Science

Bennu asteroid reveals its contents to scientists − and clues to how the building blocks of life on Earth may have been seeded

NASA’s OSIRIS-REx mission returned samples from asteroid Bennu, revealing insights into life’s ingredients on Earth, paralleling those found in the Revelstoke meteorite’s analysis.

Published

2 months ago

February 3, 2025

The Conversation

This photo of asteroid Bennu is composed of 12 Polycam images collected on Dec. 2, 2024, by the OSIRIS-REx spacecraft. NASA

Timothy J McCoy, Smithsonian Institution and Sara Russell, Natural History Museum

A bright fireball streaked across the sky above mountains, glaciers and spruce forest near the town of Revelstoke in British Columbia, Canada, on the evening of March 31, 1965. Fragments of this meteorite, discovered by beaver trappers, fell over a lake. A layer of ice saved them from the depths and allowed scientists a peek into the birth of the solar system.

Nearly 60 years later, NASA’s OSIRIS-REx mission returned from space with a sample of an asteroid named Bennu, similar to the one that rained rocks over Revelstoke. Our research team has published a chemical analysis of those samples, providing insight into how some of the ingredients for life may have first arrived on Earth.

Born in the years bracketing the Revelstoke meteorite’s fall, the two of us have spent our careers in the meteorite collections of the Smithsonian Institution in Washington, D.C., and the Natural History Museum in London. We’ve dreamed of studying samples from a Revelstoke-like asteroid collected by a spacecraft.

Then, nearly two decades ago, we began turning those dreams into reality. We joined NASA’s OSIRIS-REx mission team, which aimed to send a spacecraft to collect and return an asteroid sample to Earth. After those samples arrived on Sept. 24, 2023, we got to dive into a tale of rock, ice and water that hints at how life could have formed on Earth.

An illustration of a small spacecraft with solar panels and an extending arm hovers above an asteroid's rocky surface in space. — In this illustration, NASA’s OSIRIS-REx spacecraft collects a sample from the asteroid Bennu. NASA/Goddard/University of Arizona

The CI chondrites and asteroid Bennu

To learn about an asteroid – a rocky or metallic object in orbit around the Sun – we started with a study of meteorites.

Asteroids like Bennu are rocky or metallic objects in orbit around the Sun. Meteorites are the pieces of asteroids and other natural extraterrestrial objects that survive the fiery plunge to the Earth’s surface.

We really wanted to study an asteroid similar to a set of meteorites called chondrites, whose components formed in a cloud of gas and dust at the dawn of the solar system billions of years ago.

The Revelstoke meteorite is in a group called CI chondrites. Laboratory-measured compositions of CI chondrites are essentially identical, minus hydrogen and helium, to the composition of elements carried by convection from the interior of the Sun and measured in the outermost layer of the Sun. Since their components formed billions of years ago, they’re like chemically unchanged time capsules for the early solar system.

So, geologists use the chemical compositions of CI chondrites as the ultimate reference standard for geochemistry. They can compare the compositions of everything from other chondrites to Earth rocks. Any differences from the CI chondrite composition would have happened through the same processes that formed asteroids and planets.

CI chondrites are rich in clay and formed when ice melted in an ancient asteroid, altering the rock. They are also rich in prebiotic organic molecules. Some of these types of molecules are the building blocks for life.

This combination of rock, water and organics is one reason OSIRIS-REx chose to sample the organic-rich asteroid Bennu, where water and organic compounds essential to the origin of life could be found.

Evaporites − the legacy of an ancient brine

Ever since the Bennu samples returned to Earth on Sept. 24, 2023, we and our colleagues on four continents have spent hundreds of hours studying them.

The instruments on the OSIRIS-REx spacecraft made observations of reflected light that revealed the most abundant minerals and organics when it was near asteroid Bennu. Our analyses in the laboratory found that the compositions of these samples lined up with those observations.

The samples are mostly water-rich clay, with sulfide, carbonate and iron oxide minerals. These are the same minerals found in CI chondrites like Revelstoke. The discovery of rare minerals within the Bennu samples, however, surprised both of us. Despite our decades of experience studying meteorites, we have never seen many of these minerals.

We found minerals dominated by sodium, including carbonates, sulfates, chlorides and fluorides, as well as potassium chloride and magnesium phosphate. These minerals don’t form just when water and rock react. They form when water evaporates.

