Equinox derives from Latin for “equal night,” actually referring to equal length of day and night. It is not true that day and night are exactly the same length everywhere around the globe, but they are nearly. Read more
To humans, the sense of smell has a direct link to emotions. Who among us has not, at one time or another, had a memory and its associated feelings come rushing at us when catching a whiff of perfume, theater popcorn or one of thousands of smells that we associate with events from our past? Read more
Although detailed climate records exist for only 150 years or so, several Earth sensors keep records that allow us to infer past climate information. These “proxy climate data sources” substitute for actual weather instruments. Read more
Touch screens are everywhere: smartphones, laptop screens, supermarket checkouts, restaurant tills, ATMs, airport check-in kiosks, museum information booths and GPS devices, to name a few. Read more
The landscape is something we see every day. It is as familiar as a member of the family, yet we seldom think about how it got to be that way. Read more
Homo sapiens are fascinated to watch ourselves in mirrors, but we must watch others for models of how to behave. Read more
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The Pineapple Express, a local name for the atmospheric disturbance that drenches the U.S. West Coast, is one of several atmospheric rivers, a relatively narrow region in the atmosphere that is responsible for most of the horizontal transport of water vapor outside the tropics. Read more
Everybody knows what “greasy” means, even if only from that coating on your hands after downing a bucket of the colonel’s finest. But rendered animal fat is a different kind of grease from that used for lubrication. Read more
Sunlight is the primary illuminator. Its spectrum is a familiar rainbow with maximum emittance in a color that most of us would call yellow-green. Read more
Stars have an average lifetime of 5 billion years, so we obviously cannot study one from birth to death. Read more
There is a universe in a grain of sand. Three of the four known forces of nature combine to hold together the nuclei of atoms and their electron clouds. Contained within the atomic and crystal structure of the sand and all atoms are all of the forces that exist in the universe. Read more
Some say they have seen it, but most never have. Others say it does not exist, and yet others think they have seen it but really have not. Read more
Clouds have a dual personality. On one hand, they form beautiful piles of fluffy white cumulus, flat sheets of stratus and feathers of icy cirrus, all of which entertain with spectacular yellow, orange and red sunrises and sunsets. Read more
Carbon is undoubtedly the most important chemical element on Earth. It is the element of life, the source of most of the world’s energy, the basis of plastics and the major industrial pollutant in the atmosphere. Read more
Over the past 30 years, research has clearly identified the adverse health effects of trans fatty acids, most notably on coronary heart disease. Read more
The chance that any one of us will consume some fermented food or beverage today is 100%. That is to say, it is certain. Bread, cheese, yogurt, beer and wine, cured salami, cocoa and pickled foods such as sauerkraut and kimchi are some examples of fermented products. Read more
On June 8 people around the globe celebrated World Oceans Day. National Geographic magazine had a special reason for celebration: The frigid waters that flow around Antarctica have long been known as the Southern Ocean because its properties are relatively uniform throughout. Read more
When we hear the word “isotope,” most of us would think of radioactivity. Radioactive analysis is the most commonly known form of isotopic analysis, but it is only a part. Read more
Using nothing but a compass as a navigational tool, ancient mariners from China to Sumer navigated the world’s oceans. Even in the modern age of GPS, the magnetic compass is an unfaltering navigational tool for seagoing vessels, airplanes and hikers on the ground. Read more
Rock salt is a mineral, halite. It occurs in massive underground deposits on all continents. In its pure form it is sodium chloride, a crystalline substance composed of equal numbers of sodium and chlorine atoms. Read more
Thermonuclear reactions deep in the sun’s interior consistently generate the same amount of energy as 2.5 billion 500-megawatt generators, the largest on Earth. In one short second the sun produces enough energy to power New York City for 100 years. Read more
