My Science School

When you snap your finger, your finger moves at about 20 mph. In Ancient Greece snapping of fingers was used by musicians and dancers as a way to keep the rhythm. Finger snapping today may be used as a substitute for hand clapping.

Finger snaps last only about seven milliseconds — that’s roughly 20 times as fast as the blink of an eye, says biophysicist Saad Bhamla of Georgia Tech in Atlanta. After slipping off the thumb, the middle finger rotates at a rate up to 7.8 degrees per millisecond, nearly what a professional baseball pitcher’s arm can achieve, the team found. And a snapping finger accelerates almost three times as fast as pitchers’ arms.

When covered with high-friction rubber or low-friction lubricant, fingers made snaps that fell flat, the team found, indicating that bare fingers have a level of friction ideal for a speedy snap. That friction between thumb and middle finger allows energy to be stored before it’s suddenly unleashed. Too little friction means less pent-up energy and a slower snap. But too much friction impedes the finger’s release, also slowing the snap.

Credit : Science News

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There are more trees on earth than stars in our galaxy. NASA believes there could be anywhere from 100 billion to 400 billion stars in the Milky Way galaxy. But the number of trees around the world is much higher: 3.04 trillion! Scientists calculated what's called "tree wealth" based on estimates of the number of trees in every country in the world in relation to factors like the country's physical size and population. The world's overall tree leader is Russia with 642 billion trees, followed by Canada (318 billion) and Brazil (302 billion). There are roughly 422 trees for every human on earth.

The total is "astonishing," study co-author Thomas Crowther, who did the research as a postdoctoral student at Yale University, told reporters. When Crowther asked forestry experts to predict the total, they made wildly incorrect guesses, he said in a separate interview. "No one could comprehend the scale of the things we were seeing."

In a more sobering find, Crowther and his team calculated that roughly 15.3 billion trees are cut down each year, and humanity has reduced the Earth's tree population by nearly half since civilization began. Around the world, one of the biggest influences on the number of trees is the corps of humans wielding chainsaws and axes.

The scientists didn't have to count the world's trees one by one. But they still needed two years, data amassed by thousands of tree huggers and a good chunk of supercomputer time to add up all those oaks and palms and pines. The team combined actual tree counts made in wooded areas, around the world, with satellite pictures. By counting actual trees and comparing them to satellite pictures, they learned how to predict the number of trees in places where satellite views were the only source of information. The result is the first full-coverage map of the entire planet's tree density and one of the very few estimates that sees the trees and not just the forest.

Credit : USA Today 

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It's getting harder and harder to run a stoplight in Carmel, Indiana, because there are fewer and fewer of them around. Every year, at intersections throughout this thriving city, traffic lights and stop signs have disappeared, replaced with roundabouts.

There is a roundabout decorated with the local high school mascot, a greyhound, and another with giant steel flowers. A 3-mile stretch of Carmel's Main Street has 11 roundabouts alone. The roundabout that locals perhaps prize the most features box hedges and a three-tier bronze fountain made in France. In 2016, it was named "International Roundabout of the Year" by no less than the UK Roundabout Appreciation Society, which, according to the Carmel mayor, Jim Brainard, is largely made up of "three guys in a pub."

Carmel, a city of 102,000 north of Indianapolis, has 140 roundabouts, with more than a dozen still to come. No US city has more. The main reason is safety; compared with regular intersections, roundabouts significantly reduce injuries and deaths.

But there's also a climate benefit. Because modern roundabouts don't have red lights where cars sit and idle, they don't burn as much gasoline. While there are few studies, the former city engineer for Carmel, Mike McBride, estimates that each roundabout saves about 20,000 gallons of fuel annually which means the cars of Carmel emit many fewer tons of planet-heating carbon emissions each year. And US high way officials broadly agree that roundabouts reduce tailpipe emissions.

They also don't need electricity, and, unlike stoplights, keep functioning after bad storms a bonus in these meteorologically turbulent times.

The reason that Carmel has so many roundabouts is Brainard, the city's seven-term Republican mayor.

Brainard first encountered roundabouts in the 1980s, when he studied at the University of Oxford and became taken with European traffic flow. After getting elected mayor in 1995, he asked a consultant to look into building a roundabout in Carmel. The consultant refused, saying they were dangerous and pointing to an effort in Massachusetts to remove them. "People love them here," he said during a recent tour of Carmel in his hybrid Ford Escape. "You couldn't take one out." Not everyone is a fan. "I hate them," said Corey Hill, a call center director from nearby Avon who said he often gets stuck behind confused out-of-towners.

