosphere.”
South Africa has already been providing global networks with information about the ionosphere above the country in periodic batches, relying on satellite and ground data from international space weather programs. The new network will give Africa its first access to 24/7 local details on how the sun’s behavior is affecting the atmosphere overhead, researchers say.
“While there are international data available, if you want to look at what’s happening on the African continent, then you need to take measurements in Africa,” says John Bosco Habarulema, a space scientist at SANSA. Habarulema, researcher Daniel Okoh of Nigeria’s National Space Research and Development Agency, and their colleagues developed a model last year that maps electron density in the ionosphere and fills in measurement gaps. (Tshisaphungo is also a co-author.) The new local receivers will boost this model’s accuracy and let it describe fluctuations over the full continent.
“We need to have the global perspective and put that [data] into our global models,” says Terry Onsager, a physicist at the U.S. National Oceanic and Atmospheric Administration’s Space Weather Prediction Center. “But at the same time, space weather disturbances can vary enormously from location to location.” And it is becoming increasingly important to model the ionosphere’s behavior, he says, because “we’re getting more and more reliant on technologies that are reliant on space weather.”
Signs of the gas phosphine in Venus’s atmosphere have faded—but they’re still there, according to a new data analysis.
In September, an international team of astronomers made headlines when it reported finding phosphine—a potential marker of life—in the planet’s atmosphere. Several studies questioning the observations and conclusions quickly followed. Now, the same team has reanalysed part of its data, citing a processing error in the original data set. The researchers confirmed the phosphine signal, but say that it’s fainter than before.
The work is an important step forward in resolving the most exciting Venus debate in decades. “I’ve waited all my life for this,” says Sanjay Limaye, a planetary scientist at the University of Wisconsin–Madison, who says the debate has reinvigorated the field.
The reanalysis, based on radio-telescope observations at the Atacama Large Millimeter/submillimeter Array (ALMA) in Chile, concludes that average phosphine levels across Venus are about one part per billion—approximately one-seventh of the earlier estimate. Unlike in their original report, the scientists now describe their discovery of phosphine on Venus as tentative.
It is the researchers’ first public response to the criticisms that have been levelled against them in the past two months. “The scientific process is working,” says Bob Grimm, a planetary scientist at the Southwest Research Institute in Boulder, Colorado, who is not involved with any of the phosphine studies. Researchers tend to respond to big claims with big efforts to gather evidence and either prove or disprove them.
Taking another look
In its September report, the team used data from ALMA and the James Clerk Maxwell Telescope (JCMT) in Hawaii to make its discovery. Team leader Jane Greaves, an astronomer at Cardiff University, UK, says she and her colleagues redid the work because they had learnt that the original ALMA data contained a spurious signal that could have affected the results. ALMA posted the corrected data on 16 November, and Greaves and her team ran a fresh analysis that night and posted it ahead of peer review on the preprint server arxiv.org. “We’ve been working like crazy,” she told a meeting of the Venus Exploration Analysis Group, a NASA community forum, on 17 November.
According to Greaves and her colleagues, the ALMA data show the spectral signature of phosphine, a molecule made of one phosphorus and three hydrogen atoms. They say no other compound can explain the data. Finding phosphine on Venus would be tantalizing because microbes produce the gas on Earth. If the signal is real and indeed due to phosphine, it’s possible that microbes living in and drifting among the planet’s clouds could be producing the gas — but it’s also possible there might be a non-living source that scientists have yet to identify. Before they can determine whether either of these scenarios is true, researchers first need to confirm phosphine’s presence.
In one critique of the original study, researchers suggested that the signal reported as phosphine might really be coming from sulfur dioxide, a gas that is common in Venus’s clouds but is not produced by life there. Greaves and her team fired back in their latest report that that can’t be the case, because of how the phosphine fingerprint appears in data collected by the second telescope they used, the JCMT. Other critiques have focused on the difficulty of extracting a phosphine signal out of complicated data.
The reanalysis found that phosphine concentrations in Venus’s atmosphere occasionally peak at five parts per billion. That means levels of the gas might wax and wane over time at different places on the planet, said Greaves—a situation similar to methane spikes appearing on Mars.
One other new strand of evidence supports phosphine on Venus. Inspired by Greaves’s original report, a team led by Rakesh Mogul, a biochemist at California State Polytechnic University in Pomona, dug through decades-old data from NASA’s 1978 Pioneer Venus mission. This spacecraft dropped a probe that measured the chemistry of clouds in the planet’s atmosphere as it fell. It detected a phosphorus signal that could be attributed to phosphine or another phosphorus compound. But “we believe the simplest gas that fits the data is phosphine”, Mogul said at the meeting on 17 November.
Work still ahead
Where the phosphine comes from remains a mystery. Even at the one-part-per-billion level, there’s too much of it to be explained by volcanic eruptions at the planet’s surface or by lightning strikes in the atmosphere, several scientists said at the meeting. But phosphorus-based compounds might be produced by geological processes and then transform into other chemicals, such as phosphine, as they rise into the clouds, said Mogul.
The only spacecraft currently orbiting Venus, Japan’s Akatsuki, does not carry instruments that could help settle the debate. The Indian Space Research Organisation is planning a Venus mission that would launch in 2025 and could potentially carry instruments capable of looking for phosphine. In the meantime, Greaves and other researchers are applying for more time on Earth-based telescopes, including ALMA.
Researchers are investigating many other aspects of Venus, says David Grinspoon, an astrobiologist at the Planetary Science Institute who is based in Washington DC. “There are 1,001 reasons to go back to Venus, and if the phosphine ‘goes away’ through further observations and analysis, there will still be 1,000 reasons to go.”