We’ve never seen most of these sodium-rich minerals in meteorites, but they’re sometimes found in dried-up lake beds on Earth, like Searles Lake in California.

Bennu’s rocks formed 4.5 billion years ago on a larger parent asteroid. That asteroid was wet and muddy. Under the surface, pockets of water perhaps only a few feet across were evaporating, leaving the evaporite minerals we found in the sample. That same evaporation process also formed the ancient lake beds we’ve seen these minerals in on Earth.

Bennu’s parent asteroid likely broke apart 1 to 2 billion years ago, and some of the fragments came together to form the rubble pile we know as Bennu.

These minerals are also found on icy bodies in the outer solar system. Bright deposits on the dwarf planet Ceres, the largest body in the asteroid belt, contain sodium carbonate. The Cassini mission measured the same mineral in plumes on Saturn’s moon Enceladus.

We also learned that these minerals, formed when water evaporates, disappear when exposed to water once again – even with the tiny amount of water found in air. After studying some of the Bennu samples and their minerals, researchers stored the samples in air. That’s what we do with meteorites.

Unfortunately, we lost these minerals as moisture in the air on Earth caused them to dissolve. But that explains why we can’t find these minerals in meteorites that have been on Earth for decades to centuries.

Fortunately, most of the samples have been stored and transported in nitrogen, protected from traces of water in the air.

Until scientists were able to conduct a controlled sample return with a spacecraft and carefully curate and store the samples in nitrogen, we had never seen this set of minerals in a meteorite.

An unexpected discovery

Before returning the samples, the OSIRIS-REx spacecraft spent over two years making observations around Bennu. From that two years of work, researchers learned that the surface of the asteroid is covered in rocky boulders.

We could see that the asteroid is rich in carbon and water-bearing clays, and we saw veins of white carbonate a few feet long deposited by ancient liquid water. But what we couldn’t see from these observations were the rarer minerals.

We used an array of techniques to go through the returned sample one tiny grain at a time. These included CT scanning, electron microscopy and X-ray diffraction, each of which allowed us to look at the rock at a scale not possible on the asteroid.

Cooking up the ingredients for life

From the salts we identified, we could infer the composition of the briny water from which they formed and see how it changed over time, becoming more sodium-rich.

This briny water would have been an ideal place for new chemical reactions to take place and for organic molecules to form.

While our team characterized salts, our organic chemist colleagues were busy identifying the carbon-based molecules present in Bennu. They found unexpectedly high levels of ammonia, an essential building block of the amino acids that form proteins in living matter. They also found all five of the nucleobases that make up part of DNA and RNA.

Based on these results, we’d venture to guess that these briny pods of fluid would have been the perfect environments for increasingly complicated organic molecules to form, such as the kinds that make up life on Earth.

When asteroids like Bennu hit the young Earth, they could have provided a complete package of complex molecules and the ingredients essential to life, such as water, phosphate and ammonia. Together, these components could have seeded Earth’s initially barren landscape to produce a habitable world.

Without this early bombardment, perhaps when the pieces of the Revelstoke meteorite landed several billion years later, these fragments from outer space would not have arrived into a landscape punctuated with glaciers and trees.

Timothy J McCoy, Supervisory Research Geologist, Smithsonian Institution and Sara Russell, Professor of Planetary Sciences, Natural History Museum

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

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Urbanism

New Construction Project at Phoenix Sky Harbor Airport

Published

2 hours ago

April 13, 2025

Rod Washington

Phoenix Sky Harbor International Airport, a major transportation hub in Arizona, is set to undergo significant improvements with a new construction project at Terminal 3. According to AZ Family, the work is officially commencing this month on a project that will enhance the airport’s infrastructure, making it more accommodating for travelers.

Expansion at Sky Harbor

The upcoming expansion, which boasts a budget of $326 million, will introduce a new concourse on the north side of Terminal 3. This new addition is designed to increase the terminal’s capacity by adding six new passenger gates, bringing the total to 26 gates. The construction will encompass a vast 173,000 square feet, ultimately providing more flight options and enhanced facilities for travelers.

