A fossil mammal tooth smaller than a grain of rice does not announce itself loudly. It must be hard won from sediment and stone. Then, under a microscope, it reveals itself – no longer just a speck of blackness but a surface of cusps, ridges and worn edges.

It is a small object, easily missed. Yet five such teeth from northern Alaska, belonging to three newly discovered species of long-extinct rodent-like mammals, hold an unexpectedly large history: of polar environments, shifting continents, winter darkness – and of mammals moving through this world that was colder, stranger and more connected than we once imagined.

The fossil mammal teeth at the centre of my new study with US colleagues come from the Late Cretaceous Prince Creek Formation, around 73 million years ago. At that time, northern Alaska’s palaeolatitude was roughly 80-85°N (10-15° closer to the north pole than it is today).

Our discovery shows the Arctic was not simply a cold, lifeless edge of the Cretaceous world, but a place where mammals adapted, diversified, migrated and originated. It raises deeper questions about what it means for a species to be native to a place whose landscapes, climates and inhabitants are forever changing.

The Arctic is not an empty landscape now, and nor was it in the deep past. It was a distinctive and demanding biome, with months of winter darkness, freezing temperatures and strong seasonality.

Rivers crossed this landscape. Plants grew through the long light of summer. Dinosaurs lived and thrived there, and evidence suggests they reared their young in the Arctic. There was also a diversity of birds, fish and mammals: tenacious denizens of the polar dark.

The teeth we found

Finding miniscule fossil mammals is not the kind of palaeontology that begins with a spectacular skeleton weathering from a cliff. It begins with bulk sediment. Bags and buckets of it.

The material is dug out, washed, sieved through fine screens, dried, then meticulously sorted grain by grain beneath a microscope.

Mammalian palaeontology often depends on fragments: a tooth cusp, a root, a worn edge of enamel. It asks for patience more than drama. The field site may be remote, the landscape vast, but the discovery happens at the scale of a fingertip. It is an act of attention.

The five teeth described in our new study are multituberculates: a group of rodent-like mammals that lived alongside dinosaurs. They are the longest-lived mammal group to date, with a history spanning well over 100 million years. Our own species Homo sapiens, by comparison, is only a few hundred thousand years old.

But their success was not permanent. After surviving for longer than any other mammalian lineage, multituberculates eventually vanished, with their last representatives disappearing around the Eocene-Oligocene boundary, roughly 34 million years ago.

The teeth we found at Prince Creek represent three new species: Camurodon borealis, Kaniqsiqcosmodon polaris and Qayaqgruk peregrinus. The last of these sits especially close to the heart of the story.

Qayaqgruk peregrinus has close evolutionary affinities with a group of multituberculates discovered in Mongolia,, indicating that, many millions of years ago, these minute mammals moved between Asia and North America through a polar land corridor.

This was not the world of Pangaea, the single giant continent of earlier Earth history. By 73 million years ago, the continents were taking on more familiar shapes, but they had not yet settled into the map we know today.

North America was split by a shallow inland sea, and its far northwestern edge lay near northeastern Asia, creating a high-latitude corridor through which animals could move between continents.

The Arctic corridor itself was not unknown. Fossils of dinosaurs, birds and some mammals have shown that animals were migrating between Asia and North America during the Cretaceous.

But for multituberculates, the picture was much less clear. Their fossil record left open whether they crossed between the continents early and repeatedly, or only later in the Cretaceous. Qayaqgruk peregrinus helps close that gap.

Its name draws on the language of the Iñupiat, Alaska Native people, from the region where the fossils were found. Qayaq is a legendary Iñupiaq hero and wanderer whose journeys are told in The Epic of Qayaq.

Many of its Mongolian relatives carry the suffix -baatar, meaning hero in Mongolian, so the name also links its Alaskan discovery to its Asian evolutionary affinities.

Kaniqsiqcosmodon polaris is the oldest known member of the Microcosmodontidae family of multituberculates, suggesting this lineage, later known from North America, may have had a polar origin. Camurodon borealis represents the northernmost known occurrence of the North American family Cimolomyidae.

Five teeth are not a complete ecosystem, but they are enough to show these mammals were not occasional strays at the edge of their range. They belonged to the Arctic.

