- Draperies are getting longer and longer. One of the best ways to add height to any room is to place window treatments just below the ceiling line. Use this designer trick in any room that could use a little lift.
- If you are planning a new kitchen, don’t miss the chance to build in space — creating touches such as a drawer-front that pulls out to reveal a useful extra work surface. Some ranges even incorporate drawers into the base area below the cabinets.
- As well as serving as decorative features and essential dressing aids, mirrors also play a less obvious role in a room scheme. They are invaluable for reflecting light, and can increase the illusion of space in a small room.
- Adding a skylight is one of the quickest ways to make any room brighter, creating an open and airy feeling. Skylights produce a top-lit architectural drama that windows often can’t match. Plus, dollar-for-dollar, they’ll usually bring in more light than windows.
- To make the most of a shared bathroom, consider these guidelines. For adequate elbowroom, the minimum clearance between two sinks in the bath should be 30 inches, centerline to centerline. Using pocket doors rather than hinged doors in the entrance way can save space.
- Changing the spindles on a covered porch or patio can easily change the style of the facade. Using a smooth, more rounded spindle creates a Victorian feel while the use of a square, more angular spindle can reflect either a Craftsman, Rustic, Modern or Classic style influence to a design. Staying true to the overall design style of the home will make choosing a spindle style much easier and one that will better complement the home overall.
- Adding wainscoting to an existing room can add a cottage feel and creates an old-fashioned look especially when added to a kitchen or bedroom. This design idea works well when an update is needed to an older home but you don’t want the renovation looking “too new” that it doesn’t integrate with the rest of the home.
- Barstools at a counter or center island in the kitchen are a convenient place for breakfast and other quick meals or school projects and homework that may need supervision or assistance from a parent.
- Reconfigure a porch, sunroom or large living area for semi-outdoor living by installing ceiling fans, screens and natural stone floors that will weather. Outfit garden-style furnishings with weather-resistant cushions and pillows.
- To help bring the outdoors in to your home use natural materials. Stone, wood and all different kinds of tile are great for contributing to an outdoor feel. Granite, iron or bamboo are other elements that help add color and texture creating contrast to an interior.
- One of the top trends in home design currently is the use of “flexible” floor plans. Traditionally designed styles with separate living and dining rooms are being replaced by large family areas or great rooms which offer more flexibility for family living.
- When planning a computer desk, you need a desk surface that is at least 24 inches deep unless you are using a laptop. But, keep in mind even more surface space will be welcomed for files and papers.
- Planning the layout of a living room is as important as choosing the color scheme. To make the task a little easier, draw a floor plan to scale on graph paper and cut out separate pieces for thefurniture. Place these on the plan and move them around until you have an arrangement that suits your needs.
- Partitions help distinguish the edge of rooms within a home and can be flexible or fixed. They can take the form of walls, glass panels, doors or even fireplaces. Low partitions are especially appealing because they allow the overall space to remain open and airy.
- Clutter can really detract from an open floor plan. When planning your living area, make a list of all of the items that will need to be stored. Everything from media equipment to children’s toy bins should be considered. Also, don’t forget to list books and collectibles. Often times when rooms are designed there is not enough storage for all of the everyday living items and rooms pile up with unwanted clutter. Designing a room initially with these needs in mind will not compromise the overall beauty of the space once all of your belongings are in place.
- Positioning the sink beneath a window gives a cheery outlook to anyone on washing-up duty.
- An unfinished portion of a basement is the perfect place to incorporate wine storage or a wine cellar. With its cooler temperature year-round and little amount of light, it’s a natural choice for storing these refreshments.
- When designing the kitchen, locate the preparation area between the refrigerator and the sink. Place any ingredients, mixing equipment or bowls here for best usage.
- If you want to add an island to the kitchen, think thin. A narrow island will still provide a great work surface without compromising the overall space.
Sunday, May 8, 2011
facts about design
Sunday, April 24, 2011
human eye can detect sound
The human eye can detect millions of colors and is sensitive to light and sounds. Yes, sound. University research studies show that mild and incidental noises cause the pupils of the eyes to dilate.
