Tuesday, April 26, 2011
Combating lice may be assisted by a new genome
By Randolph e. Schmid, associated PressWASHINGTON — research sometimes may be lousy job. Literally in 1957 their quest to understand how life works, researchers reported Monday they have Sequenced the genome of the human body Packet.This law, those annoying little root, that live on human blood and place their eggs in the clothes.From a practical point of view of the findings may lead to better ways of eliminating this parasite, which can transmit disease to humans, according to the researchers, who were led by Ewen f. Kirkness j. Craig Venter Institute in Rockville, Md and Barry r. Pittendrigh from University of IllinoisUrbana For its digestionhumans Wesz is based on specific types of bacteria that are resistant to antibiotics. So find a way to get drugs to the bacteria can kill lice too. For more information about lice knowing can also lead to new kinds of repellents.Genome lonowa is small and contains relatively few genes associated with light reception or reacting to smell and taste, the research found.The researchers said, it seems that humans evolved from humans Wesz lonowa head of the people, time to start wearing clothes, offering lice another place to hide.In addition, they noted that lonowa people and lonowa chimpanzee evolved from a common ancestor between 5 million and 7 million years ago.It was more than annoyance, ever since then, potentially carrying typhus, Relapsing fever and Trench fever. "In addition to its importance in the context of the health of the human genome louse is essential for understanding the evolution of the insects, "said may, Berenbaum, head of the Department of Entomology at the University of Illinois, in a statement.Genome Sequencing effort involved researchers at institutions in the u.s., Europe, 28, Australia and South Korea Copyright 2010 The Associated Press. All rights reserved. This material may not be published, broadcast, rewritten or redistributed. Guidelines: You share in the USA TODAY Community, so please keep your comments smart and civil. Don't attack other readers personally and keep your language decent. Use the "report abuse" button to make the difference. Learn more.
U.S.-Russian crew blasts to space station
By Peter Leonard, PressBAIKONUR, Kazakhstan — two Us Astronauts and a Russian Wigura issue, successfully Wednesday with the mission to the international space station, which will see the last ever swing visits with the orbiting Mir space laboratory.Astronauts U.S. Douglas Wheelock and Shannon Walker and Russian Fyodor Yurchikhin drawn in the Russian Soyuz rocket, its Pobudzacze incendiary Starry sky over Central Asia making steppe. Their Soyuz TMA-19 spacecraft is set to reach stations Friday The trio will be on board the space station to see the final Shuttle — Endeavour — to depart from its last planned mission to the laboratory in November before the fleet is finally withdrew.Wheelock said he was saddened to see shuttle Go, but described his mission as an exciting new beginning. "Of course, is the change in our program ... but not always bad, is to change the "Wheelock, who takes over as Commander of the 25 Expedition as only the current crew returns to Earth in approximately three months, said the draft Conference news.From the airport szczekowych Venerable Soyuz will take over as the only means through which astronauts will be able to travel to the space station, which has raised some concerns about over-reliance on craft designed Soviet. Crowd astronauts relatives, space officials and others gasped in awe as they watched the rocket slowly dissapearing on distanceleaving ghostly white cloud. Broke into applause at the announcement of successful entry into orbit craft nine minutes after launch. "This was probably one of the more beautiful runs ever seen, "said NASA Spokesman Josh Byerly. shortly after the people at home Saw glittering dot space station quickly moving overhead in a rare coincidence.On Wednesday the rocket marked a landmark landmark, is the hundredth flight in the station.Wheelock said their mission will be the first to take full advantage of the capacity of the station as the orbiting Mir space lab. He said he was especially enthralled by your contribution to the engineering of new materials and its role in ensuring that the achievements in the field of medicine. "We are finally getting to the point when we use the international space station for its original purpose and that is that science and research, "Byerly said after the run.Wheelock, Colonel United States Army, returns to the space station for the first time since his club two weeks on the discovery at the end of 2007, when he and his colleagues, earned accolades for their work repairing facility energy generation.Walker is making her first trip to the space station, and thus the in the footsteps of her husband, Andrew Thomas, one of a handful of U.S. astronauts to live on board the Russian Mir station, the old in the 1990s.Like the other starts from the Baikonur Cosmodrome leased Russian in southern Kazakhstan, their mission had verified the routine.After installation of Poland for their pressure suits just passed to the North, the crew received the final message of encouragement from officials, including the head of the Russian space agency.In the final salute before mounting the bus to the console is to launching a group of well-wishers were welcomed by Walker with the letters spelling out "Go Shannon!"Before the bus engines, Yurchikhin by young daughter, Yelena, were held aloft and kissed her father through the glass.In the console the astronauts satellite, closely linked to their seats in the rocket some two hours before the start, when their families and colleagues waited anxiously on the platform to display a little more than one kilometre from the hotel.Against the background of the steppe, starkly dim light on the gantry up rocket Soyuz shimmered on the «known as Gagarin's Pad. Is the site from which the SOVIET UNION sent Yuri Gagarin in 1961, in addition to become the first man in space.Within one hour prior to the launch of regular updates on the final preparations crackled with speakers platform view.When it came time, rocket roared to life and not touching the ground before gradually lifted off to heaven wywracania, dramatically moving shadow sky white phosphorous.Three person crew include the Russian commander Alexander Skvortskov, a NASA flight engineer Tracy Caldwell Dyson and Russian Mikhail Kornienko, who on the orbiting Mir space laboratory since April. Copyright 2010 Associated Press. All rights reserved. This material may not be published, broadcast, rewritten or redistributed. Guidelines: You share in the USA TODAY Community, so please keep your comments smart and civil. Don't attack other readers personally and keep your language decent. Use the "report abuse" button to make the difference. Learn more.