Surviving mass extinction

Survival in this environment was not a passive condition. Multituberculates survived through the end-Cretaceous mass extinction, 66 million years ago, when as much as 75% of all life on Earth went extinct, including the non-avian dinosaurs.

The adaptations that helped these ancient Arctic species live though deep winter cold, short dark days and seasonal scarcity may have given them advantages when the world’s ecosystems were devastated.

This is not to say the Arctic was a refuge in any simple sense. Evolution is rarely simple – it is full of bottlenecks and unexpected openings. But tiny mammals already adapted to seasonal scarcity may have carried some advantages into a disrupted world.

The Alaskan multituberculates did not belong to the Arctic because they had always been there, or because their lineages had never moved. They belonged because they were part of that ecosystem for a time: shaped by its dark, its cold, its flora, its fauna, its seasons and its routes of passage.

Fossils make this kind of belonging harder to define, but more interesting. They give the word indigenous, at least when we use it for species, a chronology: deep time shows that belonging is not always a matter of original presence, but of ecological participation across changing landscapes.

These five multituberculate teeth from the Prince Creek Formation are small enough to vanish in a pinch of sediment. Yet in their enamel are continents, seasons, darkness, ancestry and journeys.

They show that the ancient Arctic was not an evolutionary margin. It was a living biome, a passage between worlds, and part of the deep history of mammalian evolution.

Sarah Shelley, Post Doctoral Research Associate in Evolutionary Palaeobiology, School of Natural Sciences., University of Lincoln

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

Magnetic fields are a fundamental part of the universe. They govern how small particles – the building blocks of planets, stars, and ultimately galaxies – move through space.

We still don’t know how magnetic fields came to exist in the universe, but we do know they’re everywhere. Earth itself has a magnetic field that compasses and migrating birds respond to.

With radio telescopes, astronomers can use the light from distant galaxies to illuminate these otherwise invisible areas in space.

In our study, published today in Publications of the Astronomical Society of Australia, we’ve used Australia’s most powerful radio telescope to create the largest and most detailed map of cosmic magnetic fields ever made.

Giant batteries that control galaxies

Magnetic fields greatly vary across the universe. Extremely dense objects, such as neutron stars and black holes, have magnetic fields thousands of billions times stronger than Earth’s own.

In the space between stars we’ve also measured magnetic fields a million times weaker than Earth’s. Despite their weakness, we know these fields are incredibly important for controlling how galaxies evolve. They act like giant batteries and store huge amounts of energy, slowing down or even preventing the formation of new stars.

But to us, magnetic fields are invisible. To find them in space, astronomers are limited to using light from distant stars and galaxies. That’s because light is a wave of electric and magnetic fields (that’s where the “electromagnetic spectrum” gets its name).

As light travels across the universe, it interacts with any magnetic fields it passes through. This will twist the direction the light is waving – we call this “polarisation”. So, light waving up and down has a different polarisation to light waving side to side.

Astronomers can catch this polarisation, especially when looking at the sky in radio waves, which are part of the electromagnetic spectrum.

Seeing the invisible

Australian telescopes have been at the forefront of both radio astronomy and detecting magnetic fields since their first detection. Murriyang, CSIRO’s Parkes radio telescope, was the first to detect the twisting polarisation of light from magnetic fields beyond Earth in 1962.

Ever since, astronomers have been pushing to find more and more sources that show us this twisting light. With enough measurements, we can create a map of magnetic fields in the universe.

Each point in the map is an object detected by our telescope, and the object’s light has illuminated the magnetic fields between us and that distant source. The more sources we detect, the more detailed our map becomes.

The last large map of magnetic fields was made in 2009. It has not seen a true successor in the intervening 17 years, limiting the depth and scope of the inquiries astronomers have sought to answer.

Across different areas of the universe, including our own Milky Way galaxy, we’re yet to understand the full strength and structure of cosmic magnetic fields. Not only do we not know how they came to exist, we don’t know how they’ve changed across time since the Big Bang.

To begin solving these problems, we need a new class of radio telescope.

