Quarks to Quasars

Space is not empty; it’s thought to be buzzing with “virtual particles” popping in and out of existence.

(Source: news.discovery.com)

The relatively small Halley’s comet weighs as much as 665 Empire State Buildings.

7 Myths and Facts about Chocolate

Whether you prefer a gooey chocolate truffle or a mug of hot cocoa, chocolate is the number one indulgence for most of us—especially on Valentine’s Day. But this indulgence comes at a price, right? After all, isn’t chocolate bad for us, full of caffeine and saturated fat? Not so fast—new research has shown that chocolate can be a part of a healthy diet after all.

Here are some common myths about this Valentine’s Day (or any day) treat, along with the facts to set the record straight.

Myth: Chocolate is high in caffeine. 
Fact: While eating chocolate may perk you up, chocolate is actually not very high in caffeine. A 1.4-ounce chocolate bar or an 8-ounce glass of chocolate milk both contain 6 mg of caffeine, the same amount as a cup of decaffeinated coffee. (For reference, regular coffee contains about 65-135mg of caffeine.)

Myth: Chocolate is loaded with saturated fat and is bad for your cholesterol. 
Fact: Stearic acid, the main saturated fat found in milk chocolate, is unique. Research has shown that it doesn’t raise cholesterol levels the same way that other types of saturated fats do. In fact, eating a 1.4 ounce chocolatebar instead of a carbohydrate-rich snack has been shown to increase HDL (good) cholesterol levels.

Myth: Chocolate lacks any nutritional value. 
Fact: Chocolate is a good source of magnesium, copper, iron and zinc. It also contains polyphenols (an antioxidant also found in tea and red wine) that have been associated with a decreased risk of coronary disease. An average chocolate bar contains about the same amount of antioxidants as a 5-ounce glass of red wine.

A daily serving of dark chocolate, which contains more antioxidants than milk chocolate, can also help lower blood pressure and improve insulin resistance according to a joint study between Tufts University in Boston and the University of L’Aquila in Italy. The findings do not suggest that people with high blood pressure consume dark chocolate in lieu of taking their prescribed medication, but that the flavonoids in dark chocolate may have a positive effect on blood pressure and insulin resistance. Learn more about the health properties of chocolate.

Myth: Chocolate causes cavities. 
Fact: Candy alone is not responsible for cavities. Cavities are formed when bacteria in the mouth metabolize sugars and starches from any type of food (soda, candy, juice, bread, rice and pasta) to produce acid. This acid then eats through the enamel of the tooth, causing a cavity.

The protein, calcium and phosphate content of milk chocolate may actually protect tooth enamel, and its naturally-occurring fat content means that chocolate clears the mouth faster than other candy, reducing the amount of time its sugars remain in contact with tooth surfaces.

Regular fluoride use, proper oral hygiene to remove fermentable carbohydrate residue and the application of plastic sealants can all help prevent the formation of cavities—whether you avoid chocolate or not.

Myth: Chocolate causes headaches. 
Fact: While sited as a common cause of migraines, a study by the University of Pittsburgh has shown no link between chocolate and headaches. The results of that double-blind study of 63 participants known to suffer chronic headaches were published in the neurology journal Cephalalgia. Chronic headaches were once thought to be caused by amines in foods (including histamine and beta-phenylethylamine) such as cheddar cheese, peanuts, cured meats, chocolate and alcohol, but this study eliminated chocolate as a possible headache cause.

Myth: Chocolate causes acne. 
Fact: Regardless of what your parents or grandparents may still say, studies in the past twenty years have eliminated chocolate as a cause of acne. In fact, many dermatologists doubt that diet plays any significant role in the development of acne. Acne is now believed to be caused by a combination of high bacterial levels and oil on the skin. For more information about the causes and treatment of acne, click here.

Myth: Chocolate causes weight gain. 
Fact: Any food can be part of a healthy diet if consumed in moderation. An average chocolate bar contains 220 calories, which is low enough to be a part of a weight control diet if other high-calorie foods are eliminated. Enjoying the occasional piece of chocolate may reduce the risk of severe bingeing, which can occur when you feel deprived of your favorite foods.

Chocolate’s bad reputation is slowly changing and research now shows that chocolate can be a part of an overall healthy lifestyle, when consumed in moderation. If you keep your portion sizes small and select dark chocolate whenever possible, the occasional treat can be a guilt-free part of your diet.


Ten things you probably didn’t know about Caterpillars

1. A caterpillar has just one job – to eat. 
During the larval stage, the caterpillar must consume enough to sustain itself into adulthood. Without proper nutrition, it may not have the energy to complete its metamorphosis, or may be unable to develop eggs as an adult. Caterpillars can eat an enormous amount during a life cycle stage that typically lasts several weeks. Some consume 27,000 times their body weight during this life phase.

