NASA recently announced the discovery of a new, Earth-sized planet in the habitable zone of a nearby star called TOI-700. We are two of the astronomers who led the discovery of this planet, called TOI-700 e. TOI-700 e is just over 100 light years from Earth – too far away for humans to visit – but we do know that it is similar in size to the Earth, likely rocky in composition and could potentially support life.

You’ve probably heard about some of the many other exoplanet discoveries in recent years. In fact, TOI-700 e is one of two potentially habitable planets just in the TOI-700 star system.

Habitable planets are those that are just the right distance from their star to have a surface temperature that could sustain liquid water. While it is always exciting to find a new, potentially habitable planet far from Earth, the focus of exoplanet research is shifting away from simply discovering more planets. Instead, researchers are focusing their efforts on finding and studying systems most likely to answer key questions about how planets form, how they evolve, and whether life might exist in the universe. TOI-700 e stands out from many of these other planet discoveries because it is well suited for future studies that could help answer big question about the conditions for life outside the solar system.

From 1 to 5,000

Astronomers discovered the first exoplanet around a Sun-like star in 1995. The field of exoplanet discovery and research has been rapidly evolving ever since.

At first, astronomers were finding only a few exoplanets each year, but the combination of new cutting-edge facilities focused on exoplanet science with improved detection sensitivity have led to astronomers’ discovering hundreds of exoplanets each year. As detection methods and tools have improved, the amount of information scientists can learn about these planets has increased. In 30 years, scientists have gone from barely being able to detect exoplanets to characterizing key chemical clues in their atmospheres, like water, using facilities like the James Webb Space Telescope.

Today, there are more than 5,000 known exoplanets, ranging from gas giants to small rocky worlds. And perhaps most excitingly, astronomers have now found about a dozen exoplanets that are likely rocky and orbiting within the habitable zones of their respective stars.

Astronomers have even discovered a few systems – like TOI-700 – that have more than one planet orbiting in the habitable zone of their star. We call these keystone systems.

A pair of habitable siblings

TOI-700 first made headlines when our team announced the discovery of three small planets orbiting the star in early 2020. Using a combination of observations from NASA’s Transiting Exoplanet Surveying Satellite mission and the Spitzer Space Telescope we discovered these planets by measuring small dips in the amount of light coming from TOI-700. These dips in light are caused by planets passing in front of the small, cool, red dwarf star at the center of the system.

By taking precise measurements of the changes in light, we were able to determine that at least three small planets are in the TOI-700 system, with hints of a possible fourth. We could also determine that the third planet from the star, TOI-700 d, orbits within its star’s habitable zone, where the temperature of the planet’s surface could allow for liquid water.

The Transiting Exoplanet Surveying Satellite observed TOI-700 for another year, from July 2020 through May 2021, and using these observations our team found the fourth planet, TOI-700 e. TOI-700 e is 95% the size of the Earth and, much to our surprise, orbits on the inner edge of the star’s habitable zone, between planets c and d. Our discovery of this planet makes TOI-700 one of only a few known systems with two Earth-sized planets orbiting in the habitable zone of their star. The fact that it is relatively close to Earth also makes it one of the most accessible systems in terms of future characterization.

The bigger questions and tools to answer them

With the successful launch of the James Webb Space Telescope, astronomers are now able to start characterizing the atmospheric chemistry of exoplanets and search for clues about whether life exists on them. In the near future, a number of massive, ground-based telescopes will also help reveal further details about the composition of planets far from the solar system.

But even with powerful new telescopes, collecting enough light to learn these details requires pointing the telescope at a system for a long period of time. With thousands of valuable scientific questions to answer, astronomers need to know where to look. And that is the goal of our team, to find the most interesting and promising exoplanets to study with the Webb telescope and future facilities.