A telescope built for speed

Radio astronomy is currently undergoing a revolution as the SKA Observatory is being built in South Africa and Australia. In preparation, a generation of telescopes, known as SKA precursors and pathfinders, are already operating around the world.

The ASKAP radio telescope is one of these precursors. Located at Inyarrimanha Ilgari Bundara, the CSIRO Murchison Radio-astronomy Observatory on Wajarri Yamaji Country in Western Australia, it’s made up of 36 12-metre dishes. These dishes can each see a huge section of the sky at once, giving astronomers an ultrawide view of the universe.

The flagship project to make a map of the universe’s magnetic fields is known as the Polarisation Sky Survey of the Universe’s Magnetism (POSSUM).

In preparation for it, the telescope’s team produced the Rapid ASKAP Continuum Surveys (RACS). It’s like making an atlas of the universe. The most recent versions of these surveys have identified nearly 4 million distant galaxies, with about 2 million having never been seen before.

The magnetic sky

Our new map, called SPICE-RACS, has come from a collaboration between the two survey teams.

Our goal was to look towards every galaxy found by RACS, and observe the signs of changing polarisation caused by magnetic fields. Using the latest release of the survey, we found 350,000 galaxies of the original 4 million we could use for this.

Our collection of sources is nearly ten times larger than the previous largest, and five times larger than all observations ever combined together. As a result, we’ve obtained the largest and most detailed map to date.

The map has red colours showing magnetic fields pointing towards us, and blue pointing away, like the North and South of a compass. Most of the swirling and bubbly structure we can see is from our own Milky Way galaxy. In the fine details of the map are the signatures from even more distant parts of the universe.

The new map is already enabling new science around the world, and the data is publicly available to the research community online. In the future, we plan to combine all versions of RACS to create an even larger and more detailed map.

Meanwhile, the POSSUM project is expected to finish observations by 2030. The sharper magnetic map from this survey will open up a new window on distant cosmic magnetic fields, allowing us to see further back into the history of the universe.

Alec Thomson, SKA-Low Commissioning Scientist, Square Kilometre Array Observatory; and Affiliate, Space and Astronomy, CSIRO

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

Why do we dream? Vishnu, aged nine, Kerala

That’s a really interesting question, and people have been asking it for thousands of years. But it’s difficult to answer because dreams are difficult to study scientifically.

Think about it: how easy do you find it to remember your dreams every night? Not everyone can do this. If we can’t remember our dreams, we can’t study them.

Curious Kids is a series by The Conversation that gives children the chance to have their questions about the world answered by experts. If you have a question you’d like an expert to answer, send it to curiouskids@theconversation.com and make sure you include the asker’s first name, age and town or city. We won’t be able to answer every question, but we’ll do our very best.

Some ancient cultures like the Egyptians, the Greeks and the Romans believed that dreams were important messages from the gods. But even they could not agree about exactly where dreams come from, why they happen or what they might mean.

In the last 100 years, many scientists across the world have learned a lot about the science of dreaming. But even still, there is disagreement.

Some scientists think dreams have an important job, others do not. I’ll explain some of the most well-known ideas.

Around the year 1900, an Austrian psychologist (someone who studies how we think) called Sigmund Freud published an influential book called The Interpretation of Dreams. In it, Freud wrote about his experiences of talking to other people about their dreams (and his own dreams too).

He believed that dreams came from wishes or desires buried deep in the mind. He thought these wishes were usually transformed in some way to disguise them in the dream, as they could be quite scary or rude.

Freud would help people to work out what these hidden wishes and desires might be, so they could address them in waking life. He also wrote that dreams are a part of the process that helps keep us asleep, that dreams protect sleep from disturbances. And there is some evidence to support that idea.

Freud’s ideas had a great influence on thinking about dreams for many decades. But since Freud’s time, we have learned much more about how sleep works. And that has inspired new ideas about what dreams might (or might not) be doing.

In the 1970s, scientists like Allan Hobson started to reject Freud’s ideas about dreams, and suggested that perhaps dreams don’t do anything important. In Hobson’s view, dreams had no hidden meaning or function to them.

He thought they might just be random side-effects of chemical processes going on in the brain during sleep. It is one good explanation for why dreams often seem so strange. Hobson thought little bits and pieces of knowledge and imagination get activated and merge together meaninglessly.

