Big Questions About Our Planet

It is healing. NOAA and NASA ranked the 2025 Antarctic ozone hole the fifth smallest since 1992, when the Montreal Protocol began to take effect, and the ozone layer remains on track to recover fully later this century.

Humanity has already moved one. NASA's DART spacecraft hit the asteroid moonlet Dimorphos in 2022 and shortened its orbit by 33 minutes and 15 seconds.

It won't. Apophis will safely pass close to Earth on April 13, 2029, and NASA is confident there is no risk of it impacting our planet for at least 100 years.

In early 2025 it briefly had a small chance of hitting Earth. More observations showed it poses no significant risk to Earth, and in 2026 NASA ruled out a Moon impact too.

NOAA says it plainly: when a coral bleaches, it is not dead. If the stress is not severe, corals have been known to recover.

NOAA's SOLAR-1 watches the Sun from about a million miles away and is a cornerstone of the U.S. space weather early warning system, delivering storm imagery to forecasters within 30 minutes of capture.

Agencies are acting. ESA guided its Aeolus satellite down in 2023 in the first assisted reentry of its kind, and ESA's Zero Debris approach aims to sharply limit new debris from its missions by 2030.

NASA says the wall isn't visible from the Moon, and is difficult or impossible to see from Earth orbit without high-powered lenses. Astronaut Leroy Chiao did photograph it from the International Space Station, but only…

NASA calls this "equal transit time" idea the most popular incorrect theory of lift. Air over the top of a lifting wing really moves much faster than that idea predicts.

At the space station's height, Earth's gravity is still about 90 percent as strong as on the ground. Astronauts float because they and their spacecraft are falling around Earth together.

Earth's tilted axis causes the seasons. In the Northern Hemisphere, winter actually comes when Earth is closest to the Sun.

NASA says "shooting stars" are meteors: bits of space rock that burn up as they enter Earth's atmosphere at high speed. If a piece survives the trip and lands on the ground, it's called a meteorite.

NOAA says it isn't a solid island. Much of the debris is small pieces of floating plastic that are hard to see, spread out by wind and waves.

NOAA says the ocean is blue because water absorbs the red part of sunlight, leaving the blue part for us to see. Floating particles can make it look green or red, and below about 3,280 feet (1,000 m) no sunlight reaches…

Ocean solutions that are working now: The Ocean Cleanup's systems and river Interceptors, 4ocean's cleanup crews, and Plastic Bank's recycling economy.

4ocean removes plastic from oceans, rivers, and coastlines with full-time cleanup crews, funded by products made from recovered plastic.

The Environment Agency – Abu Dhabi tracks more than 18.5 million mangroves planted across over 1,775 hectares with its new Mangrove Observatory.

More than 20 kelp farms grow ribbon, giant, bull and sugar kelp in Alaska's cold, nutrient-rich waters (Alaska Mariculture Alliance).

The Alaska SeaLife Center in Seward is a nonprofit aquarium and research center that rescues stranded marine animals and studies Alaska's marine ecosystems.

On 18 September 2026, Norway's government created the Andfjorden Marine Protected Area across Andøy, Harstad and Senja (Norwegian government).

Close to 4,000 robotic floats dive through the ocean and send back temperature and salinity data, free to everyone. The 3 millionth profile came in 2024.

A satellite system that tracks wildlife and ocean instruments from tiny transmitters, following more than 8,000 animals every month for conservation science.

A 2026 study of 28 atoll islands found that removing rats and restoring native plants boosts the seabirds, reefs and sand that help atolls keep up with rising seas.

A New York nonprofit restoring the harbor with oyster reefs, aiming for one billion oysters by 2030 (nonprofit figures).

River interceptors catch plastic in the rivers that carry most of it to the ocean. Each solution page lists its own sourced figures.

American Rivers has worked directly on more than 200 dam removals; in 2025 the U.S. removed 100 dams and reconnected more than 4,893 river miles.

In Oregon's Bridge Creek, beavers given simple dam starters raised juvenile steelhead survival 52% and production 175% (NOAA Fisheries).

Seoul removed an ageing road and elevated motorway that covered the Cheonggyecheon stream and restored it along a 5.84 km corridor through the city centre.

Since 1966, the Chesapeake Bay Foundation has worked to save the Bay and its rivers, adding more than 21 million oysters in fiscal year 2026 (CBF).

Two Elwha River dams came down between 2011 and 2014, and more than 20 million tons of trapped sediment flowed downstream to rebuild the river and coast.

FreshWater Watch trains citizen scientists to test rivers, lakes and ponds: 80,000+ datasets from 22,000+ volunteers (organization figures).

Free global river flood forecasts up to 30 days ahead, plus 4-month outlooks, from the Copernicus Emergency Management Service.

Lake plastic recovery: pulling submerged litter from freshwater lakes, scuba divers, Great Lakes capture technology, and ROV deep-water cleanup.