Obama Plan to land on the asteroid may be unrealistic to 2025
By Traci Watson, Special for USA TODAYMillions of miles from Earth, two astronauts hover weightlessly next to a giant space rock, selecting pebbles for scientific research. The spaceship where they'll sleep floats just overhead. Beyond it, barely visible in the sky, is a glittering speck. It's Earth.It sounds like a science-fiction movie, but this surreal scene could, if President Obama has his way, become a reality. However, unlike Hollywood depictions in such movies as Armageddon, it's going to be a lot harder to pull off.
Almost 50 years after President Kennedy proposed sending a man to the moon "before this decade is out," Obama has set an equally improbable goal. He has proposed a 2025 date for NASA to land humans on an asteroid, a ball of rock hurtling around the sun.
The moon is 240,000 miles away. A trip to an asteroid would be 5 million miles — at a minimum.
Why go?
If the mission ever gets launched, it would mark a milestone just as significant as Neil Armstrong's "small step" on the moon, experts say. To go to an asteroid, humans would have to venture for the first time into "deep space," where the sun, not the Earth, is the main player.
An asteroid trip "would really be our first step as a species outside the Earth-moon system," says planetary scientist Andy Rivkin of the Applied Physics Laboratory. "This would be taking off the training wheels."
Asteroids have always been passed over as a destination for human explorers. Then-president George H.W. Bush wanted NASA to go to Mars, while his son, George W. Bush, chose the moon. During the past six years, NASA spent $9 billion building a spaceship, rocket and other gear to help reach the second Bush's goal of returning humans to the lunar surface by 2020.
In February, Obama took steps toward killing Bush's moon program, which was beset by technical troubles and money woes. Two months later, in a speech at Cape Canaveral, Obama announced that the astronauts' next stop is an asteroid.
So far, the Obama administration has been quiet on the need for a major sum of money to accomplish his goal. And unlike Kennedy, who used Sputnik to promote the moon mission, Obama doesn't have a geopolitical imperative to justify the goal. Congress is resisting Obama's change of direction, which could delay investment in the program.
If Obama wants to bolster his cause, there's a rationale he could cite: An asteroid could wipe out as many human lives as a nuclear bomb. The dominant scientific theory posits that dinosaurs went extinct because of a direct hit from an asteroid as wide as San Francisco. A space rock big enough to kill thousands slams into Earth every 30,000 years, according to a January report from the National Research Council.
That scenario provided the rationale for asteroid missions in various Hollywood movies, including Armageddon. The 1998 film, which starred Bruce Willis, grossed more than $200 million at box office in the U.S. and more than $500 million worldwide. It went on to be a staple on cable television.
But if Americans think they have an understanding of the challenge of going to an asteroid, they're wrong. "I loved the movie," says Laurie Leshin, a top NASA official who is involved in the early planning stages of an asteroid mission, although "it was completely inaccurate."
Obama's plans for NASA have drawn many opponents, including Armstrong, but their criticism centers on the administration's reliance on private space companies to ferry astronauts to orbit. The goal of an asteroid hasn't been questioned as much.
That doesn't mean it would be easy. Although experts agree it could be done, here are four asteroid-size reasons why life won't imitate art.
•Astronauts can't hop on a space shuttle to get there.
In Armageddon, Willis' character and his crew blast off in two modified space shuttles to reach the killer asteroid. But NASA has long planned to retire the shuttles within the next year. And even if they weren't all headed to museums, they're useless as asteroid transporters.
The shuttles were built only to circle Earth, says Dan Adamo, a former mission control engineer who has studied human missions to asteroids. They don't carry the fuel to jump into deep space, and their heat shields aren't designed to withstand the extra-high temperatures of returning from a destination other than the Earth's orbit.
What's needed instead is a giant rocket on the scale of the monstrous Saturn V — taller than Big Ben — that propelled man to the moon in the 1960s and 1970s. Such a project is "a difficult challenge" that will cost in the multiple billions of dollars, says Ray Colladay, a member of NASA's advisory council.
NASA spent more than $52 billion in 2010 dollars to develop and build the Saturn V. Building a 21st-century version can be done but will require a sharp increase in the NASA budget later this decade, some space experts say.
"That's the issue everybody wants to duck right now, because it's uncomfortable to face that," Colladay says.
NASA would also need to build a spaceship where the astronauts can live and store all the oxygen, food and water needed for a long voyage. One option is to launch a small space pod carrying the crew, then, once safely in space, unleash an inflatable habitat, Leshin says.
NASA has little practice with such a blow-up spacecraft.
•The trip takes a long, long time.
Willis and company arrive at their target asteroid in a few days, if not a few hours. Admittedly, it's streaking toward Earth at the time. NASA would prefer to go to one before it gets to that stage.
Studies by Adamo, former astronaut Thomas Jones and others show that a round trip to a target asteroid would typically take five to six months. That assumes NASA shoots for one of the 40 or so asteroids that come closest to the Earth's path in the 2020s and 2030s and relies on spacecraft similar to those NASA had designed for Bush's moon mission.
Another problem during the journey — the crew would spend months "cooking" in space radiation, says NASA's Dave Korsmeyer, who has compiled a list of the most accessible asteroids. Shuttle passengers are somewhat screened from such radiation by Earth's magnetic field. Astronauts who leave Earth's orbit have no such protection.