But other scientists since then have noticed that not all dreams are strange. Many of them are in fact quite ordinary, and some have content that is important to the dreamer.

Perhaps you have dreamed about something that happened in your life recently, like a fun day out with your school friends or family, or maybe you dreamed you were in a film you watched the day before.

We often dream about things that had a significant effect on us in waking life, or are related to worries we carry with us. And this I think is the most important thing we need to realise: our dreams are connected with our waking lives.

Some scientists now believe that dreaming about these things might help us to process them, or give us new ideas about what to do in our waking life. This is still difficult to test though. Whether or not this is what dreams are really doing by themselves, you have the choice to look at your dreams and decide what new ideas you can draw from them.

Another interesting idea is that dreams evolved long ago to help us survive threats. A lot of people seem to report dreaming about being chased by monsters or dangerous animals. Maybe you have too.

Some scientists see this as evidence for a threat simulation system that emerged back when we were living in caves and had to hunt for our food while trying not to be hunted ourselves.

If we survive a threatening encounter in a dream, that could better prepare us for surviving real threats when we are awake. The problem with this idea though is that it is too dangerous to test properly.

Even if someone dreams about fighting a tiger, for example, scientists cannot then lock people in a cage with a real tiger and see how well they survive!

That’s one of the exciting things about being a scientist. There are still lots of questions to answer and we’re learning new things all the time.

Anthony Bloxham, Lecturer in Psychology, Nottingham Trent University

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

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.

Who invented the light bulb? – Preben, age 5, New York City

When people name the most important inventions in history, light bulbs are usually on the list. They were much safer than earlier light sources, and they made more activities, for both work and play, possible after the Sun went down.

More than a century after its invention, illustrators still use a lit bulb to symbolize a great idea. Credit typically goes to inventor and entrepreneur Thomas Edison, who created the first commercial light and power system in the United States.

But as a historian and author of a book about how electric lighting changed the U.S., I know that the actual story is more complicated and interesting. It shows that complex inventions are not created by a single genius, no matter how talented he or she may be, but by many creative minds and hands working on the same problem.

Making light − and delivering it

In the 1870s, Edison raced against other inventors to find a way of producing light from electric current. Americans were keen to give up their gas and kerosene lamps for something that promised to be cleaner and safer. Candles offered little light and posed a fire hazard. Some customers in cities had brighter gas lamps, but they were expensive, hard to operate and polluted the air.

When Edison began working on the challenge, he learned from many other inventors’ ideas and failed experiments. They all were trying to figure out how to send a current through a thin carbon thread encased in glass, making it hot enough to glow without burning out.

In England, for example, chemist Joseph Swan patented an incandescent bulb and lit his own house in 1878. Then in 1881, at a great exhibition on electricity in Paris, Edison and several other inventors demonstrated their light bulbs.

Edison’s version proved to be the brightest and longest-lasting. In 1882 he connected it to a full working system that lit up dozens of homes and offices in downtown Manhattan.

But Edison’s bulb was just one piece of a much more complicated system that included an efficient dynamo – the powerful machine that generated electricity – plus a network of underground wires and new types of lamps. Edison also created the meter, a device that measured how much electricity each household used, so that he could tell how much to charge his customers.

Edison’s invention wasn’t just a science experiment – it was a commercial product that many people proved eager to buy.

Inventing an invention factory

As I show in my book, Edison did not solve these many technical challenges on his own.

At his farmhouse laboratory in Menlo Park, New Jersey, Edison hired a team of skilled technicians and trained scientists, and he filled his lab with every possible tool and material. He liked to boast that he had only a fourth grade education, but he knew enough to recruit men who had the skills he lacked. Edison also convinced banker J.P. Morgan and other investors to provide financial backing to pay for his experiments and bring them to market.

Historians often say that Edison’s greatest invention was this collaborative workshop, which he called an “invention factory.” It was capable of launching amazing new machines on a regular basis. Edison set the agenda for its work – a role that earned him the nickname “the wizard of Menlo Park.”