This article is reproduced with permission and was first published on November 17 2020.
The future that NASA dared to dream of for a decade has finally become reality.
Crew-1, SpaceX’s first operational mission to the International Station Station (ISS) for NASA, arrived at the orbiting lab late Monday night (Nov. 16), 27 hours after launching from Kennedy Space Center in Florida atop a Falcon 9 rocket.
About two hours after the Crew Dragon capsule “Resilience” docked with the station, NASA astronauts Victor Glover, Mike Hopkins and Shannon Walker and Japan’s Soichi Noguchi floated from the private craft into the ISS, beginning their six-month stay on the orbiting lab.
That moment meant a lot to NASA, whose Commercial Crew Program began nurturing the development of private astronaut taxis way back in 2010. The goal was to fill the crew-carrying shoes of the agency’s space shuttle fleet, which was grounded in 2011, leaving Russian Soyuz spacecraft as the only ride to and from orbit available to astronauts.
In 2014, the Commercial Crew Program inked multibillion-dollar contracts with SpaceX and Boeing to finish work on their vehicles and fly at least six crewed missions to and from the station apiece. Crew-1 is the first of those contracted flights to lift off, and its crewmembers have now made it safely onto the orbiting lab.
“This mission was a dream,” NASA human spaceflight chief Kathy Lueders said during a news conference early Tuesday morning (Nov. 17). “It was a dream of us to be able to one day … have crew transportation services to the International Space Station. And today that dream became a reality.”
“It’s the start of a new era,” Lueders added.
That era will include crewed missions by Boeing, but the aerospace giant’s CST-100 Starliner capsule isn’t ready to carry astronauts just yet. Starliner must first refly an uncrewed test flight to the station, after failing to meet up with the ISS during a December 2019 attempt. That second try is scheduled to launch early next year.
SpaceX now has two crewed flights to the ISS under its belt. The first, the Demo-2 test mission, carried NASA astronauts Bob Behnken and Doug Hurley to the station for a two-month stay this past summer. Demo-2’s success paved the way for Crew-1 and other operational flights.
“Huge shoutouts to the NASA and SpaceX teams—excellent job; many hard years of work,” Ven Feng, deputy manager of NASA’s Commercial Crew Program, said during Tuesday morning’s news conference. “And we’re looking forward to making this a very successful first operational mission, and many more to follow.”
The Crew-1 astronauts joined three other spaceflyers already aboard the ISS—NASA astronaut Kate Rubins and cosmonauts Sergey Kud-Sverchkov and Sergey Ryzhikov, the latter of whom commands the station’s current Expedition 64 mission.
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On September 9, 2018, a robotic telescope on its routine patrol of the night sky detected what looked like a new star. Over the next few hours, the “star” grew 10 times brighter, triggering a flag by software I had written to identify unusual celestial events. It was nighttime in California, and I was asleep, but my colleagues on the other side of the world reacted quickly to the alert. Twelve hours later we had obtained enough additional data from telescopes on Earth and in space to confirm that this was the explosion of a star—a supernova—in a distant galaxy. But this was no ordinary supernova.
Tying together the evidence from different telescopes, we concluded that after shining for millions of years, the star did something surprising and mysterious: it abruptly cast off layers of gas from its surface, forming a cocoon around itself. A few days or a week later the star exploded. The debris from the blast collided with the cocoon, producing an unusually bright and short-lived flash of light. Because the explosion took place in a galaxy far away—the light took almost a billion years to reach Earth—it was too dim to be seen with the naked eye but bright enough for our observatories. Through a retrospective search of telescope data, we were even able to detect the star in the act of shedding two weeks before it exploded, when it was one one-hundredth as bright as the explosion itself.
This was just one of several recent discoveries that have shown us that stars die in surprisingly diverse ways. Sometimes, for example, the remnant of a star’s core that is left over after a supernova remains active after the star has collapsed—it can launch a jet of material moving at hyperrelativistic speeds, and the jet itself can destroy the star with more energy than a normal supernova. Sometimes, in the final days to years of its life, a star blows away a significant fraction of its gas in a series of violent eruptions. These extreme deaths appear to be rare, but the fact that they happen at all tells us there is much we still do not understand about the basics of how stars live and die.
Now my colleagues and I are amassing a collection of unusual stellar endings that challenge our traditional assumptions. We are beginning to be able to ask and answer fundamental questions: Which factors determine how a star dies? Why do some stars end their lives with eruptions or violent jets, while others simply explode?
A New Star
The story of stellar birth, life and death is a tale of competing forces. Stars are formed in interstellar clouds of hydrogen gas when the force of gravity pulls part of the cloud inward strongly enough to overcome the outward push of magnetic fields and gas particles traveling at high speeds. As the cloud fragment collapses, it becomes 20 orders of magnitude denser and heats up by millions of degrees—temperatures high enough for the hydrogen atoms to collide and stick together to form helium. Fusion has begun, and a new star is born.
Like a cloud, a star is itself a battleground, with gravity pushing in and pressure from nuclear fusion pushing out. The evolution of a star depends on its temperature, which in turn depends on its mass. The heavier the star, the heavier the elements it can forge, and the faster it burns through its fuel. The lightest stars fuse hydrogen to helium and stop there—the sun is more than four billion years old and is still burning its hydrogen. Heavier stars live much shorter lives, only 10 million years or so, yet manufacture a much longer chain of elements: oxygen, carbon, neon, nitrogen, magnesium, silicon and even iron.
