The Nancy Grace Roman Space Telescope launched last Sunday aboard a SpaceX rocket from the Kennedy Space Centre in Florida. When it becomes operational early next year, it will transform our view of the universe.

With a mirror the same size as the one in the Hubble Space Telescope but a field of view over 100 times larger, NASA’s newest tool is designed to survey vast swaths of sky quickly. It will hunt for dark energy’s fingerprints and detect perhaps 100,000 exoplanets.

In August 2018, just four months before she died on December 25, I had the great fortune to fly from Sydney to Washington DC to interview the woman this telescope is named after. She was 93 years old and over the hours we spent talking, she shared with me her remarkable life story.

A childhood passion for the stars

Nancy Grace Roman was born on May 16 1925, in Nashville, Tennessee, and grew up captivated by the night sky. Her mother, Georgia Frances Smith Roman, encouraged this early curiosity, walking with her young daughter to point out constellations and the aurora borealis.

By age eleven, Nancy Grace – never Nancy! – had already organised an astronomy club among her classmates in Reno, Nevada, where the family briefly lived. By high school she had decided, against the advice of nearly everyone around her, that she wanted to become a professional astronomer.

That ambition ran headlong into the sexism of 20th century academia. When Nancy Grace asked her high school guidance counsellor for permission to take a second year of algebra instead of yet more Latin, the counsellor reportedly asked her, “What lady would take mathematics instead of Latin?” She took the maths anyway. She went on to Swarthmore College, where she earned a bachelor’s degree in astronomy in 1946, and then to the University of Chicago, where she completed a PhD in astronomy in 1949.

Her doctoral research focused on stellar dynamics and the motions of stars in the Milky Way, work that would foreshadow her lifelong interest in stellar populations and galactic structure.

After earning her doctorate, Nancy Grace remained at the University of Chicago and worked at the Yerkes Observatory, where she conducted research on stellar spectroscopy. This is the technique of spreading a star’s light into a rainbow and then analysing faint features in the spectrum.

She made a name for herself with a landmark 1955 paper demonstrating a correlation between a star’s motion through the Milky Way and its chemical composition. Younger, metal-rich stars tend to move in more circular orbits, while older, metal-poor stars follow more eccentric ones.

This finding provided important evidence for how galaxies like the Milky Way evolve over time. Despite this success, she recognised that as a woman in academic astronomy, she faced a ceiling on promotion and tenure that her male colleagues did not. So she began looking for opportunities elsewhere.

Taking on an extraordinary responsibility

In 1955, Nancy Grace took a position at the Naval Research Laboratory, where she worked on radio astronomy, a field still in its infancy. It was there that she gained a reputation not just as a skilled researcher but as an effective administrator and communicator of science. These skills would soon define the second, more consequential half of her career.

In 1959, Nancy Grace was recruited by the newly formed National Aeronautics and Space Administration to help build its space science program essentially from scratch. She became NASA’s first chief of astronomy, the first woman to hold an executive position at the agency.

It was an extraordinary responsibility. NASA had no established framework for space-based astronomy, and Nancy Grace was tasked with defining what such a program should even look like.

Nancy Grace’s most enduring legacy grew out of an idea she championed for decades (along with American astronomer Lyman Spitzer) before it became reality: a large space telescope that could observe the universe without the blurring and light pollution imposed by Earth’s atmosphere.

The project she nurtured through its most difficult years became the Hubble Space Telescope, launched in 1990. Because of her foundational role in conceiving, justifying, and organising the mission decades before it flew, Nancy Grace became widely known as the “Mother of Hubble”.

An extraordinary legacy

Beyond Hubble, Nancy Grace also helped establish several other NASA astronomy missions. These included the Orbiting Solar Observatory series and the Orbiting Astronomical Observatory, precursors that helped prove the value and feasibility of space-based observation.

She retired from NASA in 1979. She received numerous honours over her lifetime, including election to the National Women’s Hall of Fame and an asteroid, 2516 Roman, named in her honour.

