Ask a science teacher: What creates the wind?

Wind is caused by a difference in pressure from one area to another area on the surface of the Earth. Air naturally moves from high to low pressure, and when it does so, it is called wind.

Generally, we can say that the cause of the wind is the uneven heating of the Earth’s surface by the Sun. The Earth’s surface is made of different land and water areas, and these varying surfaces absorb and reflect the Sun’s rays unevenly. Warm air rising yields a lower pressure on the Earth, because the air is not pressing down on the Earth’s surface, while descending cooler air produces a higher pressure.

But there are many other factors affecting wind direction. For example, the Earth is spinning, so air in the Northern Hemisphere is deflected to the right by what is known as the Coriolis force. This causes the air, or wind, to flow clockwise around a high-pressure system and counter-clockwise around a low-pressure system.

The closer these low- and high-pressure systems are together, the stronger the “pressure gradient,” and the stronger the winds. Vegetation also plays a role in how much sunlight is reflected or absorbed by the surface of the Earth. Furthermore, snow cover reflects a large amount of radiation back into space. As the air cools, it sinks and causes a pressure increase.

And wind can get even more complex. Some parts of the Earth, near the equator, receive direct sunlight all year long and have a consistently warmer climate. Other parts of the Earth, near the polar regions, receive indirect rays, so the climate is colder.

As the warm air from the tropics rises, colder air moves in to take the place of the rising warmer air. This movement of air also causes the wind to blow. It’s a dynamic, complex mechanism, which is why weather forecasting is not quite a precise science.

Today we see windmills, used to make electricity, in operation in all parts of the United States, but especially along our coasts. Coastal regions tend to have fairly strong winds blowing in from ocean to land during the day and out from land to ocean during the night. The cause of this phenomenon is that land heats up and cools down faster than water, again creating a pressure gradient.

From the book, "Ask a Science Teacher: 250 Answers to Questions You’ve Always Had About How Everyday Stuff Really Works"; Copyright © Larry Scheckel, 2013. Publishes December 17; available wherever books are sold.

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Can new clues solve mystery of Roanoke's Lost Colony?

It's the coldest case in American history.

The settlers who inhabited the 16th century North Carolina colony of Roanoke mysteriously disappeared centuries ago, leaving behind only two clues: the words "Croatoan" and "Cro" carved into a fort's gatepost and a nearby tree.

Many conspiracy theories have been concocted as to what happened in 1590, a mere three years after the colonists arrived in North America, but none have proven fruitful. Until now. Technological advances and the discovery of a cover-up on an ancient map have let researchers unearth new clues that may help bring an end to the mystery of America's lost colony.

Researchers began reinvestigating the mysterious disappearance after they noticed two strange patches on a long-forgotten map of the area called "La Virginea Pars" drawn by the colony's governor John White. Researchers at the First Colony Foundation in Durham, N.C., believed the two patches might be covering up something revealing. 

The map was analyzed by scientists at the British Museum, who discovered a small red-and-blue symbol.

"Our best idea is that parts of [Sir Walter] Raleigh's exploration in North America were a state secret, and the map 'cover-up' was an effort to keep information from the public and from foreign agents," historian and principal investigator Eric Klingelhofer of Mercer University in Macon, Ga., told National Geographic, which partially funded the effort.

we get the oldest maps we can find—so we can get a historic sense of what was there and what's there now—and orient them,"

- Malcolm LeCompte, research associate at Elizabeth City State University in North Carolina

Historians believe that the symbol may have been the location of a fort the settlers fled to, running from violence or disease.

"It's obvious that that's the only way they could have survived. No single Indian tribe or village could have supported them ... They were over a hundred people," Klingelhofer said.

The current theory is that the colonists fled 50 miles south to Hatteras Island, then known as Croatoan Island. Klingelhofer suggests they may have gone in a different direction.

He believes the settlers traveled west via the Albermarle Sound to the Chowan River where there might have been a protected inlet occupied by a friendly tribe.

"It's a very strategic place, right at the end of Albemarle Sound," he said. "You can go north up the Chowan River to Virginia or west to the Blue Ridge Mountains. They were big trading partners with other Native American tribes."

Once the researchers uncovered the secrets of the "La Virginea Pars" map, they scheduled a trip to visit the area along with the help of magnetometers and ground-penetrating radar (GPR).