As reported by AZ Central, the expansion is much-needed, given that Terminal 3 is the oldest terminal at Sky Harbor. McCarthy Building Cos. Inc. has been entrusted with the construction, and they are committed to creating an exceptional experience for passengers. Thomas Assante, McCarthy’s senior project director, stated, “Every portion of the new Terminal 3 concourse will provide an exceptional experience for Sky Harbor passengers.” Notably, McCarthy has experience with airport projects, having recently completed a five-gate concourse at Mesa Gateway Airport, which opened in February 2024.

In addition to expanding gate capacity, the new Terminal 3 concourse plans to feature improvements beyond functionality. Travelers can look forward to new dining options, including three food and beverage spaces, as well as two retail spaces, alongside a passenger lounge. Greg Roybal, an airport spokesman, has confirmed these plans, emphasizing the project’s focus on improving the overall passenger experience.

The anticipated completion date for the new concourse is set for 2027. Once finished, this expansion will not only bolster the terminal’s capabilities but also enhance the amenities available to travelers. The airlines currently operating out of Terminal 3 include Delta, United, Frontier, and Alaska Airlines, among others.

As this construction project unfolds, we will keep readers updated with the latest developments and milestones. With these enhancements on the horizon, Sky Harbor Airport is poised to deliver an even better travel experience for passengers in the coming years. Stay tuned!

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News

3D printing will help space pioneers make homes, tools and other stuff they need to colonize the Moon and Mars

Published

1 day ago

April 12, 2025

The Conversation

3D printing will help space pioneers make homes, tools and other stuff they need to colonize the Moon and Mars

file 20250120 15 ugid1c.jpg?ixlib=rb 4.1 — 3D printing could make many of the components for future structures on Mars. 3000ad/iStock via Getty Images Plus

Sven Bilén, Penn State

Throughout history, when pioneers set out across uncharted territory to settle in distant lands, they carried with them only the essentials: tools, seeds and clothing. Anything else would have to come from their new environment.

So they built shelter from local timber, rocks and sod; foraged for food and cultivated the soil beneath their feet; and fabricated tools from whatever they could scrounge up. It was difficult, but ultimately the successful ones made everything they needed to survive.

Something similar will take place when humanity leaves Earth for destinations such as the Moon and Mars – although astronauts will face even greater challenges than, for example, the Vikings did when they reached Greenland and Newfoundland. Not only will the astronauts have limited supplies and the need to live off the land; they won’t even be able to breathe the air.

Instead of axes and plows, however, today’s space pioneers will bring 3D printers. As an engineer and professor who is developing technologies to extend the human presence beyond Earth, I focus my work and research on these remarkable machines.

3D printers will make the tools, structures and habitats space pioneers need to survive in a hostile alien environment. They will enable long-term human presence on the Moon and Mars.

An astronaut holding a wrench poses for the camera. — NASA astronaut Barry Wilmore holds a 3D-printed wrench made aboard the International Space Station. NASA

From hammers to habitats

On Earth, 3D printing can fabricate, layer by layer, thousands of things, from replacement hips to hammers to homes. These devices take raw materials, such as plastic, concrete or metal, and deposit it on a computerized programmed path to build a part. It’s often called “additive manufacturing,” because you keep adding material to make the part, rather than removing material, as is done in conventional machining.

Already, 3D printing in space is underway. On the International Space Station, astronauts use 3D printers to make tools and spare parts, such as ratchet wrenches, clamps and brackets. Depending on the part, printing time can take from around 30 minutes to several hours.

For now, the print materials are mostly hauled up from Earth. But NASA has also begun recycling some of those materials, such as waste plastic, to make new parts with the Refabricator, an advanced 3D printer installed in 2019.

Manufacturing in space

You may be wondering why space explorers can’t simply bring everything they need with them. After all, that’s how the International Space Station was built decades ago – by hauling tons of prefabricated components from Earth.

But that’s impractical for building habitats on other worlds. Launching materials into space is incredibly expensive. Right now, every pound launched aboard a rocket just to get to low Earth orbit costs thousands of dollars. To get materials to the Moon, NASA estimates the initial cost at around US$500,000 per pound.

Still, manufacturing things in space is a challenge. In the microgravity of space, or the reduced gravity of the Moon or Mars, materials behave differently than they do on Earth. Decrease or remove gravity, and materials cool and recrystallize differently. The Moon has one-sixth the gravity of Earth; Mars, about two-fifths. Engineers and scientists are working now to adapt 3D printers to function in these conditions.