In May 2020, NASA announced that its next-generation flagship observatory would be named the Nancy Grace Roman Space Telescope, making her one of the very few scientists honoured with a major space telescope named after them.

Nancy Grace’s career stands as a testament to persistence against institutional barriers and to the outsized impact that scientific vision can have. All astronomers continue to benefit from her extraordinary legacy.

Joss Bland-Hawthorn, Laureate Professor, Director of Sydney Institute for Astronomy, Faculty of Science, University of Sydney

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This is an article from Curious Kids, a series for children. The Conversation is asking kids to send in questions they’d like an expert to answer. All questions are welcome – serious, weird or wacky!

Why it is that the things close to the train windows zoom by really fast, but things further away seem to go by much slower? – Ada, age 7, Katoomba.

Superb question, Ada!

Things close to the train window seem to zoom by very fast because they appear much larger than things that are far away.

Imagine looking out of a window. Suppose you see a big tree, one that is 10 metres wide, far away in the distance. When you push your thumb against the window, you can cover the whole tree, even though the tree is much bigger than your thumb.

Now, imagine you have an ant on the nail of your thumb. As you have your thumb pressed against the window, the ant takes one second to walk from the left to the right of your thumbnail.

Now imagine at the same moment, a cat runs halfway across the 10 metre wide tree in the distance.

Even though the cat is faster than the ant (it has run five metres in one second), in your eyes, the cat seems to have only travelled half a thumb width in one second, while the ant has travelled one whole thumb width in one second. The ant seems to zoom by faster than the cat, even though in reality, it is much slower.

If you look at an aeroplane high in the sky, what you discover is even more fascinating. Imagine covering the image of the plane with your thumb as it zooms across the sky. The ant took one second to cross your thumb. The cat needed two seconds. The plane might need five seconds! So, the plane seems to be slower than both the ant and the cat, but we know that planes are in fact much faster.

Things appear to move slower when they are far away because they seem smaller, and take longer to cross our line of vision. Likewise, they appear to move faster when they are close by, because they seem bigger.

PS: You have the same first name as a very famous scientist! Ada Lovelace was one of the first people to think of how to design a computer. She was also one of the first to write computer programmes. This was super clever for someone born over 200 years ago, and her work has helped shape the world we live in today.

Hello, curious kids! Have you got a question you’d like an expert to answer? Ask an adult to send your question to us. You can:

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David Paganin, Adjunct Professor (Research) in Physics, Monash University

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This is an article from Curious Kids, a series for children. The Conversation is asking kids to send in questions they’d like an expert to answer. All questions are welcome – serious, weird or wacky!

Why do we count to 10? – Quentin, age 5, Randwick.

Counting is perhaps one of the oldest scientific operations still in use today.

From a young age we learn to count the numbers 0, 1, 2, 3, 4, 5, 6, 7, 8, 9. These are called the digits. But there is a problem with ten: we have to write it differently because we used up all our digits!

What do we do now?

We use two digits. The number 10 has a left digit “1” which has a new meaning. It represents the number of times we ran out of digits. The right digit “0” is the same as before and lets us continue counting again. Mathematicians call this a place-value number system, and counting in tens is called the decimal system. Australia and the UK use the decimal system to count money, distances and lots of other things we need to measure or count.

Machines also count, but not in tens.

Nature gave us ten fingers, and so it is natural for us to count in tens. But machines are built using switches, so it is natural for them to count only off (0) and on (1). This is like counting on one hand that only has one finger.

Machines count bigger numbers in the same way we do: by counting how many times they run out of digits. This system is called binary and the binary number 10 means the machine ran out of digits one time. A human would call this number two.

Today, these are the main ways of counting. But they are just two different ways of doing the same thing.

What about time?

The big hand of a clock has 60 different digits: 0, 1, 2, all the way up to 59. But what happens when we have used up all of those digits?

Like before, we count the number of times we run out digits, and we call each one an hour. Counting in this way is called sexagesimal.

But why do we use a different measurement for time?