Space radiation raises the risk of cancer and in extreme cases causes nausea and vomiting, says Walter Schimmerling, former program scientist of NASA's space radiation program. The astronauts might need to take drugs to prevent the ill effects of radiation.
Then there's the "prolonged isolation and confinement" that the crew will have to endure, says Jason Kring of Embry-Riddle Aeronautical University. "This crew will be more on their own than any other crew in history."
If there's an emergency halfway into the trip, the astronauts would not be able to get home in a few days, as the Apollo 13 crew did. Instead it would take weeks, if not months.
•Humans can't walk or drive on an asteroid.
Once they land on the asteroid "the size of Texas," the heroes of Armageddon run over the spiky terrain, except when they're steering two tank-like vehicles. In reality, even the biggest asteroids have practically no gravity. So anything in contact with the surface could easily drift away.
"You don't land on an asteroid," says former Apollo astronaut Rusty Schweickart, a longtime advocate of asteroid studies. "You pull up to one and dock with it. ... And getting away from it, all you have to do is sneeze and you're gone." He envisions a spaceship hovering next to the asteroid and occasionally firing its thrusters to stay in place.
Astronauts wouldn't walk on an asteroid. They would drift next to it, moving themselves along with their gloved hands.
To keep from floating into space, crewmembers could anchor a network of safety ropes to the asteroid's surface, but "that has its own risks, because we don't understand how strong the surfaces of asteroids are and whether (they) would hold an astronaut in place," says Daniel Scheeres, a planetary scientist at the University of Colorado.
The minimal gravity also means that any dust the astronauts stir up will hang in a suspended cloud for a long time. Because there's no weather on an asteroid, there's no erosion to smooth the dust particles.
"It's all going to stay pretty razor-sharp. ... It's not the most friendly stuff in the universe," Korsmeyer says. Keeping humans safe as they explore an asteroid "is going to be really tricky."
•Humanity doesn't hang in the balance.
In Armageddon, NASA must send a crew to an asteroid or life on Earth will be wiped out. "Even the bacteria," says the NASA chief, played by Billy Bob Thornton.
In the real world, that irrefutable motivation is absent. By 2025, Obama's target date, there will have been four presidential elections. Any could result in the mission's cancellation, just as Obama canceled Bush's moon plan. "The politics of this is far more challenging than the engineering," Colladay says.
The Obama administration has promised to increase NASA's budget by $6 billion over the next five years, but priorities may change. The Bush administration, for example, in 2007 cut long-term funding for its own moon program by $1.2 billion.
As the deficit looms larger, "especially as the November elections come along ... I would just not be surprised if enthusiasm for some big human spaceflight mission ends," says Marcia Smith, founder of spacepolicyonline.com.
As it is, the extra $6 billion Obama has promised NASA is inadequate for all the tasks the agency is supposed to tackle, Jones says. "The declaration that we're going to deep space is not matched by budget reality," he says.
Leshin, the NASA official, responds that the agency is embarking on a research program that will lead to new, less costly technologies. The agency will build new spacecraft over a period of many years, so the costs don't pile up all at once, she says.
"If we're making progress toward goals that are exciting and important to the American people, then it should be a sustainable program," Leshin says.
She is optimistic that relatively soon, NASA astronauts will speed toward a rendezvous with an asteroid, and that it will be better than in the movies.
"The first time we send humans beyond the cradle of the Earth-moon system, it's going to be extraordinary," Leshin says. "We will have gone further with humans in space than ever before. It will be an incredible first."
Guidelines: You share in the USA TODAY community, so please keep your comments smart and civil. Don't attack other readers personally, and keep your language decent. Use the "Report Abuse" button to make a difference. Read more.
Almost 50 years after President Kennedy proposed sending a man to the moon "before this decade is out," Obama has set an equally improbable goal. He has proposed a 2025 date for NASA to land humans on an asteroid, a ball of rock hurtling around the sun.
The moon is 240,000 miles away. A trip to an asteroid would be 5 million miles — at a minimum.
Why go?
If the mission ever gets launched, it would mark a milestone just as significant as Neil Armstrong's "small step" on the moon, experts say. To go to an asteroid, humans would have to venture for the first time into "deep space," where the sun, not the Earth, is the main player.
An asteroid trip "would really be our first step as a species outside the Earth-moon system," says planetary scientist Andy Rivkin of the Applied Physics Laboratory. "This would be taking off the training wheels."
Asteroids have always been passed over as a destination for human explorers. Then-president George H.W. Bush wanted NASA to go to Mars, while his son, George W. Bush, chose the moon. During the past six years, NASA spent $9 billion building a spaceship, rocket and other gear to help reach the second Bush's goal of returning humans to the lunar surface by 2020.
In February, Obama took steps toward killing Bush's moon program, which was beset by technical troubles and money woes. Two months later, in a speech at Cape Canaveral, Obama announced that the astronauts' next stop is an asteroid.
So far, the Obama administration has been quiet on the need for a major sum of money to accomplish his goal. And unlike Kennedy, who used Sputnik to promote the moon mission, Obama doesn't have a geopolitical imperative to justify the goal. Congress is resisting Obama's change of direction, which could delay investment in the program.
If Obama wants to bolster his cause, there's a rationale he could cite: An asteroid could wipe out as many human lives as a nuclear bomb. The dominant scientific theory posits that dinosaurs went extinct because of a direct hit from an asteroid as wide as San Francisco. A space rock big enough to kill thousands slams into Earth every 30,000 years, according to a January report from the National Research Council.