Having greener intersections dovetails with Brainard's climate mitigation efforts. Carmel's city vehicles are either hybrid or run by biofuels, green spaces sown with native plants have exploded in number and size, and solar panels help fuel the city's water treatment and sewage plants.

The US has been slow to adopt modern roundabouts, though that is changing somewhat. By one count, they now number about 7,900 countrywide, with hundreds added each year. Still, hesitation remains.

Credit : Hindustan Times

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Sea water, freezing cold and some magic!

Brinicles. What kind of a natural structure would have such a fascinating name? Think of ice stalactites forming inside seawater - it deserves an awesome name, doesn't it? Brinicles typically form when the sea surface gets frozen, which happens around the South and North Poles. Cold and salty seawater pockets gather on the underside of the sea. This mixture is denser than the seawater and slowly sinks to the bottom while the fresh water below this brine freezes around it as it sinks. Take a moment to picture this beauty.

Three suns?

Popularly called the 'sun dog', and considered to be the whacky cousin of the rainbow, this phenomenon is caused by light refracting from the ice crystals in the atmosphere. What results is a halo-like shape around the sun with two spots on either side, making it look like there are three suns.

When nature gives you donuts...

Who said snow rolled down a hill only like a boring ball? It can form a donut shape provided it's in the right mood, or let's say, the right conditions. When the temperature is just perfect, a mass of snow gets blown by the wind and catches on to another mass of snow. When the wind or gravity is in favour, the middle section of the snowball collapses and forms a rare donut shape!

A spiky field up in the mountains

Imagine a field of icy spikes, each about 4 metres high! These amazing ice formations called 'penitentes', not surprisingly, form in high altitudes like the Andes mountain ranges. How can something like this form? When the sun's hot rays fall on a field of snow, some of the snow directly vapourizes without becoming liquid. The snow pockets attract even more sunlight and sublimate more. All the spiky snow structures are those that were lucky enough to miss all the heat.

Clouds inspired by UFOs

Called lenticular clouds, these lenses shaped clouds form at high altitudes when air is forced to flow upwards along mountain tops. Sometimes they form several layers and look so awesome that many UFO explanations have been attributed to the sighting of this cloud type.

A deadly combo

What are two phenomena that are really scary? Lightning? Why, yes! And volcanos? Of course. But what about volcanic lightning? No, we're not kidding. Imagine a lightning storm happening at exactly the same time as a volcanic eruption. The volcano ejects positively-charged particles into the atmosphere that react with negatively-charged particles from the lightning. What you get is a spectacular firework display that's scary and fascinating at the same time. Makes you glad that you weren't anywhere close to where it was happening!

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Birds do not produce urine. Instead they excrete uric acid. Their kidneys do extract waste from the bloodstream and this waste comes out in the form of uric acid, which emerges as a thick, white paste. However, the waste is not all white; you could spot brown or green specks in the centre of the white paste, which is the actual bird faeces. Since birds do not have separate urinary and digestive tracts, the uric acid gets expelled along with the faeces.

The way it's excreted is also a little weird compared to the rest of us. Most bird species don’t have “traditional” penises and vaginas (though there are some bizarre exceptions). Instead, both sexes have a cloaca — an all-purpose entrance and exit for the intestinal, reproductive, and urinary tracts. It’s used to expel waste, lay eggs and have sex (which, for birds, happens in the form of a “cloacal kiss”). This orificial multitasking explains the dark bullseye that’s often in the center of the white acid waste. That’s the actual “poop” part, or stool. Because the acid and poop are expelled at the same time from the same opening, but from two different bodily systems, they don’t have much time to blend, and you get a bird dropping with two distinct parts that looks like a poor man’s Rorschach test.

The acidic attributes of bird poop are a detriment to your car’s paint job, but it's highly sought after for what it can do to your face. Maybe not your face, but certain celebrities go nuts for bird poop facials, where Japanese Nightingale poop is mixed with rice bran and water and used to exfoliate the skin.

