The inhabitability of the Martian environment presents significant colonization risks

Besides Earth, Mars is the only possibly habitable planet in our solar system

Sending humans to Mars in the following decades poses significant challenges, from the vast distance covered to get materials there to powering technology during weekslong dust storms. Research is ongoing to develop life support systems that can regenerate or recycle consumables.

Inhabiting Mars without terraforming might be accomplished with 'worldhouses'

A network of interconnected, airtight bubbles would require several orders of magnitude fewer materials than those required to re-establish the entire planet's atmosphere to resemble Earth. However, the whole network would be compromised by a single micrometeor impact that destroys the air seal.

Imagining the best places to live on Mars

Because conditions on Mars are pretty extreme for humanity, we tend not to think about living there, since everywhere on Mars feels a bit threatening. This imaginative essay uses current geographical knowledge of Mars to visualize what it would look like if humanity could alter its climate to make it widely habitable, a process known to sci-fi readers as terraforming. Given that transformation, where would the hottest neighborhoods be located?

Why extremophiles may play an important role in terraforming Mars

Possessing unique biochemicals that can detoxify extreme environments and resilience against the Martian surface that is lethal to humans, scientists are exploring whether colonies of these organisms can transform small areas of the Red Planet into future habitats for humans. Extremophiles may also be best equipped to serve as microscopic factories for the fabrication of essential polymers.

Particles found in Martian air pose significant risks to human lungs

Ultrafine dust, just 3 micrometers wide, is small enough to bypass lung defenses and enter the bloodstream, where its highly reactive chemicals can cause thyroid disease. Silica in the dust can also cause silicosis, a chronic and incurable lung disease.

NASA uses extreme Earth environments to prepare for space exploration

Analog missions in volcanic terrains and craters mimic Martian and lunar environments. Crew members operating in these missions, including at sites in Utah, Nevada, Arizona, and Hawai'i, test suits and specialized space instruments under simulated conditions.

Martian skies and sunsets resembled Earth's hundreds of millions of years ago

Evidence suggests that Mars has had a thicker atmosphere, which included greenhouse gases, and a magnetic field in its past, resembling Earth's current composition. After losing its magnetic field—the protection from solar wind—the atmosphere and its associated atmospheric phenomena gradually disappeared.

Mold growth in space raises the hypothesis of life being brought to Earth

Panspermia suggests that life could be carried throughout the cosmos by asteroids, comets, and other objects, but it requires organisms that can withstand the extreme cold of space travel, stellar radiation, lack of water, and intense heat of planetary impacts. The discovery of mold on the International Space Station and experiments showing it can withstand radiation in outer space-like conditions increase the plausibility of the hypothesis.

A prototype greenhouse for Biosphere 2 is now part of a test habitat for Mars

The Space Analog for the Moon and Mars combines the Test Module greenhouse with a workshop, kitchen, common area, sleeping quarters, and a yard that mimics lunar and Martian surfaces. A blind crew member in SAM’s first mission, Inclusion I, helped assess accessibility in potential future space habitats.

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,...

Stagnant lids found on Mercury, Mars, and the moon prevent tectonic activity

Unlike Earth’s lithosphere, which is composed of plates dragged by convection, the outer shells of observed terrestrial bodies in the solar system are not exposed to sufficient stress to be pulled apart. Earth is expected to develop a stagnant lid in about 1.45 billion years.

Tardigrades have not been shown to survive all space conditions at once

A 2007 mission launched several species into low-Earth orbit, exposing them to microgravity in temperature-controlled modules. Survivability rates were high for microgravity exposure alone, but plummeted when combined with exposure to the full UV spectrum and the vacuum of space.

Experts ponder nuclear rockets to send humans to Mars

Nuclear rocket technology might be the fastest, safest way to get to the red planet. But if NASA wants to go, it should start development now.

Explore a timeline of NASA's exploration of Mars

NASA has studied Mars extensively over 60 years using telescopes, orbiters, and rovers. From April 2021 to January 24, the Ingenuity helicopter completed its technology demonstration objective by flying more than 17 kilometers above the Martian surface.

How NASA plans to build a lunar base, from roads to habitats

The Apollo program aspires to return humans to the moon—and to build humanity's first permanent habitat on its surface. The project involves complex construction plans, including creating roads from moon dust, baking bricks to build habitats, and more.

There are no established minimum fitness standards for spaceflight

Microgravity is known to cause arterial hardening, bone weakening, and other health issues, but the novelty of space tourism and the minimal exposure time for suborbital trips have limited the number of research studies. Many companies have participants sign extensive waivers to bypass the requirement of specific medical standards.

Read the NASA overview of the results of Viking’s biological experiments on Mars

Three experiments on the Viking 1 and 2 landers searched for signs of metabolic activity in soil samples, indicating the presence of microorganisms. No definitive evidence of life was found in any experiment or lander imaging.