According to David Louis’s book of Fascinating Facts, it is believed that this is why surgeons, watchmakers, and others who perform delicate manual operations are so bothered by uninvited noise: the sounds cause their pupils to change focus and blur their vision.
The “millions of colors” that the eye can detect are the three primary colors of red, green and blue and the millions of combinations that result from these three colors. (In 1878, Ewald Hering proposed the theory that the four unique hues of red, green, blue, and yellow form the basis of all colors.)
animal facts
Mammals are the only animals with flaps around the ears.
African elephants only have four teeth to chew their food with.
There are about one billion cattle in the world of which 200 million are in India.
A house fly lives only 14 days.
A dog was the first in space and a sheep, a duck and a rooster the first to fly in a hot air balloon.
The Big Five is a group of animals of Africa: cape buffalo, elephant, leopard, lion and rhino.
The oldest breed of dog is the Saluki.
The bee hummingbird of Cuba is the smallest bird in the world.
An ostrich can run up to 43mph (70 km/h).
An annoyed camel will spit at a person.
The world’s smallest dog is the Chihuahua, which means “tiny dog in the sky.”
Pea crabs (the size of a pea) are the smallest crabs in the world.
75% of wild birds die before they are 6 months old.
The pig is rated the fourth most intelligent animal but are mentioned only twice in the Bible
Sheep are mentioned 45 times and goats 88 times in the Bible. Dogs are mentioned 14 times and lions 89 times, but
domestic cats are not mentioned.
domestic cats are not mentioned.
Pork is the world’s most widely-eaten meat.
In Denmark there are twice as many pigs as people.
Dinosaurs did not eat grass: there weren’t any at that time.
The coyote is a member of the dog family and its scientific name, “canis latrans” means barking dog.
A giraffe can clean its ears with its 50cm (20 in) tongue.
A group of geese on the ground is a gaggle – a group of geese in the air is a skein. More animal collective nouns
The South American giant anteater eats more than 30,000 ants a day.
It is impossible to out-swim a shark – sharks reach speeds of 44 mph (70 km/h). Humans can run about 21 mph (35 km/h).
The sailfish is the fastest swimmer, reaching 68 mph (109 km/h), although a black marlin has been clocked at 80 mph (128 km/h).
The slowest fish is the Sea Horse, which moves along at about 0.01 mph (0.016 km/h).
Dolphins can reach 37 mph (60 km/h).
Of the 650 types of leeches, only the Hirudo medicinalis is used for medical treatments.
The heart of a blue whale is the size of a small car.
The tongue of a blue whale is as long as an elephant.
A blue whale weighs as much as 40 rhinos.
The eel is the only fish in the world that spawns in the middle of an ocean but spends its adult lives in rivers.
The scales of a crocodile are made of ceratin, the same substance that hooves and fingernails are made of.
A crocodile’s tongue is attached to the roof of its mouth and cannot move it.
A snail has two pairs of tentacles on its head. One pair is longer than the other and houses the eyes. The shorter pair is used for smelling and feeling its way around. (Some snail species have only one pair of tentacles, thus they have just one eye.)
The heaviest crustacean ever found was a lobster weighing 42 lb (19 kg), caught in 1934.
The largest jellyfish ever caught measured 7’6″ (2,3 m) across the bell with a tentacle of 120 ft (36 m) long.
The largest giant squid ever recorded was captured in the North Atlantic in 1878. It weighed 4 tons. Its tentacles measured 10 m (35 ft) long.
The giant squid has the biggest eyes of any animal: its eyes measure 16 inches (40 cm) in diameter.
Domestic cats purr at about 26 cycles per second, the same frequency as an idling diesel engine.
Sharks are immune to almost all known diseases.
Sharks and rays also share the same kind of skin: instead of scales, they have small tooth-like spikes called denticles. The spikes are so sharp that shark skin has long been used as sandpaper.
Animals also are either right-handed or left-handed. Polar bears are left-handed – and so is Kermit the Frog.
There are 701 types of pure breed dogs. There are about 54 million dogs in the US, and Paris is said to have more dogs than people.
Some bird species, usually flightless birds, have only a lower eyelid, whereas pigeons use upper and lower lids to blink.
Fish and insects do not have eyelids – their eyes are protected by a hardened lens.
