Astronauts agree: The moon smells like gunpowder

Scientists determine the smells of objects in outer space

Using spectrographic techniques, scientists determine the chemical composition of planetary atmospheres, comets, and other objects in space. Combining these chemicals in labs on Earth has revealed locations in space that smell like nail polish remover, rotten fish, and urine.

Muted smell and taste in microgravity complicate meal enjoyment

Astronauts primarily consume freeze-dried meals, which are rehydrated with water recycled from urine and perspiration, directly from bags. Condiments and select cultural items from crew members can enhance the meal experience by boosting flavor. Many individuals report experiencing "food fatigue" due to a lack of fresh produce, limited menu variety, and lingering scents.

Spacecraft remnants and human waste left behind on the moon add to the trash in space

As more countries reach the moon with successful probe landings and unsuccessful crashes, more materials are left behind, adding to the amount of trash that needs to be retrieved. A United Nations treaty declared the moon a common heritage of humanity, exempting any one country from exclusive responsibility for cleanup.

Scientists used to speculate about life on the moon

In the 17th century, Galileo's observations suggested the moon could be inhabited, leading to fictional speculations about lunar life. In the 19th century, stories were published claiming the discovery of various creatures, including human bats. The Apollo missions in the 20th century explored the possibility of life there, but further exploration showed this idea to be less likely than before.

Apollo astronauts left items in the moon's 'toss zone,' including golf balls, family photos, and bags of human waste, to make room for lunar rocks.

The moon's little-known, incredibly thin atmosphere

Earth's colorless, lifeless moon is often portrayed as devoid of an atmosphere. However, this fascinating article describes the very thin layer of gases floating above the surface of our celestial neighbor, a layer so thin it's technically known as...

A history of water on the moon

Is there water on the moon? In 2020, NASA's SOFIA mission confirmed the existence of water on the sunlit area of the lunar surface. Early astronomers mistook the dark spots on the Moon for oceans, but they are actually plains of dark, lava-produced...

Why some people say the moon is made of cheese

Mental Floss digs into the history behind the fable, which dates back as far as the 1500s, when it was mentioned in "The Proverbs of John Heywood." Even NASA has gotten in on the joke, tweeting a (supposedly) doctored photograph showing the moon's expiration date.

The big problem with the story of the moon's origins

Physics simulations predict the moon should be made mostly of the planet that struck early Earth—but lunar rocks are chemically identical to Earth's own mantle. Every proposed fix to the giant impact hypothesis, from total vaporization to multiple smaller strikes, creates a new contradiction it can't resolve. Howtown takes a nerdy look at the question in this polished 20-minute video.

The origins of Neil Armstrong's moon landing quote is still debated

When Neil Armstrong stepped onto the moon on July 20, 1969, his first words, transmitted across the globe, became legendary. Decades later, historians still debate whether he meant to say "one small step for a man," and where the phrasing may have originated.

Simulating the moon's surface in the desert

And why is the next cohort headed there? The geological conditions in Flagstaff, Arizona, can easily echo those of the moon, making the area a prime spot to train astronauts. This article explains how scientists crafted these training grounds and why astronomers are drawn to the nearly century-old city.

The US once had a plan to nuke the moon

In the 1950s, the US considered detonating a hydrogen bomb on the moon as part of a Cold War show of force. Known as Project A119, the classified plan aimed to create a visible explosion from Earth to signal American dominance in the Space Race.

The most unique-smelling places on Earth

Have you ever picked a travel destination by smell? This Atlas Obscura piece cultivates a list of the most distinct-smelling spots in the world. Learn about these obscure scents to potentially book a trip to a spring that smells like rotten eggs, or a desert valley filled with frankincense trees.

Geological tremors on the moon provide evidence that it is shrinking

Apollo seismometers have collected moonquake data, which scientists have analyzed to map the moon's interior and reveal that fault slips producing tremors are the result of sublunar cooling and contraction. It also revealed that the moon's inner core is about 500 kilometers (311 miles) across.

An oxygen tank explosion forced Apollo 13 to abort its moon landing

The 1970 mission—intended to be the third lunar landing—forced astronauts Jim Lovell, Jack Swigert, and Fred Haise to focus solely on their survival. They engineered a makeshift filter to handle the carbon dioxide they produced, which exceeded the lunar module's capacity.

We don't know why astronauts get motion sick

Between 60% and 90% of astronauts get motion sick in space—and many also get motion sick during the first few days upon return. Motion sickness on Earth does not seem to correlate with whether or not astronauts get motion sick in space, so it's not possible to predict who will get ill.

Protecting astronauts against space radiation

Outside the protective atmosphere of Earth, astronauts are constantly bombarded by radiation, which, among other dangers, increases the risk cancer. While those of us on Earth can mitigate the effects of similar radiation by limiting exposure,...

Fear has a specific 'smell'—at least to machines

This excerpt from a Mythbusters episode takes on the smell-of-fear question, comparing the sweat composition of individuals exposed to snakes, rats, and scorpions with that of people exercising. Molecularly, the sweats are different to a gas chromatography machine, but to most noses would be indistinguishable.

Extraterrestrial volcanoes spew material present during their formation

Unlike Earth's volcanoes that release lava, cryovolcanoes on distant moons erupt cold jets of water, ammonia, and other light gases present during the formation of their host planet. The movement of internal heat produced during formation is thought to drive icy plume movement.