A star’s mass also determines how it will die. Lightweight stars—those that weigh less than around eight times the mass of the sun—die relatively peacefully. After exhausting their supplies of nuclear fuel, the outer layers of these stars blow out into space, forming beautiful planetary nebulae and leaving the stars’ cores exposed as white dwarfs—hot, dense objects with about half the mass of the sun that are only slightly larger than Earth.
Heavier stars, however, meet a violent end because of the enormous temperatures and pressures in their cores. Around the time they reach iron in the nuclear burning chain, conditions are so hot that things fall apart—iron atoms can start breaking into smaller pieces. The chain of fusion is cut off, and the star loses its internal pressure. Gravity takes over, and the core collapses until its constituent atoms are so close together that another opposing force steps in: the strong nuclear force. Now the core has become a neutron star, an exotic and dense state of matter made mostly of neutrons. If the star is massive enough—say, more than 20 times the mass of the sun—gravity overcomes even the strong nuclear force, and the neutron star collapses further into a black hole. Either way, some of the energy released when the core collapses pushes the outer layers of the star into space, creating an explosion so bright that for a few days it outshines the rest of the stars in the galaxy combined.
Human beings have spotted supernovae by eye for thousands of years. In 1572 a Danish astronomer named Tycho Brahe noticed a new star in the constellation Cassiopeia. It was as bright as Venus and stayed that bright for months before fading away. He wrote that he was so shocked that he doubted his own eyes. Today the aftermath of the explosion—the debris—is still visible and is known as Tycho’s Supernova Remnant.
For a supernova to be bright enough to be seen by the unaided eye, it must be in the Milky Way, as Tycho’s supernova was, or in one of its satellite galaxies, and this is rare. I might not see a supernova without the help of a telescope in my lifetime, although I can hope. In the past century astronomers began using telescopes to find supernovae beyond the Milky Way by taking repeated observations of the same set of galaxies and looking for changes, called transients. Our telescopes are now roboticized and outfitted with modern cameras, enabling us to discover thousands of supernovae every year.
An early sign that some stars die in extreme ways was the 1960s discovery of gamma-ray bursts (GRBs), so named because of the bright blasts of gamma-ray light they emit. We believe we see them when a massive star collapses into a neutron star or a black hole, the newborn compact object launches a narrow jet of matter, that jet successfully tunnels from the core through what remains of the star, and the jet just happens to be pointing at Earth.
What might create such a jet? The basic idea is the following. When a normal star runs out of fuel and dies, its core collapses into a neutron star or a black hole, and that is the end of that. In a gamma-ray burst, however, the corpse stays active. Perhaps the nascent black hole is absorbing mass from a disk of material around it, releasing energy in the process. Or maybe the newly created neutron star is rotating quickly, and a powerful magnetic field acts as a brake, releasing energy as the star slows down. Either way, this “central engine” pumps out energy that gets funneled into a jet of extremely hot plasma that tunnels from the center of the star out through the infalling material, glowing in gamma rays.
The passage of the jet through the star causes it to explode in a special supernova dubbed “Type Ic-BL,” which is 10 times more energetic than ordinary supernovae. As the jet plows into the surrounding gas and dust, it produces light all across the electromagnetic spectrum, called an afterglow. Afterglows are difficult to find because although they are 1,000 times brighter than typical supernovae, they are 100 times more fleeting, appearing and disappearing in just a few hours. The best hope for finding an afterglow is to wait for a gamma-ray burst to be discovered by a satellite and then immediately point your telescope to the reported location of the burst.
By waiting for a satellite to discover a burst, though, you limit the kinds of phenomena you can discover. A lot of things have to go right for a GRB to be produced: the jet has to be launched, make it through the star, and be pointing at you. In fact, it seems extremely unlikely for GRBs to occur: the gamma-ray photons emitted by the jet should get trapped unless the jet is moving at 99.995 percent of the speed of light. But to reach such speeds, the jet would need to somehow make it through the star without dragging along the star’s matter with it. What if most jets actually do get slowed down by the star, and we see only the small fraction that make it through unscathed? In other words, perhaps gamma-ray bursts represent the rare occasions that jets escape their stars and don’t slow down too much. If that were true, there would be a huge number of extreme stellar deaths out there that are totally invisible to gamma-ray satellites.
For my thesis, I set out to find afterglows without relying on a trigger from a satellite. My plan was to use the Zwicky Transient Facility, a robotic telescope at the Palomar Observatory in California, to patrol the sky for unusually fleeting, unusually bright points of light—and then react quickly. When I presented my thesis proposal in May 2018, my faculty advisers warned me that I might not find what I was looking for. They urged me to keep an open mind because new avenues of inquiry might arise. One month later that is exactly what happened. And two years later when I graduated, my thesis looked very different from what I had expected.
When I began my work, I wrote a program to find celestial phenomena that were changing in brightness more rapidly than ordinary supernovae. On a normal day I examined 10 to 100 different candidates and concluded that none of them were what I was looking for. On some days, though, I encountered something that gave me pause.
In June 2018 I saw a report from a robotic telescope facility called ATLAS, reporting a strange event dubbed AT2018cow. “AT” stood for “astronomical transient,” the prefix automatically given to all new transients, “2018” for the year of discovery, and “cow” was a unique string of letters. In the next couple of days there were reports of similarities between this event and gamma-ray bursts, yet there had been no detected show of gamma rays. “Aha,” I thought, “this is it!” Because AT2018cow was so bright and so nearby, there was intense worldwide interest in this object, and astronomers observed it all across the electromagnetic spectrum. I immediately made plans to observe AT2018cow using a radio telescope in Hawaii called the Submillimeter Array.