Each year, Adopt-a-Beach volunteers remove tens of thousands of pounds of litter from Great Lakes beaches, about 85% of it plastic.

Since 1994, Jordan's Royal Society for the Conservation of Nature has been restoring the Azraq wetland in the eastern desert (RSCN).

In 2000, the Chilika Development Authority opened a new mouth between India's Chilika Lake and the sea, and the lagoon and its fisheries recovered (CDA).

Clean Lakes Alliance works to improve water quality in Madison's Yahara lakes; it reports 81 monitoring stations and over $1.4 million in grants (its figures).

Clean Up the Lake removes submerged litter from freshwater lakes using scuba divers and volunteers, and GPS-pins, sorts and weighs every piece it finds.

The Great Lakes Plastic Cleanup captures plastic across the world's largest freshwater system using Seabins, drones, and beach robots.

Keep Tahoe Blue, the League to Save Lake Tahoe, has protected the lake for decades, and its volunteers picked up 1,330 pounds of litter after July 4, 2026.

Forest solutions: three trees for every one removed, native biodiverse reforestation, and large-scale European planting.

African Parks manages 24 protected areas in 13 countries, covering over 20 million hectares, in partnership with governments and local communities (nonprofit).

The Altyn Dala Conservation Initiative, led by ACBK, is restoring Kazakhstan's steppe, with the saiga antelope as its flagship (Altyn Dala).

Water breathed out by Amazon trees starts the rainy season two to three months before winds alone would bring it (NASA JPL).

Since 1875, American Forests has worked to restore U.S. forests, from big natural landscapes to city streets, with more than 63 million trees planted.

Captive breeding and reintroductions brought the Arabian oryx back, with about 1,000 in the wild by 2011 (IUCN).

Since 1972, the Arbor Day Foundation says it has planted more than half a billion trees, working in more than 60 countries (nonprofit figures).

Cool Earth gave 211 Indigenous people in three communities in Peru's central Amazon an unconditional basic income for two years (University of Bath).

Costa Rica's FONAFIFO pays the owners of forests and forest plantations for the environmental services they provide, under Forestry Law 7575 (FONAFIFO).

Eden: People+Planet restores landscapes with local communities, including a 394,000-hectare project in Tanzania's Rubeho Mountains (Eden).

Space is part of Earth’s environment. Solutions for orbit: active debris removal, sustainable in-orbit servicing and orbital data centers, each with sources.

Earth Observation solutions: NASA-ISRO NISAR, ESA Biomass, Tanager-1 methane detection and DSCOVR EPIC, measuring land, forests, leaks and ozone.

Planetary defense solutions: ESA Hera at the asteroid DART moved, NASA NEO Surveyor, Webb and asteroid 2024 YR4, and Jupiter, the natural shield.

From the first uncrewed test flight in 2022 to Artemis II, the farthest humans have traveled, and the Moon missions still to come.

ESA guided its retired Aeolus wind satellite down in the first assisted reentry of its kind, cutting the already low debris risk by a factor of 150.

JAXA's DAICHI-4 radar sees through clouds over a 200 km swath, continuing the radar record used for deforestation alerts.

ESA's Ariel will study the atmospheres of a thousand planets orbiting other stars, revealing what they are made of (ESA).

Astroscale inspects, services and removes debris in orbit: ELSA-d, ADRAS-J's 2024 close-up of an H-IIA upper stage, and ADRAS-J2, targeted for fiscal 2027.

Four robotic telescopes, two in Hawaiʻi, search the entire dark sky every 24 hours for asteroids that could hit Earth, so people can be warned.

Atmospheric drag is Earth's natural space debris removal: it pulls low-orbit junk down to burn up, faster when the Sun is active, but barely works up high.

After eight years in space, BepiColombo enters orbit around Mercury on 21 November 2026, the first mission to put two spacecraft there (ESA).

ESA's Biomass satellite, launched April 29, 2025, carries the first P-band radar in space, seeing through forest canopies to measure the carbon stored in trees.

Free, university-level STEM and aerospace learning in six languages. Start from first principles and work all the way to designing what flies, with every lesson tied to real work that helps people and the planet.

Our alignment; not reviewed by the standards bodies.

Our alignment; not reviewed by the standards bodies.

Our alignment; not reviewed by the standards bodies.

A printable one-page sheet for every solution: the Five W's, a kid-friendly summary, sources and three discussion questions.

Pick the door that fits you. Every path uses the same free guides, math pages, labs and calculators.

Find lessons, facts and activities on this site. SI answers only from Saving Planets pages and links the pages it used.

U.S. Next Generation Science Standards (NGSS) and Common Core.

A four-year aerospace and STEM study track with labs, quizzes and printable study guides. Start with General Chemistry I + Lab · All courses

College and university lessons with worked examples, auto-checked practice and instructor notes: 🎓 Learn: all tracks · Orbits Explained · Orbit Lab · How Flight Works · Aero Lab · Physics Explained · Physics Lab

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