In a world first, NASA has crashed a spacecraft into an asteroid in an attempt to push the rocky traveler off its trajectory. The Double Asteroid Redirection Test – or DART – is meant to test one potential approach that could prevent an asteroid from colliding with Earth. David Barnhart is a professor of astronautics at the University of Southern California and director of the Space Engineering Research Center there. He watched NASA’s live stream of the successful mission and explains what is known so far.

1. What do the images show?

The first images, taken by a camera aboard DART, show the double asteroid system of Didymos – about 2,500 feet (780 meters) in diameter – being orbited by the smaller asteroid Dimorphos that is about 525 feet (160 meters) long.

As the targeting algorithm on DART locked onto Dimorphos, the craft adjusted its flight and began heading towards the smaller of the two asteroids. The image taken at 11 seconds before impact and 42 miles (68 kilometers) from Dimorphos shows the asteroid centered in the camera’s field of view. This meant that the targeting algorithm was fairly accurate and the craft would collide right at the center of Dimorphos.

The second-to-last image, taken two seconds before impact shows the rocky surface of Dimorphos, including small shadows. These shadows are interesting because they suggest that the camera aboard the DART spacecraft was seeing Dimorphos directly on but the Sun was at an angle relative to the camera. They imply the DART spacecraft was centered on its trajectory to impact Dimorphos at the moment, but it’s also possible the asteroid was slowly rotating relative to the camera.

The final photo, taken one second before impact, only shows the top slice of an image but this is incredibly exciting. The fact that NASA received only a part of the image implies that the shutter took the picture but DART, traveling at around 14,000 miles per hour (22,500 kilometers per hour) was unable to transmit the complete image before impact.

2. What was supposed to happen?

The point of the DART mission was to test whether it is possible to deflect an asteroid with a kinetic impact – by crashing something into it. NASA used the analogy of a golf cart hitting the side of an Egyptian pyramid to convey the relative difference in size between tiny DART and Dimorphos, the smaller of the two asteroids. Prior to the test, Dimorphos orbited Didymos in roughly 16 hours. NASA expects the impact to shorten Dimorphos’ orbit by about 1%, or roughly 10 minutes. Though small, if done far enough away from Earth, a nudge like this could potentially deflect a future asteroid headed towards Earth just enough to prevent an impact.

3. What do we know already?

The last bits of data that came from the DART spacecraft right before impact show that it was on course. The fact that the images stopped transmitting after the target point was reached can only mean that the impact was a success.

While there is likely a lot of information to be learned from the images taken by DART, the world will have to wait to learn whether the deflection was also a success. Fifteen days before the impact, DART released a small satellite with a camera that was designed to document the entire impact. The small satellite’s sensors should have taken images and collected information, but given that it doesn’t have a large antenna onboard, the images will be transmitted slowly back to Earth, one by one, over the coming weeks.

4. What does the test mean for planetary defense?

I believe this test was a great proof-of-concept for many technologies that the U.S. government has invested in over the years. And importantly, it proves that it is possible to send a craft to intercept with a minuscule target millions of miles away from Earth. From that standpoint DART has been a great success.

Over the course of the next months and years, researchers will learn just how much deflection the impact caused – and most importantly, whether this type of kinetic impact can actually move a celestial object ever so slightly at a great enough distance to prevent a future asteroid from threatening Earth.

David Barnhart, Professor of Astronautics, University of Southern California

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Michelle Martin is the Beverly Cleary Professor for Children and Youth Services in the Information School at the University of Washington. She primarily teaches students who will be youth services librarians who work with children and young adults in libraries or other information science spaces. Below are highlights from an interview with The Conversation U.S. Answers have been edited for brevity and clarity.

How did you get to where you are today?

I have a doctorate in English, specializing in children’s and young adult literature. I spent the first half of my 25-year career in English departments, teaching education and English majors. And then I shifted to social science when I joined the University of South Carolina’s library school in 2011. Since 2016, I have taught future librarians at University of Washington in the Information School (which began as the Library School).

What would surprise someone about the work you do if they don’t know about what you study?

Some of my publications have more to do with children in books than with real children who read books. Those who study children’s literature from an English studies perspective look at children’s books as literary and artistic artifacts and attend to aspects like the art, character development and applying different theoretical readings to texts for young people rather than focusing on what children and young adults do with books. But I care deeply about children and how they interact with books, which is often more of a focus of those who teach children’s literature in library science and education departments. My teaching, research and service cross all three disciplines.

