High Altitude

Have you ever read the directions on a box of cake mix? There are special instructions for high-altitude baking. Has anyone who visited the Rocky Mountains told you how hard it was to breathe there? Have you ever wondered why pilots who fly in high-flying planes wear breathing masks? In higher altitudes, reduced air pressure makes it harder for ...

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Benjamin Franklin, Science Founding Father

While popularly known for his role as one of the United States' founding fathers, Benjamin Franklin was also a renowned scientist who made a number of substantial contributions in the field of Earth ... Continue reading


What Is Reduction?

Long ago, in a laboratory far, far away...before the development of the atomic theory we now use, scientists believed in a principle called animism, and that the chemistry of different materials was ... Continue reading


A Humongous Fungus Among Us

Did you ever wonder what the world's largest organism is? If we had to guess, maybe we'd pick an elephant, a giant sequoia or a whale. Well, those choices would be wrong; this organism is actually a ... Continue reading


Let Go, Gecko!

Geckos are small, insect-eating, noisy lizards that live in many parts of the world. While geckos have become common pets, the way that they manage to stick to smooth ceilings has remained a mystery. ... Continue reading


Will the Sun Shine Forever?

SunLifetimeThe Sun is a huge nuclear furnace. It operates by converting hydrogen into helium. In this process, which is called nuclear fusion, it loses mass and produces energy according to Einstein's famous equation: E=mc^2. This energy is dissipated in the form of light that we see and heat that we feel. In addition, some of this energy comes as X-rays, and a host of accelerated particles.

Our Sun has been converting hydrogen into helium for approximately 4.5 billion years. During this period it has converted 25% of its total mass into helium. About 75% of its mass is still hydrogen, and a very small remaining fraction accounts for oxygen, carbon and other elements. Based on a crude extrapolation, one would think that everything would be just fine for at least the next 13.5 billion years; however this is not the case.

The latest estimates show that our Sun will start dying approximately 5 billion years from now. What will happen to it? It will first gradually become brighter; in 5 billion years it will be about twice as bright as it is today. Then the internal energy from the fusion will start decreasing as the hydrogen becomes scarce. Gravity will win and the Sun's core will collapse on itself. This collapse will produce enough heat that the outer layers will expand violently, engulfing Mercury, stripping Venus of its atmosphere and scorching Earth. After this transformation, our Sun will be known as a red giant.