Water is the substance that makes Earth unique in our solar system. While traces of water have been found elsewhere, no other planet or moon contains the abundance of liquid water as Earth does. Around 70% of our planet’s surface is covered by oceans, with additional freshwater found in lakes, rivers, and underground aquifers.
The chemical composition of water is remarkably simple: H₂O – two hydrogen atoms bonded to one oxygen atom. This molecular structure gives water unusual properties that make it essential for life. It can exist in three states (solid, liquid, and gas) within Earth’s temperature range, and it’s an excellent solvent, often called the “universal solvent.”
Humans need water to survive. The average adult body contains about 60% water, and we can only survive a few days without drinking it. According to the World Health Organization, access to clean water is a fundamental human right, yet billions of people still lack this basic necessity.
Climate change is affecting global water systems through altered precipitation patterns, increased evaporation, and rising sea levels. Scientists at the NASA Earth Observatory continue to monitor these changes to help predict future impacts on water availability.
Conservation efforts have become increasingly important as population growth places greater demands on freshwater resources. Simple actions like fixing leaky faucets, taking shorter showers, and using water-efficient appliances can help preserve this precious resource for future generations.