2. Caterpillars increase their body mass by as much as 1,000 times or more.
The larval stage of the life cycle is all about growth. Within the span of a few weeks, the caterpillar will grow exponentially. Because its cuticle, or skin, is only so pliable, the caterpillar will molt multiple times as it gains size and mass. The stage between molts is called an instar, and most caterpillars go through 5-6 instars before pupating.

3. A caterpillar’s first meal is usually its eggshell.
In most cases, when a caterpillar ecloses (hatches) from its egg, it will consume the remainder of the shell. The outer layer of the egg, called the chorion, is rich in protein, and provides the new larva with a nutritious start.

4. A caterpillar has as many as 4,000 muscles in its body.
That’s one seriously muscle-bound insect! By comparison, humans have just 629 muscles in a considerably larger body. The caterpillar’s head capsule alone consists of 248 individual muscles, and about 70 muscles control each body segment. Remarkably, each of the 4,000 muscles is innervated by one or two neurons.

5. Caterpillars have 12 eyes.
On each side of its head, a caterpillar has 6 tiny eyelets, called stemmata, arranged in a semi-circle. One of the 6 eyelets is usually offset a bit, and located closer to the antennae. You would think an insect with 12 eyes would have excellent eyesight, but that’s not the case. The stemmata serve merely to help the caterpillar differentiate between light and dark. If you watch a caterpillar, you’ll notice it sometimes moves its head from side to side. This most likely helps it judge depths and distances.

6. Caterpillars produce silk.
Using modified salivary glands along the sides of their mouth, caterpillars can produce silk as needed. Some caterpillars, like gypsy moths, disperse by “ballooning” from the treetops on a silken thread. Others, such as eastern tent caterpillars or webworms, construct silk tents in which they live communally. Bagworms use silk to join dead foliage together into a shelter. Caterpillars also use silk when they pupate, either to suspend a chrysalis or to construct a cocoon.

7. Caterpillars have 6 legs, just as adult butterflies or moths do.
But wait! There are way more than 6 legs on most caterpillars you’ve seen, right? Most of those legs are false legs, called prolegs, which help the caterpillar hold onto plant surfaces and allow it to climb. The 3 pairs of legs on the caterpillar’s thoracic segments are the true legs, which it will retain in adulthood. A caterpillar may have up to 5 pairs of prolegs on its abdominal segments, usually including a terminal pair on the hind end. The

8. Caterpillars move in a wavelike motion, from back to front.
Caterpillars with a full complement of prolegs move in a fairly predictable motion. Usually, the caterpillar will first anchor itself using the terminal pair of prolegs, and then reach forward with one pair of legs at a time, starting from the hind end. There’s more going on than just leg action, though. The caterpillar’s blood pressure changes as it moves forward, and its gut, which is basically a cylinder suspended inside its body, advances in sync with the head and rear end. Inchworms and loopers, which have fewer prolegs, move by pulling their hind ends forward in contact with the thorax, and then extending their front half.

9. Caterpillars get creative when it comes to self defense.
Life at the bottom of the food chain can be tough, so caterpillars employ all kinds of strategies to avoid becoming a bird snack. Some caterpillars, such as the early instars of black swallowtails, look like bird droppings. Certain inchworms in the family Geometridae mimic twigs, and bear markings that resemble leaf scars or bark. Other caterpillars use the opposite strategy, making themselves visible with bright colors to advertise their toxicity. A few caterpillars, like the spicebush swallowtail, display large eyespots to deter birds from eating them. If you’ve ever tried to take a caterpillar from its host plant, only to have it fall to the ground, you’ve observed it using thanatosis to thwart your efforts to collect it. A swallowtailcaterpillar can be identified by its smelly osmeterium, a special defensive stink gland just behind the head.

10. Many caterpillars use the toxins from their host plants to their own advantage.
Caterpillars and plants co-evolve. Some host plants produce toxic or foul-tasting compounds meant to dissuade herbivores from munching their foliage. But many caterpillars can sequester the toxins in their bodies, effectively using these compounds to protect themselves from predators. The classic example of this is the monarch caterpillar and its host plant, milkweed. The monarch caterpillar ingests glycosides produced by the milkweed plant. These toxins remain within the monarch through adulthood, making the butterfly unpalatable to birds and other predators.

Ten things you probably did’nt know about dark energy

Dark energy is the biggest mystery in the cosmos, pervading the vast emptiness of space for billions of light-years. But if you thought you knew everything there was to know about this strange force, think again.

Discovery Space sat down with Michael Turner, a cosmologist at the University of Chicago, to pin down the 10 biggest things you didn’t know about dark energy.

10. Dark Energy’s Discoverer Didn’t Coin the Term

Who came up with the term? “I did,” Turner said. “That’s because when you find something new and weird, you have to name it. It can’t just be ‘the funny stuff that helps the universe speed up.’”

The term is also used to say that it’s different than dark matter, which is yet another weird constituent of the cosmos, and behaves more like energy than anything else that we know of.