That scenario provided the rationale for asteroid missions in various Hollywood movies, including Armageddon. The 1998 film, which starred Bruce Willis, grossed more than $200 million at box office in the U.S. and more than $500 million worldwide. It went on to be a staple on cable television.
But if Americans think they have an understanding of the challenge of going to an asteroid, they're wrong. "I loved the movie," says Laurie Leshin, a top NASA official who is involved in the early planning stages of an asteroid mission, although "it was completely inaccurate."
Obama's plans for NASA have drawn many opponents, including Armstrong, but their criticism centers on the administration's reliance on private space companies to ferry astronauts to orbit. The goal of an asteroid hasn't been questioned as much.
That doesn't mean it would be easy. Although experts agree it could be done, here are four asteroid-size reasons why life won't imitate art.
•Astronauts can't hop on a space shuttle to get there.
In Armageddon, Willis' character and his crew blast off in two modified space shuttles to reach the killer asteroid. But NASA has long planned to retire the shuttles within the next year. And even if they weren't all headed to museums, they're useless as asteroid transporters.
The shuttles were built only to circle Earth, says Dan Adamo, a former mission control engineer who has studied human missions to asteroids. They don't carry the fuel to jump into deep space, and their heat shields aren't designed to withstand the extra-high temperatures of returning from a destination other than the Earth's orbit.
What's needed instead is a giant rocket on the scale of the monstrous Saturn V — taller than Big Ben — that propelled man to the moon in the 1960s and 1970s. Such a project is "a difficult challenge" that will cost in the multiple billions of dollars, says Ray Colladay, a member of NASA's advisory council.
NASA spent more than $52 billion in 2010 dollars to develop and build the Saturn V. Building a 21st-century version can be done but will require a sharp increase in the NASA budget later this decade, some space experts say.
"That's the issue everybody wants to duck right now, because it's uncomfortable to face that," Colladay says.
NASA would also need to build a spaceship where the astronauts can live and store all the oxygen, food and water needed for a long voyage. One option is to launch a small space pod carrying the crew, then, once safely in space, unleash an inflatable habitat, Leshin says.
NASA has little practice with such a blow-up spacecraft.
•The trip takes a long, long time.
Willis and company arrive at their target asteroid in a few days, if not a few hours. Admittedly, it's streaking toward Earth at the time. NASA would prefer to go to one before it gets to that stage.
Studies by Adamo, former astronaut Thomas Jones and others show that a round trip to a target asteroid would typically take five to six months. That assumes NASA shoots for one of the 40 or so asteroids that come closest to the Earth's path in the 2020s and 2030s and relies on spacecraft similar to those NASA had designed for Bush's moon mission.
Another problem during the journey — the crew would spend months "cooking" in space radiation, says NASA's Dave Korsmeyer, who has compiled a list of the most accessible asteroids. Shuttle passengers are somewhat screened from such radiation by Earth's magnetic field. Astronauts who leave Earth's orbit have no such protection.
Space radiation raises the risk of cancer and in extreme cases causes nausea and vomiting, says Walter Schimmerling, former program scientist of NASA's space radiation program. The astronauts might need to take drugs to prevent the ill effects of radiation.
Then there's the "prolonged isolation and confinement" that the crew will have to endure, says Jason Kring of Embry-Riddle Aeronautical University. "This crew will be more on their own than any other crew in history."
If there's an emergency halfway into the trip, the astronauts would not be able to get home in a few days, as the Apollo 13 crew did. Instead it would take weeks, if not months.
•Humans can't walk or drive on an asteroid.
Once they land on the asteroid "the size of Texas," the heroes of Armageddon run over the spiky terrain, except when they're steering two tank-like vehicles. In reality, even the biggest asteroids have practically no gravity. So anything in contact with the surface could easily drift away.
"You don't land on an asteroid," says former Apollo astronaut Rusty Schweickart, a longtime advocate of asteroid studies. "You pull up to one and dock with it. ... And getting away from it, all you have to do is sneeze and you're gone." He envisions a spaceship hovering next to the asteroid and occasionally firing its thrusters to stay in place.
Astronauts wouldn't walk on an asteroid. They would drift next to it, moving themselves along with their gloved hands.
To keep from floating into space, crewmembers could anchor a network of safety ropes to the asteroid's surface, but "that has its own risks, because we don't understand how strong the surfaces of asteroids are and whether (they) would hold an astronaut in place," says Daniel Scheeres, a planetary scientist at the University of Colorado.
The minimal gravity also means that any dust the astronauts stir up will hang in a suspended cloud for a long time. Because there's no weather on an asteroid, there's no erosion to smooth the dust particles.
"It's all going to stay pretty razor-sharp. ... It's not the most friendly stuff in the universe," Korsmeyer says. Keeping humans safe as they explore an asteroid "is going to be really tricky."
•Humanity doesn't hang in the balance.
In Armageddon, NASA must send a crew to an asteroid or life on Earth will be wiped out. "Even the bacteria," says the NASA chief, played by Billy Bob Thornton.
In the real world, that irrefutable motivation is absent. By 2025, Obama's target date, there will have been four presidential elections. Any could result in the mission's cancellation, just as Obama canceled Bush's moon plan. "The politics of this is far more challenging than the engineering," Colladay says.
The Obama administration has promised to increase NASA's budget by $6 billion over the next five years, but priorities may change. The Bush administration, for example, in 2007 cut long-term funding for its own moon program by $1.2 billion.
As the deficit looms larger, "especially as the November elections come along ... I would just not be surprised if enthusiasm for some big human spaceflight mission ends," says Marcia Smith, founder of spacepolicyonline.com.
