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. The green flash occurs in that fleeting, nearly subliminal instant just as the top of the sun dips below the horizon before the mind can really wrap around it.
It is a mystery whether Earth's water formed along with Earth or if it came after Earth formed. There is good scientific evidence for either scenario. Water is common in the universe. Telescopes have located spectral signatures of water in nebulae in distant reaches of the galaxy.
We've all heard of virtual reality, but virtual water is the current buzz phrase among water conservationists. According to the World Water Council, virtual water is the amount of water that is embedded in food or other products.
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.
There has been increasing discussion about preparedness in STEM subjects. The focus on science, technology, engineering and mathematics often drifts away from the central issues that subliminally affect all of us, specifically in mathematics.
According to J.L. Mero's 1965 book "Mineral Resources of the Sea," more than a trillion tons of manganese nodules on the floor of the Pacific Ocean comprised a virtually inexhaustible supply of manganese, cobalt, nickel and copper ores that was growing faster than it could be exploited.
One of the greatest quests of the new physics has been to reconcile quantum theory with general relativity. This situation parallels that of 17th-century scientists who were trying to reconcile the way things fell on Earth with the greater motions of the planets.
Acidic foods taste sour from vinegar, which is acetic acid; fruit acids, which contain citric and ascorbic acids; or carbonation. Acid in food rounds out the flavors, and it can make the difference between a bland dish and one with lots of taste.
No one knows what the universe was like before the Big Bang, what caused it or exactly how the process took place. We do know that the standard model is consistent with the astronomical evidence that the universe is expanding.
Atoms were ancient Greek philosophers' answer to the question, What happens if you could take a piece of matter and cut it in half, then again, halving it until it was reduced to the smallest possible size?
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.
There is a universe is 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.
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. The study of landscape and its formation is called geomorphology.
Got to have that morning rush, whether it is from coffee, tea, chocolate, a soft drink, energy drink or some other form of caffeine? You are not alone. In North America 90 percent of adults use caffeine. It is the most widely consumed psychoactive drug, yet it is legal and largely unregulated.
One hundred years ago Niels Bohr discovered the inner workings of atoms that finally convinced the scientific community of their existence after more than a century of discovery, denial and brilliant intuition.
Just in case you missed it, take note that the summer solstice occurred last night at 7:04 p.m. as the sun reached its northernmost point of 23.26 degrees latitude in its annual journey through the sky.
It was exactly 10 years ago, April 14, 2003, that the human genome project reported the first complete sequence of human DNA. Now the U.S. Supreme Court is hearing arguments over whether certain human gene sequences can be patented, a ruling that could affect how science and law intersect for years, if not decades.
For six millennia we humans have deliberately manipulated genes; modern corn is as distantly related to its wild ancestor as a Chihuahua is to a wolf. In 1944, American biologist Norman Borlaug began 30 years in Mexico developing new strains of wheat.
How long are your telomeres? A telomere shortening mechanism limits cells to a fixed number of divisions, and animal studies suggest that this is responsible for aging on the cellular level. In other words, it may be the mechanism that sets a limit on life spans.
Cobalt-60 is a common source of medical and industrial radiation. In medicine its primary use is in cancer radiotherapy. In industry it is used to test welds and casings and a variety of measuring instruments.
Which came first, the chicken or the egg? This is a very old question, and it seems at first to have no definitive answer. Many problems like this one are confusing because we look at them the wrong way or ask the wrong questions.
Nuclear radiation bombards us every day of our lives. Some comes from natural sources and some comes from human activity. Natural sources include cosmic radiation from space, unstable atomic nuclei produced by interactions of cosmic radiation with atoms in the atmosphere and radioactive decay of natural nuclides in Earth's crust.
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.
Before the development of magnetic resonance imaging, X-rays were the only way to image inside the body. X-rays are too energetic and show hard structures such as bones while they penetrate connective tissue and organs that show only as ghostly images.
Normally we think of an ecosystem in reference to the environment in which we humans live. From the perspective of a microscopic organism living inside us, however, the human body is the ecosystem and indeed the whole universe.
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.
Listening to commercials, one would think that chemicals are harmful and should be avoided. Ads for carpet cleaning, household products, toiletries, pet foods and other products claim to be chemical free.
Coral reefs are among the most complex ecosystems on the planet. Often called "rain forests of the sea," coral reefs occupy less than 0.1 percent of the world ocean surface. Their low abundance belies their great importance.
Behold the ubiquitous gecko climbing a vertical wall in the blink of an eye or scurrying across the ceiling in gravity-defying dashes. For at least 2,000 years people have wondered what made geckos' feet stick, because the footpads do not feel sticky to the touch.
Ocean thermal energy conversion (OTEC) as a means for generating electricity has been around for a long time. French physicist Jacques Arsene d'Arsonval proposed it in 1881. One of his students, Georges Claude, built a 22-kilowatt experimental system at Matanzas Bay, Cuba, in 1930.
The rare earths are a relatively abundant group of 17 elements that are so chemically similar that 15 of them occupy a single row and column in the periodic table. They occur as oxides, or 'earths' in the old chemical jargon, and they are not really so rare.