A lot of the work that I do now really helps adults understand the importance of exposing children to diverse perspectives in books and for children to be able to see their own experiences in the books that they read. The books that you grew up on might not necessarily be good for or the most entertaining to children you’re working with now.

I need to really do my homework and read widely to be able to teach and recommend books that represent kids’ life experiences and families who come from different backgrounds.

How has the role of libraries shifted as a result of the pandemic?

Libraries have been under a lot of the same stresses that everyone else has. But even though many libraries closed physically, they continued to serve their communities. Libraries have worked hard to to meet their communities where they are, especially those that have been hardest hit by the pandemic – from providing virtual storytimes to career assistance. For instance, many libraries extended their Wi-Fi into the parking lot so that parents could drive their kids to the library, download their homework and go home and do it. Even though many students had a laptop provided by the school, if they lived in rural areas where there’s no internet, they did not have what they needed to succeed in school. Libraries helped to support many of these families.

I’ve heard so many stories of ways libraries met the needs of the community during the pandemic, such as providing clothing or food or enhancing information access by offering no-contact, curbside pickup, or turning personal vehicles into a bookmobiles to deliver books to those who could not get to the library.

Some readers might think of libraries as institutions that don’t change. And maybe the pandemic has proved that libraries can adapt and change with the times as we need them to.

I’m working on a research project right now called Project VOICE that seeks to help libraries plan outreach with, not for, their communities with a social justice lens and with participatory design. We recommend that librarians work closely with the community and community partner organizations to discern what the community’s assets and values are and take a strengths-based approach to creating outreach programs rather than the deficit model that focuses on weaknesses and needs.

We’re encouraging libraries to depart from the approach that says, “Hey, we’re the library, here’s what we do well. Can you use it?” and instead ask, “As members of this community, you know best what the community’s values and assets are. How can we, as the library, partner with you to support your goals and aspirations?”

Because communities across the country are more diverse than ever, and becoming more so, it’s really important for librarians to spend time and effort building relationships with those in the community. This will ensure that libraries continue to understand the nuances of how to best serve their community, especially as the face of that community changes rapidly.

Michelle H. Martin, Beverly Cleary Professor for Children & Youth Services, University of Washington

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Wetlands are areas of land that are covered by water, or have flooded or waterlogged soils. They can have water on them either permanently or for just part of the year.

Whether it’s year-round or seasonal, this period of water saturation produces hydric soils, which contain little or no oxygen. But this doesn’t mean that they are lifeless: Wetlands are full of unique water-loving plants and wildlife that have adapted to wet environments.

Wetlands can take many different forms, depending on the local climate, water conditions and land forms and features. For example, swamps are dominated by woody trees or shrubs. Marshes often have more grasslike plants, such as cattails and bulrushes. Bogs and fens are areas that accumulate peat – deposits of dead and partly decomposed plant materials that form organic-rich soil.

Trillions of dollars in ecological benefits

Wetlands are important environments for many reasons. They provide ecological services whose value has been estimated to be worth more than US$47 trillion per year.

For example, wetlands support very high levels of biodiversity. Scientists estimate that 40% of all species on Earth live or breed in wetlands.

Wetlands are critical homes or stopovers for many species of migratory birds. In the central U.S. and Canada, for example, wetlands in the so-called prairie pothole region on the Great Plains support up to three-quarters of North America’s breeding ducks.

Along with providing important habitat for everything from microbes to frogs to waterfowl, wetlands also work to improve water quality. They can capture surface runoff from cities and farmlands and work as natural water filters, trapping excess nutrients that otherwise might create dead zones in lakes and bays. Wetlands can also help remove other pollutants and trap suspended sediments that cloud water bodies, which can kill aquatic plants and animals.

Because wetlands are often in low-lying areas of the landscape, they can store and slowly release surface water. Wetlands can be extremely important for reducing the impacts of flooding. In some places, water entering wetlands can also recharge groundwater aquifers that are important for irrigation and drinking water.

Wetlands also act as important carbon sinks. As wetland plants grow, they remove carbon dioxide from the atmosphere. They they die, sink to the bottom of the wetland and decompose very slowly.