As it is, the extra $6 billion Obama has promised NASA is inadequate for all the tasks the agency is supposed to tackle, Jones says. "The declaration that we're going to deep space is not matched by budget reality," he says.
Leshin, the NASA official, responds that the agency is embarking on a research program that will lead to new, less costly technologies. The agency will build new spacecraft over a period of many years, so the costs don't pile up all at once, she says.
"If we're making progress toward goals that are exciting and important to the American people, then it should be a sustainable program," Leshin says.
She is optimistic that relatively soon, NASA astronauts will speed toward a rendezvous with an asteroid, and that it will be better than in the movies.
"The first time we send humans beyond the cradle of the Earth-moon system, it's going to be extraordinary," Leshin says. "We will have gone further with humans in space than ever before. It will be an incredible first."
Guidelines: You share in the USA TODAY community, so please keep your comments smart and civil. Don't attack other readers personally, and keep your language decent. Use the "Report Abuse" button to make a difference. Read more.
Ask USA today weather
Doyle Rice, the USA TODAY weather editor, is available to answer your weather and climate questions. Send your questions to askweather@usatoday.com. If your question is selected, you can look for the answer below. Due to the volume of questions received, not all can be answered, either individually or on this page. ***********************************************
Q: Why is Texas so humid?— D.A. Marquez
A: Eastern Texas and the entire southeastern part of the USA receive plenty of moisture blown in from the nearby Gulf of Mexico, along with evaporated moisture from lakes, rivers, the ground and vegetation. With extensive heating from the spring, summer and fall sun high in the sky at these low latitudes, the evaporation potential is high, and the combination of warm temperatures and high-moisture content makes it really feel muggy.
However, while eastern Texas can be very humid and muggy, much of western Texas is quite dry, thanks to mountain air that dries out as it descends into Texas from Mexico and New Mexico. The dividing line is most pronounced in summer and is known as a dryline, which separates the different air masses.
Our state weather snapshot of Texas has more about the climate of the Lone Star State. — Doyle Rice
******************************************************************************************
Q: My 8-year old son asked me the other day, "At what temperature can you see your breath?" Can you help us? — John Robinette
A: That was a tough one, so I asked for help from an expert at the National Weather Service, meteorologist James Peronto. Here is his answer:
You can see your breath at a variety of temperatures (even as high as 70 degrees). It really depends on how much moisture is in the air (relative humidity). When you exhale, the air has water vapor in it. That exhaled water vapor is at a certain temperature (typically warmer than the surrounding air you are exhaling into). Warmer air can hold more water vapor.
Therefore, as your exhaled air hits the cooler surrounding air, the water vapor condenses into tiny water droplets (the same way clouds form). The higher the relative humidity of the surrounding air you exhale into, the better chance of creating water droplets from your breath.
So, getting back to your original question, the temperature at which you see your breath can really vary, depending upon the relative humidity of the surrounding air. I've seen my own breath at temperatures around 60 degrees in very moist air! Hope this helps. — James Peronto
******************************************************************************************
Q: Can it be too cold too snow?— James Hoffman
A: No, it can snow even at very cold temperatures if there's a source of moisture and some way to lift or cool the air. But when temperatures drop into the single digits or below zero, the air's capacity for water vapor becomes very small, making heavy snow unlikely. Most heavy snowfalls happen with relatively warm air temperatures near the ground — usually 15 degrees or above.
One example of a cold place that doesn't get much snow is Barrow, Alaska, where an average of only two inches of snow falls in January, when the average high temperature is only 2 degrees and the average low is -20 degrees.
A little snow even falls at the South Pole, where the temperature hardly ever rises above zero – the highest ever there is 7 degrees. But, the colder the air, the less moisture it has to make snow, which is why a year's worth of South Pole snow melts down to less than two or three inches of water.
The National Snow and Ice Data Center has an FAQ with much more info about snow. — Doyle Rice
******************************************************************************************
Q: I would like to know the direction of the sunset, when facing the horizon, over several weeks, in the months of September and October. Would the sunset move to the right or to the left on the horizon over 5-day intervals?— Sophia Deno
A: In the Northern Hemisphere, between the summer solstice (roughly June 21) and the winter solstice (roughly Dec. 21), the location at which the sun sets, relative to the observer, moves a fraction toward the left each day. The process reverses between the winter and summer solstices, as the sunset location would move a bit to the right each day.
This USA TODAY resource page and this FAQ page have much more about the seasons, solstices, equinoxes, and the length of days. — Doyle Rice
******************************************************************************************
Q: I often wonder why the sky, which starts-out brilliant clear on October mornings, usually clouds-up around 10 a.m.? I am a photographer and the clouds dull the colors of the foliage. What's even stranger is that folks just 40 miles to the south, at about 1,000 feet lower altitude, say the sky was sunny all day. Any explanation? This has happened quite a few times. Around 3 p.m., suddenly the clouds dissipate but it's too late for me by then. — Myron Shulman
A: First, when the air is unstable, despite a clear start, clouds tend to increase in the late-morning and into the afternoon.
According to the excellent weather textbook A World of Weather: Fundamentals of Meteorology, these clouds are known as fair-weather cumulus clouds, those shorter heaps of puffy clouds that often develop on a tranquil, sunny day as parcels of surface air are heated by the ground and buoyed upward. Sometimes enough clouds form to entirely cover the sky and rain will fall. The clouds will diminish later in the day as the sun's heating fades away.
This blog entry from Nick Borelli at FoxWeather details more about this.
The air's stability is important for our weather, as it helps determine what types of clouds form and what kinds of precipitation fall from them. This USA TODAY resource page explains much more about atmospheric stability and instability.