Flatfish (halibut, flounder, turbot, and sole) hatch like any other “normal” fish. As they grow, they turn sideways and one eye moves around so they have two eyes on the side that faces up.
Measured in straight flight, the spine-tailed swift is the fastest bird. It flies 106 mph (170 km/h). Second fastest is the Frigate, which reaches 94 mph (150 km/h).
Millions of trees are accidentally planted by squirrels who bury nuts and then forget where they hid them.
There are more than 150 million sheep in Australia, a nation of 21 million people.
New Zealand is home to 4 million people and 70 million sheep.
sports facts
Fishing is the biggest participant sports in the world.
Football (soccer) is the most attended or watched sport in the world.
Boxing became a legal sport in 1901.
More than 100 million people hold hunting licenses.
Jean Genevieve Garnerin was the first female parachutists, jumping from a hot air balloon in 1799.
In 1975 Junko Tabei from Japan became the first woman to reach the top of Everest.
The record for the most Olympic medals ever won is held by Soviet gymnast Larissa Latynina. Competing in three Olympics, between 1956 and 1964, she won 18 medals.
The record for the most major league baseball career innings is held by Cy Young, with 7,356 innings.
The first instance of global electronic communications took place in 1871 when news of the Derby winner was telegraphed from London to Calcutta in under 5 minutes.
In 1898, one of the first programs to be broadcasted on radio was a yacht race that took place in British waters.
Sports command the biggest television audiences, led by the summer Olympics, World Cup Football and Formula One racing.
Gymnasiums were introduced in 900BC and Greek athletes practiced in the nude to the accompaniment of music. They also performed naked at the Olympic Games.
The very first Olympic race, held in 776 BC, was won by Corubus, a chef.
The first modern Olympic Games were held in Athens, Greece in 1896. There were 311 male but no female competitors.
In his time, Michael Schumacher was the highest paid sportsman, ahead of Tiger Woods and Arnold Palmer. (Not including sponsorship endorsements.)
The high jump method of jumping head first and landing on the back is called the Fosbury Flop.
The Major League Baseball teams use about 850,000 balls per season.
About 42,000 tennis balls are used in the plus-minus 650 matches in the Wimbledon Championship.
The longest tennis match took place at Wimbledon 2010 when John Isner of the United States beat Nicolas Mahut of France 6-4, 3-6, 6-7 (7), 7-6 (3), 70-68 in a match that lasted 11 hours and 5 minutes, played over 3 days, June 22, 23 and 24.
A baseball ball has exactly 108 stitches, a cricket ball has between 65 and 70 stitches.
A soccer ball is made up of 32 leather panels, held together by 642 stitches.
Basketball and rugby balls are made from synthetic material. Earlier, pigs’ bladders were used as rugby balls.
The baseball home plate is 17 inches wide.
The very first motor car land speed record was set by Ferdinand Verbiest.
The record for the most NASCAR wins is held by Richard Petty: 200 wins (and 7 championships).
Golf the only sport played on the moon – on 6 February 1971 Alan Shepard hit a golf ball.
Bill Klem served the most seasons as major league umpire – 37 years, starting in 1905. He also officiated 18 World Series.
The oldest continuous trophy in sports is the America’s Cup. It started in 1851, with Americans winning for a straight 132 years until Australia took the Cup in 1983.
Volleyball was invented by William George Morgan of Holyoke, Massachusetts in 1895.
A badminton shuttle easily travels 180 km/h (112 mph).
Ferenc Szisz from Romania, driving a Renault, won the first Formula One Grand Prix held at Le Mans, France in 1906.
facts about our body
The length from your wrist to your elbow is the same as the length of your foot.
Your heart beats 101,000 times a day. During your lifetime it will beat about 3 billion times and pump about 400 million litres (800 million pints) of blood.
It is impossible to lick your elbow. Well, for almost everyone… but a few can.
Your mouth produces 1 litre (1.8 pints) of saliva a day.
The human head contains 22 bones. More on the head and brains
On average, you breathe 23,000 times a day.
Breathing generates about 0.6g of CO2 every minute.
On average, people can hold their breath for about one minute. The world record is 21 minutes 29 seconds, by David
Merlini.