9. Albert Einstein First Stumbled on Dark Energy’s Path

Thing is, Einstein didn’t even know it.

The German-born scientist derived an historic ”cosmological constant” to make the universe static — or in other words, prevent gravity from steering the cosmos into a “big crunch” billions of years in the future.

"Instead of counteracting gravity, however, Einstein’s cosmological constant overpowers it and causes the universe to expand at an accelerating pace," Turner told Discovery Space. "People like to say that even when Einstein thought he made a mistake he was right, but that’s a bit of a stretch."

If Einstein’s cosmological constant does exist, it’s about four times stronger than he first anticipated.

"We don’t think the universe is static," he said. "It’s inconsistent with what we see out there."

8. Dark Energy Could Be Nothing

The “gravity” of dark energy is repulsive, making it a large-scale anti-gravity that acts like an overzealous traffic cop between clusters of galaxies. What’s between those galaxies? Empty space.

"The simplest explanation for dark energy is that it’s associated with something called the ‘quantum vacuum,’" Turner said.

According to quantum mechanics — which explains how the universe works on a small scale — empty space is full of particles living on borrowed time and energy, Turner explained. So it’s not too unreasonable to suggest dark energy might also occupy that “empty” space.

7. Dark Energy Can’t Be Broken into Particles

About 2,500 years ago, Democritus suggested there were four elements in the universe: air, fire, earth and water, later adding “ether.”

"He started on this path that everything is made of indivisible particles called atoms, and that path eventually led us to subatomic particles called quarks today," Turner said. "But dark energy isn’t made of quarks, or any other particle."

6. Dark Energy Is Everywhere

According to Einstein’s famous equation E=MC^2, matter can be converted completely into energy, and the universe can be divided into a “pie” of energy.

"One of the most important things about dark energy is that it makes up most of the stuff in the universe," Turner told Discovery Space. " however, locally, we don’t notice it."

The breakdown of the pie is roughly like this:

  • 74 percent is dark energy
  • 22 percent is dark matter
  • 3.6 percent is nearly invisible gas between stars
  • 0.4 percent is stars, planets, moons and everything else. Including you.

5. Dark Energy Is the Most Elastic Substance Ever

"It’d be safe to say it’s more than a zillion times more elastic than anything we know of," Turner said. "Even NASA’s most stretchy material, whatever it may be."

If one were to “weigh” the energy of dark energy in a large coffee cup, it would be about 1 x 10^-27 grams (0.000000000000000000000000001 grams) or, in other words, not a whole lot.

If you do the math, Turner explained, contracting a volume of dark energy between here and the sun would create enough juice to power the Earth for about nearly 100,000 years.

4. Dark Energy Shaped the Universe

The Big Bang is thought to have kick-started the universe we live in, but after the event, dark energy began to seize its grip on matter and overcome gravity.

"Our universe was shaped by battle between dark energy and matter," Turner said. "For the first 8 billion years or so of the universe’s existence, the gravity of matter held sway and clusters of galaxies formed."

Roughly five billion years after that — or about one billion years ago — dark energy took over, and “put its foot on accelerator,” Turner said. “The expansion of the universe began speeding up and no larger structures were built.”

3. Dark Energy May Not be Energy at All

If it’s not made of particles, and may be nothing, is it really safe to call it energy?

"Not in the least bit," Turner told Discovery Space. "There may very well be no dark energy at all."

Instead, Turner suggested that Einstein’s ideas about gravity might need to be replaced.

"Few people think Einstein got the last word on gravity. His story didn’t incorporate the details of the universe at the atomic level,” he said, which is what might hold the key to gravity.”

2. Dark Energy Holds the Destiny of the Cosmos

Until we understand what dark energy is, Turner thinks we won’t really know what the fate of the universe is.

"It could continue to accelerate as it is," he said. "If it does, then in about 100 billion years the galaxies around us will be speeding away from us too quickly to see."

Another scenario is that the acceleration of the universe’s expansion may be doubled. And that’s bad news for everyone that might be out there — the cosmos will rip itself to shreds.

"We don’t know if the acceleration we see today is accelerating," Turner said. "If it is, the ‘big rip’ will occur in roughly 20 billion years."

One last option is equally as frightening.

"Maybe dark energy’s next trick is to decelerate expansion and lead to the collapse of the universe," Turner said. "We’ve trapped ourselves time and time again believing in the simplest case, only to correct ourselves. If you want to be squeaky-clean correct, we can’t confidently guess the future of the universe yet."

1. No One Knows What Dark Energy Is

If you thought you were clueless, even the experts don’t know.

"Welcome to the club," Turner said. "It’s the most profound mystery in all of science. It ties together the destiny of the universe, mysteries about gravity and quantum nothingness. How’s that for a mystery?”