"What we do is we get the oldest maps we can find—so we can get a historic sense of what was there and what's there now—and orient them," said research associate Malcolm LeCompte at Elizabeth City State University in North Carolina, who was responsible for the GPR.

He looked for similarities between the old map and the current topography. The researchers than used GPR, which sends radio waves into the ground and measures the echo of the signals that bounce off of objects underground.

LeCompte and his team found a previously undiscovered pattern that indicated the possibility of multiple wooden structures approximately 3 feet underground.

"I don't know if it's one or a group [of structures]," he said, adding that they "could be joined or they could be close together."

The mere presence of the buried structure indicates that there was a colonial presence in the area. However, while the new information has begun to give archaeologists a clearer view as to what might have happened to the Roanoke colony, there are still pieces to the puzzle that remain unfound. What's the next step in solving this age-old mystery? 

"We have to go in and dig some holes, I guess," Swindell said.

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Mars One unveils first stage of plan to colonize Red Planet

All components of Mars One's settlement are slated to reach their destination by 2021. The hardware includes two living units, two life-support units, a second supply unit and two rovers.Bryan Versteeg/Mars One

An artist's depiction of the private Mars One lander for a unmanned mission to Mars slated to launch in 2018. The design is based on NASA's Phoenix Mars lander.Mars One Foundation

An ambitious project that aims to send volunteers on a one-way trip to Mars unveiled plans for the first private unmanned mission to the Red Planet Tuesday, a robotic vanguard to human colonization that will launch in 2018.

The non-profit Mars One foundation has inked deals with Lockheed Martin Space Systems and Surrey Satellite Technology Ltd. (SSTL) to draw up mission concept studies for the private robotic flight to Mars. Under the plan, Lockheed Martin will build the Mars One lander, and SSTL will build a communications satellite, the companies' representatives announced at a news conference here today.

"We're very excited to have contracted Lockheed Martin and SSTL for our first mission to Mars," Mars One co-founder and CEO Bas Lansdorp said in a statement. "These will be the first private spacecraft to Mars and their successful arrival and operation will be a historic accomplishment." [Photos: How Mars One Wants to Colonize the Red Planet]

Lockheed Martin designed, built and operated the lander for NASA's 2007 Phoenix Mars lander mission to look for water ice beneath the surface of the Martian arctic, and the Mars One Lander will be based on the design of Phoenix.

"This is an ambitious project and we're already working on the mission concept study, starting with the proven design of Phoenix," Ed Sedivy, civil space chief engineer at Lockheed Martin, said in a statement.

The Mars One lander will have a robotic arm capable of scooping up soil, just like the Phoenix lander; an experiment to extract water from the soil; a power experiment to demonstrate the use of thin-film solar panels on the planet's surface; and a camera for continuous video recording.

The lander will also carry aboard the winner of a worldwide university challenge that Mars One plans to launch in 2014, as well as several Science, Technology, Engineering and Mathematics (STEM) education challenge winners.

The satellite, to be built by SSTL, will be in synchronous orbit around Mars and will provide a high-bandwidth link to relay data and live video from the lander back to Earth.

"This study gives us an unprecedented opportunity to take our tried and tested approach and apply it to Mars One's imaginative and exhilarating challenge of sending humans to Mars through private investment," Sir Martin Sweeting, executive chairman of SSTL, said in a statement.

Mars One invited anyone over age 18 to apply to be an astronaut. About 165,000 people answered the first call for applications, which closed at the end of August. There will be four rounds of selection before the finalists are chosen.

Mars One estimates it will cost $6 billion to get the first four people to Mars, and $4 billion for each subsequent trip. The funding will come from sponsorships and exclusive partnerships, and the company recently announced a reality TV show to pay for the project. The foundation is also launching a crowd-funding campaign through the website Indiegogo. Contributors will earn the right to vote on several mission decisions, including the winners of STEM and university challenges, Mars One says.

"Our 2018 mission will change the way people view space exploration as they will have the opportunity to participate," Lansdorp said. "They will not only be spectators, but also participants."

Copyright 2013 SPACE.com, a TechMediaNetwork company. All rights reserved. This material may not be published, broadcast, rewritten or redistributed.