Merlini.
On average, you speak almost 5,000 words a day – although almost 80% of speaking is self-talk (talking to yourself).
Over the last 150 years the average height of people in industrialized nations increased by 10 cm (4 in).
In the 19th century, American men were the tallest in the world, averaging 1,71 metres (5’6″). Today, the average height for American men is 1,763 m (5 feet 9-and-half inches), compared to 1,815 m (5’10″) for Swedes, and 1,843 m (5’11″) for the Dutch, the tallest Caucasians.
The tallest nation in the world is the Watusis of Burundi: 1.98 m (6 feet 6 inches) tall.
If the amount of water in your body is reduced by just 1%, you’ll feel thirsty.
It is impossible to sneeze and keep one’s eyes open at the same time.
55% of people yawn within 5 minutes of seeing someone else yawn.
Hippocrates, the Father of Medicine, suggested that a woman could enlarge her bust line by singing loudly and often.
A person can live without food for about a month, but only about a week without water.
You’ll drink about 75,000 litres (20,000 gallons) of water in your lifetime.
After a certain period of growth, hair becomes dormant. That means that it is attached to the hair follicle until replaced
by new hair.
by new hair.
Hair on the head grows for between two and six years before being replaced. In the case of baldness, the dormant hair was not replaced with new hair.
Men loose about 40 hairs a day. Women loose about 70 hairs a day.
In the Middle Ages the length from the tip of the middle finger to the elbow was called an ell.
A person remains conscious for eight seconds after being decapitated.
The first successful human sex change took place in 1950 when Danish doctor Christian Hamburger operated on New Yorker George Jorgensen, who became Christine Jorgensen.
The muscle that lets your eye blink is the fastest muscle in your body. It allows you to blink 5 times a second.
On average, you blink 15 000 times a day. Women blink twice as much as men.
A typical athlete’s heart churns out 25 to 30 litres (up to 8 gallons) of blood per minute.
We have four basic tastes plus umami. The salt and sweet taste buds are at the tip of the tongue, bitter at the base, and sour along the sides; umami is a mixture of tastes sensed along the center of the tongue.
Not all our taste buds are on our tongue; about 10% are on the palette and the cheeks.
Unless food is mixed with saliva you cannot taste it.
The liver is the largest of the body’s internal organs. The skin is the body’s largest organ.
On average a hiccup lasts 5 minutes.
Fingernails grow nearly 4 times faster than toenails.
Your middle fingernail grows the fastest.
Your finger nails grow at 1 nanometre per second (0.000 000 001 m/s). Your hair grows at 4 nanometres per second (0.000 000 004 m/s).
It takes about 3 months for the transplanted hair to start growing again.
About 13% of people are left-handed. Up from 11% in the past.
In 1900, a person could expect to live to be 47. Today, the average life expectancy for men and women in developed countries is longer than 70 years.
A newborn baby’s head accounts for one-quarter of its weight.
King Henry I, who ruled in the England in the 12th century, standardized the yard as the distance from the thumb of his outstretched arm to his nose.
The bones in your body are not white – they range in color from beige to light brown. The bones you see in museums are white because they have been boiled and cleaned.
Our eyes are always the same size from birth.
Every person has a unique tongue print.
If all your DNA is stretched out, it would reach to the moon 6,000 times.
Approximately two-thirds of a person’s body weight is water. Blood is 92% water. The brain is 75% water and muscles are 75% water.
The colored part of the eye is called the iris. Behind the iris is the soft, rubbery lens which focuses the light on to a layer, called the retina, in the back of the eye. The retina contains about 125 million rods and 7 million cones. The rods pick up shades of gray and help us see in dim light. The cones work best in bright light to pick up colors.
We actually do not see with our eyes – we see with our brains. The eyes basically are the cameras of the brain.
Saturday, April 23, 2011
earthquake facts
An earthquake is caused by a sudden slip on a fault. A fault is a fracture in the crust of the earth along which rocks on one side have moved relative to those on the other side. Stresses in the earth’s outer layer push the sides of the fault together, pressure builds up and the rocks slip suddenly, releasing energy in waves that travel through the rock to cause the shaking that we feel during an earthquake.
