Sunglasses

Don't Let the Sun Blind You on a Hike in Montana
Photo Courtesy of NASA
Sunglasses are indispensible for any sort of outdoor activity. Whether you are hiking, fishing, backpacking, biking or floating, a quality set of sunglasses does many things. First, sunglasses protect the eye from the sun's harmful rays (described below). Secondly, a good pair of sunglasses will also provide suberb protection from dirt, sand, snow and other "impacts" that have a tendency to find their way into your eyes during active outdoor activities.


The Sun's Harmful Rays

As most people know, the Sun throws out many harmful rays that, over time, can lead to some serious eye problems. Since few people know about the exact type of rays, this section describes the types of rays that is produced by the Sun that are also harmful to the naked eye - especially over extended periods of time.

The Sun's Ultraviolet (UV) Rays : What They Are
UV Rays are ultraviolet rays emitted from the sun. While some wavelenghts of UV Rays are visible (such as "black light"), the harmful UV rays that are emitted from the sun - and which you need to worry about - are invisible. As such, UV Rays are sort of a silent, stealthy light ray that can cause serious damage to the eye over time.

There are three spectrums to UV Rays, the lower spectrum, the middle spectrum and the upper spectrum.

The lower spectrum consists of UVA Rays, which are probably the most "well known" of the Sun's ultraviolet radiation.

The middle spectrum consists of UVB Rays, which are more powerful - and harmful - than UVA Rays.

The upper spectrum, which consists of UVC Rays, are the most powerful of the Sun's UV light.


Blue Light

If the three UV spectrums from the sun are not enough of a problem, a person also needs to worry about Blue Light. Blue Light, which few people are familar with, are called High Energy Visible (HEV) Wavelenghs. Unlike UV Rays, HEV Rays are visible - on the upper end of the visible spectrum. Indeed, HEV Rays are responsible for allowing you to perceive the blue and purple colors.

Unfortunatley, too much exposure to Blue Light can, over time, lead to macular degeneration of the eye. While Blue Light is not as powerful as the Sun's UV Rays, it is still strong enough to cause damage over time.

NASA's probe sends back first pictures of Sun

First pictures of the Sun. Photo: EPA
The Solar Dynamics Observatory, NASA’s probe launched in early February, has beamed home its first pictures of the Sun. The high-resolution images shed light on the mystery of the Sun’s inner processes, particularly as regards solar matter ejected into space. The SDO filmed the solar flares that took place on March 30. During its five-year mission, the probe will be studying the magnetic field of the Sun and how it influences the Earth’s atmosphere.

Fake Astronaut Gets Hit by Artificial Solar Flare

June 3, 2009: In 1972, Apollo astronauts narrowly escaped a potential

catastrophe. On August 2nd of that year, a large and angry sunspot app

eared and began to erupt, over and over again for more than a week,

producing a record-setting fusillade of solar proton radiation. Only pure

luck saved the day. The eruptions took place during the gap between

Apollo 16 and 17 missions, so astronauts missed the storm.

Researchers still wonder, what would have

happened if the timing had been just a little

different, what if astronauts had been caught

unprotected on the surface of the Moon?

Right: One of the August 1972 solar flares.

Click on the image to launch a movie recorded

at the Big Bear Solar Observatory.

NASA needs to know. The agency is in high

gear preparing to send people to the Moon

to set up a manned outpost, a step toward eventually sending humans

to Mars or elsewhere in the solar system. These missions will take

astronauts outside the protection of Earth's magnetic field for months

or even years at a time, and NASA must know how to keep its explorers

safe from extreme solar storms.

So scientists are creating an artificial solar radiation storm right here on

Earth. And they're testing its effects on an artificial human: Matroshka,

the Phantom Torso.

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The European Space Agency's Matroshka and his NASA counterpart
Fred have already flown in experiments aboard the Space Shuttle and
the International Space Station that have shown how other kinds of
space radiation such as cosmic rays penetrate the human body. Now,
scientists at Brookhaven National Laboratory in Upton, New York, are
subjecting an artificial torso to a beam of protons to learn how
astronauts would be affected by the 1972 event.

"We want to know how close it comes to a dangerously acute

exposure," says Francis Cucinotta, the Chief Scientist for NASA's

Radiation Program at the Johnson Space Center in Houston, Texas.

In the parlance of radiation experts, "acute exposure" is brief but

intense. Radiation strikes the body over a relatively short period

of time ranging from minutes to hours—just like a solar flare. This

is different from the "chronic exposure" astronauts normally

experience as they travel through space. Cosmic rays hit their

bodies in a slow drizzle spread out over weeks or months. With chronic

exposure, the body has time to repair or replace damaged cells as it

goes along, but an acute exposure gives the body little time to cope

with the damage.