Second, as for why more clouds tend to form at higher elevations, it has to do with orographic lift, when air is forced up and over mountains. This air rises, cools, and forms clouds.
For more info, this Google page has lots of photos and diagrams about orographic lift. — Doyle Rice
******************************************************************************************
Q: Does anyone track the number of daily record high temperatures or daily low temperatures that are set across the USA? It would be interesting to see if there are more record high temperatures than record low temperatures, in view of global warming.— Jack Lucero Fleck
A: Yes. Meteorologist Guy Walton of the Weather Channel has kept track of this since 2000. Through last week, since Jan. 1, 2000, he says there have been 310,437 daily record highs and 152,064 daily record lows. The numbers for all-time record highs and lows are even more striking: Since Jan. 1, 2000, there have been 1,470 all-time record highs and only 40 all-time record lows.
Walton uses this U.S. records database from the National Climatic Data Center to track this.
Walton co-authored a 2009 study in the journal Geophysical Research Letters about this. According to the article abstract, the current ratio of daily record high maximum temperatures to record low minimum temperatures, when averaged across the USA, is about two to one.... Based on one of the global warming scenarios from the Intergovernmental Panel on Climate Change, this ratio is projected to continue to increase, with ratios of about 20 to 1 by mid-century, and roughly 50 to 1 by the end of the century. — Doyle Rice
******************************************************************************************
Q: With more carbon dioxide and other gases being released into the atmosphere as a result of climate change, is the standard atmospheric pressure at sea level increasing? And, are lighter gases being displaced into outer space because of the increase in CO2, etc.?—David Glass
A: I turned to an expert, Andrew Gettelman, a scientist at the National Center for Atmospheric Research, for help with these questions. He determined that the answer to both questions is no:
"The gases that are being released add only a little bit of mass to the atmosphere. Carbon dioxide comprises oxygen that's already in the air, as well as carbon stored in the ground. However, the amounts are small and many orders of magnitude less than the changes in mass and pressure caused by regular surface pressure variations due to storms.
The atmosphere, below 60 miles, has a mixture of major long-lived gases (such as oxygen, nitrogen, argon and carbon dioxide), which are not displaced by the gases that are being released by human activities. The gases mix with the other gases, the mixture we call 'air.'" — Andrew Gettelman
******************************************************************************************
Q: Which presses down on Earth's surface more, a high- or low-pressure area?— Allen Langley
A: High pressure presses down on the Earth more than low pressure, since air sinks in high pressure and rises in low pressure.
As the name says, an area of "high" pressure is an area where the air's pressure is higher than the pressure of the surrounding air. A "low' is where it's lower. Meteorologists don't have any particular number that divides high from low pressure; it's the relative differences that count.
The pressure is high at the surface where air is slowly descending — much too slowly to feel. And, this is going on over a large area, maybe a few hundred square miles. As air descends, it warms, which inhibits the formation of clouds. This is why high pressure is usually associated with nice weather.
The air that descends in high-pressure areas has to get to high altitudes in some way, and its done by rising in areas where the pressure at the surface is low. As air rises it cools. As the air cools, the humidity in it begins to condense into tiny drops of water, or if it's cold enough, into tiny ice crystals. If there's enough water or ice, rain or snow begin to fall. This is why low pressure is associated with bad weather.
Incidentally, I wrote an article last year about new research into how high and low pressure might be a trigger for earthquakes. — Doyle Rice
******************************************************************************************
Q: What kind of winter are we expecting in the Middle Atlantic states?— Sue Lasater
A: The Climate Prediction Center, the best source for long-term climate forecasts, shows that for the months of December 2010, January 2011 and February 2011, most of the southern tier of states should be warmer than average. The areas that are expected to be colder-than-average are the northern Plains, the Northwest, and much of Alaska. The rest of the nation — including the Mid-Atlantic — should see temperatures close to average. This map shows this.
As for rain and snow, most of the southern tier should be drier-than-average, while the western Great Lakes, Ohio Valley, and Northwest should be wetter than average. Most of the Mid-Atlantic should see a typical amount of rain and snow, with southern Virginia and the Carolinas seeing less precipitation than normal. Winter precipitation map.
These forecasts will continue to be refined and updated over the next several months, with their "official" winter forecast coming out in November.
This forecast is based partially on the fact that the USA has entered a La Nina climate pattern. During typical La Nina winters, significant cold-air outbreaks can be more frequent across the northern tier of the USA, while the southern states experience less storminess and precipitation. In the eastern USA, during a La Nina winter, there are generally fewer coastal storms and more Alberta Clippers than normal.
This USA TODAY graphic shows more about La Nina and El Nino.
AccuWeather also came out with its winter forecast earlier this month. — Doyle Rice
******************************************************************************************
Q: In a 365-day cycle, does every point on Earth have an equal number of daylight/night minutes?— G. Kiner
A: That's an excellent question, one that stumped me. For help, I contacted Travis Metcalfe, an astrophysicist at the National Center for Atmospheric Research in Boulder, Colo. Here is his answer:
"For questions like this, I find it helpful to think of the extreme cases (with fictional flat horizons). Someone on the equator gets 12 hours of daylight and 12 hours of darkness every day, 365 days a year (no seasons). Someone at one of the poles gets 24 hours of daylight for half the year, and 24 hours of darkness for the other half. This means that at the poles, there is only one sunrise and one sunset per year, as the sun just spirals upwards in the sky for a few months, and then spirals back down.