AT2018cow stunned just about everyone. It unfolded completely differently than any cosmic explosion seen before. We were like the people in a classic parable who are trying to identify an elephant in the dark. One person feels its trunk and says it is a waterspout, whereas another feels the ear and thinks it must be a fan, and a third feels the leg and says it is a tree. Similarly, AT2018cow shared characteristics with several different classes of phenomena, but it has been difficult to put a complete picture together.
My collaborators and I spent long days and nights going over our data repeatedly, trying to figure out how to interpret them. Some of those moments—calculating the properties of the shock wave together on a chalkboard, a team member running down the hallway waving a piece of paper with new results, and meeting a colleague’s eyes in shock when a beautiful new measurement came in—remain my most treasured memories from graduate school. In the end, we concluded that there were two important components to AT2018cow. The first was a central engine, as in a gamma-ray burst, but lasting for much longer—weeks rather than the typical days; x-rays shining from the heart of the explosion stayed bright for much longer than expected. The second was that for some reason, when the star burst apart, it was surrounded by a cocoon of gas and dust with about one one-thousandth the mass of the sun. Our evidence for the cocoon is indirect: when the star exploded, we saw a flash of optical light and radio waves that seemed to indicate debris hitting a mass surrounding the star. Such cocoons have been seen in other types of explosions, but we do not know how they get there—it may be that the material is shed by the star shortly before exploding.
If this theory is correct, it would be the first time astronomers have directly witnessed the birth of a compact object like a neutron star or a black hole; most of the time the corpse is completely shrouded by what remains of the star. In the case of AT2018cow, we think we could actually see down to the compact object that produced all of this amazingly variable and bright x-ray emission. Still, we are left with many questions. What kind of star exploded? Was the central engine a neutron star or a black hole? Why did the star shed mass shortly before exploding? To make progress, we needed to find similar events, so my colleagues and I set out to find another AT2018cow using the Zwicky Transient Facility.
Three months later I thought we found one—the bright, fast-rising explosion of September 9, 2018. Initially it looked very similar to AT2018cow. Within a week, however, it became clear that this event was a Type Ic-BL supernova—the kind associated with gamma-ray bursts. Its name was SN2018gep. I was excited. Sure, it was not another AT2018cow, but we finally had something that looked like a gamma-ray burst. Within five days we had collected detailed observations all across the electromagnetic spectrum. We searched the data for evidence of a jet—but we found none. Instead, yet again, my collaborators and I concluded that we were seeing bright, fast-evolving optical emission from the collision of explosion debris with a cocoon of material.
This was a surprise. Although cocoons have been seen surrounding other types of stars, they are not commonly observed in the types of supernovae associated with gamma-ray bursts. Our discovery implies that more stars shed gas at the end of their lives than we thought. We know the gas was lost in the final moments of the star’s life because it was so close to the star at the time of the explosion; if it had been cast off earlier, it would have had time to get farther away. That means the star lost a significant chunk of its outer atmosphere in the final days to weeks of its life, after shining for millions to tens of millions of years. It seems, then, that this shedding heralds the death of the star.
Once again, we were left with questions. How prevalent are these death omens in different types of stars? What is the physical mechanism that produces them? I realized that I had a new direction to my research now—not just gamma-ray bursts and jets but also the warning signs of soon-to-explode massive stars. And perhaps these different phenomena were even connected.
It was not until the final six months of my Ph.D. program that I finally found a gamma-ray burst afterglow. On January 28, 2020, I did my usual candidate review when I saw something that looked promising. I knew better than to get excited—there had been many, many false starts over the years. I immediately requested additional observations with a telescope in La Palma in the Canary Islands, and they confirmed that this source was fading away quickly, as would be expected for an afterglow. That night I requested urgent observations on the 200-inch Hale Telescope at the Palomar Observatory that showed the source was still fading. The next night I obtained observations with the Swift X-ray space telescope and detected x-rays from the event, all but confirming this was truly a GRB afterglow. The night after that I got a brief window of time on the Keck Telescope on Mauna Kea in Hawaii, with the hope of measuring how far away the explosion was.
I slept in a sleeping bag in the remote observing room at my university, the California Institute of Technology, and set an alarm for 4 A.M. When the time came, I felt panicked—I was squeezing in this observation right at the end of the night, the sky was getting brighter quickly, the source was very faint, and I was terrified of being too late. I did the best that I could. When it was too bright to observe any longer, I called my colleague Dan Perley of Liverpool John Moores University in England on Skype, and we looked at the data together. I was lucky. The source was faint, but there was a big, booming, obvious feature in the light from the event that enabled us to measure the distance, which was vast: a redshift of 2.9, which means its light had significantly reddened during its journey through the cosmos. When this star exploded, the universe was only 2.3 billion years old. The photons from the blast took 11.4 billion years to reach Earth. Today the physical location of the burst is 21 billion light-years away—the explosion happened so long ago that the universe has expanded significantly since then. This was the real deal.
A few months after finding our first afterglow, we found a second. To put that in perspective, prior to the Zwicky Transient Facility, only three afterglows had ever been found without a gamma-ray burst first occurring and telling astronomers where to look, and we found two in just a few months. Now that we have our search strategy ironed out and working, I hope we can find these routinely. Still, even with two afterglows in hand, I cannot definitively answer the questions I originally set out to answer. It is difficult to tell whether any given afterglow is something new or just a normal gamma-ray burst that high-energy satellites happened to miss. We will need to find more events before we can tell if we are witnessing truly different phenomena.