Over time, the carbon they contain accumulates in wetland soils, where it can be stored for hundreds of years. Conserving and restoring wetlands is an important strategy for regulating greenhouse gases and mitigating the impacts of climate change.

Resources at risk

Despite the many valuable services they provide, wetlands are constantly being destroyed by draining them or filling them in, mainly for farming and development. Since 1970, the planet has lost 35% of its wetlands, a rate three times faster than the loss of forests.

Destruction and degradation of wetlands has led to the loss of many organisms that rely on wetland habitat, including birds, amphibians, fish, mammals and many insects. As one example, many dragonfly and damselfly species are declining worldwide as the freshwater wetlands where they breed are drained and filled in. A marsh or bog may not look like a productive place, but wetlands teem with life and are critically important parts of our environment.

Jon Sweetman, Assistant Research Professor of Ecosystem Science and Management, Penn State

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People have been exploring the surface of Mars for over 50 years. According to the United Nations Office for Outer Space Affairs, nations have sent 18 human-made objects to Mars over 14 separate missions. Many of these missions are still ongoing, but over the decades of Martian exploration, humankind has left behind many pieces of debris on the planet’s surface.

I am a postdoctoral research fellow who studies ways to track Mars and Moon rovers. In mid-August 2022, NASA confirmed that the Mars rover Perseverance had spotted a piece of trash jettisoned during its landing, this time a tangled mess of netting. And this is not the first time scientists have found trash on Mars. That’s because there is a lot there.

Where does the debris come from?

Debris on Mars comes from three main sources: discarded hardware, inactive spacecraft and crashed spacecraft.

Every mission to the Martian surface requires a module that protects the spacecraft. This module includes a heat shield for when the craft passes through the planet’s atmosphere and a parachute and landing hardware so that it can land softly.

The craft discards pieces of the module as it descends, and these pieces can land in different locations on the planet’s surface – there may be a lower heat shield in one place and a parachute in another. When this debris crashes to the ground, it can break into smaller pieces, as happened during the Perseverance rover landing in 2021. These small pieces can then get blown around because of Martian winds.

A lot of small, windblown trash has been found over the years – like the netting material found recently. Earlier in the year, on June 13, 2022, Perseverance rover spotted a large, shiny thermal blanket wedged in some rocks 1.25 miles (2 km) from where the rover landed. Both Curiosity in 2012 and Opportunity in 2005 also came across debris from their landing vehicles.

Dead and crashed spacecraft

The nine inactive spacecraft on the surface of Mars make up the next type of debris. These craft are the Mars 3 lander, Mars 6 lander, Viking 1 lander, Viking 2 lander, the Sojourner rover, the formerly lost Beagle 2 lander, the Phoenix lander, the Spirit rover and the most recently deceased spacecraft, the Opportunity rover. Mostly intact, these might be better considered historical relics than trash.

Wear and tear take their toll on everything on the Martian surface. Some parts of Curiosity’s aluminum wheels have broken off and are presumably scattered along the rover’s track. Some of the litter is purposeful, with Perseverance having dropped a drill bit onto the surface in July 2021, allowing it to swap in a new, pristine bit so that it could keep collecting samples.

Crashed spacecraft and their pieces are another significant source of trash. At least two spacecraft have crashed, and an additional four have lost contact before or just after landing. Safely descending to the planet’s surface is the hardest part of any Mars landing mission – and it doesn’t always end well.

When you add up the mass of all spacecraft that have ever been sent to Mars, you get about 22,000 pounds (9979 kilograms). Subtract the weight of the currently operational craft on the surface – 6,306 pounds (2,860 kilograms) – and you are left with 15,694 pounds (7,119 kilograms) of human debris on Mars.

Why does trash matter?

Today, the main concern scientists have about trash on Mars is the risk it poses to current and future missions. The Perseverance teams are documenting all debris they find and checking to see if any of it could contaminate the samples the rover is collecting. NASA engineers have also considered whether Perseverance could get tangled in debris from the landing but have concluded the risk is low.

The real reason debris on Mars is important is because of its place in history. The spacecraft and their pieces are the early milestones for human planetary exploration.

Cagri Kilic, Postdoctoral Research Fellow in Robotics, West Virginia University

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