We inherited the sexagesimal system from the Sumerians more than 4,000 years ago. It has lasted for so long because you can easily divide a number into two, three, four, five or six equal parts. Try dividing an hour into three equal parts and you will see there are 20 minutes each. Now try dividing a dollar into three equal parts and you will see there are 33, 33 and 34 cents each.

Our world uses many different place-value number systems, and they are all useful for different reasons.

Hello, curious kids! Have you got a question you’d like an expert to answer? Ask an adult to send your question to us. You can:

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Daniel Mansfield, Associate Lecturer in Mathematics, UNSW

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This is an article from Curious Kids, a series for children. The Conversation is asking kids to send in questions they’d like an expert to answer. All questions are welcome – serious, weird or wacky!

Where did the trees come from? - Grace, age 6, West Pymble.

Excellent question. It’s so good that we have to answer it in three parts.

The first part of the answer is that trees come from other trees!

Each tree starts as a dormant seed. That’s a fancy way of saying that the seed was asleep.

The seed starts to grow after it gets wet. It then can grow into a tree. If you want to know how this happens you can look at this article.

Trees make seeds, which can then grow into other trees. So each tree has a mother and a father, and the seeds are their babies.

Every seed is different

The second part of the answer is that not all seeds grow into trees. Some seeds grow into trees and other seeds grow into other kinds of plants. That’s because different kinds of plants make different kinds of seeds. The seeds of daisies can only grow into daisies, and the seeds of pine trees can only grow into new pine trees.

This is all because of an amazing chemical called DNA. DNA stands for deoxyribonucleic acid, but everyone just calls it DNA.

DNA is like a set of instructions that tells the seed how to grow and what kind of plant to grow into. Every person, every plant, and every animal has its own DNA that is just a little bit different from the DNA of any other plant or animal. That means that DNA gives every person, every animal, and every plant their own special instructions.

When a tree makes a seed, it does something really important. It puts some DNA into the seed. That DNA is almost the same as the DNA of the mother and father trees. That means that the seed will grow up into a tree of the same type as its mother and father.

Where did the first trees come from?

Each plant or animal has slightly different DNA from its parents. This is where we come to the third part of the answer: over long periods of time plants and animals can change, they evolve.

This might happen, for example, by a small plant making seeds with DNA that has instructions for growing bigger plants. Then those bigger plants do well and make more seeds. Some of these seeds have DNA with instructions for even bigger plants. This happens many times and eventually you can have big trees.

The very first plants on land were tiny. This was a very long time ago, about 470 million years ago. Then around 350 million years ago, many different kinds of small plants started evolving into trees. These made the first great forests of the world.

Since then, many different kinds of plants have evolved into trees. Here are some of them.

This is a giant sequoia - the biggest living thing on Earth. It is a type of tree called a conifer. Look how tall it is!

This one below is a tree fern. Most ferns are small, but some have evolved to become trees.

There are two very different kinds of trees in this next picture below. The two slender trees at the front are Kingia, which is a strange relative of palm trees. It lives in Western Australia. There are gum trees in the background as well.

We are so glad you are interested in trees. We really need to look after our trees because they help make clean air for us to breathe. Without trees, humans would be in a lot of trouble.

Hello, curious kids! Have you got a question you’d like an expert to answer? Ask an adult to send your question to us. They can:

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Greg Jordan, Associate Professor, University of Tasmania and Matilda Brown, PhD, University of Tasmania

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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.

Why does gravity pull us down and not up? - Gracie, age 9, Brookline, Massachusetts

Gravity is the reason things with mass or energy are attracted to each other. It is why apples fall toward the ground and planets orbit stars.

Magnets attract some types of metals, but they can also push other magnets away. So how come you feel only the pull of gravity?

In 1915, Albert Einstein figured out the answer when he published his theory of general relativity. The reason gravity pulls you toward the ground is that all objects with mass, like our Earth, actually bend and curve the fabric of the universe, called spacetime. That curvature is what you feel as gravity.

What is spacetime?

Before getting into the complicated world of gravity, you need to understand spacetime.

