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 This email address is being protected from spambots. You need JavaScript enabled to view it..

What is dark matter and what is antimatter? Are they the same or different? – Namrata, age 13, Ghaziabad, India

Imagine an epic video game with your favorite hero as a character. Another character is a mirror-image twin who shows up occasionally, exploding everything they touch. And, to add an extra level of difficulty, the game includes a mysterious hive of minions hiding at every corner, changing the rules of the game, but never showing themselves.

If you think of these characters as types of matter, this video game is basically how our universe works.

The hero is regular matter, which is everything we can see around us. Antimatter is the mirror-image explosive twin that scientists understand well but can barely find. And dark matter is the invisible minions. It is everywhere, but we cannot see it, and scientists have no idea what it is.

Despite having similar-sounding names, dark matter and antimatter aare completely different. Interestingly, physicists like me know exactly what antimatter is, but there is almost none of it around. On the other hand, we have no idea what dark matter is, but there is a lot of it everywhere.

Antimatter: The mirror-image twin

All the regular matter around you is made of basic building blocks called atoms. Atoms have positively charged particles called protons surrounded by tiny negatively charged electrons.

Think of antimatter as regular matter’s oppositely charged twin.

All particles, like protons and the electrons, have antimatter siblings. Electrons have positrons, which are anti-electrons, while protons have antiprotons. Antiprotons and positrons make up antimatter atoms, or anti-atoms. They’re like mirror images, but with their electric charges flipped. When matter and antimatter meet, they destroy each other in a flash of light and energy and vanish.

Luckily, antimatter is very rare in our universe. But some special regular matter atoms, such as potassium, can decay to produce antimatter. For example, when you eat a banana, or any food rich in potassium, you are eating tiny amounts of these antimatter-producing atoms. The amount is too small to affect your health.

Antimatter was discovered almost 100 years ago. Today, scientists can create, store and study antimatter in the laboratory. They understand its properties very well. Doctors even use it for PET scans. They inject tiny amounts of antimatter-producing atoms into your body, and as these atoms travel through your body, the scan takes pictures of the flashes of light from the annihilation of the antimatter and regular matter in your body. This process lets doctors see what is happening inside your body.

Scientists have also figured out that when the universe was born, there were almost equal amounts of matter and antimatter. They met and annihilated each other. Fortunately, just a tiny bit more regular matter survived to make stars, planets and all of us.

Dark matter: The invisible minions

Dark matter is far more mysterious. Have you ever spun very fast on a merry-go-round? If so, you know how hard it is to stay on it without getting thrown off, especially if you’re the only one on the merry-go-round.

Now imagine there are a bunch of invisible minions on that merry-go-round with you. You can’t see them and you can’t touch them, but they hold you and keep you from flying off as it spins super-fast. You know they’re there because the merry-go-round is heavier than it looks, and it is harder to push and get it spinning. The invisible minions don’t play or talk to anybody; they just hang around, adding their weight to everything.

About 50 years ago, astronomer Vera Rubin discovered a similar mystery in spiral galaxies. She looked at spinning galaxies, which are like cosmic merry-go-rounds, and noticed something strange: The outer stars in these galaxies were spinning much faster than they should. They should have gone flying off into space like sparks from a firework display. But they did not.

It was like watching kids on a merry-go-round move at incredible speed but somehow stay perfectly in place.

The only explanation? There must be a sea of invisible “stuff” holding everything together with their extra gravity. Scientists called this mystery material “dark matter.”

Since then, astronomers have observed similar strange behavior happening throughout the universe. Galaxies within large clusters move in unexpected ways. Light gets bent around galaxies more than it should be. Galaxies stick together far more than the visible matter alone can explain.

It is as if our cosmic playground has swings moving by themselves, and seesaws tipping with nobody visible sitting on them.

Dark matter is just a placeholder name until scientists figure out what it is. For the past 50 years, many scientists have been running experiments that are trying to detect dark matter or produce it in the lab. But so far, they have come up empty-handed.

We don’t know what dark matter is, but it’s everywhere. It could be unusual particles scientists have not discovered yet. It could be something completely unexpected. But astronomers can tell by observing how fast galaxies rotate that there is about five times more dark matter than all the regular matter in the entire universe.

Hello, curious kids! Do you have a question you’d like an expert to answer? Ask an adult to send your question to This email address is being protected from spambots. You need JavaScript enabled to view it.. 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.

Dipangkar Dutta, Professor of Nuclear Physics, Mississippi State University

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

For much of the 20th century, teaching was a stable, middle-class job in the U.S. Now it’s becoming a lot harder to survive on a teacher’s salary: Wages have been stagnant for decades, according to a study from the Economic Policy Institute, and teachers earn 5% less than they did a decade ago when adjusting for inflation.

That’s one reason why there’s a widespread teacher shortage, with tens of thousands of positions going unfilled. At the same time, according to a 2022 report from the Annenberg Institute at Brown University, there are more than 160,000 underqualified teachers in the classroom, meaning they don’t meet full certification or credentialing standards.

