In the late 1980s, NASA was looking for ways to purify the air in its space stations. They conducted a study to find the best plants for filtering toxins and converting carbon dioxide into oxygen.

In 1989, their results were published in a clean air study that provided a definitive list of plants that are the most effective at cleaning indoor air.

Which plants made the list?

NASA’s study recommended placing at least one plant for every 100 square feet of indoor space, whether at home or in the office. These are the plants that proved most effective.

1. Dwarf Date Palm

From the Arecaceae family.
assets.rebelmouse.io | From the Arecaceae family.

2. Boston Fern

From the Nephrolepidaceae family.
assets.rebelmouse.io | From the Nephrolepidaceae family.

3. Kimberly Queen Fern

From the Nephrolepidaceae family.
assets.rebelmouse.io | From the Nephrolepidaceae family.

4. Spider Plant

From the Asparagaceae family.
assets.rebelmouse.io | From the Asparagaceae family.

5. Chinese Evergreen

From the Araceae family.
assets.rebelmouse.io | From the Araceae family.

6. Bamboo Palm

From the Arecaceae family.
assets.rebelmouse.io | From the Arecaceae family.

7. Weeping Fig

From the Moraceae family.
assets.rebelmouse.io | From the Moraceae family.

8. Devil’s Ivy

From the Arum family.
assets.rebelmouse.io | From the Arum family.

9. Flamingo Lily

From the Arum family.
assets.rebelmouse.io | From the Arum family.

10. Lilyturf

From the Asparagaceae family.
assets.rebelmouse.io | From the Asparagaceae family.

11. Broadleaf Lady Palm

From the Arecaceae family.
assets.rebelmouse.io | From the Arecaceae family.

12. Barberton Daisy

From the Aster family.
assets.rebelmouse.io | From the Aster family.

13. Cornstalk Dracena

From the Asparagaceae family.
assets.rebelmouse.io | From the Asparagaceae family.

14. English Ivy

From the Araliaceae family.
assets.rebelmouse.io | From the Araliaceae family.

15. Varigated Snake Plant

From the Asparagaceae family.
assets.rebelmouse.io | From the Asparagaceae family.

16. Red-Edged Dracaena

From the Century Plant family.
assets.rebelmouse.io | From the Century Plant family.

17. Peace Lily

From the Araceae family.
assets.rebelmouse.io | From the Araceae family.

18. Florist’s Chrysanthemum

From the Aster family.
assets.rebelmouse.io | From the Aster family.

What’s in our air?

NASA’s interest in air-purifying plants wasn’t just a matter of aesthetics. The air inside space stations—and even many homes—is often laced with invisible chemicals that can pose serious health risks when inhaled in high concentrations.

Trichloroethylene – Found in printing inks, paints, lacquers, varnishes, adhesives, and paint removers. Symptoms associated with short-term exposure include: excitement, dizziness, headache, nausea, and vomiting, followed by drowsiness and coma.

Formaldehyde – Found in paper bags, waxed papers, facial tissues, paper towels, plywood paneling, and synthetic fabrics. Symptoms associated with short-term exposure include: irritation to the nose, mouth, and throat, and in severe cases, swelling of the larynx and lungs.

Benzene – Used to make plastics, resins, lubricants, detergents, and drugs. Also found in tobacco smoke, glue, and furniture wax. Symptoms associated with short-term exposure include: irritation to eyes, drowsiness, dizziness, headache, increased heart rate, confusion, and in some cases can result in unconsciousness.

Xylene – Found in rubber, leather, tobacco smoke, and vehicle exhaust. Symptoms associated with short-term exposure include: irritation to the mouth and throat, dizziness, headache, confusion, heart problems, liver and kidney damage, and coma.

Ammonia – Found in window cleaners, floor waxes, smelling salts, and fertilizers. Symptoms associated with short-term exposure include eye irritation, coughing, and a sore throat.