Ten things you may not know about the Saturn

  1. Saturn Is Both Hot and Cold - Saturn is, on average, 900 million miles from the Sun, making it the sixth farthest planet out in the solar system. Because of this distance, the cloud tops of the planet’s thick atmosphere do not get much solar energy and are quite cold, at -285 degrees Fahrenheit. But the interior of the planet is much warmer, probably due to energy being generated by sinking helium. Saturn emits two and a half times as much heat as it receives from the sun.
  2. Aurora on Saturn - Saturn experiences the aurora just as Earth does. Auroras are sometimes also called the Northern Lights (or Southern Lights, for those in the Southern Hemisphere). When solar plasma interacts with magnetic fields in the atmosphere of Saturn, particles become excited and emit light.
  3. Saturn Can Be a Stormy Place - Besides magnetic storms/aurorae, spacecraft visiting Saturn have observed some strong storm systems, including one hurricane-like storm with an eye and a long-lasting hexagonal cloud formation.
  4. Saturn Could Float on Water - It’s a fact often spouted about Saturn, but what does this mean? Saturn is the least dense of the planets. Considering its large size, one would expect it be more massive, or weigh more. But the planet is mostly gas (96% hydrogen) with a small rocky core.
  5. There Are Thousands of Rings - Although Saturn has a handful of main ring systems, the entire system is actually composed of thousands of tiny rings. The rings themselves are made of billions of pieces of ice, rock, and dust.
  6. Saturn’s Rings Occasionally “Disappear” - Saturn tilts in its orbit with respect to Earth. Therefore, sometimes Saturn shows a wide expanse of its rings, and sometimes the planet is tilted so that the rings are pointing directly at Earth. Because the ring system is extremely narrow, the rings can seem to disappear when they are aimed edge-on to Earth.
  7. Its Moons Could Hold Life - Saturn’s largest moon, Titan, is the only other body in the solar system besides Earth to have a substantial nitrogen atmosphere. It also has lakes, although these lakes are made of methane and not water. Its moon Enceladus also has a wet surface with icy geysers.
  8. Shepherd Moons - Saturn has small moons that can be found near its giant ring system that keep the rings in line. Just as a shepherd tends to his flock by keeping the sheep in line and ushering them from one field to another, a shepherd moon influences the rocks and ice that make up Saturn’s ring system, its gravity helping to keep the particles from drifting out of line.
  9. No One Discovered Saturn - Saturn is easy to see without binoculars or a telescope. When it is up in the sky, it looks just like a bright star. Its existence has been known by many different cultures for thousands of years, even though they haven’t always understood just what it is they were looking at.
  10. Cassini Discovered Many Features of Saturn - Cassini’s name is often associated with Saturn. Giovanni Domenico Cassini was an Italian astronomer who discovered the division in Saturn’s rings that is now named after him. He also was the first to study four of Saturn’s moons. A spacecraft sent to explore Saturn was named after Cassini.

Need more information about Saturn? Read Saturn Facts.

Source: NASA, GIF from B and C

20 Things You Didn’t Know About Eclipses

1  The longest total solar eclipse of the century occurred on July 22 over India, Nepal, Bhutan, and China. It peaked over the Pacific Ocean, but even there the darkness lasted a mere 6 minutes and 29 seconds.

2  Fast and furious: The moon’s shadow zooms across Earth’s surface at up to 5,000 miles per hour.

Canadian astronomer and renowned eclipse chaser J. W. Campbell traveled the world for 50 years trying to see 12 different eclipses. He ran into overcast skies every time.

4  Don’t repeat J. W.’s mistakes: Monsoon season throughout south Asia means that there is a good chance the eclipse this July will be clouded out too.

5  Just before full eclipse, dazzling “Baily’s beads” appear where sunlight shines through valleys on the moon. The last bead creates the impression of a diamond ring in the sky.

6  On eclipse-viewing expeditions, this phenomenon is frequently accompanied by a marriage proposal.

7  The beautiful symmetry of a total solar eclipse happens because—by pure chance—the sun is 400 times larger than the moon but is also 400 times farther from Earth, making the two bodies appear the exact same size in the sky.

8  In case you were thinking about relocating: Earth is the only place in the solar system where that happens.

9  Other planets get other kinds of fun, though. Jupiter can have a triple eclipse, in which three moons cast shadows on the planet simultaneously. The event is easily visible through a backyard telescope.

10  The Chinese word for solar eclipse is shih, meaning “to eat.” In ancient China people traditionally beat drums and banged on pots to scare off the “heavenly dog” believed to be devouring the sun.

11  Then again, China also produced the first known astronomical recordings of solar eclipses, inscribed in pieces of bone and shell called “oracle bones,” from around 1050 B.C. or earlier.

12  By comparing those ancient records with modern calculations of eclipse patterns, scientists have determined that the day is 0.047 second longer today than it was back then.

13  Tidal friction, which causes that lengthening of the day, is also making the moon drift away. In about 600 million years it will appear too small to cover the sun, and there will be no more total solar eclipses.