A slight subtlety is that because Earth is not on a perfectly circular orbit around the sun, the number of days between the spring and fall equinox (186.32 days in 2010) differs from the number of days between fall and spring equinox (178.84 days in 2009-10).
The Earth moves slightly faster when it is closer to the sun (with the peak speed around the New Year), so someone at the North Pole gets 2% less than six months of darkness, while someone at the South Pole gets 2% more than six months. At the mid-latitudes here in the USA, the asymmetry is slightly smaller.
So the final answer would be no, every point on Earth does not get an equal amount of darkness and light in a given year." — Travis Metcalfe
******************************************************************************************
Q: Why is Texas so humid?— D.A. Marquez
A: Eastern Texas and the entire southeastern part of the USA receive plenty of moisture blown in from the nearby Gulf of Mexico, along with evaporated moisture from lakes, rivers, the ground and vegetation. With extensive heating from the spring, summer and fall sun high in the sky at these low latitudes, the evaporation potential is high, and the combination of warm temperatures and high-moisture content makes it really feel muggy.
However, while eastern Texas can be very humid and muggy, much of western Texas is quite dry, thanks to mountain air that dries out as it descends into Texas from Mexico and New Mexico. The dividing line is most pronounced in summer and is known as a dryline, which separates the different air masses.
Our state weather snapshot of Texas has more about the climate of the Lone Star State. — Doyle Rice
******************************************************************************************
Q: My 8-year old son asked me the other day, "At what temperature can you see your breath?" Can you help us? — John Robinette
A: That was a tough one, so I asked for help from an expert at the National Weather Service, meteorologist James Peronto. Here is his answer:
You can see your breath at a variety of temperatures (even as high as 70 degrees). It really depends on how much moisture is in the air (relative humidity). When you exhale, the air has water vapor in it. That exhaled water vapor is at a certain temperature (typically warmer than the surrounding air you are exhaling into). Warmer air can hold more water vapor.
Therefore, as your exhaled air hits the cooler surrounding air, the water vapor condenses into tiny water droplets (the same way clouds form). The higher the relative humidity of the surrounding air you exhale into, the better chance of creating water droplets from your breath.
So, getting back to your original question, the temperature at which you see your breath can really vary, depending upon the relative humidity of the surrounding air. I've seen my own breath at temperatures around 60 degrees in very moist air! Hope this helps. — James Peronto
******************************************************************************************
Q: Can it be too cold too snow?— James Hoffman
A: No, it can snow even at very cold temperatures if there's a source of moisture and some way to lift or cool the air. But when temperatures drop into the single digits or below zero, the air's capacity for water vapor becomes very small, making heavy snow unlikely. Most heavy snowfalls happen with relatively warm air temperatures near the ground — usually 15 degrees or above.
One example of a cold place that doesn't get much snow is Barrow, Alaska, where an average of only two inches of snow falls in January, when the average high temperature is only 2 degrees and the average low is -20 degrees.
A little snow even falls at the South Pole, where the temperature hardly ever rises above zero – the highest ever there is 7 degrees. But, the colder the air, the less moisture it has to make snow, which is why a year's worth of South Pole snow melts down to less than two or three inches of water.
The National Snow and Ice Data Center has an FAQ with much more info about snow. — Doyle Rice
******************************************************************************************
Q: I would like to know the direction of the sunset, when facing the horizon, over several weeks, in the months of September and October. Would the sunset move to the right or to the left on the horizon over 5-day intervals?— Sophia Deno
A: In the Northern Hemisphere, between the summer solstice (roughly June 21) and the winter solstice (roughly Dec. 21), the location at which the sun sets, relative to the observer, moves a fraction toward the left each day. The process reverses between the winter and summer solstices, as the sunset location would move a bit to the right each day.
This USA TODAY resource page and this FAQ page have much more about the seasons, solstices, equinoxes, and the length of days. — Doyle Rice
******************************************************************************************
Q: I often wonder why the sky, which starts-out brilliant clear on October mornings, usually clouds-up around 10 a.m.? I am a photographer and the clouds dull the colors of the foliage. What's even stranger is that folks just 40 miles to the south, at about 1,000 feet lower altitude, say the sky was sunny all day. Any explanation? This has happened quite a few times. Around 3 p.m., suddenly the clouds dissipate but it's too late for me by then. — Myron Shulman
A: First, when the air is unstable, despite a clear start, clouds tend to increase in the late-morning and into the afternoon.
According to the excellent weather textbook A World of Weather: Fundamentals of Meteorology, these clouds are known as fair-weather cumulus clouds, those shorter heaps of puffy clouds that often develop on a tranquil, sunny day as parcels of surface air are heated by the ground and buoyed upward. Sometimes enough clouds form to entirely cover the sky and rain will fall. The clouds will diminish later in the day as the sun's heating fades away.
This blog entry from Nick Borelli at FoxWeather details more about this.
The air's stability is important for our weather, as it helps determine what types of clouds form and what kinds of precipitation fall from them. This USA TODAY resource page explains much more about atmospheric stability and instability.
Second, as for why more clouds tend to form at higher elevations, it has to do with orographic lift, when air is forced up and over mountains. This air rises, cools, and forms clouds.
For more info, this Google page has lots of photos and diagrams about orographic lift. — Doyle Rice
******************************************************************************************
Q: Does anyone track the number of daily record high temperatures or daily low temperatures that are set across the USA? It would be interesting to see if there are more record high temperatures than record low temperatures, in view of global warming.— Jack Lucero Fleck
A: Yes. Meteorologist Guy Walton of the Weather Channel has kept track of this since 2000. Through last week, since Jan. 1, 2000, he says there have been 310,437 daily record highs and 152,064 daily record lows. The numbers for all-time record highs and lows are even more striking: Since Jan. 1, 2000, there have been 1,470 all-time record highs and only 40 all-time record lows.