Earth is currently the only data point in the search for life. It is possible alien life could be vastly different from life as we know it, but for now, places similar to the home of humanity with liquid water on the surface offer a good starting point. We believe that keystone systems with multiple planets that are likely candidates for hosting life – like TOI-700 – offer the best use of observation time. By further studying TOI-700, our team will be able to learn more about what makes a planet habitable, how rocky planets similar to Earth form and evolve, and the mechanisms that shaped the solar system. The more astronomers know about how star systems like TOI-700 and our own solar system work, the better the chances of detecting life out in the cosmos.

Joey Rodriguez, Assistant Professor of Physics and Astronomy, Michigan State University and Andrew Vanderburg, Assistant Professor of Physics, Massachusetts Institute of Technology (MIT)

This article is republished from The Conversation under a Creative Commons license. Read the original article.

An outbreak of H5N1 avian influenza that started in 2021 has become the largest bird flu outbreak in history, both in the U.S. and worldwide. In the U.S. the virus has led to the destruction of millions of commercially raised chickens, turkeys, ducks and geese, and has killed thousands of wild birds.

Many virologists are concerned that this virus could spill over to humans and cause a new human pandemic. University of Colorado Boulder virologists Sara Sawyer, Emma Worden-Sapper and Sharon Wu summarize the compelling story of H5N1 and why scientists are closely watching the outbreak.

1. Is this virus a serious threat to humans?

H5N1 is a specific type of influenza virus, predominantly harbored by birds, that was first detected on a goose farm in China in 1996. Recently it has begun infecting an exploding diversity of bird and mammalian species around the globe.

The virus is highly pathogenic to birds, meaning that infections often cause extreme symptoms, including death. But its impact on humans is complicated. There have been relatively few human infections detected – fewer than 900 documented globally over several decades – but about half of those infected individuals have died.

The good news about H5N1 for humans is that it currently doesn’t spread well between people. Most people who have contracted H5N1 have gotten it directly from interacting with infected poultry – specifically chickens, turkeys, ducks and geese, which often are raised in close quarters on large commercial farms.

There are only a small handful of examples of human-to-human spread. Because H5N1 doesn’t spread well between people, and because direct infection of humans by infected birds is still relatively rare, H5N1 has not yet erupted into a human epidemic or pandemic.

2. Why is this outbreak suddenly getting so much attention?

The first reason that so much attention is being paid to bird flu right now is that currently H5N1 is causing the largest “bird pandemic” ever recorded. A certain viral variant that arose in 2020, called H5N1 2.3.4.4b, is driving this outbreak.

In agricultural poultry flocks, if a few birds test positive for H5N1, the whole flock is killed regardless of symptoms or infection status. Higher prices for eggs and poultry meat in the U.S. are one result. The Biden administration is considering vaccinating farmed poultry flocks, but the logistics could be quite complicated.

The second reason for increased attention is that H5N1 is now infecting more bird and mammalian species than ever before. The virus has been detected in a broad array of wild birds and in diverse mammals, including badgers, black bears, bobcats, coyotes, ferrets, fisher cats, foxes, leopards, opossums, pigs, skunks and sea lions.

As H5N1 infects more species, it also increases its geographical range and produces more viral variants that could have new biological properties.

The third and most worrisome reason that this virus is getting so much press is that H5N1 now seems to be transmitting well between individuals of at least one mammalian species. In late 2022, mammal-to-mammal spread occurred in Spain in farmed minks. H5N1 spread very efficiently between the minks and caused clinical signs of illness and death in the mink populations where it was detected.

Sea lions in Peru are also succumbing to H5N1 virus in massive numbers. It hasn’t been confirmed definitively whether the sea lions are spreading the virus to each other or are contracting it from birds or H5N1-infected water.

Here’s the key question: If H5N1 can achieve spread in minks and possibly sea lions, why not humans? We are also mammals. It is true that the farmed minks were confined in close quarters, like chickens on a poultry farm, so that may have contributed. But humans also live in high densities in many cities around the world, providing the virus similar tinder should a human-compatible variant arise.