'On the return trip home, gazing through 240,000 miles of space toward the stars and the planet from which I had come, I suddenly experienced the universe as intelligent, loving, harmonious..'

-Apollo 14 astronaut Edgar Mitchell, in "The Way of the Explorer"

Understanding why suction cups rely on Earth's atmosphere to work

When pressed against a surface, air is squeezed out of a sealed volume, causing the internal pressure to drop below the surrounding atmospheric pressure, and this imbalance creates the "sticking." For this reason, astronauts do not use suction cups or related technologies to stay on spacecraft during spacewalks.

Watch the Space Olympics from the International Space Station

From "synchronized space swimming" to "weightless sharpshooting," crew members in 2021 competed in microgravity versions of events from the summer Games. The "lack-of-floor routine" featured mid-air gymnastics as astronauts floated through space station modules.

Space tourism rockets emit up to 100 times more CO₂ per passenger than airplanes

Rocket launches release significant amounts of water vapor, nitrous oxide, and rocket propellants, which generate greenhouse gases and air pollutants. High-altitude emissions can persist for years, affecting the ozone layer.

On average, people smell worse if they're sick

For a small 2014 research study, a panel was tasked with sniffing the smelly t-shirts of people who had been injected with a compound known to activate the immune system and those of controls without the shot. It found that those who were acting as if unwell (due to the injection) generally smelled worse. Subsequent work found that those who sniffed unpleasant odors had a mild immune response of their own—perhaps to protect them from disease. (Some users may experience a paywall.)

Ammonium may be the sixth basic taste

Researchers have proposed various candidates for the sixth official taste, including "fat." But research published in 2023 posits that ammonium should be considered the sixth taste since they found humans can apparently detect ammonium chloride, which the scientists describe as "bitter, salty, and a little sour." Detecting ammonia could be a survival mechanism to help detect when certain foods, including seafood, are no longer safe to eat. The work hinged on experiments with human cells exposed to ammonium chloride as well as rodent research.

Stars appear to twinkle because turbulence in the motion of molecules in Earth's atmosphere causes light to bend and wiggle rapidly on its way to the surface—a phenomenon called scintillation.

Ballistic experiments show that tardigrades are unlikely to be an alien species

Those fired from guns at speeds as high as 825 meters per second (1,845 mph) could be resuscitated after impact. Shock pressure from greater speeds tore apart the samples, suggesting they could not survive asteroid impacts if brought to Earth from outer space.

Before humans, the Soviet Union and the United States sent animals—including apes, dogs, and cats—to space during the Space Race.

While atoms are normally made of protons, neutrons, and electrons, exotic ones have been built with antimatter—alternate versions of normal matter that live for fractions of a second and are about a billion times as rare.

Learn more about the history of fireworks, which dates back to an accidental invention during an alchemist's quest for information about immortality.

An investigation suggests a Scottish island became awash in forever chemicals via seafoam and seaspray—raising questions about what that means for the safety of other coastal areas.

Astronauts have repaired genetic damage in space using CRISPR—a molecular tool that can make precise changes to DNA and is used in single-celled organisms to attack invasive viruses.

Explore our favorite visualization of the immense scale of space, from an astronaut to the size of the observable universe

Sunflowers have long been a symbol of nuclear disarmament because they can extract large amounts of radioactive cesium from soil.

SpaceX's S-1 or 'prospectus' revealed many previously unknown details about the company, including its unprofitability despite doing $18.7B in revenue in 2025, exactly how many voting shares Elon Musk will have in the company (roughly 85%), and more.

Browse a detailed visual analysis of over 200,000 similes—comparisons that often use 'like' or 'as'—from popular fiction to see how frequently writers the same idiomatic expressions.

The Mona Lisa's celebrity status and repeated restorations have obscured what made the painting so revolutionary for its time

One disco producer saw 'Star Wars' four times on its opening weekend and was so inspired that he recorded the album 'Star Wars and Other Intergalactic Funk,' which produced a chart-topping single.

When caught in the mouths of cardinal fish, seed shrimp release glowing, bioluminescent chemicals, which alert predators of the cardinal fish, prompting the shrimp's ejection.

A pickleball's loud 'pop' sound can reach 120 decibels, which is equivalent to a hammer hitting a nail

After her fellow cult members tried to kill her with an LSD-infused hamburger, one member of the Manson Family, the murderous cult led by Charles Manson, decided to testify against the group's leader.

Researchers believe the brain consolidates memories, processes emotions, and plans for the future during dream states

Tattoos remain visible on your skin thanks to immune cells called macrophages

Volcanoes 'die' when their supply of magma runs out, if they are shifted away from their underlying magma reservoir, or if they get clogged by collapsing or their magma cooling back into rock.

The price of gas is a composite made up of several different factors, with the federal gas tax making up less than 20% of what drivers pay at the pump.

Budweiser stores yeast derived from the original 1800s strain in a secret bunker, which only the Head of Yeast Management can access—not even the CEO

Abraham Lincoln was almost assassinated weeks before his inauguration as he traveled from Illinois to DC through Baltimore in 1861; it took two independent claims for Lincoln to be convinced the threat was real

Existentialist writer Jean-Paul Sartre coined the famous phrase 'Hell is—other people' in his play 'No Exit'

Lesser-known phobias include turophobia, or the fear of cheese, and nomophobia, the fear of being without your cell phone.

Poison ivy's characteristic rash is caused by an allergic response to an oily compound in the plant called urushiol.