So whether you’re looking to freshen up your home, boost your indoor air quality, or simply add a little life to your space, NASA’s list offers a natural, low-maintenance solution. Just remember to choose pet-safe options if you share your space with furry companions. A few well-placed plants won’t just liven up a room—they might also help you breathe a little easier.

This article originally appeared last year.

  • ‘Star Trek’ and NASA have intertwined legacies – the show championed diversity and inspired generations of real space scientists
    Photo credit: NASAGene Roddenberry, second from right, and Star Trek cast members visit the Space Shuttle Enterprise in 1976 with NASA Administrator James C. Fletcher, left. NASA

    “Star Trek” began as a television series but grew into a cultural phenomenon.

    When it premiered in 1966, no one could have predicted that it would lead to more than a dozen spinoff shows, more than a dozen movies and one of the most enduring fandoms in popular culture.

    “Star Trek” is also unusual for its close connections to NASA, both in its storylines and in the real world. Decades of “Star Trek” adventures have ignited a love of spaceflight across generations, inspiring many who now work as space professionals.

    I’m a cultural anthropologist who studies why people work in space exploration. I’ve interviewed astronomers, engineers, flight surgeons and astronauts. Although I focus more on science fact than science fiction, I’ve noticed in my interviews how much the two threads intertwine.

    Because of this, I found myself at a “Star Trek” convention in early August 2026, just ahead of the show’s 60th anniversary on Sept. 8. The convention participants included people of widely different ages, appearances and identities. I was struck by just how much those gathered reflected the series’ values.

    When NASA met Star Trek

    In the original series, the show’s creator, Gene Roddenberry, came up with a philosophy held by the Vulcan people. He called it IDIC: infinite diversity in infinite combinations. It suggests that an ideal society is made up of many different types, all working together.

    It represented Roddenberry’s rejection of conformity. It also explained why the Enterprise crew included a Russian alongside Americans, and Black, Japanese and female characters all in positions of responsibility and authority. While many ordinary viewers absorbed “Star Trek’s” lessons of camaraderie and acceptance, those involved in real space exploration also took notice.

    A black-and-white photo of four characters wearing Starfleet uniforms, including two white men, an Asian man and a Black woman.
    The cast of ‘Star Trek: The Original Series’ included a diverse crew of characters. Walters Art Museum

    Roddenberry established relationships with NASA personnel in the early days of his series. NASA provided photographs of planetary bodies and advice about the realities of spaceflight, as well as stock footage and access to certain NASA facilities.

    Leonard Nimoy, who played the popular character Mr. Spock, was even brought to the National Space Club’s Goddard Memorial Dinner in 1967 as a special guest. Then-Vice President Hubert Humphrey gave the keynote speech. Afterward, though, it was Nimoy, not Humphrey, who found himself surrounded by the club’s members, including NASA employees, aerospace engineers, members of the military and government officials, all eager to meet the actor portraying the starship Enterprise’s first officer.

    The relationship between NASA and “Star Trek” benefited the show by legitimizing the series. It also helped NASA by publicizing its work and depicting a positive future where its efforts to land on the Moon would eventually lead to visits to distant worlds – and amazing scientific advances like the show’s transporter and warp drive.

    The connection between the space show and space agency was reflected in NASA’s decision to name its first space shuttle Enterprise, after some encouragement from the “Star Trek” fan community.

    Inspiring astronauts

    In 1977, actress Nichelle Nichols, who portrayed communications officer Uhura, was hired to recruit for NASA. The space agency had expanded its pool of astronauts to include scientists and other “mission specialists.” For the first time, an astronaut no longer needed to be a pilot to participate in a space mission.

    NASA selected its first Black astronaut candidates and its first female astronaut candidates in 1978. While this move toward inclusivity may not have been directly influenced by infinite diversity in infinite combinations, it was compatible with it. “Star Trek” inspired many of NASA’s future employees. In interviews for my book “The Ultraview Effect,” a quarter of the space professionals I spoke with mentioned “Star Trek” as an influence.