Expanding the Catalog
Since the discovery of an unexpected new type of engine-driven explosion in AT2018cow, my search has uncovered a variety of unusual stellar displays. There was the weird Ic-BL supernova (the kind associated with GRBs) crashing into a cocoon of material but showing no evidence for a powerful jet (the hallmark of a GRB). Then there was another event similar to AT2018cow. There were also two Ic-BL supernova that probably had jets, but these were less energetic and wider than those in traditional gamma-ray bursts. And finally, right at the end of graduate school, two actual cosmological afterglows, one of which turned out to have an associated gamma-ray burst.
So far we astronomers have been like zoologists, going out into relatively uncharted territory and characterizing all the different creatures (in this case, explosions) that we see. The next stage will be to look for patterns. What are the relative rates of each type of blast? Do they seem to occur in one type of galaxy but not another? Are these different categories actually different “species” or just different manifestations of the same phenomenon?
To answer these questions, we will need a much larger catalog. Beginning in a few years, the Vera C. Rubin Observatory, currently under construction in Chile, will use the largest digital camera ever constructed (three billion pixels) to spot 10 million potential transients every night—10 times more than the Zwicky Transient Facility does now. With more data, I would like to investigate which stars lose some of their mass right before they die and how often. I want to study how we can tell if there was a jet that got choked inside a star and how to recognize the kind of faint emission emitted during a star’s death throes to predict where and when a star will explode. Ultimately I would like to probe questions about the factors that lead to these unusual deaths—perhaps it is something about a star’s rate of spin or its history of interactions with other stars that causes it to die in such a spectacular and rare way.
The 2020 U.S. election could not have come at a more tumultuous time—amid a global pandemic, widespread unemployment, demands for racial justice, all amplified by blatant disdain for science, evidence and human rights. From shepherding and normalizing hatred and bigotry as domestic policy to slowing down meaningful progress on climate to eroding the pillars of our democracy, the impacts of the 2016 U.S. election will continue to ripple through the world for decades to come. The last four years have shown us just how deeply white supremacy, patriarchy and oppressive societal norms are embedded into every fiber of our society. We know these problems didn’t start with the 2016 election and they won’t end come 2021.
Today, we breathe a collective sigh of relief and celebrate a victory, but let us be clear: it should never have been this close. Over 71 million Americans cast their ballots either in outright celebration of bigotry, hatred and lies—or with a callous indifference to their effects. And lest we forget, a large portion of those ballots were cast by college-educated white women who have either excused or delighted in the rhetoric of the last four years. Progress towards an equitable and just society doesn’t hinge on one election, and the 2020 U.S. election has proven that we have our work cut out for us.
As an organization, we of 500 Women Scientists are a long way from where we started in November 2016, as we watched a vastly unqualified and unprepared man get the most powerful job in the world over a supremely qualified woman—an experience intimately familiar to most women in STEM. That election was a wake-up call for many of us. We have spent the last four years learning the ropes of grassroots activism, building a powerful network and calling women scientists to action, all with the goal of dismantling systemic barriers that hold women back in science and launching women into positions of power.
Since 2016, we have grown to thousands of members and almost 500 pods (local chapters) worldwide. We created a platform to abolish manels and make it easy to find a woman scientist with expertise in any discipline (13,000 experts and counting!), edited thousands of Wikipedia pages to make sure women’s contributions to science are acknowledged, launched a fellowship for women of color, and grew a network of thousands of women scientists and supporters who are working on making science open, inclusive and accessible.
WHAT THE 2020 ELECTION MEANS TO US
Watching President-elect Biden and Vice President-elect Harris’s remarks on November 7 was emotional; the despair and trauma of the last four years released into tears of relief, pride and joy. The Biden-Harris victory is historic for many reasons. Kamala Harris is the first woman to occupy the post of vice president, the first Black person, the first Indian and Asian American, a child of immigrants, and the daughter of a scientist! The new Biden-Harris administration has expressed a commitment to embedding science and equity into all aspects of their work, from launching new federal programs to combat the climate and water crises to specific mandates for investments in lower income and historically marginalized communities.
Our goals now more closely align with an administration that understands and supports the role of science, research and innovation in solving some of our most pressing challenges. However, in the midst of relief and celebration, we would be remiss not to acknowledge that President-elect Biden and Vice President-elect Harris have also harmed marginalized and vulnerable communities, particularly Black and Indigenous communities, in the past. Representation alone has never been, and will never be, enough; we need tangible, material benefits from Biden, Harris and our government. Therefore, we remain committed to holding our institutions accountable in support of broadening participation in STEM fields, centering marginalized communities in policy development, and a commitment to improving public health, environmental quality, and gender and racial equity.
We stand ready to help meet our collective goals and, when needed, hold the new administration accountable for following through. We will continue to push for a progressive science-based agenda, including the Green New Deal, pay equity, accountability for harassment and discrimination, equitable access to health care, defunding the police, and investing in our communities to ensure everyone has the opportunity to thrive.
“I will name a group of leading scientists and experts to lead the transition.” — @JoeBiden
— Dr. Ayana Elizabeth Johnson ���� (@ayanaeliza) November 8, 2020
As the new Biden-Harris administration takes charge on January 20, 2021, our priorities for the new administration include ensuring:
Scientists, specifically women and BIPOC, in leadership positions in the administration. Immediate steps to rebuild and reinvigorate the federal STEM workforce that has been depleted during the Trump administration. Aggressive and ambitious steps to address climate change in an equitable and just way, beyond re-entering the Paris Agreement on climate. Comprehensive family-leave policies that support parents and ensure women’s careers are not negatively affected by having children. Gender pay equity. Steps to level the playing field for parents and kids from all racial and economic backgrounds. Universal health care. Removal of barriers to voting, especially in historically disenfranchised communities. Support for international science collaboration to solve our most pressing global challenges including: COVID-19, cancer, environmental degradation and climate change.