Above: The radiation beamline at NASA's Space radiation Lab in Brookhaven. [Larger image]

"The biological effects are very sensitive to the dose rate," Cucinotta explains.

"A dose of radiation delivered over a short amount of time is two to three

times more damaging than the same dose over a few days."

At first glance, the 1972 event would seem to fall into the acute category—

it was after all a solar flare. But there's a problem. It was actually a series

of flares producing a radiation storm that was longer and less impulsive

than normal. Radiation exposure would have been neither chronic nor

clearly acute, but somewhere in between. In this gray area, details about

how much of the radiation actually reaches a person’s vital organs —

versus how much is blocked by their spacesuit, skin and muscles —

can make all the difference.

Matroshka is helping scientists understand these details. He's a life-

size plastic replica of a human torso, sans arms and legs. The plastic

closely matches the density of organs and tissues in the human body,

and this Phantom Torso is embedded with hundreds of radiation sensors

throughout his body. He even has real human blood cells.

Right: Matroshka in and out of his white traveling poncho. [Larger image]

"We put blood cells in small tubes in the stomach and in some places in the

bone marrow," some of which are deep within the torso while others are

close to the surface where there's less "tissue" to block radiation. "One

of the questions we have is whether the less shielded parts of the bone

marrow will be [much harder hit]," raising the risks of leukemia and other

cancers.

Using real blood cells lets scientists see how much the radiation damages

the cells' DNA. High-speed particles of proton radiation can smash into

DNA, breaking the string-like molecules. Cells can usually repair these

breaks, but if several breaks occur within a short period of time, the

damage can be irreparable. At best, the cell will then self-destruct. At

worst, it will go haywire and grow out of control, becoming cancerous.

To subject Matroshka to a 1972-style radiation storm, scientists have

devised a way to simulate that event using a high-energy proton beam

at NASA's Space Radiation Lab in Brookhaven. The beam fans out so

that, at the point where Matroshka sits, it's 60 cm across — large

enough to engulf the entire torso. By stepping the energy of the

beam through a series of energy levels, scientists can mimic the

unique energy spectrum of the protons in the 1972 event.

In the upcoming experiment, led by Guenther Reitz of the German

Aerospace Center (DLR) in Cologne, Matroshka's radiation sensors

will reveal how much proton radiation reaches various parts of the

mannequin's body. "With protons, you might have an order of magnitude

(a factor of ten) difference from one part of the body to another," notes

Cucinotta.

The readings will help mission planners figure out how much shielding is

necessary to protect real astronauts from a 72-style storm. The results

will also point researchers in the right direction for medical treatments that

might help mitigate the effects of such an event.

Unlike a real astronaut, Matroshka can withstand multiple flares with no

lasting side effects. A quick transfusion of blood cells and voilà--Matroshka

is ready for another blast.

So let the flares begin—and stay tuned for results.

Source:NASA

Return of the Mars Hoax

For the sixth year in a row, a message about the Red Planet is popping up

in email boxes around the world. It instructs readers to go outside after

dark on August 27th and behold the sky. "Mars will look as large as the full

moon," it says. "No one alive today will ever see this again."

Don't believe it.

Here's what will really happen if you go

outside after dark on August 27th. Nothing.

Mars won't be there. On that date, the red

planet will be nearly 250 million km away

from Earth and completely absent from

the evening sky.

Right: Only in Photoshop does Mars appear

as large as a full Moon.

The Mars Hoax got its start in 2003 when Earth and Mars really did have a

close encounter. On Aug. 27th of that year, Mars was only 56 million km

away, a 60,000-year record for martian close approaches to Earth. Someone

sent an email alerting friends to the event. The message contained some

misunderstandings and omissions—but what email doesn't? A piece of

advanced technology called the "forward button" did the rest.

Tolerant readers may say that the Mars Hoax is not really a hoax, because
it is not an intentional trick. The composer probably believed everything he
or she wrote in the message. If that's true, a better name might be the "Mars
Misunderstanding" or maybe the "Confusing-Email-About-Mars-You-Should-
Delete-and-Not-Forward-to-Anyone-Except-Your-In-Laws."

Another aspect of the Mars Hoax: It says Mars will look as large as the full

Moon if you magnify it 75x using a backyard telescope. The italicized text

is usually omitted from verbal and written summaries of the Hoax. (For

example, see the beginning of this story.) Does this fine print make the

Mars Hoax true? After all, if you magnify the tiny disk of Mars 75x, it does

subtend an angle about the same as the Moon.