14  In any given location, a total solar eclipse happens just once every 360 years on average.

15  Luckiest place on Earth Carbondale, Illinois, will beat the odds: Folks there will see an eclipse on August 21, 2017, and again on April 8, 2024.

16  In contrast, everyone on the night side of the world can see a lunar eclipse, where the moon slips into Earth’s shadow.

17  During a total lunar eclipse, the moon takes on a deep reddish hue due to the sunlight filtering through our atmosphere—the cumulative glow of all the world’s sunsets.

18  While stranded in Jamaica, Christopher Columbus was famously saved by the lunar eclipse of February 29, 1504, which he had read about in his almanac. After a fracas with the locals, Columbus warned that the moon would disappear if they did not start supplying his men with food.

19  When the moon vanished, the locals promptly complied, and Columbus breathed a huge sigh of relief: His almanac was calibrated for Germany, and he was not sure that he had adjusted correctly for local time.

20  Who knows—it might be useful to you, too. The next lunar eclipse visible from the United States will take place on December 21, 2010.

Pink is not an actual color. It is white light without the color green.

(Source: news.discovery.com)

C’s in Physics

Calorie: A unit of heat, 1Calorie = 4.186 joules.

Candela: The S.I. unit of luminous intensity defined as the luminous intensity in a given direction of a source that emits monochromatic photons of frequency 540 x 1012 Hz & has a radiant intensity in that direction of 1/683 W/sr

Capacitance: The ratio of charge stored per increase in potential difference.

Capacitor: Electrical device used to store charge and energy in the electrical field.

Capillarity: The rise or fall of a liquid in a tube of very fine bore.

Carnot’s theorem: No engine operating between two temperatures can be more efficient than a reversible engine working between the same two temperatures.

Centrifugal force: An outward pseudo force acting on a body in circular motion.

Centripetal force: The radial force required to keep an object moving in a circular path; it is equal to mv2/r.

Charles’ law: For a given mass of a gas at constant pressure, the volume is directly proportional to the temperature.

Chromatic aberration: An optical lens defect causing color fringes, because the lens brings different colors of light to focus at different points.

Clausius’ statement of second law of Thermodynamics: It is not possible that at the end of a cycle of changes heat has been transferred from a colder body to a hotter body without producing some other effect.

Closed system: The system which cannot exchange heat or matter with the surroundings.

Coefficient of linear expansion: The increase in length per unit original length per degree rise in temperature.

Coefficient of superficial expansion: The increase in area per unit original area per degree rise in temperature.

Coefficient of volumetric expansion: The increase in volume per unit original volume per degree rise in temperature.

Coherent source: A source in which there is a constant phase difference between waves emitted from different parts of the source.

Condensation point: The temperature at which a gas or vapor changes back to liquid.

Conduction: The transfer of heat from a region of higher temperature to a region of lower temperature by increased kinetic energy moving from molecule to molecule.

Convection: The transfer of heat by the actual transfer of matter.

Coulomb’s law: The force between any two charges is directly proportional to the product of charges and inversely proportional to the square of the distance between the charges.

Critical angle: The angle of incidence in a denser medium for which angle of refraction is .

Cyclotron: A device used to accelerate the charged particles.

Top 5 Ways to Get Smarter

What is smart? Some people judge smarts by standard benchmarks like test scores and grade point averages. Others think common sense, problem solving abilities and “street smarts” define intelligence. Standardized testing scores have proven unreliable and biased along racial and socioeconomic lines, and cramming for classes can lead to GPAs that aren’t a true indicator of intelligence. 

While we can’t all agree on a standard for intelligence, we can agree that the human brain is the key to all of them. It has a great capacity to adapt, rewire and grow. Neural networks expand and strengthen through learning experiences. Stimuli make the brain stronger and more vital. This reinforcement of the brain’s power affects intelligence across all standards, from street smarts to testing scores. Here are five ways you can increase your brain’s capacity to take in and store new data. Or, said more simply, here’s how you can get smarter.

5: Meditate

For thousands of years, we’ve known the benefits of meditation. The practice of meditation can be different for each person, but it generally involves quiet, focused breathing exercises in which the practitioner is able to achieve a state of mental calm. Regardless of whether you believe that this mental calm is an enlightened state of consciousness, no one can deny the benefits of relaxed, focused breathing. FMRI scans have revealed that regular meditation also affects the actual structure of the brain. Researchers believe that memory, function, attention span and focus all benefit from meditation. One study showed that regular daily meditation can even increase the size of parts of the cerebral cortex. Not surprisingly, some of the world’s leading and forward-thinking corporations offer meditation classes for their employees.

4: Exercise Your Brain

The brain, like many parts of the human body, needs regular exercise in order to maintain strength and vitality. Some more common brain strengthening exercises include fun activities like crossword puzzles, Sudoku, and other word- and number-based brain teasers. There are other more academic ways as well, like completing math word problems and exercises relating to spatial relationships and geometry. Even simply reading this article gives your brain a slight workout. If these ideas are a little too scholarly for you, try simple things like mixing up your routine. Just brushing your teeth with the opposite hand or walking a different way to work forces your brain to work harder than usual, which is ultimately what you want to do.