Walton uses this U.S. records database from the National Climatic Data Center to track this.
Walton co-authored a 2009 study in the journal Geophysical Research Letters about this. According to the article abstract, the current ratio of daily record high maximum temperatures to record low minimum temperatures, when averaged across the USA, is about two to one.... Based on one of the global warming scenarios from the Intergovernmental Panel on Climate Change, this ratio is projected to continue to increase, with ratios of about 20 to 1 by mid-century, and roughly 50 to 1 by the end of the century. — Doyle Rice
******************************************************************************************
Q: With more carbon dioxide and other gases being released into the atmosphere as a result of climate change, is the standard atmospheric pressure at sea level increasing? And, are lighter gases being displaced into outer space because of the increase in CO2, etc.?—David Glass
A: I turned to an expert, Andrew Gettelman, a scientist at the National Center for Atmospheric Research, for help with these questions. He determined that the answer to both questions is no:
"The gases that are being released add only a little bit of mass to the atmosphere. Carbon dioxide comprises oxygen that's already in the air, as well as carbon stored in the ground. However, the amounts are small and many orders of magnitude less than the changes in mass and pressure caused by regular surface pressure variations due to storms.
The atmosphere, below 60 miles, has a mixture of major long-lived gases (such as oxygen, nitrogen, argon and carbon dioxide), which are not displaced by the gases that are being released by human activities. The gases mix with the other gases, the mixture we call 'air.'" — Andrew Gettelman
******************************************************************************************
Q: Which presses down on Earth's surface more, a high- or low-pressure area?— Allen Langley
A: High pressure presses down on the Earth more than low pressure, since air sinks in high pressure and rises in low pressure.
As the name says, an area of "high" pressure is an area where the air's pressure is higher than the pressure of the surrounding air. A "low' is where it's lower. Meteorologists don't have any particular number that divides high from low pressure; it's the relative differences that count.
The pressure is high at the surface where air is slowly descending — much too slowly to feel. And, this is going on over a large area, maybe a few hundred square miles. As air descends, it warms, which inhibits the formation of clouds. This is why high pressure is usually associated with nice weather.
The air that descends in high-pressure areas has to get to high altitudes in some way, and its done by rising in areas where the pressure at the surface is low. As air rises it cools. As the air cools, the humidity in it begins to condense into tiny drops of water, or if it's cold enough, into tiny ice crystals. If there's enough water or ice, rain or snow begin to fall. This is why low pressure is associated with bad weather.
Incidentally, I wrote an article last year about new research into how high and low pressure might be a trigger for earthquakes. — Doyle Rice
******************************************************************************************
Q: What kind of winter are we expecting in the Middle Atlantic states?— Sue Lasater
A: The Climate Prediction Center, the best source for long-term climate forecasts, shows that for the months of December 2010, January 2011 and February 2011, most of the southern tier of states should be warmer than average. The areas that are expected to be colder-than-average are the northern Plains, the Northwest, and much of Alaska. The rest of the nation — including the Mid-Atlantic — should see temperatures close to average. This map shows this.
As for rain and snow, most of the southern tier should be drier-than-average, while the western Great Lakes, Ohio Valley, and Northwest should be wetter than average. Most of the Mid-Atlantic should see a typical amount of rain and snow, with southern Virginia and the Carolinas seeing less precipitation than normal. Winter precipitation map.
These forecasts will continue to be refined and updated over the next several months, with their "official" winter forecast coming out in November.
This forecast is based partially on the fact that the USA has entered a La Nina climate pattern. During typical La Nina winters, significant cold-air outbreaks can be more frequent across the northern tier of the USA, while the southern states experience less storminess and precipitation. In the eastern USA, during a La Nina winter, there are generally fewer coastal storms and more Alberta Clippers than normal.
This USA TODAY graphic shows more about La Nina and El Nino.
AccuWeather also came out with its winter forecast earlier this month. — Doyle Rice
******************************************************************************************
Q: In a 365-day cycle, does every point on Earth have an equal number of daylight/night minutes?— G. Kiner
A: That's an excellent question, one that stumped me. For help, I contacted Travis Metcalfe, an astrophysicist at the National Center for Atmospheric Research in Boulder, Colo. Here is his answer:
"For questions like this, I find it helpful to think of the extreme cases (with fictional flat horizons). Someone on the equator gets 12 hours of daylight and 12 hours of darkness every day, 365 days a year (no seasons). Someone at one of the poles gets 24 hours of daylight for half the year, and 24 hours of darkness for the other half. This means that at the poles, there is only one sunrise and one sunset per year, as the sun just spirals upwards in the sky for a few months, and then spirals back down.
A slight subtlety is that because Earth is not on a perfectly circular orbit around the sun, the number of days between the spring and fall equinox (186.32 days in 2010) differs from the number of days between fall and spring equinox (178.84 days in 2009-10).
The Earth moves slightly faster when it is closer to the sun (with the peak speed around the New Year), so someone at the North Pole gets 2% less than six months of darkness, while someone at the South Pole gets 2% more than six months. At the mid-latitudes here in the USA, the asymmetry is slightly smaller.
So the final answer would be no, every point on Earth does not get an equal amount of darkness and light in a given year." — Travis Metcalfe
******************************************************************************************
Subscribe to:
Posts (Atom)