Here was the beginning of what we now call “research and development” – the network of universities and laboratories that produce technological breakthroughs today, ranging from lifesaving vaccines to the internet, as well as many improvements in the electric lights we use now.

Sparking an electric revolution

Many people found creative ways to use Edison’s light bulb. Factory owners and office managers installed electric light to extend the workday past sunset. Others used it for fun purposes, such as movie marquees, amusement parks, store windows, Christmas trees and evening baseball games.

Theater directors and photographers adapted the light to their arts. Doctors used small bulbs to peer inside the body during surgery. Architects and city planners, sign-makers and deep-sea explorers adapted the new light for all kinds of specialized uses. Through their actions, humanity’s relationship to day and night was reinvented – often in ways that Edison never could have anticipated.

Today people take for granted that they can have all the light they need at the flick of a switch. But that luxury requires a network of power stations, transmission lines and utility poles, managed by teams of trained engineers and electricians. To deliver it, electric power companies grew into an industry monitored by insurance companies and public utility regulators.

Edison’s first fragile light bulbs were just one early step in the electric revolution that has helped create today’s richly illuminated world.

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.

Ernest Freeberg, Professor of History, University of Tennessee

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

Who invented art? – Grace, aged nine, Belfast, UK

Before we can answer this question, we need to think about another one: “what is art?” Art is something people make to share ideas or feelings. It can make others think or feel something too. Art can be many things including music, stories, paintings or drawings.

Cave paintings are often called the first art ever made. However, it’s possible the people who created the paintings thought of them as mysterious and powerful, quite different from art as we think of it today.

So who made them, why did they make them, and where can we find them? In a cave called Chauvet in southern France, archaeologists found drawings of animals such as woolly rhinos and mammoths that died out over 10,000 years ago. The people who made the drawings used black charcoal and red ochre – a colour made from crushed-up rocks that were chewed and spat into the artist’s hand, then pressed against the cave walls. Similar cave paintings have been found in Australia, India and Somaliland.

Curious Kids is a series by The Conversation that gives children the chance to have their questions about the world answered by experts. If you have a question you’d like an expert to answer, send it to curiouskids@theconversation.com and make sure you include the asker’s first name, age and town or city. We won’t be able to answer every question, but we’ll do our very best.

Some people think the cave paintings weren’t just for fun or decoration. They believe the drawings were supposed to be a kind of “magic”. By drawing animals like deer or bison, they argue, the person who made the picture (maybe a hunter) thought it would give them magical power over the animal they were hoping to catch.

Early thinking about art

A long time ago, a Greek thinker named Aristotle said that the point of art was to imitate the world around us. For him, art wasn’t just painting or drawing – it also included acting and even giving speeches. Because artists used their hands to make things, people thought of them like workers or craftspeople – similar to cooks, hairdressers, or blacksmiths.

In 13th- and 14th-century Europe, art was mostly connected to the church, and was made to help people feel closer to God. Artists were part of groups called guilds, based on the kind of work they did, and people saw them more as skilled workers than as creative individuals.

It wasn’t until the 15th and 16th centuries, known as the Renaissance in Europe, that artists began to see themselves as creators, not just craftsmen. A big change happened in 1436 when a man named Leon Battista Alberti wrote a famous book called On Painting, which claimed that art was just as important as poetry and science. His ideas had a huge effect in the city of Florence in Italy, where three very famous artists worked: Leonardo da Vinci, Michelangelo and Raphael.

People started to think more about artists as special individuals, which was shown in another important book, Lives of the Artists, written by Giorgio Vasari in 1550.

Art began to be divided into two groups. The first was called the “fine arts”, which included painting, sculpture and drawing. These were seen as more important because they expressed big ideas and emotions. The second group was called the “decorative arts”, like glass-making, wood-carving and book decorations. These were thought to be less important because they were more about looking nice or being useful.

Changing how people think about art

In the late 19th century, people started to like the decorative arts more, because artists wanted to focus on handmade things instead of factory-made items. But painting was still seen as the most important kind of art. Then, in 1914, a French artist named Marcel Duchamp changed how people thought about art.