No. Even with magnification, Mars does not look the same as a full Moon.

This has more to do with the mysterious inner workings of the human brain

than cold, hard physics. Looking at Mars magnified 75x through a slender

black tube (the eyepiece of a telescope) and looking at the full Moon shining

unfettered in the open sky are two very different experiences.

Above: Mars in August 2003 during a 60,000-year record close approach.

Even then, the planet resembled a bright star, not a full Moon. Photo credit:

John Nemy & Carol Legate of Whistler, B.C.

A good reference is the Moon Illusion. Moons on the horizon look huge; Moons

directly overhead look smaller. In both cases, it is the same Moon, but the human

mind perceives the size of the Moon differently depending on its surroundings.

Likewise, your perception of Mars is affected by the planet's surroundings. Locate

the planet at the end of a little dark tunnel, and it is going to look tiny regardless

of magnification.

Bummer!

To see Mars as big as a full Moon, you'll need a rocketship, and that may take

some time. Meanwhile, beware the Mars Hoax.

source:NASA

Active Mercury

	04.30.2009
April 30, 2009: A NASA spacecraft gliding over the surface of Mercury has revealed that the planet's atmosphere, magnetosphere, and its geological past display greater levels of activity than scientists first suspected. The probe also discovered a large impact basin named "Rembrandt" measuring about 430 miles in diameter. These new findings and more are reported in four papers published in the May 1 issue of Science magazine. The data come from the Mercury Surface, Space Environment, Geochemistry, and Ranging spacecraft--MESSENGER for short. On Oct. 6, 2008, MESSENGER flew by Mercury for the second time, capturing more than 1,200 high-resolution and color images of the planet. Right: The Rembrandt impact basin discovered by MESSENGER during its second flyby of Mercury in October 2008. Credit: NASA/Johns Hopkins University Applied Physics Laboratory/Smithsonian Institution/Carnegie Institution of Washington. [more] "This second Mercury flyby provided a number of new findings," said Sean Solomon, the probe's principal investigator from the Carnegie Institution of Washington. "One of the biggest surprises was how strongly [Mercury's magnetosphere] had changed from what we saw during the first flyby in January 2008." Sign up for EXPRESS SCIENCE NEWS delivery The magnetosphere is a region of space around Mercury enveloped by the planet's magnetic field. Gusty solar wind buffeting the global bubble of magnetism can potentially trigger magnetic storms and other space weather-related phenomena. "During the first flyby, MESSENGER measured relatively calm dipole-like magnetic fields close to the planet. Scientists didn't detect any dynamic features other than some Kelvin-Helmholtz waves," said James Slavin of NASA's Goddard Space Flight Center. Slavin is a mission co-investigator and lead author of one of the papers. "But the second flyby was a totally different situation," he says. MESSENGER observed a highly dynamic magnetosphere with "magnetic reconnection" events taking place at a rate 10 times greater than what is observed at Earth during its most active intervals. "The high rate of solar wind energy input was evident in the great amplitude of the plasma waves and the large magnetic structures measured by the spacecraft's magnetometer throughout the encounter." Above: An artist's concept of Mercury's surprisingly active magnetosphere. Credits: Image produced by NASA/Goddard Space Flight Center/Johns Hopkins University Applied Physics Laboratory//Carnegie Institution of Washington. Image reproduced courtesy of Science/AAAS. [more] Another exciting result is the discovery of a previously unknown large impact basin. The Rembrandt basin is more than 700 kilometers (430 miles) in diameter and if formed on the east coast of the United States would span the distance between Washington, D.C., and Boston. Rembrandt formed about 3.9 billion years ago, near the end of the period of heavy bombardment of the inner Solar System, suggests MESSENGER Participating Scientist Thomas Watters, lead author of another of the papers. Rembrandt is significant, not only because it is big, but also because it is giving researchers a peek beneath the surface of Mercury that other basins have not. "This is the first time we've seen terrain exposed on the floor of an impact basin on Mercury that is preserved from when it formed," explains Watters. "Landforms such as those revealed on the floor of Rembrandt are usually completely buried by volcanic flows." Half of Mercury was unknown until a little more than a year ago. Globes of the planet were blank on one side. Spacecraft images have since revealed 90 percent of the planet's surface at high resolution. This near-global coverage is showing, for the first time, how Mercury's crust was formed. Right: In this interpretive map of Mercury's surface, shades of yellow denote smooth plains of mainly volcanic origin. This type of terrain covers approximately 40% of the planet. The white (empty) slice is the portion of Mercury not yet photographed. Credit: NASA/Johns Hopkins University Applied Physics Laboratory/Arizona State University/Carnegie Institution of Washington. [more] "After mapping the surface, we see that approximately 40 percent is covered by smooth plains," said Brett Denevi of Arizona State University in Tempe, a team member and lead author of a paper. "Many of these smooth plains are interpreted to be of volcanic origin, and they are globally distributed. Much of Mercury's crust may have formed through repeated volcanic eruptions in a manner more similar to the crust of Mars than to that of the moon." Another finding of the flyby is the first detection of magnesium in Mercury's exosphere. The exosphere is an ultrathin atmosphere where the molecules are so far apart they are more likely to collide with the surface than with each other. Material in the exosphere comes mainly from the surface of Mercury itself, knocked aloft by solar radiation, solar wind bombardment and meteoroid vaporization: The probe's Mercury Atmospheric and Surface Composition Spectrometer instrument detected the magnesium. Finding magnesium was not surprising to scientists, but the abundance was unexpected. The instrument also measured other exospheric constituents including calcium and sodium. Researchers believe that big day-to-day changes in Mercury's thin atmosphere may be caused by the variable shielding of Mercury's active magnetosphere. "This is an example of the kind of individual discoveries that the science team will piece together to give us a new picture of how the planet formed and evolved," said William McClintock of the Laboratory for Atmospheric and Space Physics at the University of Colorado at Boulder. McClintock is co-investigator and lead author of one of the four papers. "The third Mercury flyby [coming up on Sept. 29th] is our final dress rehearsal for the main performance of our mission, the insertion of the probe into orbit around Mercury in March 2011," said Solomon. "The orbital phase will be like staging two flybys per day and will provide continuous collection of information about the planet and its environment for one year." "Mercury has been coy in revealing its secrets slowly so far, but in less than two years the innermost planet will become a close friend." Source:NASA