Credit : Mental Floss 

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The sun was born about 4.6 billion years ago. Many scientists think the sun and the rest of the solar system formed from a giant, rotating cloud of gas and dust known as the solar nebula. As the nebula collapsed because of its gravity, it spun faster and flattened into a disk. Most of the material was pulled toward the center to form the sun.

The sun has enough nuclear fuel to stay much as it is now for another 5 billion years. After that, it will swell to become a red giant. Eventually, it will shed its outer layers, and the remaining core will collapse to become a white dwarf. Slowly, the white dwarf will fade, and will enter its final phase as a dim, cool theoretical object sometimes known as a black dwarf.

Sunspots are relatively cool, dark features on the sun's surface that are often roughly circular. They emerge where dense bundles of magnetic field lines from the sun's interior break through the surface.

The number of sunspots varies as solar magnetic activity does — the change in this number, from a minimum of none to a maximum of roughly 250 sunspots or clusters of sunspots and then back to a minimum, is known as the solar cycle, and averages about 11 years long. At the end of a cycle, the magnetic field rapidly reverses its polarity. 

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A dearth of bright spots on the sun might have contributed to a frigid period known as the “little ice age" in the middle of the past millennium, researchers suggest.

From the 1500s to the 1800s, much of Europe and North America were plunged into what came to be called the little ice age. The coolest part of this cold spell coincided with a 75-year period beginning in 1645 when astronomers detected almost no sunspots on the sun, a time now referred to as the Maunder Minimum.

Past studies had mulled over whether the decreased solar activity seen during the Maunder Minimum might have helped cause the little ice age. Although sunspots are cool, dark regions on the sun, their absence suggests there was less solar activity in general. Now scientists suggest there might have been fewer intensely bright spots known as faculae on the sun as well during that time, potentially reducing its brightness enough to cool the Earth.

The dip in the number of faculae in the 17th century might have dimmed the sun by just 0.2 percent, which may have been enough to help trigger a brief, radical climate shift on Earth, researcher Peter Foukal, a solar physicist at research company Heliophysics in Nahant, Mass., told LiveScience.

"The sun may have dimmed more than we thought," Foukal said.

Foukal emphasized this dimming might not have been the only or even main cause of the cooling seen during the little ice age. "There were also strong volcanic effects involved — something like 17 huge volcanic eruptions then," he said.

Foukal also cautioned these findings regarding the sun did not apply to modern-day global warming. "Increased solar activity would not have anything to do with the global warming seen in the last 100 years," he explained.

Foukal and his colleagues detailed their findings May 27 at the American Astronomical Society meeting in Boston.

Credit : NBC News

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The temperature of the umbra is roughly 3,000–4,500 K (2,700–4,200 °C), in contrast to the penumbra at about 5,780 K (5,500 °C) leaving sunspots clearly visible as dark spots, occasionally visible even to the naked eye. 

If you are within the Moon's umbra and look into the direction of the Sun, you will see a total solar eclipse as the Moon blocks the all of the Sun. On its journey through space, the Moon always casts an umbra. This means that somewhere in space, on the dark side of the Moon, a total solar eclipse is happening right now.

The reason why solar eclipses are so rare is that the Moon's umbra rarely hits the Earth's surface. Even during a total solar eclipse, the umbra only covers a small area on Earth.

As both the Moon and the Earth are in constant motion, the umbra moves across the face of the Earth during the eclipse, so the total phase can usually only be seen along a slim eclipse path. For example, the total solar eclipse on April 8, 2024 will only be visible along a narrow belt stretching across the United States, Mexico, and Canada.

Like the Moon, Earth always casts an umbra. In fact, we travel through it quite regularly. It is called: night. Every time the Sun goes down, we delve into the darkness created by Earth's umbra. However, as with total solar eclipses, lunar eclipses only occur every so often because they require the Moon to enter the Earth's umbra.

The Earth's umbra is involved in both total and partial lunar eclipses. During a total lunar eclipse, the entire Moon enters the umbra. A partial lunar eclipse occurs when the umbra covers only part of the Moon's surface.

A penumbral lunar eclipse occurs when the Moon enters the Earth's penumbra.

Credit : Time and Date

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The Eta Aquarids are pieces of debris from Halley's Comet, which is a well-known comet that is viewable from Earth approximately every 76 years. Also known as 1P/Halley, this comet was last viewable from Earth in 1986 and won't be visible again until the middle of 2061. The annual Eta Aquarid meteor shower gets its name because the radiant -- or direction of origin -- of the meteors appears to come from the constellation Aquarius.