An illustration of an astronaut looking at a base camp on Mars. 3D Printing — An artist’s impressions of what a Mars base camp might look like. peepo/E+ via Getty Images

Using otherworldly soil

On alien worlds, rather than plastic or metal, 3D printers will use the natural resources found in these environments. But finding the right raw materials is not easy. Habitats on the Moon and Mars must protect astronauts from the lack of air, extreme temperatures, micrometeorite impacts and radiation.

Regolith, the fine, dusty, sandlike particles that cover both the lunar and Martian surfaces, could be a primary ingredient to make these dwellings. Think of the regolith on both worlds as alien dirt – unlike Earth soil, it contains few nutrients, and as far as we know, no living organisms. But it might be a good raw material for 3D printing.

My colleagues began researching this possibility by first examining how regular cement behaves in space. I am now joining them to develop techniques for turning regolith into a printable material and to eventually test these on the Moon.

But obtaining otherworldly regolith is a problem. The regolith samples returned from the Moon during the Apollo missions in the 1960s and 70s are precious, difficult if not impossible to access for research purposes. So scientists are using regolith simulants to test ideas. Actual regolith may react quite differently than our simulants. We just don’t know.

What’s more, the regolith on the Moon is very different from what’s found on Mars. Martian regolith contains iron oxide –that’s what gives it a reddish color – but Moon regolith is mostly silicates; it’s much finer and more angular. Researchers will need to learn how to use both types in a 3D printer. https://www.youtube.com/embed/J1TWlNWHrsw?wmode=transparent&start=0 See models of otherworldly habitats.

Applications on Earth

NASA’s Moon-to-Mars Planetary Autonomous Construction Technology program, also known as MMPACT, is advancing the technology needed to print these habitats on alien worlds.

Among the approaches scientists are now exploring: a regolith-based concrete made in part from surface ice; melting the regolith at high temperatures, and then using molds to form it while it’s a liquid; and sintering, which means heating the regolith with concentrated sunlight, lasers or microwaves to fuse particles together without the need for binders.

Along those lines, my colleagues and I developed a Martian concrete we call MarsCrete, a material we used to 3D-print a small test structure for NASA in 2017.

Then, in May 2019, using another type of special concrete, we 3D-printed a one-third scale prototype Mars habitat that could support everything astronauts would need for long-term survival, including living, sleeping, research and food-production modules.

That prototype showcased the potential, and the challenges, of building housing on the red planet. But many of these technologies will benefit people on Earth too.

In the same way astronauts will make sustainable products from natural resources, homebuilders could make concretes from binders and aggregates found locally, and maybe even from recycled construction debris. Engineers are already adapting the techniques that could print Martian habitats to address housing shortages here at home. Indeed, 3D-printed homes are already on the market.

Meanwhile, the move continues toward establishing a human presence outside the Earth. Artemis III, now scheduled for liftoff in 2027, will be the first human Moon landing since 1972. A NASA trip to Mars could happen as early as 2035.

But wherever people go, and whenever they get there, I’m certain that 3D printers will be one of the primary tools to let human beings live off alien land.

Sven Bilén, Professor of Engineering Design, Electrical Engineering and Aerospace Engineering, Penn State

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

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The Earth

How many types of insects are there in the world?

Published

1 day ago

April 12, 2025

The Conversation

insects — This is a close-up photo of an ordinary garden fly. Amith Nag Photography/Moment via Getty Images

Nicholas Green, Kennesaw State University Curious Kids is a series for children of all ages. If you have a question you’d like an expert to answer, send it to CuriousKidsUS@theconversation.com.

How many types of insects are there in the world? – Sawyer, age 8, Fuquay-Varina, North Carolina

Exploring anywhere on Earth, look closely and you’ll find insects. Check your backyard and you may see ants, beetles, crickets, wasps, mosquitoes and more. There are more kinds of insects than there are mammals, birds and plants combined. This fact has fascinated scientists for centuries. One of the things biologists like me do is classify all living things into categories. Insects belong to a phylum called Arthropoda – animals with hard exoskeletons and jointed feet. All insects are arthropods, but not all arthropods are insects. For instance, spiders, lobsters and millipedes are arthropods, but they’re not insects. Instead, insects are a subgroup within Arthropoda, a class called “Insecta,” that is characterized by six legs, two antennae and three body segments – head, abdomen and the thorax, which is the part of the body between the head and abdomen.