3. What features could help H5N1 spread well in humans?

Birds experience influenza as a gastrointestinal infection and spread flu predominantly through defecating in water. By contrast, humans experience influenza as a respiratory infection and spread it by breathing and coughing.

Over the centuries, some of these avian influenza viruses have been passed from birds to humans and other mammalian species, although this is a relatively rare event.

This is because bird influenza viruses must mutate in several ways to infect mammals efficiently. The most important mutational changes affect the tissue tropism of the virus – its ability to infect a specific part of the body.

Avian flu viruses have evolved to infect cells of the intestine, while human flu viruses have evolved to infect cells of the respiratory tract. However, sometimes a flu virus can acquire mutations that allow it to infect cells in a different part of the body.

Which cells influenza infects is partially dictated by the specific receptor that it binds. Receptors are the molecules on the surface of host cells that a virus exploits to enter those cells. Once viruses are in cells, they may be able to produce copies of themselves, at which point an infection has been achieved.

Both human and bird influenza viruses use receptors called sialic acids that are common on the surfaces of cells. Bird influenza viruses, such as H5N1, use a version called α2,3-linked sialic acid, while human flu viruses use α2,6-linked sialic acid – the predominant variant in the human upper respiratory tract. Thus, to become efficient at infecting humans, H5N1 would likely need to mutate to use α2,6-linked sialic acid as its receptor.

This is a concern because studies have shown that only one or two mutations in the viral genome are enough to switch receptor binding from α2,3-linked sialic acid to the human α2,6-linked sialic acid. That doesn’t seem like much of a genetic obstacle.

4. Why don’t we make a vaccine just in case?

With avian influenza viruses, it is not possible to make effective human vaccines in advance, because we don’t know exactly what the genetics of the virus will be if it starts to spread well in humans. Remember that the seasonal flu vaccine must be remade every year, even though the general types of flu viruses that it protects against are the same, because the specific genetic variants that affect humans change from year to year.

Right now, the best way people can protect themselves from H5N1 is to avoid contact with infected birds. For more information about prevention, especially for people who keep domesticated birds or are bird-watching hobbyists, the Centers for Disease Control has a list of guidelines for avoiding H5N1 and other bird flu viruses.

Sara Sawyer, Professor of Molecular, Cellular and Developmental Biology, University of Colorado Boulder; Emma Worden-Sapper, PhD Student in Molecular, Cellular and Developmental Biology, University of Colorado Boulder, and Sharon Wu, PhD Student in Interdisciplinary Quantitative Biology and Molecular, Cellular, and Developmental Biology, University of Colorado Boulder

This article is republished from The Conversation under a Creative Commons license. Read the original article.

Historian Vicki Crawford was one of the first scholars to focus on women’s roles in the civil rights movement. Her 1993 book, “Trailblazers and Torchbearers,” dives into the stories of female leaders whose legacies have often been overshadowed.

Today she is the director of the Morehouse College Martin Luther King Jr. Collection, where she oversees the archive of his sermons, speeches, writings and other materials. Here, she explains the contributions of women who influenced King and helped to fuel some of the most significant campaigns of the civil rights era, but whose contributions are not nearly as well known.

An activist in her own right

Coretta Scott King is often remembered as a devoted wife and mother, yet she was also a committed activist in her own right. She was deeply involved with social justice causes before she met and married Martin Luther King Jr., and long after his death.

Scott King served with civil rights groups throughout her time as a student at Antioch College and the New England Conservatory of Music. Shortly after she and King married in 1953, the couple returned to the South, where they lent their support to local and regional organizations such as the NAACP and the Montgomery Improvement Association.

They also supported the Women’s Political Council, an organization founded by female African American professors at Alabama State University that facilitated voter education and registration, and also protested discrimination on city buses. These local leadership efforts paved the way for widespread support of Rosa Parks’ resistance to segregation on public busing.