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Moon walk or Death Star? China’s lunar plans a mystery

An artist's conception of China's Chang'e 3 robot on the moon.ESA

A Chinese satellite has entered lunar orbit and should drop a robotic probe on the moon as early as Friday -- the first such moon landing in nearly four decades. But China's ultimate plans are unclear, whether simply scientific or the first steps toward a military base on the moon.

The Chang’e 3 satellite was launched from southwest China on Dec. 2 and entered orbit around the moon on Dec. 6. It will deposit a robotic rover on the moon as early as Dec. 14. China’s long range goals are murky, according to Thomas Reiter, director for human spaceflight and operations with the European Space Agency (ESA). Yet militarizing the moon would be a shame, he said.

“I could not imagine that human exploration is getting … pushed by military consideration,” Reiter told FoxNews.com. “It would really be a pity.”

'It could indicate interest in the next decade in bringing humans to the lunar surface.'

- Thomas Reiter, director of human spaceflight and operations at the ESA

The ESA is helping China to the moon, a landing that will be the first controlled descent since Russia’s Luna-24 landed in 1976. The space agency’s worldwide network of satellites are tracking the science mission while expert teams on the ground are lending technical assistance. But not even the ESA knows exactly what China has planned.

“The strategic long-term goals of China in human exploration … are not very clear yet,” Reiter said. China’s goals could include landing men on the moon, a feat only the United States has managed to do, the last time 41 years ago, he said.

“I believe they are taking a clear path with some first steps, and I could imagine yes, this could be interest in the next decade in bringing humans to the lunar surface.”

Russia also has shown interest in the moon, Reiter said. Yet the ESA, like NASA, has no concrete plans to do more than help when it comes to lunar exploration.

“NASA is not going to the moon with a human as a primary project probably in my lifetime,” NASA administrator Charles Bolden said at an April panel in Washington. NASA spokesman David Weaver echoed that sentiment, telling FoxNews.com that it is working with international partners to plan missions to the moon and elsewhere.

“We are deeply involved in lunar science, with two satellites currently orbiting the moon,” he said. “The global community is committed to working together on a unified deep-space exploration strategic plan, with robotic and human missions to destinations that include near-Earth asteroids, the moon and Mars. 

Reiter also put the moon on a short list, including low-Earth orbit and Mars. But due to budgetary restrictions, the ESA has no plans of its own to visit the moon.

“For the moment, we do not have a dedicated lunar exploration program,” he told FoxNews.com. At a recent conference in Naples, the space agency proposed a program for a European lunar landing mission to the south pole.

“Due to the overall economic situation of the member states, this could not be approved,” Reiter said. “We are looking into a cooperative mission with the Russian partners.”

Yet Reiter said the agency remains focused on the moon, despite a decades-long dry spell in lunar landings.

“I believe the moon is still a very important destination,” he said. “If we really intend to take a human mission to Mars … in two decades or maybe a little more, this way leads by the moon.”

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How many people heard the Sermon on the Mount? Or the Gettysburg Address?

Have you ever wondered how many people in the audience actually heard the Gettysburg Address? How about the Sermon on the Mount or Moses at Sinai?

The answer to those questions, according to two New York University researchers, is more than you think.

People gave famous speeches for millennia without amplification. But how many people in the crowd could understand what was being said? In Monty Python's film, "Life of Brian," a large crowd shows up to hear Jesus' sermon, but by the time Jesus' words made it to the fringes of the crowd some clarity was lost. ("Blessed are the cheese-makers.")

The two researchers, Braxton Boren and Agnieszka Roginska at NYU's Music and Audio Research Lab, replicated a famous experiment by Benjamin Franklin using modern scientific techniques, and reported their findings at a meeting of the Acoustical Society of America in San Francisco last week.

The story begins in the late 1730s. A preacher, George Whitefield, was drawing immense crowds at his outdoor sermons in London. At one sermon, held in Mayfair, Whitefield claimed to have addressed 80,000 people, all of whom he presumed could understand him. Franklin didn't believe it and took an opportunity to test the claim in 1739 when Whitefield spoke in Philadelphia.

"I had the curiosity to learn how far he could be heard," Franklin wrote.

Whitefield was described as handsome, slim, and slightly cross-eyed, with a voice "like a lion," according to contemporary reports. He was one of the founders of Methodism in America and was among the most famous preachers of his time.