3: Ingest Bacteria

In June 2010, researchers at The Sage Colleges presented findings that show certain types of bacteriacommonly found in dirt made mice “smarter.” The mice given Mycobacterium vaccae performed better in maze tests and showed fewer signs of anxiety and higher levels of serotonin in the forebrain, the area that takes care of higher-order thinking. The bacteria seem to promote the growth of neurons as well. This doesn’t mean that we should all go out and start shoveling dirt in our mouths: You can actually ingest it by doing yard work, gardening and even by simply taking a walk through the woods.

2: Get Some Sleep

Wakeful exercises for the brain are great and necessary to help improve brain function so you can get smarter. But what about sleep? Not a whole lot is known about sleep, but we know now that scientists were wrong for years with the belief that the brain simply shut down during sleep to recharge. Research now indicates that the brain may actually do a little nighttime filing during sleep. The information from the previous day is catalogued and put in the proper mental folders so it can make the journey from short-term memory to long-term. Sleeping problems have been known to exacerbate other brain issues, so it makes sense that a good night’s sleep can help increase the brain’s function and ability to focus. It varies from person to person, but between six and eight hours of sleep for adults is generally recommended.

1: Take Care of Your Body

The human body is all connected, so you can’t take care of one part of it without benefiting some other part. Physical exercise is important for good health, for both the body and the brain. Simply increasing your blood flow kicks up the oxygen and glucose levels in the brain. The coordination it takes to perform exercises also gives the brain a workout, especially if you’re trying something new. Exercise also means you’re battling sedentary lifestyle, or one free from mental stimuli.

Food is also important. There are many foods that have been associated with brain health, including fish oil, eggs, protein and dark green vegetables. Green tea, herbal tea and nuts are also good “brain food.” Eating right, getting the required amount of sleep and exercises, both mental and physical, are the keys to improving memory and overall brain function.

Space is not empty; it’s thought to be buzzing with “virtual particles” popping in and out of existence.

(Source: news.discovery.com)

20 Things You Didn’t Know About Relativity

Galileo invented it, Einstein understood it, and Eddington saw it.

1  Who invented relativity? Bzzzt—wrong. Galileo hit on the idea in 1639, when he showed that a falling object behaves the same way on a moving ship as it does in a motionless building.

2  And Einstein didn’t call it relativity. The word never appears in his original 1905 paper, “On the Electrodynamics of Moving Bodies,” and he hated the term, preferring “invariance theory” (because the laws of physics look the same to all observers—nothing “relative” about it).

3  Space-time continuum? Nope, that’s not Einstein either. The idea of time as the fourth dimension came from Hermann Minkowski, one of Einstein’s professors, who once called him a “lazy dog.”

4  But Einstein did reformulate Galileo’s relativity to deal with the bizarre things that happen at near-light speed, where time slows down and space gets compressed. That counts for something.

5  Austrian physicist Friedrich Hasenöhrl published the basic equation E = mc2 a year before Einstein did.

6  Never heard of Hasenöhrl? That’s because he failed to connect the equation with the principle of relativity. Verdammt!

7  Einstein’s full-time job at the Swiss patent office meant he had to hash out relativity during hours when nobody was watching. He would cram his notes into his desk when a supervisor came by.

8  Although Einstein was a teetotaler, when he finally completed his theory of relativity, he and his wife, Mileva, drank themselves under the table—the old-fashioned way to mess with the space-time continuum.

9  Affection is relative. “I need my wife, she solves all the mathematical problems for me,” Einstein wrote while completing his theory in 1904. By 1914, he’d ordered her to “renounce all personal relations with me, as far as maintaining them is not absolutely required for social reasons.”

10  Rules are relative too. According to Einstein, nothing travels faster than light, but space itself has no such speed limit; immediately after the Big Bang, the runaway expansion of the universe apparently left light lagging way behind.

11  Oh, and there are two relativities. So far we’ve been talking about special relativity, which applies to objects moving at constant speed. General relativity, which covers accelerating things and explains how gravity works, came a decade later and is regarded as Einstein’s truly unique insight.

12  Pleasure doing business with you, chum(p): When Einstein was stumped by the math of general relativity, he relied on his old college pal Marcel Grossmann, whose notes he had studied after repeatedly cutting class years earlier.

13  Despite that, the early version of general relativity had a major error, a miscalculation of the amount a light beam would bend due to gravity.

14   Fortunately, plans to test the theory during a solar eclipse in 1914 were scuttled by World War I. Had the experiment been conducted then, the error would have been exposed and Einstein would have been proved wrong.

15  The eclipse experiment finally happened in 1919 (you’re looking at it on this very page). Eminent British physicist Arthur Eddington declared general relativity a success, catapulting Einstein into fame and onto coffee mugs.