Earth is the only terrestrial planet with a magnetic field

Its magnetosphere emerges from a complex interior process of electrical conduction, heat, and motion known as the geodynamo. The magnetic field shields the Earth from unsafe cosmic radiation, providing one of the many conditions required for life.

Billionaires are racing to space to control future markets

Although different companies have described focuses ranging from luxury tourism to Martian space colonies, all are building infrastructure to capitalize on the shift away from government-only control and betting big on reusability and scale. By securing public contracts and subsidies, they aim to develop strategic partnerships toward dominance in low Earth orbit.

Viking mission planning director Gentry Lee (1942–) on getting to Mars

"We didn't know then what we know now, which is how tough it really is to land on Mars."

Tidally locked exoplanets experience extreme atmospheric temperatures

On worlds like WASP 76b, which orbits its host star approximately 3% the Earth-sun distance, temperatures on its day side can vaporize iron. Winds more than 14 times the speed of sound blow this material to its night side, where it condenses and falls as liquid metal.

As of 2025, humans have only dug 0.2% the way to Earth's center

The Kola Superdeep Borehole revealed two billion-year-old fossils and underground water, but the immense temperature and pressure prevented further tunneling. Beyond those depths, scientists know of Earth's interior by analyzing how seismic waves move.

Supersonic parachutes have allowed rovers to safely land on Mars' surface

The disk-band-gap parachute design was first developed for the Viking Project in the 1970s. Since then, it has been reinforced and uses stronger materials to handle larger payloads—including the 2020 Perseverance rover—landing it a world record.

Without greenhouse gases, Earth's average surface temperature would be below freezing

Atmospheric molecules that absorb and emit infrared radiation from the planet's surface effectively trap additional incident solar energy that would otherwise escape to space. Without the greenhouse effect, the planet's average surface temperature would be approximately -18 degrees Celsius (0 degrees Fahrenheit).

A scientist debunks theories for why aliens might invade Earth

While TV and films offer common tropes for why aliens would invade Earth, many of those reasons aren't actually feasible. For example, a species with technology advanced enough to allow it to travel between planets likely doesn't need to enslave flawed humans to carry out its labor.

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.

Massive 3D printers have been used to build homes by stacking layers of 'concrete toothpaste,' a fire-resistant material that effectively insulates against outside noise.

Scientists can determine Earth's past climate conditions by analyzing air trapped in microscopic bubbles within ice cores—columns of compressed snow layers that build up over hundreds of thousands of years.

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.

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.

Watch how deep-sea mining equipment collects and processes polymetallic nodules—metal-rich, potato-shaped rocks—from the ocean floor and creates environmentally damaging plumes of sediments.

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

Human-to-human transmission of hantavirus remains extremely rare, so the 2026 hantavirus cruise ship outbreak doesn't mean we're facing a COVID-style pandemic risk.

A 2019 Facebook event called on attendees to "Storm Area 51, They Can't Stop All of Us," resulting in countless memes, the creation of a music festival, and eventually the arrests of those who did try to approach the area.

The boiling temperature of water decreases with increasing elevation because the molecules need less energy to overcome the lower atmospheric pressure associated with thinner air.

The use of fungi to detoxify land and water—a process known as mycoremediation—has been used to clean up natural resources affected by the 2025 California wildfires.

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.

Discover the catastrophic consequences of a failure of the US electrical grid—something that is more likely than many Americans think.

Apeirophobia is an overwhelming fear of living forever, perhaps stemming from the brain's inability to conceptualize an infinite life.

Shooting stars, or meteors, are fragments of asteroids and comets that burn up as they enter Earth's atmosphere, creating streaks in the sky called meteor showers.

Children are now three times more likely to say they want to be a YouTuber when they grow up than an astronaut, with some even attending 'YouTube camps' that teach kids how to create content for the platform.

Poison ivy will likely become both larger and more resilient due to climate change.

While the sun's gravity keeps the planets in orbit, their gravity also pulls on the sun, causing it and everything else in the solar system to orbit around a mutual balance point called the barycenter—the true center of the solar system.

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

Louisiana's 'Cancer Alley' is infamous for having some of the highest industrial pollution, toxic air emissions, and cancer risks in the US.

Despite being favored by 87% of Americans, Congress does not have term limits.

Stanford built a Google Maps for the Roman Empire, revealing how much it cost to travel in the ancient world

About 2,000 US babies are born annually without some portion of their limbs, potentially leading to a lifetime of pricey prosthetics.

Take a 3D tour of the Hajj, Islam's annual pilgrimage to Mecca, undertaken by over 1.5 million Muslims.

American dance legend Martha Graham, sometimes called 'the Picasso of dance,' refused to perform at the 1936 Olympics in Berlin and conceived the piece 'Chronicle' in response to the experience.