    A woman wearing a blue jumpsuit sitting in the pilot's chair in a space shuttle cockpit simulator
    Nichelle Nichols sits in the space shuttle simulator at the Johnson Space Center in March 1977. NASA

    An Apollo astronaut I interviewed, for instance, said he believed humans would eventually “be able to go anywhere in the universe, just like ‘Star Trek.’”

    A young engineer who had grown up in the 1990s told me his motivation came from the “opening line of ‘Star Trek’… to explore strange new worlds.”

    A space shuttle mission specialist emphasized Roddenberry’s decision to make the starship crew multicultural, explaining: “Today I look at the diversity of it … he was setting the stage back when it wasn’t acceptable [in order] to be acceptable!”

    A changing future

    That influence has accompanied a changing astronaut corps.

    Both the 2025 astronaut class, which for the first time included more women than men, and the crew of Artemis II, which sent the first woman, first Black astronaut and first Canadian on a lunar mission, resemble the future that “Star Trek” imagined.

    The “Star Trek” fans at the convention I attended were even more diverse. It was clear to me that Roddenberry’s “infinite diversity in infinite combinations” isn’t just a concept from the series, but something that has become a defining value of contemporary Trek fandom.

    A photo of space, with some bright spots representing nebulae, including a bright spot that looks like the disc-shaped hull of the starship Enterprise from Star Trek
    NASA’s Spitzer Space Telescope captured a region of the galaxy that looks a little like the USS Enterprise, which NASA highlighted in a news release in 2016. NASA/JPL-Caltech

    One such fan, Bjo Trimble, holds special status. She is credited with “saving ‘Star Trek’” when the series was almost canceled in 1968 after two seasons. Wearing a rainbow “IDIC” pin, she signed autographs at the SyFy Sistas booth, where T-shirts featuring Black “Star Trek” icons such as Uhura and Benjamin Sisko were on display.

    However, with the Trump administration’s recent orders to dismantle all of NASA’s diversity, equity, inclusion and accessibility programs and policies, institutional support for “Star Trek’s” vision of acceptance and inclusivity, which flourishes in its fan base, is being undone. This rollback occurred just as NASA’s crews were reaching new milestones in representing the diverse future that “Star Trek” has encouraged for decades.

    Sixty years later, some of the diverse future that “Star Trek” imagined has become part of everyday spaceflight. Other parts of that ideal remain unfinished.

    This article originally appeared on The Conversation. You can read it here.

  • Spanish zoo study suggests that giraffes can do basic math
    Photo credit: CanvaA study is showing giraffes could be using math.
    ,

    Spanish zoo study suggests that giraffes can do basic math

    These hoofed mammals can understand addition.

    The results of an experiment done in a Barcelona zoo suggest that giraffes are capable of doing basic mathematics.

    A group of researchers from the University of Leipzig, the Max Planck Institute for Evolutionary Anthropology, and the University of Barcelona published their study observing four giraffes at the Barcelona Zoo. The experiment involved the giraffes observing containers that had different amounts of carrot pieces inside.

    How did this experiment work?

    The researchers showed each giraffe the two yellow containers and the amount of carrots within each one. After a few seconds, they closed the containers, keeping the carrots out of sight. They then showed each giraffe a green container which had extra carrots inside. Researchers took the carrot pieces from the green container and placed them into one of the closed yellow containers. They then let each giraffe independently choose which of the two closed yellow containers they preferred, without them seeing the total number of carrot pieces within each box.

    The results found the giraffes would choose the container that had the most carrot pieces around 68% of the time. This suggests to the scientists that the giraffes were mentally adding the carrots up in each container before making their choice. After all, there have been past studies suggesting that other hoofed mammals, such as horses, had similar capability of basic quantity tracking.

    The researchers did the experiment again. Only this time they subtracted the amount of carrots in each container. The giraffes were mostly unsuccessful at finding the container with the most pieces. So while giraffes showed signs of knowing addition, they don’t quite process all forms of arithmetic.

    Math = Survival

    Scientists believe that this understanding of addition helped giraffes survive in the wild. They cite that acacia trees, a dietary staple for wild giraffes, can be spread far apart in Africa. Being able to figure out which area has the most trees and the most leaves can help them decide where to graze next.