He started using everyday objects and turning them into art just by choosing them and signing them. He called these “readymades”. His most famous one was called Fountain – it was actually a type of toilet (a urinal) that he signed with a fake name, “R. Mutt”, and tried to put in an art show in New York in 1917. Duchamp said that picking an ordinary object and calling it art was enough to make it art, because the artist made the choice.

Duchamp helped change art by showing that it isn’t just about painting or making statues – it’s also about ideas.

Today, many artists use their work to talk about important issues and to make people think. In this way, they are no different from the artists of the past – such as the first cave dwellers who exerted power over their prey, or Duchamp, who challenged the very meaning of art.

And so the answer to the question “who invented art?” is quite simple. Humankind invented art – from the moment we were able to trace a pattern in the sand, or transfer a simple idea to the wall of a cave.

Frances Fowle, Personal Chair of Nineteenth-Century Art, History of Art, University of Edinburgh

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

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.

Are there thunderstorms on Mars? – Cade, age 7, Houston, Texas

Mars is a very dry planet with very little water in its atmosphere and hardly any clouds, so you might not expect it to have storms. Yet, there is lightning and thunder on Mars – although not with rain, nor with the same gusto as weather on Earth.

More than 10 years ago, my planetary science colleagues and I found the first evidence for lightning strikes on Mars. In the following decade, other researchers have continued to study what lightning might be like on the red planet. In November 2025, a Mars rover first captured the spectacular sounds of lightning sparking on the Martian surface.

Lightning on Mars

On Earth, lightning is an electric discharge that begins inside big clouds.

But because Mars is so dry, it doesn’t have clouds of water – instead, it has clouds of dust. With little water to weigh down dirt on Mars, dust clouds can quickly grow into huge, windy dust storms a few times taller than Earth’s tallest thunderstorms.

When smaller dust particles and larger sand particles collide with each other while being whipped around by these storms, they pick up a static charge. Smaller dust particles take on a negative charge, while larger sand particles become positive. The smaller dust particles are lighter and will float higher, while the heavier sand tends to fall closer to the ground.

Because oppositely charged particles don’t like to be apart, eventually the energy building between the negative charges higher up in the dust storm and the positive charges closer to the ground becomes too great and is released as electricity – similar to lightning.

The air around the electricity rapidly warms up and expands – on Earth, this creates the shock waves that you hear as thunder.

Nobody has seen a flash of lightning on Mars, but we suspect it’s more like the glow from a neon light rather than a powerful lightning bolt. The atmosphere near the surface of Mars is about 100 times less dense than on Earth: It’s much more similar to the air inside neon lights.

Releasing radio waves

Besides shock waves and visible light, lightning also produces other types of waves that the human eye can’t see: X-ray and radio waves. The ground and the top of the atmosphere both conduct electricity well, so they guide these radio waves and cause them to produce signals with specific radio frequencies. It’s kind of like how you might tune into specific radio channels for news or music, but instead of different channels, scientists can identify the radio waves coming from lightning.

While nobody has ever seen visible light from Martian lightning, we have heard something similar to the radio waves created by lightning on Earth. That’s the noise that the Perseverance rover reported at the end of 2025. They sound like electric sparks do on Earth. The rover recorded these signals on a microphone as small, sandy tornadoes passed by.

Searching for Martian lightning

When my colleagues and I went hunting for lightning on Mars a decade ago, we knew the red planet emitted more radio waves during dust storm seasons. So, we searched for modest increases in radio signals from Mars using the large radio dishes that NASA uses to talk to its spacecraft. The dishes function like big ears that listen for faint radio signals from spacecraft far from Earth.

We spent from five to eight hours every day listening to Mars for three weeks. Eventually, we found the signals we were looking for: radio bursts with frequencies that matched up with the radio waves that lightning on Earth can create.

To find the particular source of these lightning-like signals, we searched for dust storms in pictures taken by spacecraft orbiting Mars. We matched a dust storm nearly 25 miles (40 kilometers) tall to the time when we’d heard the radio signals.

Learning about lightning on Mars helps scientists understand whether the planet could have once hosted extraterrestrial life. Lightning may have helped create life on Earth by converting molecules of nitrogen and carbon dioxide in the atmosphere into amino acids. Amino acids make up proteins, tens of thousands of which are found in a human body.