Following her husband’s assassination in 1968, Scott King devoted her life to institutionalizing his philosophy and practice of nonviolence. She established the King Center for Nonviolent Social Change, led a march of sanitation workers in Memphis and joined efforts to organize the Poor People’s Campaign. A longtime advocate of workers rights, she also supported a 1969 hospital workers’ strike in South Carolina, delivering stirring speeches against the treatment of African American staff.

Scott King’s commitment to nonviolence went beyond civil rights at home. During the 1960s, she became involved in peace and anti-war efforts such as the Women’s Strike for Peace and opposed the escalating war in Vietnam. By the 1980s, she had joined protests against South African apartheid, and before her death in 2006, she spoke out in favor of LGBT rights – capping a lifetime of activism against injustice and inequalities.

Women and the March

While Scott King’s support and ideas were particularly influential, many other women played essential roles in the success of the civil rights movement.

Take the most iconic moment of the civil rights struggle, in many Americans’ minds: the Aug. 28, 1963, March on Washington for Jobs and Freedom, at which King delivered his landmark “I Have a Dream” speech on the steps of the Lincoln Memorial.

As the 60th anniversary of the march approaches, it is critical to recognize the activism of women from all walks of life who helped to strategize and organize one of the country’s most massive political demonstrations of the 20th century. Yet historical accounts overwhelmingly highlight the march’s male leadership. With the exception of Daisy Bates, an activist who read a short tribute, no women were invited to deliver formal speeches.

Women were among the key organizers of the march, however, and helped recruit thousands of participants. Dorothy Height, president of the National Council of Negro Women, was often the lone woman at the table of leaders representing national organizations. Anna Arnold Hedgeman, who also served on the planning committee, was another strong advocate for labor issues, anti-poverty efforts and women’s rights.

Photographs of the march show women attended in large numbers, yet few historical accounts adequately credit women for their leadership and support. Civil rights activist, lawyer and Episcopalian priest Pauli Murray, among others, called for a gathering of women to address this and other instances of discrimination a few days later.

Hidden in plain view

African American women led and served in all the major campaigns, working as field secretaries, attorneys, plaintiffs, organizers and educators, to name just a few roles. So why did early historical accounts of the movement neglect their stories?

There were women propelling national civil rights organizations and among King’s closest advisers. Septima Clark, for example, was a seasoned educator whose strong organizing skills played a consequential role in voter registration, literacy training and citizenship education. Dorothy Cotton was a member of the inner circle of the Southern Christian Leadership Conference, of which King was president, and was involved in literacy training and teaching nonviolent resistance.

Yet women’s organizing during the 1950s and 1960s is most evident at local and regional levels, particularly in some of the most perilous communities across the deep South. Since the 1930s, Amelia Boynton Robinson of Dallas County, Alabama, and her family had been fighting for voting rights, laying the groundwork for the struggle to end voter suppression that continues to the present. She was also key in planning the 50-mile Selma-to-Montgomery march in 1965. Images of the violence that marchers endured – particularly on the day that came to be known as Bloody Sunday – shocked the nation and eventually contributed to the passage of the landmark Voting Rights Act of 1965.

Or take Mississippi, where there would not have been a sustained movement without women’s activism. Some names have become well known, like Fannie Lou Hamer, but others deserve to be.

Two rural activists, Victoria Gray and Annie Devine, joined Hamer as representatives to the Mississippi Freedom Democratic Party, a parallel political party that challenged the state’s all-white representatives at the 1964 Democratic Convention. A year later, the three women represented the party in a challenge to block the state’s congressmen from taking their seats, given ongoing disenfranchisement of Black voters. Though the congressional challenge failed, the activism was a symbolic victory, serving note to the nation that Black Mississippians were no longer willing to accept centuries-old oppression.

Many African American women were out-front organizers for civil rights. But it is no less important to remember those who assumed less visible, but indispensable, roles behind the scenes, sustaining the movement over time.

Vicki Crawford, Professor of Africana Studies, Morehouse College

This article is republished from The Conversation under a Creative Commons license. Read the original article.