We will no longer have to spend as much of our energy on defense, resisting policies that turn back the clock on human rights and that endanger lives. We are hopeful that we can now make rapid progress with an administration that appears ready to prioritize equity, justice and science. However, our work is far from done; the U.S. and the world still face an uphill battle and we must not get complacent—rooting out racism and misogyny doesn’t happen overnight. With the election of Biden and Harris, we recommit to our mission to make science and society more equitable and just.
We call on scientists and supporters across the world to join us. We seek transformation of our societal and institutional norms, and it will take time and collective effort—four years ago, we joined a lifelong fight for justice and our vision remains the same:
That social justice, diversity, equity and inclusion are foundational in a thriving society and in science. That our movement must center the most marginalized among us. That gender and sex are not binary. That trans rights are human rights. That science needs Dreamers and no person is illegal. That borders are antithetical to our shared humanity and the spirit of progress. That those who harass and bully have no place in society or in science. That we cannot address climate change without addressing racial and other forms of injustice. That evidence-based policy is central to tackling issues ranging from climate change to gun violence. That we must act on climate. That all people have a fundamental right to decide if, when and how to have children, and that parenthood should not limit women’s careers. That women should set the agenda and have the resources to succeed in science and society.
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In the search for alien life, Earth—as the only planet known to be inhabited—has always been a starting point. “We look for something that reminds us of home,” says Natalie Batalha, an astronomer at the University of California, Santa Cruz. That means a rocky planet at just the right distance from its star—a star similar to the sun—to soak up sufficient starlight to allow surface water to exist in liquid form.
But as astronomers have discovered thousands and thousands of planets, they have encountered a bewildering zoo of diverse worlds. So a rocky planet—Earth-like, as far as today’s telescopes can tell—could turn out to be something quite different than our familiar world. But how variable and unearthly could conditions on these rocky planets be? And could even extremely alien worlds harbor life?
“What are the physical processes that make them more diverse?” Batalha says. “That’s what we’re trying to understand.”
Many of those physical processes occur deep inside a planet. In particular, a world’s inner inventory of radioactive elements could have a huge impact on its habitability by heating its interior. A robust source of geophysical warmth, it is thought, is crucial for plate tectonics and the generation of a planet’s magnetic field, which in turn seems critical for life—on Earth, at least. Powered by interior heat, the conveyor-belt-like action of tectonic plates sliding around Earth’s surface helps to stabilize the planet’s climate. By recycling carbon over geologic time, plate tectonics regulates the carbon dioxide in the atmosphere. Our planet’s magnetic field, which helps protect against harsh cosmic radiation, forms from electric currents raised in whirling layers of molten iron at Earth’s core. This geologic “dynamo” depends on how much radiogenic heat is in the mantle.
Now a new study finds that a habitable world may indeed need just the right amount of these radionuclides. Too much, and a planet could lack a churning dynamo to create a strong magnetic field—but it would perhaps boast a thick, inhospitable atmosphere baked off from the hot rock. Too little, and the planet’s tepid interior could be so cold and inert that it would not be able to sustain much geologic activity at all—which might even slow the dynamo to a stop.
“Even if you find a planet with the same mass and age as Earth, it could be radically different,” says Francis Nimmo, a geophysicist at the University of California, Santa Cruz, and lead author of the study, which was published last week in the Astrophysical Journal Letters.
Got a Habitable Planet? Thank Your Lucky (Neutron) Stars
The researchers are not the first to probe how radionuclides might affect a planet’s interior. But this paper “explores, in more detail than I’ve ever seen, the geophysical and geodynamic consequences of different heat productions within terrestrial exoplanets,” says Stephen Mojzsis, a geologist at the University of Colorado Boulder, who was not part of the new research.
Within our own planet, heat convection is what drives the dynamo: hot globs of molten iron rise from the depths to meet the colder mantle above, where they then cool and sink back toward the core. This circulation delivers heat to the mantle, which then releases it through the surface via the action of plate tectonics. Hot mantle material oozes up through cracks in the crust at plate boundaries and other tectonically active regions. And cold surface rock thrusts down into the hot mantle, cooling it like ice added to a toasty beverage. Leaving aside its aforementioned importance for regulating Earth’s climate, without plate tectonics, Nimmo says, the mantle could not be efficiently cooled, thus preventing heat from escaping the core. That is, if Earth lacked plate tectonics, there would be no convection and thus no dynamo.
A rocky planet’s possession of a dynamo and plate tectonics is no foregone conclusion. Of all the terrestrial worlds orbiting our sun, only Earth boasts both, largely because of the heat still locked in its interior. Today, Mojzsis says, about half of Earth’s heat is left over from its birth—built up from the energetic impacts of countless rocks brought together by gravity across tens of millions of years. Most of the rest of our planet’s inner warmth now comes from the radionuclides thorium 232 and uranium 238.
These radionuclides, among others, are most likely forged in the cataclysmic collisions of neutron stars—superdense stellar corpses left behind after massive stars explode. During these events, neutrons glom onto heavy nuclei to build even heavier nuclei, some of which then blast out into the wider cosmos. Such collisions are rare, occurring in a large galaxy such as the Milky Way about once every 10,000 years. Each time, the events manufacture bursts of radionuclides that eventually find their way into vast clouds of gas and dust that occasionally collapse to form stars and planets. Because the collisions are so sparse, the abundance of radionuclides in stars varies widely across the Milky Way, ranging from 30 to 300 percent of “local” levels in our solar system.
