THE CRA PERSPECTIVE • EARTH SCIENCE How Much Water Is There on Earth? Can our planet ever run out of water? Exploring Earth's enormous water reserves, the freshwater shortage and the future of humanity. Water is one of the most extraordinary and essential resources on our planet. Our planet is called the Blue Planet for a reason. Approximately 71% of Earth's surface is covered by water. But does that mean we have an unlimited supply of water for human survival? Look at the oceans, rivers, lakes, glaciers and countless streams across the world. Water seems almost endless. It falls as rain, flows through rivers, disappears into the ground, freezes into ice and rises into the atmosphere as water vapour. Yet billions of people experience water shortages. Some communities struggle to obtain safe drinking water, groundwater reserves are declining in several regions, and pollution is making important water sour...
Among the countless wonders of the cosmos, black holes stand as the most mysterious and fascinating. These cosmic giants are regions of space where gravity is so strong that nothing—not even light—can escape. For centuries, they remained in the realm of theory, but today, black holes are one of the most studied phenomena in astronomy, reshaping our understanding of the universe. 🌠 What Is a Black Hole? A black hole forms when a massive star reaches the end of its life and collapses under its own gravity. The core compresses into an infinitely dense point called a singularity , surrounded by a boundary known as the event horizon —the point of no return. Singularity: The central point of infinite density. Event Horizon: The “edge” of a black hole where escape is impossible. Accretion Disk: A ring of superheated gas and dust spiraling into the black hole. 🌀 Types of Black Holes Black holes are not all the same. Astronomers classify them into categories based ...