Why Earth will be made uninhabitable by the sun far sooner than when the sun dies

What will happen and what will remain of the sun when it dies

Upon exhausting the hydrogen fuel in its core, gravitational pressure will collapse and heat up, causing a surrounding layer to become hot enough to fuse hydrogen and release energy that swells the outer layers. This will turn the sun into a red giant that will engulf Mercury, Venus, and (likely) the Earth. These outer layers will eventually be shed, leaving behind a white dwarf.

How the sun heats the Earth

We all know it: Without the sun's heat, the Earth would be uninhabitable. So how does it work? The sun fuses roughly 600 million tons of hydrogen every second, the energy from which bursts out into space—including toward our planet. Our atmosphere...

Replacing the sun with a black hole would quickly collapse life on Earth

A black hole of the sun's mass would only be six kilometers wide, but it would exert the same gravitational pull as the sun. This means the planets would keep their current orbits but no longer receive solar radiation.

Why Earth would become a more deadly environment without the ozone layer

The ozone layer blocks almost all of the sun's harmful, including dangerous UVC rays that can damage cells by breaking chemical bonds. Without it, rates of skin cancer, crop failures, oceanic die-offs, and widespread ecosystem collapse would increase significantly, making Earth largely uninhabitable.

Why Earth's atmosphere constantly loses the universe's lightest elements to space

The masses of hydrogen and helium are too small for these gases to be held by Earth's gravitational force, particularly when these atoms are given energy from collisions with high-speed particles from the sun. Although the planet loses a meter-wide balloon's worth of hydrogen every second, it will still take billions of years to exhaust the planet of this element.

Due to dark energy, the universe is expected to end as a dark, sparse place

While the sun is expected to continue shining for another five billion years, the expansion of the universe will cause nearby stars and galaxies to become ever more distant, until they are too far to observe. Once the last old, red, dim stars cool into darkness after trillions of years, the universe will settle into a state of eternal, dark emptiness.

Extremophiles were likely to have been Earth's first, and are expected to be its last, organisms

Their ability to survive in an enormous range of environmental conditions, including some resembling what has been modeled to have existed relatively shortly after Earth's formation, makes them the leading candidates for enduring the increasing solar intensity and the subsequent effects (e.g., zero-oxygen atmosphere, evaporated oceans) expected in the coming billions of years.

The lifetime of a star is determined by its initial mass

More massive stars burn through their fuel at ever-increasing rates, causing them to have shorter lifetimes than less massive stars, despite starting with more hydrogen to fuse. In clusters of stars that likely formed together, observing what mass stars are no longer fusing hydrogen estimates the age of the cluster.

Why it takes tens of thousands of years for light from the sun's core to reach its surface

Photons take about eight minutes to travel through empty space to Earth after leaving the sun's surface. However, traveling from the core to the surface involves these particles of light undergoing a random walk—scattering off charged particles deep in the sun like a pinball—causing a trip that is more than 200 times shorter to last as long as 170,000 years.

Learn about the sun's corona, which is nonlethal despite a temperature of millions of degrees

The outermost layer of the sun's atmosphere is best seen during a solar eclipse, when the moon blocks the much brighter (and significantly cooler) solar surface. Despite the high-energy particles in the corona moving fast enough to escape the sun's gravity and gradually become solar wind, their density is too low to contribute meaningfully to the region's overall radiation.

The sun is not as exceptional as once believed, but it remains rarer than most stars

Once believed to be the center of the universe, the sun is a G-class star, the same category to which about 6% of the Milky Way's stars belong. However, the sun is younger than 85%, more massive than 95%, and more metal-rich than about 93% of all stars. Unlike the sun, half of all stars also exist in multi-star systems.

Breaking down sunlight and why the sun appears yellow despite emitting green light the most

This peak intensity is produced alongside a spectrum of other colors, which, when combined, make the sun appear white in space. Since Earth's atmosphere scatters bluer and greener wavelengths of light more than red and orange wavelengths, sunlight reaching Earth's surface appears yellow, while the sky appears blue. (Some readers may experience a paywall.)

A modern-day version of the dinosaur-killing asteroid would kill billions of people

Such an asteroid would level Central America, trigger tsunamis, spark global fires, and plunge the planet into an artificial winter lasting over a decade. Bunkers would be insufficient for survival without years of provisions.

If the Earth stopped spinning, 85% of the world's population would experience supersonic winds

The planet's equator moves about 470 meters per second—over 1,000 miles per hour—and air there would continue moving at this speed for several minutes if the ground stopped rotating. These conditions would cause tsunamis, global storms, and fling debris fast enough to destroy nearly all human-made structures.