Spacetime is exactly what it sounds like: the three dimensions of space – length, width and height – combined with the fourth dimension – time. Using some very brilliant math, Einstein was the first person to realize that the laws of physics work in a universe where space and time are merged together.

What this means is that space and time are connected – if you move really fast through space, time slows down for you compared to someone who is moving slowly. This is why astronauts – who are moving very fast in space – age a tiny bit more slowly than people on Earth.

Matter makes gravity wells, not gravity hills

Remember, gravity is the idea that objects in the universe are attracted to each other because spacetime is bent and curved. When Einstein came up with general relativity, he showed that all stuff in the universe can curve spacetime – in physics terms that stuff is mass and energy.

Since your brain usually thinks about the world in three dimensions, it is really hard to think about the four dimensions of spacetime as a single idea. So to make it easier to visualize, imagine the surface of a trampoline. If there is nothing on it, it is flat. But if you stand on the trampoline, it stretches around your feet and creates a valley with you at the center. If there is a ball on the trampoline, it would roll toward your feet.

This is a two-dimensional example of how spacetime works. Your mass stretched the trampoline, creating what is called a gravity well that the ball rolls into. This is very similar to how the gravity of a heavy object – like the Earth – pulls things like you and me toward it.

To make things even weirder, since space and time are connected, time is also stretched by heavy objects!

The heavier you are, the steeper the sides of the trampoline well. That is why really massive things in the universe – like the Sun or black holes – have stronger gravity than Earth.

So why does gravity pull you down and not push you away?

Imagine someone went under the trampoline and pushed up. The ball would roll away! This would be a gravity hill, not a gravity well. As far as scientists know, matter – or stuff – always makes gravity wells and not gravity hills. Scientists can imagine things made of exotic matter or energy that would cause gravity to push you off into space, but so far, no one has found anything that could cause gravity to push you away from Earth.

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.

Mario Borunda, Associate Professor of Physics, Oklahoma State University

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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.

Why are planets round? – Daniel B., La Crosse, Wisconsin

The ancient Greeks proved over 2,000 years ago that the Earth was round and figured out how big it was by using simple observations of the Sun.

But how do people know this today? When you drop anything, gravity causes it to fall directly toward the center of the Earth, at least until it hits the ground. Gravity is a force that is caused by nearly everything that has mass. Mass is a measure of how much material there is in anything. It could be in the form of rocks, water, metal, people – anything. Everything material has mass, and therefore everything causes gravity. Gravity always pulls toward the center of mass.

The Earth and all planets are round because when the planets formed, they were composed of molten material – essentially very hot liquid. Since gravity always points toward the center of a mass, it squeezed the stuff the Earth is made of equally in all directions and formed a ball. When the Earth cooled down and became a solid, it was a round ball. If the Earth didn’t spin, then it would have been a perfectly round planet. Scientists call something that is perfectly round in all directions a “sphere.”

The gas cloud that the Earth was made from was slowly rotating in one direction around an axis. The top and bottom of this axis are the north and south poles of Earth.

Now, hold out your right hand. Point your thumb on your right hand straight up, and curl your fingers around the direction of rotation. Your thumb is pointing toward the North pole. The equator is defined as the plane, halfway between the North and South Poles.

If you ever played on a merry-go-round, you know that the spinning merry-go-round tends to throw you off. The faster it spins, the harder it is to stay on. This tendency to be flung off is called centrifugal force and pushes the mass on the equator outward. This makes the planet bulge at the equator.

The faster the spin, the more unround it becomes. Then, when it cools and hardens, it retains that shape. If a molten planet starts off spinning faster, it would be less round and have a bigger bulge.

The planet Saturn is very oblate – non-spherical – because it rotates very fast. Because of gravity, all planets are round, and because they rotate at different rates, some have fatter equators than their poles. So the shape of the planet and the speed and direction that it rotates depends on the initial condition of the material out of which it forms.

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.

James Webb, Professor and Director, Stocker AstroScience Center for Physics; Stocker AstroScience Center, Florida International University

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