    Giraffes also live in flexible groups that often change in size. One grouping can mix in with another group and then branch off or away. This means that the giraffes often have to keep track of those currently within their group and surroundings to survive.

    Can other animals do math?

    Giraffes are just the latest animal species known to have some form of mathematical skill. Chimpanzees displayed similar abilities to count as giraffes in a similar experiment that involved them picking the bowl with the most chocolate pieces rather than carrots. Chickens and black bears also showed aptitude in quantity tracking, too. 

    Scientists theorize that most of the animals that can do this basic math through evolutionary survival. After all, the animal that can deduce where more food is tends to live longer.

    One species that displays remarkable mathematical ability are Tunisian desert ants. An observation of their navigational skills of finding their way to food and back to their nest suggests they use the sun as a compass in combination with mentally keeping track of the number of steps they take in a three-dimensional space. In short, these desert ants possess basic geometric and trigonometry skills.

    While you wouldn’t want wild animals to calculate your taxes, it’s interesting to see how rudimentary math is a language that goes beyond species.

  • A bonobo’s make-believe tea party has scientists rethinking whether imagination belongs only to humans
    Photo credit: CanvaAn adorable baby bonobo.

    Childhood activities like playing house, superheroes and villains, the floor is lava, and the classic tea party all involve imagination. We create stories and worlds with rules and roles to play.

    Humans want to believe that our creativity and art make us unique. But a bonobo named Kanzi was part of research that has scientists wondering how different we really are. In three evolving experiments, Kanzi correctly identified pretend objects, demonstrating that he could understand and engage in make-believe situations.

    primate research, behavior, bonobo study
    Kanzi associates words and symbols with Sue Savage-Rumbaugh.
    Photo by William H. Calvin, Phd/ Wikimedia Commons (Cropped)

    Kanzi has a make-believe tea party

    Researchers developed a simple setup using cups, a pitcher, and actions that began as real pouring and gradually shifted into pretend play. The first experiment used real liquids. The second had a combination of real and pretend liquids. The final scenario had no real liquids and relied entirely on imagination.

    The scientists used gestures and make-believe to see if Kanzi would react differently depending on what he was being shown. He didn’t react the same way in each setup. His responses showed he was paying attention to more than just the objects, but also to the way the situation was presented.

    bonobo play, animal imagination, Kanzi bonobo, apes
    Kanzi participates in an indoor test.
    Photo by William H. Calvin, Phd/ Wikimedia Commons (Cropped)

    Animals engaging in fantasy

    The experiment revealed that non-human animals can understand and follow along with imaginary situations.

    “[It] shows that animals are capable of understanding pretence in a controlled experimental setting, which hadn’t been done before,” Dr. Amalia Bastos, first author of the research from the University of St Andrews, told The Guardian.

    Scientists involved in the research are careful about how they describe it. They don’t treat it as proof that bonobos imagine things the same way humans do. Instead, they suggest that animals are capable of responding to situations where meaning is implied rather than directly shown.

    Why scientists care about pretend play

    Albert Einstein, one of the greatest scientific minds in history, is often credited with the idea that logic gets you from A to B, but imagination can take you everywhere. This study suggests that the more we learn about animals, the more it seems the difference between us may not be as great as we once thought.

    Developmental research credits early social and cognitive growth in human children to imagining situations that aren’t physically present. A 2024 meta-analysis found that make-believe is not just entertainment but also directly linked to social understanding and real-world interpretation.

    Researchers now describe animal play as more flexible than once believed. A 2025 study of ravens revealed that play included the manipulation of sticks, stones, and other items, suggesting social awareness and responsiveness to context rather than simple instinctive behavior.

    Play and imagination may be versatile behaviors no longer seen as uniquely human traits. A broader cognitive toolkit shared across multiple species suggests the gap between humans and animals may be smaller than it once seemed. Things we’ve long believed to be uniquely human may instead exist along a spectrum of abilities expressed in different ways.

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