This issue has become particularly acute as housing costs have risen sharply across the country over the past decade. Why become a teacher if it means you’ll struggle to put a roof over your head?

In response, many states and cities, from California to Cincinnati, are exploring ways to attract and retain teachers by developing education workforce housing – affordable housing built specifically for public school teachers and staff to make it easier for them to live near where they work. In doing so, they seek to address aspects of both the teacher shortage and housing crisis.

Fertile land for housing

As professors of architecture and education and as directors of an urban teaching program at Miami University in Ohio, we work to make it easier for students to pursue teaching careers – and that includes addressing affordable housing issues in communities where they work.

A key element of this work involves collaborating with local education agencies to either build, subsidize or find housing for teachers.

Local education agencies are tasked with the administrative functions of a school district, and they often own large tracts of land.

This land can be used to build new school buildings or community health clinics. But it can also be used to build housing – a particularly attractive option in cities where land can be scarce and expensive.

California has been at the forefront of these efforts. The state’s school districts own more than 75,000 acres of potentially developable land. Meanwhile, more than one-third of the state’s public school employees are rent-burdened, meaning they spend more than 30% of their income on housing costs.

California’s Teacher Housing Act of 2016 set up a framework for local education agencies to build and develop housing on their land. Since then, education workforce housing complexes have been developed across the state, ranging from San Francisco’s Shirley Chisolm Village to 705 Serramonte in Daly City, California.

The nuts and bolts of education workforce housing vary.

It can be financed by traditional sources, such as private philanthropy and government funds. But it can also be funded through financial tools such as certificates of participation, which allow outside investors to provide funding up front and later receive a return on their investment through rental income.

In some cases, teachers are offered reduced rents for just a few years as they start their careers. In others, they’re given the opportunity to purchase their home.

Third party management companies often oversee the projects, since local education agencies usually aren’t interested in property management. This also reduces the potential for any direct disputes between employer and employee. Many programs require only that residents be employees of the school district when they enter the program, meaning if someone leaves their job, they will not be displaced.

In April 2025, UCLA’s CITYLab and the Center for Cities and Schools published a study highlighting some of the benefits and challenges of nine educator workforce housing projects built in California.

The complexes ranged in size, from 18 to 141 dwelling units, with heights that ranged from two to six stories. The researchers found that tenants were largely satisfied with their living situations: They paid rents at far below market rate, and they praised the apartment design. They also highlighted their shorter commutes.

From tiny homes to factory conversions

Since 2020, educator housing has been proposed or developed in Arkansas, Colorado, Florida, Nevada and South Carolina.

In Fort Stockton, a small, rural town in West Texas, the school district bought a motel in 2022 and converted it into teacher housing. In Arizona, the Chino Valley Unified School District built tiny homes for its teachers in 2023, renting them at US$550 per month.

In Baltimore, more than 775 teachers have recently been housed thanks to initiatives such as the Union Mill project, an 86,000-square-foot historic building converted into teacher apartments that range in price from $700 to $1200 per month.

Teacher housing does more than give educators an affordable place to live. It can forge lasting relationships. A recent assessment of teacher housing in Los Angeles found that the community spaces and programs offered on site strengthened bonds among the residents, leading to friendships and working relationships that lasted for years.

Building community in and out of the classroom

Here in Cincinnati, our own graduates now working in schools also benefit from affordable housing options.

Through a partnership between Miami University and St. Francis Seraph, early career teachers from our TEACh and Urban Cohort programs have access to affordable housing.

In 2024, the Archdiocese of Cincinnati converted an old church property in Cincinnati’s Over-the-Rhine neighborhood into teacher apartments, which recent graduates can rent at a reduced rate. Most young teachers otherwise wouldn’t be able to afford living in this area.

“I wouldn’t be able to spend my beginning years as an educator in the community without access to affordable housing,” Nicholas Detzel, a graduate teacher now living in the converted space, told us in an interview.

“Living in the community has been an amazing experience and helps you know your students on a completely different level,” he added. “It has also helped me relate to students about knowing what is going on in our community.”

Teachers like Detzel who live in Over-the-Rhine can walk or take public transportation to the local schools where they work.

Perhaps more importantly, they can better understand the world of their students. They can learn the streets that students avoid, the parks and community spaces that become popular after-school hangouts, and what community organizations offer summer programming. Ultimately, teachers grounded in the life of the community can build relationships outside of the walls of school that contribute to more trust in the classroom.

Providing affordable housing for teachers and staff also helps retention rates, particularly as many younger teachers leave the profession due to low pay and burnout.

Teacher housing programs are still in their infancy. There are roughly 3.2 million public school teachers nationwide, and there are probably fewer than 100 of these developments completed or in progress.

Yet more and more districts are expressing interest, because they help alleviate two major concerns affecting so many American communities: affordable housing and a quality education.

While the need for affordable housing spans both lower- and middle-class families, teachers or not, forging alliances between schools and affordable housing providers can serve as one path forward – and possibly serve as a model for other trades and professions.

Jeff Kruth, Assistant Professor of Architecture, Miami University and Tammy Schwartz, Director of the Urban Cohort, Miami University

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