Three versions of a rocky planet with different amounts of radiogenic heating. The middle planet is Earth-like, with plate tectonics and a dynamo-generated magnetic field. The top planet, with more radiogenic heating, has extreme volcanism but no dynamo or magnetic field. The bottom planet, lacking volcanism due to less radiogenic heating, is geologically inert. Credit: Melissa Weiss UCSC
A “Goldilocks” Dynamo
To see how such a wide range of radionuclide abundances might affect Earth-mass planets, the researchers relied on a computer model that simulates the flow of heat in a world’s interior. They found that dialing up the amount of thorium and uranium heats the mantle so much that it acts as an insulating blanket, preventing heat from escaping the liquid core. If the heat cannot escape, there is no convection, which means no dynamo—and no magnetic field. A hotter mantle also produces more gas-spewing volcanoes, which can create an oppressively dense, suffocating atmosphere.
But if the radionuclide abundance is too low, the mantle becomes so cold that it stiffens up. Plate tectonics grows sluggish, and eventually, the researchers speculate, it may cease altogether. Without plate tectonics to cool the mantle and pull heat from the core, the dynamo again shuts down.
Absent some other way to generate internal heat, then, a habitable planet might need a just-right portion of radionuclides, a bit like the middling temperature of the storied bowl of porridge in the fairy tale “Goldilocks and the Three Bears.”
To find such a planet, astronomers can measure the radionuclides in its host star by observing that star’s spectrum—the way the starlight is broken up into its constituent wavelengths, encoding the chemical fingerprints of elements. Because both star and planet are born out of the same cloud of gas and dust, their chemical compositions should be similar. In practice, thorium and uranium are difficult to measure in this way, so in the new study, the researchers propose to instead look for europium—another element produced by neutron star collisions that sports a clearer spectroscopic signature.
That is the idea, anyway. The model is simple and, for one, assumes from the start that the planet has plate tectonics like Earth does, says Craig O’Neill, a geophysicist at Macquarie University in Australia, who was not involved in the study.“Whether or not this is a valid assumption for exoplanets remains to be seen,” he says. “These models will produce magnetic fields much more easily than models without plate tectonics.”
Indeed, no one is exactly sure of every ingredient necessary for plate tectonics, Nimmo says. Water’s lubricating effects on the motions of rock, for instance, could be vital—although everyone agrees the recipe involves abundant internal heat. So how it depends on radionuclides is uncertain. “We don’t even understand how plate tectonics works in this solar system,” he says.
Mojzsis says another big unknown is planet formation, a complicated process that can lead to variations in a world’s reservoirs of radiogenic elements and internal heat. For example, do planets predominantly form via violent collisions of moon-sized rocks or a somewhat gentler accumulation of swarms of pebbles? “Depending on which model you choose, you may get different outcomes in composition,” he says. Measuring radionuclides in a host star, then, will not necessarily reflect what lies within its planets.
But if the findings turn out to be true, a search for stellar europium could help astronomers find the planetary systems most likely to harbor habitable worlds. That would be tremendously useful, says Batalha, who was not part of the research. “We will go out and measure the abundances in stars,” she adds. “And maybe that will help us refine our target selection for our initial observations with a future space mission.”
One of the joys of being a science journalist is that it’s your job to talk with people who are doing mind-bending and world-changing research and to ask them goofy questions. We ask them serious questions, too, of course, but we also encourage scientists to share the funny, tense, disappointing, surprising, human sides of their work. The goal is not to make an expert seem ridiculous but to demonstrate that we’re all just people trying to figure out how to make sense of the world.
This month’s cover story on new discoveries about how stars explode and die is an exciting look at a rapidly growing field that is studying phenomena at awesome time and size scales. But it’s also a human drama about how Anna Y. Q. Ho had to sleep in a sleeping bag in a remote observing lab, wake up at 4 A.M. and race the dawn to get a reading on an exploding star 21 billion light-years away. See Explosions at the Edge for more about her pursuit of strange star endings.
One reason we urge scientists to show us the personal side of research is that we hope it demystifies what they do. Increasingly, we’re seeing the danger of people rejecting scientific findings and claiming that certain fields are all a hoax or a conspiracy. It’s distressing but mostly harmless when people fall for fake documentaries claiming the earth is flat. It’s life-threatening when they fall for misinformation about the COVID-19 pandemic. Starting here, Filippo Menczer and Thomas Hills detail the ways conspiracy theories spread—including a disinformation campaign targeted at their own research group.
The delicate surgery required to transplant a hand is just the start of the process; the recipient must then relearn how to use it. The brain reroutes neural signals in many different areas, showing how nimble and adaptable it can be. Scott H. Frey describes how his early interest in neuroscience was inspired by his mother’s multiple sclerosis and her loss of motor control. He shares this research starting here.
The human body is actually a superorganism teeming with bacteria, fungi and hundreds of trillions of viruses. The study of the human virome is only about a decade old, and the research is accelerating as scientists respond to SARS-CoV-2, the virus that causes COVID. These viruses aren’t all bad. Some are harmless, and some might help treat diseases or fight antibiotic resistance. Turn here for David Pride’s fascinating discoveries about the viruses that live in and among us.
The idea of an international collaboration to build a fusion reactor that could produce clean energy came out of a Superpower Summit in Geneva in 1985 featuring Ronald Reagan and Mikhail Gorbachev. Now the International Thermonuclear Experimental Reactor is being built. The project feels like a series of marathons, the ITER director tells senior editor Clara Moskowitz. Parts have been made all over the world, and beginning here, you can see the stunning facility coming together.