The comet is named after English astronomer Edmond Halley, who examined reports of a comet approaching Earth in 1531, 1607 and 1682. He concluded that these three comets were actually the same comet returning over and over again, and predicted the comet would come again in 1758.

Halley didn't live to see the comet's return, but his discovery led to the comet being named after him. (The traditional pronunciation of the name usually rhymes with valley.) Halley's calculations showed that at least some comets orbit the sun.

Further, the first Halley's Comet of the space age — in 1986 — saw several spacecraft approach its vicinity to sample its composition. High-powered telescopes also observed the comet as it swung by Earth.

While the comet cannot be studied up close for many decades, scientists continue to perform comet science in the solar system, looking at other small bodies that can be compared to Halley. A notable example was the Rosetta probe, which looked at Comet 67P/Churyumov–Gerasimenko between 2014 and 2016 and concluded that the comet has a different kind of water than Earth's water.

Credit : Space.com

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Ultraviolet light ionizes the neutral gas blown off the comet, and the solar wind carries these ions straight out from the Sun to form the ion tail, which typically glows blue. The dust tail on the other hand is neutral, composed of small dust particles (similar in size to those found in cigarette smoke). Pressure from the Sun's radiation pushes these particles away from the comet’s nucleus. These particles continue to follow the comet’s orbit around the Sun, and form a diffuse, curved tail that typically appears white or pink from Earth.

The plasma tail comprises electrons and ions that are ionized by the sun's ultraviolet radiation. The dust tail consists of micrometer-scale particles. The dust tail is wide and slightly bent because of the pressure of the light from the sun and the orbital action of the comet's nucleus.

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Comets are believed to have two sources. Long-period comets (those which take more than 200 years to complete an orbit around the Sun) originate from the Oort Cloud. Short-period comets (those which take less than 200 years to complete an orbit around the Sun) originate from the Kuiper Belt.

The short-period comets are thought to originate in the Kuiper Belt, an area outside Neptune's orbit (from about 30 to 50 AU) that has many icy comet-like objects. The long-period comets tend to have orbits that are randomly oriented, and not necessarily anywhere near the ecliptic. They are thought to originate in the Oort cloud. The Oort cloud has never been observed, but is believed to have at least 1012 icy objects located between 3000 AU and 100,000 AU in a spherical distribution around the Sun.

As comets travel close to the Sun, the Sun's heat begins to vaporize the ices and causes them to form a fuzzy, luminous area of vaporized gas around the nucleus of the comet known as a coma. Outside the coma is a layer of hydrogen gas called a hydrogen halo which extends up to 1010 meters in diameter.

Credit : Las Cumbres 

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Comets go around the Sun in a highly elliptical orbit. They can spend hundreds and thousands of years out in the depths of the solar system before they return to Sun at their perihelion. Like all orbiting bodies, comets follow Kepler's Laws - the closer they are to the Sun, the faster they move.
While a comet  is at a great distance from the Sun, its exists as a dirty snowball several kilmoeters across. But as it comes closer to the Sun, the warming of its surface causes its materials to melt and vapourise producing the comet's characteristic tail. Comet tails can be as long as the distance between the Earth and the Sun.

According to Kepler's first law, all objects orbit the sun in elliptical paths. The orbits of the planets, except for Pluto, are almost circular, and so are those of asteroids and icy objects in the Kuiper belt, which is just beyond the orbit of Neptune. Comets that originate in the Kuiper belt are known as short period comets and tend to remain in the same narrow band as the planets.

Long period comets, which originate in the Oort cloud, which is beyond the Kuiper belt and on the outskirts of the solar system, are a different matter. Their orbits can be so elliptical that the comets can completely disappear for hundreds of years. Comets from beyond the Oort cloud can even have parabolic orbits, meaning they make a single appearance in the solar system and never come back again.

None of this behavior is mysterious once you understand how planets and comets came to be there in the first place. It all has to do with the birth of the sun.

Credit : Sciencing 

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Comets are frozen leftovers from the formation of the solar system composed of dust, rock, and ices. They range from a few miles to tens of miles wide, but as they orbit closer to the Sun, they heat up and spew gases and dust into a glowing head that can be larger than a planet. This material forms a tail that stretches millions of miles.