A diagram of an ant, pointing out various body parts, including the antennae, thorax and legs. — The mandibles of the ants are its jaws; the petiole is the ant’s waist. Vector Mine/iStock via Getty Images Plus

Most insects also have wings, although a few, like fleas, don’t. All have compound eyes, which means insects see very differently from the way people see. Instead of one lens per eye, they have many: a fly has 5,000 lenses; a dragonfly has 30,000. These types of eyes, though not great for clarity, are excellent at detecting movement.

What is a species?

All insects descend from a common ancestor that lived about about 480 million years ago. For context, that’s about 100 million years before any of our vertebrate ancestors – animals with a backbone – ever walked on land. A species is the most basic unit that biologists use to classify living things. When people use words like “ant” or “fly” or “butterfly” they are referring not to species, but to categories that may contain hundreds, thousands or tens of thousands of species. For example, about 18,000 species of butterfly exist – think monarch, zebra swallowtail or cabbage white. Basically, species are a group that can interbreed with each other, but not with other groups. One obvious example: bees can’t interbreed with ants. But brown-belted bumblebees and red-belted bumblebees can’t interbreed either, so they are different species of bumblebee. Each species has a unique scientific name – like Bombus griseocollis for the brown-belted bumblebee – so scientists can be sure which species they’re talking about.

This close-up of a dragonfly reveals its blue head, bulging compound eyes and black antennae. — This is what a dragonfly looks like up close. Dieter Meyrl/E+ via Getty Images

Quadrillions of ants

Counting the exact number of insect species is probably impossible. Every year, some species go extinct, while some evolve anew. Even if we could magically freeze time and survey the entire Earth all at once, experts would disagree on the distinctiveness or identity of some species. So instead of counting, researchers use statistical analysis to make an estimate. One scientist did just that. He published his answer in a 2018 research paper. His calculations showed there are approximately 5.5 million insect species, with the correct number almost certainly between 2.6 and 7.2 million. Beetles alone account for almost one-third of the number, about 1.5 million species. By comparison, there are “only” an estimated 22,000 species of ants. This and other studies have also estimated about 3,500 species of mosquitoes, 120,000 species of flies and 30,000 species of grasshoppers and crickets. The estimate of 5.5 million species of insects is interesting. What’s even more remarkable is that because scientists have found only about 1 million species, that means more than 4.5 million species are still waiting for someone to discover them. In other words, over 80% of the Earth’s insect biodiversity is still unknown. Add up the total population and biomass of the insects, and the numbers are even more staggering. The 22,000 species of ants comprise about 20,000,000,000,000,000 individuals – that’s 20 quadrillion ants. And if a typical ant weighs about 0.0001 ounces (3 milligrams) – or one ten-thousandth of an ounce – that means all the ants on Earth together weigh more than 132 billion pounds (about 60 billion kilograms). That’s the equivalent of about 7 million school buses, 600 aircraft carriers or about 20% of the weight of all humans on Earth combined.

For every person on Earth, it’s estimated there are 200 million insects.

Many insect species are going extinct

All of this has potentially huge implications for our own human species. Insects affect us in countless ways. People depend on them for crop pollination, industrial products and medicine. Other insects can harm us by transmitting disease or eating our crops. Most insects have little to no direct impact on people, but they are integral parts of their ecosystems. This is why entomologists – bug scientists – say we should leave insects alone as much as possible. Most of them are harmless to people, and they are critical to the environment. It is sobering to note that although millions of undiscovered insect species may be out there, many will go extinct before people have a chance to discover them. Largely due to human activity, a significant proportion of Earth’s biodiversity – including insects – may ultimately be forever lost.

Hello, curious kids! Do you have a question you’d like an expert to answer? Ask an adult to send your question to CuriousKidsUS@theconversation.com. Please tell us your name, age and the city where you live. And since curiosity has no age limit – adults, let us know what you’re wondering, too. We won’t be able to answer every question, but we will do our best. Nicholas Green, Assistant Professor of Biology, Kennesaw State University This article is republished from The Conversation under a Creative Commons license. Read the original article.