We’re delighted to have editor in chief emerita Mariette DiChristina back in our pages this issue. Once again, she and the World Economic Forum teamed up with a steering committee of experts in a wide range of fields to highlight 10 emerging technologies. It’s an inspiring package and a reminder that research and innovation have the potential to save and improve our lives.
At the same time, the vast majority of Americans trust scientists—so why don’t we act like it? And why don’t our policies reflect that?
One major reason is that our legal system has not caught up amidst the deepening politicization of science, so federal agency scientists like Bright have extremely limited options to protect scientific integrity from political manipulation. In particular, federal scientific integrity policies—designed to ensure that science informs policy decisions and is free from inappropriate political, ideological, financial, or other undue influence—are imperfect. Despite progress across agencies in the last decade, many agency policies are still missing key provisions and suffer from uneven enforcement.
These scientific integrity policies are largely products of the Obama administration, building upon earlier policies that prohibited plagiarism, data manipulation and other forms of research misconduct. Designed to prevent against abuses seen in previous administrations, both Republican and Democrat, these policies represent a substantial stride forward, but there are still major holes. The last few years have illustrated that much more needs to be done to guarantee that federal scientific integrity can be protected even under tremendous political pressures.
Below are 10 recommendations for the Biden administration that would dramatically improve scientific integrity protections across agencies. The recommendations span from revising the policies themselves to strengthening other aspects of government.
Clearly prohibit political interference and censorship. Unfortunately, a number of agency policies focus only on “traditional” areas of misconduct, such as plagiarism and data fraud, and do not even address censorship or other political interference. For example, the Centers for Disease Control (CDC) and National Institutes of Health (NIH) are missing these critical provisions—which means that even the most blatant efforts to undermine science can go uncontested. If ever it was clear why protecting CDC and NIH science and scientists protects the public, surely it is the federal pandemic response. Similarly, protect scientists’ communication rights. Scientists must have clear rights to speak directly to journalists and members of the public, including correcting agency communications that reference their work. Agencies vary widely in the sorts of communication rights that scientists have, which can lead to disastrous results—such as when the Trump administration successfully prevented scientists at the CDC (where scientists have weak communication rights) from speaking about the looming COVID-19 pandemic in February 2020. Preventing scientists from speaking directly to the public not only muzzles scientists but prevents the public from making informed decisions about their health and safety. Acknowledge that attempts to violate scientific integrity, even if ultimately not fruitful, are still violations. In one notable case, attempts to censor a climate report at the National Parks Service were found to be perfectly within the scientific integrity policy because the report was ultimately published intact. Meanwhile, the scientist who authored the study—and who had fought valiantly for publication—was terminated from her position. Imagine if attempted murder were not a crime, and only “successful” murders were prosecuted. Protect federal scientists’ right to provide information to Congress and other lawmakers. There have been multiple examples of scientists involved in public health, climate change and environmental toxicology being prevented from providing information to Congress or being pressured to alter their testimony on important scientific topics. Our lawmakers need to hear from scientific experts, unaltered. Commit to incorporating the best science as part of agency decisions. Unfortunately, there are many examples, at the Environmental Protection Agency and other agencies, where decisions completely ignored scientific findings. Agencies must recognize that ensuring the agency’s credibility and effectiveness are an essential part of guaranteeing the science used in agency decision-making is robust and trustworthy. Elevate agency scientific integrity policies to have the full force of law, which could be done by passing the pending House Scientific Integrity Act. This act codifies many of the basic elements needed in an effective agency scientific integrity policy, including making clear that scientists have the right to appeal decisions regarding scientific integrity violations. These measures help guarantee that agency policies are actually enforced. Publicly release anonymized information about scientific integrity complaints and their resolutions at every agency. Many agencies currently do not publish even basic information about scientific integrity complaints, which makes it impossible to see the extent of any scientific integrity issues or even if the policies are working. Providing a window into how agencies have resolved prior complaints is critical for understanding how the policy works and ensuring that application is fair. Institute an intra-agency workforce, potentially under the White House Office of Science and Technology Policy, to coordinate scientific integrity efforts across agencies, foster discussion of policy improvements, and standardize criteria for policies across agencies. Strengthen whistleblower protections: explicitly extend whistleblower laws to apply to scientific integrity complaints, expand whistleblower rights for scientific contractors and grantees, and reinstate quorum on the Merit Systems Protection Board (the main body that evaluates whistleblower complaints, which has been without the necessary quorum since January 2017). Doing so would ensure that scientists who speak up about scientific integrity violations no longer need to fear for their jobs. Ensure that policies cover all actors who will be dealing with science, including political appointees, public affairs departments and scientific advisory committee members. Unfortunately, many policies currently are unclear about who is covered, or exempt certain categories of workers—for example, it is not clear to what extent contractors are governed by the scientific integrity policy at the Department of Energy. Fixing these inconsistencies would remove confusion and loopholes, and would make clear that protecting scientific integrity is part of everyone’s job.
When asked about what went wrong with the U.S. pandemic response, Bright recently said: “The career staff and scientists were in place. They were battle tested. They knew their role. They knew the plan. And they were prepared to act. They put on their uniform to respond to this pandemic and then there was nowhere to go.” To ensure that scientists can do their job protecting the public in the next crisis, whether it be a pandemic, an earthquake or the climate crisis, we can and must ensure scientists’ voices and work are shielded from political forces. Our lives and the nation’s future depend on it.