Space Shuttle Atlantis Launches on Final Mission to Hubble

May 11, 2009: Space shuttle Atlantis with its seven-member crew launched at 2:01 p.m. EDT on Monday, May 11, from NASA's Kennedy Space Center on the final Hubble Space Telescope servicing mission. Atlantis' 11-day mission will include five spacewalks to refurbish Hubble with state-of-the-art science instruments designed to improve the telescope's discovery capabilities by up to 70 times while extending its lifetime through at least 2014. Shortly before liftoff, Commander Scott Altman thanked the teams that helped make the launch possible. "At last our launch has come along," said Altman. "...Getting to this point has been challenging, but the whole team, everyone, has pulled together to take us into space." Above: Space shuttle Atlantis lifts off Launch Pad 39A at NASA's Kennedy Space Center in Florida, beginning the STS-125 mission to service the Hubble Space Telescope. Photo credit: NASA Television Altman is joined on STS-125 by Pilot Gregory C. Johnson and Mission Specialists Megan McArthur, John Grunsfeld, Mike Massimino, Andrew Feustel and Michael Good. McArthur will serve as the flight engineer and lead for robotic arm operations while the remaining mission specialists pair up for the hands-on spacewalk work after Hubble is captured and secured in the payload bay. Altman, Grunsfeld and Massimino are space shuttle and Hubble mission veterans. Johnson, Feustel and Good are first-time space fliers. Sign up for EXPRESS SCIENCE NEWS delivery The STS-125 mission is the 126th shuttle flight, the 30th for Atlantis and the second of five planned in 2009. Hubble was delivered to space on April 24, 1990, on an earlier mission: STS-31. STS-125 is referred to as Servicing Mission 4, although it is technically the fifth servicing flight to the telescope. "Hubble has a long history of providing outstanding science and beautiful pictures," said Ed Weiler, associate administrator for NASA's Science Mission Directorate. "If the servicing mission is successful, it will give us a telescope that will continue to astound both scientists and the public for many years to come." Among Hubble's greatest discoveries is the age of the universe (13.7 billion years); the finding that virtually all major galaxies have black holes at their center; the discovery that the process of planetary formation is relatively common; the first ever organic molecule in the atmosphere of a planet orbiting another star; and evidence that the expansion of the universe is accelerating -- caused by an unknown force that makes up approximately 72 percent of the matter-energy content of the universe. Source:NASA

Wake up and smell the coffee -- on the Moon!