In Philadelphia, he spoke to an audience of perhaps 6,000 people stretched between Front Street and the Delaware River, a good crowd considering that Philadelphia's population at the time was only about 13,000. Franklin couldn't resist. He walked from the front of the crowd toward the river, listening for the point at which the preacher was no longer intelligible.

Then, he went home and did the calculations.

According to Boren, Franklin ran two numbers, the area over which Whitefield's voice was intelligible, and a guess at how many people could fit in that area. The area, he decided, was about 23,000 square meters.

Using modern modeling technology and archeological records of what Market Street looked like then, the NYU researchers thought Franklin nailed it.

Franklin also estimated each person took up 2 square feet, or about 0.2 square yards. His conclusion then was that Whitefield could have been heard by as many as 125,000 people under perfect conditions, but, Boren said, being a modest New Englander, Franklin concluded that figure was wildly off and settled on "more than 30,000," Boren said.

"There were certain things he didn't account for and certain things he over-accounted for, but by the end his estimate was a pretty good estimate," Boren said.

The original calculation was off, Boren said, because the kind of density Franklin was using is what modern acoustical researchers call "mosh-pit conditions." The crowd more likely was "solid," which is about half a square meter per person, little more than half a square yard, and much less dense.

Using those calculations Boren and Roginska concluded Whitefield could be heard by 20,000-30,000 people on a good day, a perfectly still crowd, no wind or carriages clattering by, just as Franklin said.

Still, how could someone be heard that far? Whitefield was speaking in an area of dense construction and the buildings and streets probably acted as sound reflectors.

But, it was probably more than just the acoustics of his environment.

The NYU computer models, based on Franklin's description, give one answer: Whitefield was very loud. They estimate that if you stood three yards in front of him, his voice would have registered 90 decibels, matching the loudest average sound levels from voices ever measured in a modern lab.

"The international standard for loud speech is 74 decibels," Boren said.

According to Jack Randorff, an acoustical consultant and engineer from Ransom Canyon, Texas, the NYU model assumed people could hear about 30 percent of what was being said. Since the audience knew the context of his material, their minds filled in the rest.

Additionally, the style of public speaking was different in the past. Randorff said the speakers stood up straight and might have raised and stretched their arms so their diaphragms were extended.

Speeches of the past also had an entirely different cadence. Orators often spoke in bursts of four or five words with considerable emphasis instead of long phrases. Lincoln might have said, "Four score...and seven years ago….our fathers...brought forth..." It also allowed them to take deep breaths so they could keep going.

The buildings around Whitefield would have added six decibels to his voice, which would have doubled the effective area his voice would have carried, Randorff said.

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Ancient estate and garden fountain unearthed in Israel

The remains of a wealthy estate, a mosaic fountain and a system of pipes connected to a large cistern dating back to the late 10th and early 11th centuries have been unearthed in Ramla in central Israel, archaeologists report.Assaf Peretz; courtesy of the Israel Antiquities Authority.

The remains of a wealthy estate, with a mosaic fountain in its garden, dating to between the late 10th and early 11th centuries have been unearthed in Ramla in central Israel.

The estate was discovered during excavations at a site where a bridge is slated for construction as part of the new Highway 44.

"It seems that a private building belonging to a wealthy family was located there and that the fountain was used for ornamentation," Hagit Torg, excavation director on behalf of the Israel Antiquities Authority, said in a statement. "This is the first time that a fountain has been discovered outside the known, more affluent quarters of Old Ramla."

Fountains from the Fatimid period were mostly found around the center of the Old City of Ramla called White Mosque, Torg added. [Photos: Roadside Dig Reveals 10,000-Year-Old House in Israel]

Researchers found two residential rooms within the estate along with a nearby fountain made of mosaic and covered with plaster and stone slabs; A network of pipes, some made of terra cotta and connected with stone jars, led to the fountain. Next to the estate, archaeologists also found a large cistern and a system of pipes and channels used to transport water.

Other discoveries at the site included oil lamps, parts of dolls made of bones and a baby rattle.

"This is the first time that the fountain's plumbing was discovered completely intact. The pipes of other fountains did not survive the earthquakes that struck the country in 1033 and 1068 CE," Torg said in a statement.

Ramla was founded in the eighth century by the ruler Suleiman Ibn 'Abd al-Malik. Its strategic location on the road from Cairo to Damascus and from Yafo to Jerusalem made Ramla an important economic center.