Earthquakes tend to be concentrated in narrow zones. There are 7 major crustal plates on earth, about 50 miles (80 km) thick, all in constant motion relative to one another, moving at the speed at which your fingernail grows, at between 10 and 130 mm (from less than one half to 5 inches) per year.
It is estimated that there are several million earthquakes in the world each year. Many of these earthquakes go undetected because they occur in remote areas, mostly under the sea, or have very small magnitudes. The USGS Earthquake Info Center locates about 20,000 earthquakes each year (about 50 per day). On average, about 60 earthquakes per year are classified as significant, with up to 19 classified as major. A significant earthquake is one of magnitude 6.5 or higher or one of lesser magnitude that causes casualties or considerable damage. Major earthquakes have a magnitude larger than 7.0.
In August 1999, an earthquake registering 7.4 on the open ended Richter Scale hit Turkey, killing more than 15,000 people. The next month, an earthquake registering 7.6 hit Taiwan. Later the same month, an earthquake registering 7.4 hit Mexico. In November, Turkey was hit again by an earthquake that registered 7.2.
Large earthquakes that originate from the sea bed result in tsunamis, causing huge waves to travel 500 mph (800 km/h) or more toward coasts. In 2004, the largest ever such tsunami killed more than 227,000 people in 14 countries along the Indian Ocean. It was estimated to have released more energy than 20,000 atomic bombs.
On January 12, 2010 an earthquake of magnitude 7.0 occurred 10 miles off the coast from Port-Au-Prince, Haiti, killing more than 200,000 people. The earthquake did not, however, came as a surprise to seismologists who predicted the fault slip just a week earlier. Governments and people often ignore the predictions of earthquakes.
The largest earthquake ever recorded occurred in Chile in 1960: it had a magnitude of 9.5. See the list of largest and deadliest earthquakes.
There are 2 basic types of earthquakes. A strike-slip earthquake occurs when the rock on one side of a fault slides horizontally past the other. In a dip-slip earthquake, the fault is at an angle to the surface of the earth and the movement of the rock is up or down.
Did you know? There are more earthquakes in Alaska than in California.
source : http://didyouknow.org/earthquakes/
Monday, February 28, 2011
Indonesia's Infamous Mud Volcano Could Outlive All of Us
Unstoppable. Lusi could spew mud for decades to come.
Since it roared to life in May 2006, a mud volcano near Indonesia's coastal city of Sidoarjo has swallowed homes, rice paddies, factories, and roads, killing 15 people, displacing 40,000, and harming the livelihoods of many more. As the ongoing eruption nears its 5th anniversary, observers wonder whether it will ever stop. The answer: Not anytime soon. A new study predicts the volcano will continue spewing significant amounts of mud for another 2 decades. A second study forecasts that it could grind on as long as 87 years.
The mud volcano has inflicted a punishing blow to the region of Java island 700 kilometers east of the capital, Jakarta. Nicknamed Lusi, a contraction of lumpur (Indonesian for mud) and Sidoarjo, the volcano has so far disgorged 144 million cubic meters of mud, some of which now covers an area roughly twice the size of New York City's Central Park. Much of the mud has been diverted to a nearby river, where it has formed a new 83 hectare island and extended a natural delta. Compensation and mitigation have cost at least $767 million, according to Humanitus, a nongovernmental organization in Melbourne, Australia, that is studying the disaster's social impact. That is a fraction of the real economic toll, which is still being tallied.
Lusi may be a harbinger of disasters to come. "Like a volcanic eruption, a mud eruption is just the effect of geological activity, and I'm sure in the future another mud volcano must erupt in this region," says Soffian Hadi Djojopranoto, a geologist with the Sidoarjo Mudflow Mitigation Agency. "We need very serious research to understand this phenomenon."
Despite being the most intensely studied mud volcano ever, scientists have failed to agree on the cause of the eruption, which began in the early-morning hours of 29 May 2006. Mud suddenly started gushing out of vents 200 meters from a rig drilling an exploratory gas well. Drilling logs indicate problems with the well several hours before the eruption, and many scientists believe there was an underground blowout. Others, however, suggest that a magnitude-6.3 earthquake that occurred 2 days earlier and 280 kilometers away activated a local fault. Despite the uncertainty, the Indonesian government pressured the Bakrie family, majority owners of the drilling company and one of the country's wealthiest families, to foot most of the bill for compensation and mitigation.