	05.15.2009
May 15, 2009: Have you ever wondered how you'd make your morning cup of java if you lived on another planet, or perhaps the moon? That steaming beverage would be a must on a cold lunar morning. But with rare sunlight, no coal or wood to burn, and no flowing water for hydro-electrical power, how would you make that cup of coffee, much less cook breakfast, heat your abode, and power the life support equipment and tools you needed to live and work up there? NASA, planning for a future lunar outpost, has been asking those same questions lately. There's more than one way to generate power on the moon. Fission Surface Power is one of the options NASA is considering. If this method is chosen, an engine invented in the early 1800s by Scottish brothers Robert and James Stirling could help make it work. Right: An artist's concept of a Fission Surface Power system in operation on the lunar surface. [Editor's note: If you have questions about this technology, please contact Marshall Space Flight Center Public Affairs at 256 544 0034.] The Stirlings were so proud of their creation that they made it their namesake – and with good reason. Over the years the Stirling engine -- the reliable, efficient "little engine that could" -- has earned a sterling reputation here on Earth, and it may one day prove its worth on the moon. "Inhabitants of a lunar outpost will need a safe and effective way to generate light and heat and electricity," says Mike Houts of NASA's Marshall Space Flight Center. "The tried and true Stirling engine fits the bill. It's not only reliable and efficient, but also versatile and clean." NASA is partnering with the Department of Energy to develop Fission Surface Power technology to produce heat and feed it into a Stirling engine, which, in turn, would convert heat energy into electricity for use by moon explorers. It's not certain that this kind of power system will be adopted by NASA, but it does have some very appealing qualities. Houts explains: "A key advantage to this power system is that it wouldn't need sunlight to operate. An FSP system could be used to provide power any time, any place, on the surface of moon or Mars. It could be used at the poles and away from the poles, it could weather a cold lunar night, and it would do well in places like deep craters that are always shaded. Not even a swirling, sunlight obscuring, Martian dust storm could stop it." Above: A Fission Surface Power system reference concept. Click on the image for more details. Credit: Mike Houts/NASA. NASA's engine would only need to produce 40 kW or less power – just enough for a lunar outpost. "This power level is high by space standards but extremely low by Earthly standards," says Houts. "It's about 1/20,000th of what a typical Earthly reactor puts out. We'd only need a tiny reactor on the moon – the fueled portion would be only about 10 inches wide by 1½ feet long." It would provide more power with less mass than other power systems. The whole assembly, radiator on top of Stirling engine on top of reactor, could be stowed in a fraction of the lunar lander. Before developing the final system, Houts and his team are testing with non-nuclear power for proof of concept. "We're conducting tests in a thermal vacuum to learn about operating and controlling the system on the moon," says Houts. "We're using resistance heaters to simulate nuclear heat. Electrical resistance produces heat." After the test system proves the viability of the concept, the team could be directed to build the "real thing," drawing heavily on US and international terrestrial reactor experience. Above: An artist's concept of a Fission Surface Power System embedded in lunar regolith. "It would be built from stainless steel and fueled by uranium dioxide. This combination has been used in terrestrial reactors throughout the world, so scientists and engineers are well-versed in its operation." The unit would not be active at launch, but would be "turned on" once in place on the lunar surface, where it would be surrounded by shielding to prevent any hazard from the radiation emitted. "It would be very safe," says Houts. "And the beauty of the system is that it would be practically self-regulating." Here's how it would work: Inside the reactor is a bundle of small tubes filled with uranium. Outside the reactor are control drums -- one side of each drum reflects neutrons and the other side absorbs them, providing a way to control the rate that neutrons escaping the reactor core are reflected back in. To start up the unit, the absorbent side of each control drum is turned out, away from the reactor core, so the reflective material faces in and sends escaping neutrons back in to the core. The resulting increase in available neutrons enables a self-sustaining chain reaction, which produces heat. A coolant (sodium potassium mixture)* flows through the passage-ways between the tubes, picks up the thermal heat produced by the reacting uranium, and transfers the heat to the Stirling engine. The Stirling engine then does its magic** to generate electricity. Meanwhile the coolant, which has "downloaded" some of its cargo (heat) to the Stirling engine, circulates back through the reactor core, where it picks up heat and is ready to repeat the entire cycle. The system would use only a miniscule amount of fuel -- 1 kg of uranium every 15 years – and still have enough reactivity to run for decades. "We give it a life expectancy of 8 years, though, because something else would falter before the fuel would run out." After shutdown, radiation emitted by the system would decrease rapidly. A replacement system could easily be installed at the same site. After all, coffee may be in high demand up there! Source: NASA