So, Mars does have storms, but they’re far drier and dustier than the thunderstorms on Earth. Scientists are continually studying lightning on Mars to better understand the geology of the red planet and its potential to host living organisms.

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.

Editor’s note: This story was updated on Jan. 27 to reflect the static charges of particles during a dust storm.

Nilton O. Rennó, Professor of Climate and Space Sciences Engineering, University of Michigan

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

Please can I ask how old is fire on earth, not tamed by people but since when has there been fire and flames on the planet.

Samuel, 5, London

You ask a very interesting question. For many years, scientists assumed that fire and humans were so connected that few of them gave any thought to what happened to fire before humans evolved.

Even now, after many years of research, you won’t find much information in books about ancient fire. Indeed, I first started to become interested in this question of fire in the geological past more than 50 years ago, but my work was largely ignored until recently.

Curious Kids is a series by The Conversation that gives children the chance to have their questions about the world answered by experts. If you have a question you’d like an expert to answer, send it to curiouskids@theconversation.com and make sure you include the asker’s first name, age and town or city. We won’t be able to answer every question, but we’ll do our very best.

Your question is important today as the Earth’s weather is changing quickly and we are seeing deadly wildfires around the world. Humans may have used fire for a long time but they have never been able to tame fire. The challenge for scientists at the moment is to work out which fires are caused by humans and which ones are natural. To do this, we need to understand ancient fire in the first place.

A lot of our knowledge comes from studies of charcoal found in rocks more than 350 million years old, in a period geologists call the Carboniferous Period. As I say in my book Burning Planet: The Story of Fire Through Time, charcoal preserves the detail of different parts of the plant charcoal is made from. If you visit a place where there was a recent fire that burned a lot of plants, or collect some charcoal from the remains of a bonfire and look at it under a magnifying glass you may be able to see some of this amazing detail.

Over many years I, together with my students at Royal Holloway University of London, have been collecting information on ancient charcoal to help us understand fires of the past.

The key to understanding when fire appeared on Earth comes from what we call the fire triangle and I have discussed this in my small book Fire: A Very Short Introduction.

The first side of the triangle is fuel. Fire needs plants to burn. So we would not expect to have fire on the Earth before plants evolved. Plants first lived in the sea and started to spread on to the land around 420 million years ago. So there couldn’t have been fire before then.

The second side is heat – we need heat or a spark to start the fire – and that in the ancient past would be lightning. There has always been lightning and we can see evidence of this from fused sand grains found in some ancient sediments.

Finally, we need oxygen to allow the burning process to happen, the same way we need oxygen to breathe. We know this from simple ways we might put out a fire. You can cover the flames to stop oxygen or use sand, water or other materials to cut off the oxygen from the fire. Today the air we breathe has 21% oxygen. But experiments have shown that if you reduce the level to below 17% fires will not spread.

And above 30% it would be hard to put out a fire as even wet plants can burn with that level of oxygen. That is also why no fire or smoking is allowed in hospitals where there is oxygen used for the patients.

The level of oxygen in the Earth’s air has changed a lot over time. Scientists have shown that around 350-250 million years ago was a time of high levels of oxygen between 23 and 30% in the atmosphere and a lot of fire.

Evidence of the first fires was around 420 million years ago from charcoal in sedimentary rocks. But plants were small and there weren’t many places on Earth where they could grow. That meant there weren’t many places fire could burn. It was not until around 350 million years ago that fires started burning in lots of places and burnt in some of the first forests to grow on Earth.

Another time period of high fire was between 140 and 65 million years ago when many of our famous dinosaurs such as triceratops and tyrannosaurus were living and also when flowers first appeared. Around 40 million years ago oxygen levels in the atmosphere stabilised to modern levels. Proper tropical rain forest spread widely. This probably made fire rarer as wet rain forests don’t catch alight easily.

But around 7 million years ago grasslands spread, and these were easily burned. The grass-fire cycle began. This is where regular fire kills the saplings of trees, stopping grasslands turning into forests.

It is into this fiery world that humans evolved around 1.5 million years ago.