Debate now centers on how Lusi's plumbing works. "The most important piece of work now is to estimate the longevity," says Richard Davies, a geologist at Durham University in the United Kingdom. That will determine if mud-handling countermeasures are sufficient. Dueling hypotheses have led to different forecasts. Davies argues that the eruption is driven by pressurized water from a deep aquifer in permeable material beneath an impermeable rock layer. He argues that the wellbore pierced the impermeable rock, allowing water to gush up and sweep overlying mud to the surface. Modeling this scenario using combinations of known quantities, such as total ejected mud volume after 1 year and 3 years and assumed parameters, including aquifer size, Davies and colleagues arrived at an estimated longevity of 26 years, published online on 24 February in the Journal of the Geological Society. They also predict that the ground around Lusi will subside up to 475 meters from its original elevation, with mud filling the crater.
Others augur that Lusi will be kicking around far longer. Michael Manga, a geologist at the University of California, Berkeley, contends that pressure and fluid originate not in the deep aquifer but in a shallower mud layer. In a paper in review, his team predicts that an ever-widening circle of subterranean mud will get sucked into the volcanic system and pushed to the surface. The model "is a new way of thinking about how eruptions work," Manga says. His team estimates a 50% chance that the eruption will last 40 years and a 33% chance that it will drag on for 87 years.
The predictions are getting a mixed reception. Peter Flemings, a geologist at the University of Texas, Austin, has not seen Manga's results, but he says his "gut feeling" is that tapping into a large permeable aquifer, as Davies proposes, would produce the volume of material spewing from Lusi. The "absolutely critical assumption," Flemings says, is the aquifer's size—and calculating that from limited data, he says, "is fraught with uncertainty." Davies's subsidence projections, meanwhile, "look big," says Heri Andreas, a geophysicist at the Institute of Technology Bandung in Indonesia. GPS surveys of ground deformation show that after an initial period during which the ground was sinking up to 4 centimeters per day, subsidence has tapered off to just several centimeters per year.
For more robust projections, says Manga, "we need more and better data." And more is at stake than scientific models. Long-term social, ecological, and infrastructure programs can't be planned "until this geological phenomenon is better understood," says Humanitus Director Jeffrey Richards. Humanitus is organizing a May symposium in Surabaya at which Richards hopes experts will forge a consensus on what studies are most likely to reveal Lusi's geological secrets. Davies would like to see a well drilled into the aquifer some distance from Lusi to measure pressures. Other options are 3D seismic surveys of the subsurface.
Numerous efforts to plug the volcano have failed. Fortunately, the mud flow is now manageable, says Djojopranoto. After peaking at 180,000 cubic meters per day in early 2007, the rate has tapered to 10,000 cubic meters per day. A system of 6- to 7-meter-high earthen dikes encloses some 700 hectares of ponds where mud and water is collected and then pumped into the Porong River, where it is adding to a natural delta downstream. The impact on the Porong has been minimal, given that it historically carried heavy sediment loads from magmatic volcanoes upstream, Djojopranoto says.
Environmentalists claim that authorities are understating some of Lusi's ill effects. Studies by nongovernmental organizations in 2007 indicated that high sedimentation was smothering marine life, particularly bottom-dwelling creatures like snails, says Pius Ginting of the Indonesian Forum for Environment. An ongoing concern, he says, is the mud's toxicity, which he claims is laden with carcinogenic polyaromatic hydrocarbons—a contention that Djojopranoto says has never been independently verified.
In Lusi's vicinity, the mitigation bureau has rerouted roads and resettled most families. Mud volcano tourism is providing income, says Djojopranoto, but "not enough to revive the economy." Even after the eruption ends, Lusi may erupt periodically or ooze mud for centuries. "On east Java, we have mud volcanoes that have been active for hundreds of years," Djojopranoto says. None, however, compare in size, in societal harm, or in the puzzles that Lusi continues to present to scientists.
More Evidence Against Dark Matter?