16  In retrospect, it seems that Eddington fudged the results, throwing out photos that showed the “wrong” outcome.

17  No wonder nobody noticed: At the time of Einstein’s death in 1955, scientists still had almost no evidence of general relativity in action.

18  That changed dramatically in the 1960s, when astronomers began to discover extreme objects—neutron stars and black holes—that put severe dents in the shape of space-time.

19   Today general relativity is so well understood that it is used to weigh galaxies and locate distant planets by the way they bend light.

20   If you still don’t get Einstein’s ideas, try this explanation reportedly from The Man Himself: “Put your hand on a hot stove for a minute and it seems like an hour. Sit with a pretty girl for an hour and it seems like a minute. That’s relativity.”

20 Things You Didn’t Know About Dogs

1  The sultry “dog days of summer” get their name from ancient astronomers who noticed that those days coincide with the period when Sirius, the Dog Star, rises at the same time as the sun.

2  Bad astronomy: Sirius is the brightest star in the sky, but it is just one 10-billionth as bright as the sun and has no effect on our weather.

3  Nerd. Fido will touch his nose to a computer screen if it has a picture of a dog on it but not if it shows a landscape, University of Vienna researchers have found.

4  Austrian scientists have also demonstrated that a dog seems to feel “inequity aversion” when another dog gets a better treat as a reward. The envious dog plays hard to get.

5  South Korean scientists cloned four beagle puppies with a gene that produces a fluorescent protein that glows red under ultraviolet light. (The red color is visible in the pups’ bellies and nails even under normal light, but it doesn’t glow.)

6  Maybe they should have offered a Day-Glo option. BioArts, a California company, recently closed its dog-cloning business. One reason: The market was too small.

7  Another problem: “unpredictable results,” according to BioArts. In one case, the clone of a black-and-white dog came out looking greenish yellow.

8  The number of dogs worldwide is estimated at 400 million, roughly the human population of the United States and Mexico combined.

9  They really do look like their owners. In a study conducted at England’s Bath Spa University, people matching photos of dog owners and dogs chose the right breed (out of three) more than half the time.

10  Half of all owners allow their dogs to lick them on the face, but only 10 percent share E. coli strains with their pets. The real factor in germ transmission may be whether an owner washes his hands after playing fetch.

11  Fighting a hangover by drinking “the hair of the dog that bit you” may have originated in an ancient belief that ingesting the hair of a dog that literally bit you could guard against infection.

12  A 2006 study showed that household dogs with minimal training can smell early- and late-stage lung and breast cancers. Swedish oncologists also found that dogs can distinguish among types of ovarian cancer.

13  A dog’s nose has roughly 220 million olfactory receptors, 40 times as many as humans have.

14  Penn State engineers are trying to design an artificial sniffer based on the fluid mechanics and odorant transport of the canine nose.

15  Dogs can hear frequencies up to 45,000 Hz, about twice as high as humans can. But they’re not the champs: Porpoises go to 150,000 Hz.

16  A team led by UCLA biologists concluded that small dogs descended from Middle Eastern gray wolves more than 12,000 years ago. The connection was traced through a growth-factor gene mutation not seen in larger dogs.

17  Much older canid remains have been found in Germany, Russia, and Belgium, dating as far back as 31,000 years.

18  The reference genome for doggie DNA studies is the boxer, a breed that has an unusually high degree of genetic uniformity.

19  So that’s why schnauzers look like Groucho. According to scientists at the National Human Genome Research Institute, an alteration in one gene, RSPO2, gives dogs wiry eyebrows and mustaches.

20  A variant of another gene, FGF5, produces long, silky coats, and curly hair comes from a mutation in KRT71. All three variants produce a coat like that of the Portuguese water dog adopted by the First Family.

20 Things You Didn’t Know About Crystals

 It’s all about the rhythm: Crystals are repeating, three-dimensional arrangements of atoms, ions, or molecules.

Almost any solid material can crystallize—even DNA. Chemists from New York University, Purdue University, and the Argonne National Laboratory recently created DNA crystals large enough to see with the naked eye. The work could have applications in nanoelectronics and drug development.

One thing that is not a crystal: leaded “crystal” glass, like the vases that so many newlyweds dread. (Glass consists of atoms or molecules all in a jumble, not in the well-patterned order that defines a crystal.)

 The oldest known pieces of our planet’s surface are 4.4-billion-year-old zircon crystals from the Jack Hills of western Australia.

5  The center of the earth was once thought to be a single, 1,500-mile-wide iron crystal. Seismic studies now show that the inner core is not a single solid but perhaps an aggregate of smaller crystals.

 Tiny silicate crystals, which need high temperatures to form, have been found inside icy comets from the solar system’s distant, chilly edges. Powerful flares from the sun may have provided the necessary heat.

7  In Chihuahua, 
Mexico, a limestone cavern 1,000 feet below the surface contains the largest crystals in the world: glittering gypsum formations up to 6 feet in diameter and 36 feet long, weighing as much as 55 tons.