The impacts of the solar maximum on Earth, from telecommunications to auroras

During the peak of the sun's 11-year cycle, plasma emissions stronger than the average stream of particles from the sun can compress and distort the Earth's magnetic field, allowing auroras to be seen farther from the poles. Distortions in the ionized layer of Earth's atmosphere can also alter the path of communication transmissions through the air. (Some readers may experience a paywall.)

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.

Explore Earth's future climate under different levels of warming

An incredible interactive project showing how global warming is projected to affect the world, from temperatures to rainfall, droughts and flooding, and more.

Oceans absorb 90% of warming from greenhouse gases

Oceans are providing increasingly more energy to power hurricane intensity. Current projections show rapid intensification is becoming more common, increasing the likelihood of Category 4 and 5 storms.

The solar system formed between 4.5 and 4.6 billion years ago

Its age is best estimated by studying meteorites from the early formation period of the planetary system, including Erg Chech 002 (4.565 billion years old) and NWA 11119 (4.5648 billion years old). Solar analysis and stellar evolution models estimate the sun's age to be approximately 4.57 billion years.

Some online users believe gravity will 'switch off' for 7 seconds in August 2026

Conspiracy theorists believe NASA is preparing for the gravity blackout under a classified operation called "Project Anchor." They speculate that the purpose of the secret project is to test whether Earth can survive such an event. NASA has rejected the claim. Considering the physics of a gravity blackout, the outcome would likely be chaotic but not total destruction.

Why parts of the Earth are colder when the planet is closer to the Sun

The Earth orbits the Sun in an elliptical shape, and winter in the Northern Hemisphere occurs when the Earth reaches the point in its orbit closest to the Sun, known as perihelion. The lower temperatures result from the hemisphere tilting away from the Sun.

A magnitude 25 earthquake would release enough energy to destroy the sun

Since Richter and moment magnitude scales rank earthquake energies logarithmically, theoretical magnitude values can cover an enormous range with no upper or lower mathematical limit. A particle of dust drifting onto a table would have a magnitude of about -15.

By 2030, experts estimate a 1 in 1000 chance of a plane being hit by space debris

As more satellites and spacecraft are launched, the rate of space debris re-entering Earth's atmosphere, including those that do not burn up completely, increases. International space agencies and air traffic control systems will need to coordinate to develop standardized methods and technical solutions to prevent and minimize future crisis scenarios.

In 2018, SpaceX launched a Tesla Roadster into heliocentric orbit for publicity

As of February 2023, the vehicle and its mannequin driver—dubbed "Starman"—have completed three and a quarter revolutions around the sun. One paper estimated that the car has a 22% chance of crashing into Earth within the next 15 million years.

Inside the James Webb's amazing sun shields

The Webb team has stationed its mammoth observatory in solar orbit—and brought its instruments below 40 kelvins (minus 233 ºC). Remarkably, most of the cooling has been done passively, by shielding the telescope from the sun and letting physics take care of the rest.

How fusion—which releases energy when two lighter atoms combine to form a heavier atom—differs from fission

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.

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.

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.

Neutron stars, the remains of some massive stars after they explode in a supernova, are the densest directly observable objects in the universe.

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.

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

11 people died from firework injuries in the US in 2024.

After NASA's Voyager 1 captured Earth as a single pixel as it left the solar system in 1990, astronomer Carl Sagan used the image to reflect on humanity's fragility and the responsibility to protect 'the only world we've ever known.'

All rainbows are 'raincircles' caused by water droplets separating white sunlight into a spectrum of colors, but Earth's surface blocks the bottom half of the circle from our line of sight.

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

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

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.

Indefinite cloning of some endangered species may not sustain their longevity because cloning success rates decrease as genetic mutations accumulate.

Visualize the path of every solar eclipse from 1900 to 2099 and see what each looks like when observed from different locations on Earth.

Radioactive elements can introduce software errors because the ionizing radiation they produce can detach electrons from atoms, and computer code relies on the distribution of electrons.

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.

According to the physics of black holes, our 4D reality may be a hologram—a projection of information coded on a 2D surface on the edge of the universe.

Coral reefs get their colors from zooxanthellae—microorganisms that line corals' digestive tracts and provide them with sugars in exchange for a home within this protective tissue.

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.

While El Niño moves warm Pacific Ocean waters east along the equator, La Niña moves them west, shifting where rainfall will become more common for months.

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.

Before writing 'Walden,' transcendentalist Henry David Thoreau nearly burned down his hometown with a campfire that grew out of control.

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

Bone marrow (soft tissue found inside certain bones) generates roughly 500 billion new blood cells each day