Nothing hidden. Without dark matter, MOND neatly explains the relation between the mass of visible matter in a gas-rich galaxy like this one and the galaxy's rotation speed.
Thousands of physicists, astrophysicists, and astronomers are searching for dark matter, mysterious stuff whose gravity seems to hold the galaxies together. However, an old and highly controversial theory that simply changes the law of gravity can explain a key property of galaxies better than the standard dark-matter theory, one astronomer reports. That claim isn't likely to win over many skeptics, but even some theorists who favor the standard theory say the analysis hands them a homework problem they should solve.
"The standard theory should explain this, and it doesn't yet. That's fair to say," says Simon White, a cosmologist at the Max Planck Institute for Astrophysics in Garching, Germany, who was not involved in the current analysis.
In 1933, Swiss astronomer Fritz Zwicky suggested the existence of dark matter when he found that the galaxies in a particular cluster swirl about each other too fast to be bound by their gravity alone. In the 1970s, American astronomer Vera Rubin and others discovered that the stars at the edges of individual galaxies also appear to move too fast to be held by the gravity of the stars in the center. Those outer stars ought to move more slowly than the ones circling closer in—just as Jupiter orbits the sun more slowly than Earth. Instead, the speed of the stars generally increases with the distance from the galactic center, eventually flattening out at a maximum value. That observation seemed to clinch the case for some sort of dark matter.
Or did it? In 1983, Mordehai Milgrom a physicist at the Weizmann Institute of Science in Rehovot, Israel, found that he could explain the so-called galaxy rotation curves without dark matter if he simply assumed that on the galactic scale, dynamics and gravity worked a bit differently from what Isaac Newton postulated. Specifically, Milgrom assumed that for very small accelerations, the square of the acceleration, not just the acceleration, is proportional to the gravitational force.
For the past 28 years, Milgrom's idea, known as Modified Newtonian Dynamics (MOND) has generated a long-simmering debate. Many researchers argue that ever more evidence from clusters of galaxies, the largest scale structure of the universe, and the afterglow of the big bang points to the existence of dark matter. Still, a few researchers counter that when they look at the details, MOND does a better job—at least on the galactic scale.
Now, in the latest shot from the MOND side, Stacy McGaugh, an astronomer at the University of Maryland, College Park, reports that MOND can explain an observed correlation between the mass and the rotation speed of galaxies—that is, the speed of those outer stars—called the baryonic Tully-Fisher relation. MOND researchers had tried to do this before, but for their models to work, they had to make an untested assumption about the relationship between a star's mass and the amount of light it puts out. That assumption introduces a large uncertainty, weakening the argument.
To avoid that problem, McGaugh gathered data from various sources on 47 galaxies that contain more hydrogen gas than stars. The mass of the gas can then be estimated directly. McGaugh made a plot of visible mass versus rotation speed for the galaxies. He then plotted the prediction that comes straight out of MOND in a few lines of algebra. The MOND line went right through the data. "You draw the line and the data fall right on it," McGaugh says. "No muss, no fuss." He reports the result in a paper in press at Physical Review Letters.
Crucially, McGaugh finds very little scatter in the data—just what would be expected if the mass of gas and stars was directly determining the rotation speed. It's not clear exactly what dark-matter models would predict, McGaugh says. However, such models make no strong connection between the amount of visible matter and the rotation speed. Indeed, galaxies with the same mass of dark matter can have different numbers of stars. So it would be surprising if dark-matter models yielded such a tight correlation.
"I think the data are good, and the fact that MOND fits is striking," says White, who has worked extensively on simulating the evolution of the universe. "I think Stacy is right in holding this up and saying [to dark-matter modelers], 'Look at this [correlation]. Go see if you can explain it.' " Still, White says, dark matter can explain the variations in the afterglow of the big bang and other cosmological data with which MOND struggles.
But whether MOND is right may be beside the point, says Jerry Sellwood, a theoretical astrophysicist at Rutgers University in New Brunswick, New Jersey. "The real strength of Stacy's paper is that it points to something that can't be explained in cold dark matter, irrespective of whether MOND is right." At the least, Sellwood says, McGaugh deserves credit for keeping others honest about what their models can do.
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