The entire area seems to have been abandoned in the mid-11th century, likely in the wake of an earthquake, according to the IAA.

Once the excavation is complete, the fountain will be displayed in the city's Pool of Arches compound.

Due to Israel's long history, construction projects often yield archaeological discoveries. For example, a "cultic" temple and traces of a 10,000-year-old house were discovered at Eshtaol west of Jerusalem in preparation for the widening of a road. And during recent expansions of the main road connecting Jerusalem to Tel Aviv, called Highway 1, excavators found a carving of a phallus from the Stone Age, a ritual building from the First Temple era and animal figurines dating back 9,500 years.

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European Space Agency sets tentative date for 1st comet landing Nov. 11

An artist's impression of the Rosetta orbiter deploying the Philae lander to comet 67P/ChuryumovGerasimenko. After an extensive mapping phase by the orbiter in AugustSeptember 2014, a landing site will be selected for Philae to conduct in situ measurements in November 2014.ESAC. Carreau/ATG medialab

BERLIN –  The European Space Agency has set a tentative date for the first landing of a spacecraft on a comet.

ESA says its Rosetta probe will wake up from hibernation Jan. 20 before chasing down comet 67P/Churyumov-Gerasimenko.

If all goes according to plan, Rosetta will launch a lander onto the surface of the comet on Nov. 11, 2014.

The mission is different from NASA's Deep Impact probe that fired a projectile into comet Tempel 1 in 2005 to let scientists study the plume of matter it hurled into space.

ESA's director of science, Mark McCaughrean, said Tuesday that the lander Philae will dig up samples of the comet and analyze them using on-board instruments.

One objective is to learn whether the water on Earth could have come from comets.

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Ancient Mars lake could have supported life, Curiosity rover shows

NASA's Curiosity rover has found evidence of an ancient Martian lake that could have supported life as we know it for long stretches — perhaps millions of years.

This long and skinny freshwater lake likely existed about 3.7 billion years ago, researchers said, suggesting that habitable environments were present on Mars more recently than previously thought.

"Quite honestly, it just looks very Earth-like," said Curiosity lead scientist John Grotzinger, of the California Institute of Technology in Pasadena. [Ancient Mars Could Have Supported Life (Photos)]

"You've got an alluvial fan, which is being fed by streams that originate in mountains, that accumulates a body of water," Grotzinger told SPACE.com. "That probably was not unlike what happened during the last glacial maximum in the Western U.S."

Habitable Mars
The lake once covered a small portion of the 96-mile-wide Gale Crater, which the 1-ton Curiosity rover has been exploring since touching down on the Red Planet in August 2012.

'Quite honestly, it just looks very Earth-like.'

- Curiosity lead scientist John Grotzinger, of the California Institute of Technology in Pasadena

The main task of Curiosity's $2.5 billion mission is to determine whether Gale Crater could ever have supported microbial life. The rover team achieved that goal months ago, announcing in March that a spot near Curiosity's landing site called Yellowknife Bay was indeed habitable billions of years ago.

The new results, which are reported Monday, Dec. 9, in six separate papers in the journal Science, confirm and extend Curiosity's landmark discovery, painting a more complete picture of the Yellowknife Bay area long ago.

This picture emerged from Curiosity's analysis of fine-grained sedimentary rocks called mudstones, which generally form in calm, still water. The rover obtained powdered samples of these rocks by drilling into Yellowknife Bay outcrops.

The mudstones contain clay minerals that formed in the sediments of an ancient freshwater lake, researchers said. Curiosity also spotted some of the key chemical ingredients for life in the samples, including sulfur, nitrogen, hydrogen, oxygen, phosphorus and carbon.

The lake could have potentially supported a class of microbes called chemolithoautotrophs, which obtain energy by breaking down rocks and minerals. Here on Earth, chemolithoautotrophs are commonly found in habitats beyond the reach of sunlight, such as caves and hydrothermal vents on the ocean floor.

"It is exciting to think that billions of years ago, ancient microbial life may have existed in the lake's calm waters, converting a rich array of elements into energy," Sanjeev Gupta of Imperial College London, co-author of one of the new papers, said in a statement.