As theorized by astronomer Gerard Kuiper in 1951, a disc-like belt of icy bodies exists beyond Neptune, where a population of dark comets orbits the Sun in the realm of Pluto. These icy objects, occasionally pushed by gravity into orbits bringing them closer to the Sun, become the so-called short-period comets. Taking less than 200 years to orbit the Sun, in many cases their appearance is predictable because they have passed by before. Less predictable are long-period comets, many of which arrive from a region called the Oort Cloud about 100,000 astronomical units (that is, about 100,000 times the distance between Earth and the Sun) from the Sun. These Oort Cloud comets can take as long as 30 million years to complete one trip around the Sun.

Each comet has a tiny frozen part, called a nucleus, often no larger than a few kilometers across. The nucleus contains icy chunks, frozen gases with bits of embedded dust. A comet warms up as it nears the Sun and develops an atmosphere, or coma. The Sun's heat causes the comet's ices to change to gases so the coma gets larger. The coma may extend hundreds of thousands of kilometers. The pressure of sunlight and high-speed solar particles (solar wind) can blow the coma dust and gas away from the Sun, sometimes forming a long, bright tail. Comets actually have two tails?a dust tail and an ion (gas) tail.

Most comets travel a safe distance from the Sun?comet Halley comes no closer than 89 million kilometers (55 million miles). However, some comets, called sungrazers, crash straight into the Sun or get so close that they break up and evaporate.

Credit : NASA Science 

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Christiane Nusslein-Volhard, (born October 20, 1942, Magdeburg, Germany), German developmental geneticist who was jointly awarded the 1995 Nobel Prize for Physiology or Medicine with geneticists Eric F. Wieschaus and Edward B. Lewis for their research concerning the mechanisms of early embryonic development. 

In the early 1990s Nusslein-Volhard began studying genes that control development in the zebra fish Danio rerio. These organisms are ideal models for investigations into developmental biology because they have clear embryos, have a rapid rate of reproduction, and are closely related to other vertebrates. Nusslein-Volhard studied the migration of cells from their sites of origin to their sites of destination within zebra fish embryos. Her investigations in zebra fish have helped elucidate genes and other cellular substances involved in human development and in the regulation of normal human physiology.

In addition to the Nobel Prize, Nusslein-Volhard received the Leibniz Prize (1986) and the Albert Lasker Basic Medical Research Award (1991). She also published several books, including Zebrafish: A Practical Approach (2002; written with Ralf Dahm) and Coming to Life: How Genes Drive Development (2006).

Credit : Britannica 

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The 1995 laureates in physiology or medicine are developmental biologists who have discovered important genetic mechanisms which control early embryonic development. They have used the fruit fly, Drosophila melanogaster, as their experimental system. This organism is classical in genetics. The principles found in the fruit fly, apply also to higher organisms including man.

Using Drosophila Nüsslein-Volhard and Wieschaus were able to identify and classify a small number of genes that are of key importance in determining the body plan and the formation of body segments. Lewis investigated how genes could control the further development of individual body segments into specialized organs. He found that the genes were arranged in the same order on the chromosomes as the body segments they controlled. The first genes in a complex of developmental genes controlled the head region, genes in the middle controlled abdominal segments while the last genes controlled the posterior (“tail”) region. Together these three scientists have achieved a breakthrough that will help explain congenital malformations in man.

The fertilized egg is spherical. It divides rapidly to form 2, 4 , 8 cells and so on. Up until the 16-cell stage the early embryo is symmetrical and all cells are equal. Beyond this point, cells begin to specialize and the embryo becomes asymmetrical. Within a week it becomes clear what will form the head and tail regions and what will become the ventral and dorsal sides of the embryo. Somewhat later in development the body of the embryo forms segments and the position of the vertebral column is fixed. The individual segments undergo different development, depending on their position along the “head-tail” axis. Which genes control these events? How many are they? Do they cooperate or do they exert their controlling influence independently of each other?
This year’s laureates have answered several of these questions by identifying a series of important genes and how they function to control the formation of the body axis and body segments. They have also discovered genes that determine which organs that will form in individual segments. Although the fruit fly was used as an experimental system, the principles apply also to higher animals and man. Furthermore, genes analogous to those in the fruit fly have been found in man. An important conclusion is that basic genetic mechanisms controlling early development of multicellular organisms have been conserved during evolution for millions of years.

Credit : Nobel Prize 

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