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Andrew Scott, Emeritus Professor of Geology, Royal Holloway, University of London

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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 do people know their interests? For example, one person likes art and the other does not, but how and why does that happen? – Leia K., age 12, Redmond, Washington

Standing at 5 feet 3 inches tall and weighing 136 pounds, Muggsy Bogues did not fit the typical profile of a National Basketball Association athlete when he played professionally from 1987 to 2001. The average NBA player during Bogues’ rookie season was 6 feet 7 inches tall and weighed 208 pounds.

Despite that, Bogues had a successful NBA career, finishing among the league’s all-time leaders in career assists. He even made an appearance alongside Michael Jordan in “Space Jam.”

It’s true that a person’s DNA shapes their physical traits, which can influence what activities feel possible for someone. For example, Jérémy Gohier, the 7-foot-6 Canadian eighth-grader, towers over his peers, making basketball an activity that likely felt possible and worth trying early on.

But biology alone would not fully explain why Bogues developed a lasting interest in basketball. Given his small stature, it may have suggested the opposite.

Instead, Bogues was introduced to basketball early in his life and had opportunities to learn the game in ways that helped him feel capable. He credited his coach, Leon Howard, as someone who supported him and taught him the game. Those early experiences gave him confidence and made him want to continue playing.

Bogues’ story raises a broader question that extends far beyond the world of sports: How do people recognize what they are interested in, and what motivates them to keep pursuing an activity?

Based on my research and what I have observed when teaching students in my own classroom, I believe whether people decide to stick with an interest comes down to self-efficacy: A person’s belief in their ability to succeed at a specific task.

Experience builds confidence

Motivation to keep doing specific activities often grows from access to opportunities, encouragement from others and chances to practice and improve. Moments of success in a task or activity, known as mastery experiences, can help people believe in their abilities.

Albert Bandura, a social psychologist who proposed the concept of self-efficacy, also identified other factors that shape self-efficacy. These include encouragement from others, learning by watching others be successful, and a person’s psychological and emotional state – such as whether they feel energized and excited or tense and anxious.

Bogues likely experienced all of these while practicing basketball. He benefited from coaches who believed in him, from studying the game by watching others and from learning how to perform under pressure.

In my own research, I found that how confident teachers were with using classroom technologies varied depending on how much support and opportunity to learn they had. Those same factors often shape whether people feel capable enough to keep engaging with and being interested in an activity.

I have seen something similar in my almost 15 years of teaching students ranging from middle schoolers to 70-year-olds who decided to go back to school. When students struggle to get started on an assignment, they sometimes assume they are simply bad at it. However, once they take a small step and experience even minor success, their attitude often shifts to “I can do this,” which makes them more willing to keep going and ultimately end up liking the subjects.

This was even true in my own experiences as a student. When I took my first speech course as a high school senior at Missouri University of Science and Technology, I felt like a ball of nerves. I had no inkling I would one day enjoy being a professional communicator and return to this same institution decades later, winning awards and teaching speech and writing courses to students who seem just as nervous as I once was.

Embrace new opportunities

When people have new opportunities to discover what they can do, their small moments of success can help interests blossom into full-fledged passions.

If someone never gets the chance to experience early success and encouragement, they might disengage or lose interest in an activity over time.

But success does not always mean getting better at the activity itself.

People don’t have to be the best at whatever they become interested in it. Their interests may help them accomplish other goals such as stress relief or a sense of belonging. They may stay engaged not because they feel especially skilled in the activity, but because they believe it helps them reach these other goals that matter in their lives.

A specific activity may matter because it connects to someone’s life in personal ways. It might remind them of someone they love, offer an escape from a bad home life or help them make social connections. Even if people do not feel confident in the activity itself, they can still see it helping them reach these goals, which can be enough to keep them interested.

This is why it is important for people of all ages to try new things. Without access to basketball and training opportunities, Muggsy Bogues’ path might have looked very different. And if Bob Ross had not decided to take an art class while he was in the Air Force and continue practicing, the world may have never experienced “The Joy of Painting.”

Trying new things is the first step in developing interests. After that, having opportunities to build confidence and improve can help people sustain those interests for years to come.

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.

Greg Edwards, Adjunct Lecturer of English and Technical Communications, Missouri University of Science and Technology

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