An icy Martian lake?
The shallow ancient lake may have been about 30 miles long by 3 miles wide, Grotzinger said. Based on the thickness of the sedimentary deposits, the research team estimates that the lake existed for at least tens of thousands of years — and perhaps much longer, albeit on a possibly on-and-off basis.

Taking into account the broader geological context, "you could wind up with an assemblage of rocks that represent streams, lakes and ancient groundwater systems — so for times when the lake might have been dry, the groundwater's still there. This could have gone on for millions or tens of millions of years," Grotzinger said.

The lack of weathering on Gale Crater's rim suggests that the area was cold when the lake existed, he added, raising the possibility that a layer of ice covered the lake on a permanent or occasional basis. But such conditions wouldn't be much of a deterrent to hardy microbes.

"These are entirely viable habitable environments for chemolithoautotrophs," Grotzinger said.

Researchers still don't know if the Gale Crater lake hosted organisms of any kind; Curiosity was not designed to hunt for signs of life on Mars. But if chemolithoautotrophs did indeed dominate the lake, it would put an alien twist on a superficially familiar environment.

"You can imagine that, if life evolved on Mars and never got beyond the point of chemolithoautotrophy, then in the absence of competition from other types of microbes, these systems might have been dominated by that type of metabolic pathway," Grotzinger said. "And that's an un-Earth-like situation."

Copyright 2013 SPACE.com, a TechMediaNetwork company. All rights reserved. This material may not be published, broadcast, rewritten or redistributed.

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Antarctica sets low temperature record of -135.8 degrees

FILE: In this image provided by the National Snow and Ice Data Center, sastrugi stick out from the snow surface in this photo near Plateau Station in East Antarctica. A new look at NASA satellite data revealed that Earth set a new record for coldest temperature recorded in East Antarctica. It happened in August 2010 when it hit -135.8 degrees. Then on July 31 of this year, it came close again: -135.3 degrees.NSIDC/AP

WASHINGTON –  Feeling chilly? Here's cold comfort: You could be in East Antarctica which new data says set a record for "soul-crushing" cold.

Try 135.8 degrees Fahrenheit below zero; that's 93.2 degrees below zero Celsius, which sounds only slightly toastier. Better yet, don't try it. That's so cold scientists say it hurts to breathe.

A new look at NASA satellite data revealed that Earth set a new record for coldest temperature recorded. It happened in August 2010 when it hit -135.8 degrees. Then on July 31 of this year, it came close again: -135.3 degrees.

The old record had been -128.6 degrees, which is -89.2 degrees Celsius.

Ice scientist Ted Scambos at the National Snow and Ice Data Center said the new record is "50 degrees colder than anything that has ever been seen in Alaska or Siberia or certainly North Dakota."

"It's more like you'd see on Mars on a nice summer day in the poles," Scambos said, from the American Geophysical Union scientific meeting in San Francisco Monday, where he announced the data. "I'm confident that these pockets are the coldest places on Earth."

However, it won't be in the Guinness Book of World Records because these were satellite measured, not from thermometers, Scambos said.

"Thank God, I don't know how exactly it feels," Scambos said. But he said scientists do routinely make naked 100 degree below zero dashes outside in the South Pole, so people can survive that temperature for about three minutes.

Most of the time researchers need to breathe through a snorkel that brings air into the coat through a sleeve and warms it up "so you don't inhale by accident" the cold air, Scambos said.

On Monday, the coldest U.S. temperature was a relatively balmy 27 degrees below zero Fahrenheit in Yellowstone, Wyo., said Jeff Masters, meteorology director of the private firm Weather Underground.

"If you want soul-crushing cold, you really have to go overseas," Scambos said in a phone interview. "It's just a whole other level of cold because on that cold plateau, conditions are perfect."

Scambos said the air is dry, the ground chilly, the skies cloudless and cold air swoops down off a dome and gets trapped in a chilly lower spot "hugging the surface and sliding around."

Just because one spot on Earth has set records for cold that has little to do with global warming because it is one spot in one place, said Waleed Abdalati, an ice scientist at the University of Colorado and NASA's former chief scientist. Both Abdalati, who wasn't part of the measurement team, and Scambos said this is likely an unusual random reading in a place that hasn't been measured much before and could have been colder or hotter in the past and we wouldn't know.

"It does speak to the range of conditions on this Earth, some of which we haven't been able to observe," Abdalati said.

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