 You may be sitting in a gypsum cave right now: It is a primary component of drywall.

 Are the streets of New York paved with gold? No, but the bedrock schist beneath them is studded with opal, beryl, chrysoberyl, garnet, and three kinds of tourmaline.

10  In 1885 a garnet weighing nearly 10 pounds was discovered beneath 35th Street near Broadway, close to today’s Macy’s store. According to urban lore, it was unearthed either during subway construction or by a laborer digging a sewer.

11 Cheaper by the pound: The so-called Subway Garnet was sold within a day, reportedly for $100—just $2,300 in today’s dollars.

12  The unit of measure for gemstones had humble beginnings. “Carat” comes from the Greek keration, or “carob bean,” which was used as a standard for weighing small quantities. It is equivalent to 200 milligrams, or about 0.007 ounce.

13  When Richard Burton bought Elizabeth Taylor the heart-shaped Taj-Mahal diamond, he is said to have bragged, “It has so many carats, it’s almost a turnip.”

14 A “fancy intense pink” diamond recently set a world record when it was purchased at auction for $46 million by a London jeweler.

15  The Cullinan diamond is the largest known gem diamond—or, actually, was. It weighed 3,106 carats, or nearly a pound and a half, when it was discovered in South Africa in 1905, but it has since been cut into more than 100 stones.

16  The Cullinan stones, all flawless, are now part of the British Regalia. The largest, a 530-carat behemoth, is set in one of the British royal scepters.

17  For the rest of us, there is crystallized sodium chloride, otherwise known as salt. We are literally awash in it: If the water were evaporated from the world’s oceans, we’d be left with 4.5 million cubic miles of salt, equivalent to a cube measuring 165 miles on each side.

18  Another crystal for commoners: sugar. Each American eats an average of more than 130 pounds of it per year.

19  As if sugar’s ties to obesity and tooth decay weren’t enough, new research out of Imperial College London suggests that it contributes to high blood pressure, too.

20 Snow is near-pure crystallized water, but when it collects on the ground it acts as a reservoir for atmospheric pollutants such as mercury and soot. So you probably shouldn’t eat the white snow either.

A’s in Physics

Absolute humidity:The ratio of water vapor in a sample of air to the volume of the sample.

Absolute zero:The temperature of - 273.16 or 0 K at which molecular motion vanishes.

Absorptance:The ratio of the total absorbed radiation to the total incident radiation.

Acceleration:The rate of change of velocity with respect to time.

Acceleration due to gravity:The acceleration imparted to bodies by the attractive force of the earth or any other heavenly body.

Achromatic:capable of transmitting light without decomposing it into its constituent colors.

Acoustics:The science of the production, transmission and effects of sound.

Acoustic shielding:A sound barrier that prevents the transmission of acoustic energy.

Adiabatic:Any change in which there is no gain or loss of heat.

Afocal lens:A lens of zero convergent power, whose focal points are infinitely distant.

Albedo:The fraction of the total light incident on a reflecting surface, especially a celestial body, which is reflected back in all directions.

Alpha particle:The nucleus of a helium atom (two protons and two neutrons) emitted as radiation from a decaying heavy nucleus.

Alternating current:The electric current that changes its direction periodically.

Amorphous:Solids which have neither definite form nor structure.

Ampere:S.I. Unit of electric current, one ampere is the flow of one coulomb of charge per second.

Amplitude:The maximum absolute value attained by the disturbance of a wave or by any quantity that varies periodically.

Angle of contact:The angle between tangents to the liquid surface and the solid surface inside the liquid, both the tangents drawn at the point of contact.

Angle of incidence:The angle between the incident ray and the normal.

Angle of reflection:The angle between the reflected ray and the normal.

Angle of refraction:The angle between the refracted ray and the normal.

Angle of repose:The angle of inclination of a plane with the horizontal such that a body placed on the plane is at the verge of sliding.

Angstrom:A unit of length, 1 = 10-10 m.

Angular momentum:Also called moment of momentum, it is the cross product of position vector and momentum.

Angular velocity:The rate of change of angular displacement with time.

Annihilation:A process in which a particle and antiparticle combine and release their rest energies in other particles.

Antineutrino:The antiparticle of neutrino, it has zero mass and spin ½.

Archimedes principle:A body immersed in a fluid experiences an apparent loss in weight which is equal to the weight of the fluid displaced by the body.

Atomic mass unit:It is equal to one-twelfth the mass of C -12 isotope of carbon, 1 amu = 1.66x 10-27 Kg.

Atomic number:The number of protons in an atomic nucleus.

Avogadro number:The number of molecules in a gram molecular weight of a substance, it is equal to 6.02 x 1023.

Avogadro’s law:Under the same conditions of temperature and pressure, equal volumes of all gases contain equal number of molecules.

(Source: etutorphysics.com)

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