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Ozone, the Greenhouse Gas

NASA Space Place
Ozone behaves differently at different altitudes in the atmosphere. High in the stratosphere and at mid-troposphere it has positive effects on life at the surface. At the top of the troposphere ozone is a greenhouse gas and at the surface it makes smog.
Click for larger view.
We all know that ozone in the stratosphere blocks harmful ultraviolet sunlight, and perhaps some people know that ozone at the Earth's surface is itself harmful, damaging people's lungs and contributing to smog.

But did you know that ozone also acts as a potent greenhouse gas? At middle altitudes between the ground and the stratosphere, ozone captures heat much as carbon dioxide does.

In fact, pound for pound, ozone is about 3000 times stronger as a greenhouse gas than CO2. So even though there's much less ozone at middle altitudes than CO2, it still packs a considerable punch. Ozone traps up to one-third as much heat as the better known culprit in climate change.

Scientists now have an unprecedented view of this mid-altitude ozone thanks to an instrument aboard NASA's Aura satellite called the Tropospheric Emission Spectrometer—"TES" for short.

Most satellites can measure only the total amount of ozone in a vertical column of air. They can't distinguish between helpful ozone in the stratosphere, harmful ozone at the ground, and heat-trapping ozone in between. By looking sideways toward Earth’s horizon, a few satellites have managed to probe the vertical distribution of ozone, but only to the bottom of the stratosphere.

Unlike the others, TES can measure the distribution of ozone all the way down to the heat-trapping middle altitudes. "We see vertical information in ozone that nobody else has measured before from space," says Annmarie Eldering, Deputy Principal Investigator for TES.

The global perspective offered by an orbiting satellite is especially important for ozone. Ozone is highly reactive. It is constantly being created and destroyed by photochemical reactions in the atmosphere and by lightning. So its concentration varies from region to region, from season to season, and as the wind blows.

Data from TES show that ozone's heat-trapping effect is greatest in the spring, when intensifying sunlight and warming temperatures fuel the reactions that generate ozone. Most of ozone's contribution to the greenhouse effect occurs within 45 degrees latitude from the equator.

Increasing industrialization, particularly in the developing world, could lead to an increase in mid-altitude ozone, Eldering says. Cars and coal-fired power plants release air pollutants that later react to produce more ozone.

"There's concern that overall background levels are slowly increasing over time," Eldering says. TES will continue to monitor these trends, she says, keeping a careful eye on ozone, the greenhouse gas.

Learn more about TES and the science of ozone at tes.jpl.nasa.gov/. Kids can get a great introduction to good ozone and bad ozone at spaceplace.nasa.gov/en/kids/tes/gases.

This article was provided by the Jet Propulsion Laboratory, California Institute of Technology, under a contract with the National Aeronautics and Space Administration.
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Exploring Arkansas at Coleman Observatory

Coleman Observatory
Dr Chuck Larson spills his guts about why he loves astronomy as AETN producer Chuck Dovish and camera operator Michad Holliday look on while Dr. Larson's wife Loretta (seated in background) watches the Arkansas Final Four championship game on their portable TV. Photo by Bob Moody
On April 7, an AETN film crew arrived at Coleman Observatory to tape footage for an upcoming segment of the program, "Exploring Arkansas" with host Chuck Dovish. AOAS members on hand were myself, Chuck Larson, Joe Roam, Linda Miller and Leonard Lynch, and what followed was an evening of explaining what amateur astronomy meant to each of us, and how Coleman Observatory came to be. We also touched on our Education and Public Outreach efforts, and how astronomy is currently changing for the person on the street who may be wanting to break into the hobby with "go to" telescopes.

AETN "Exploring Arkansas" host Chuck Dovish and cameraman Michad Holliday pose in CETUS's Lair at Coleman Observatory. Photo by Bob Moody
I had an idea last year to send a note to the AETN program "Exploring Arkansas" suggesting that amateur astronomy might be a possible new subject for investigation. I mentioned a couple of well-known advanced amateur astronomers in the state, and of course, I mentioned AOAS and our Coleman Observatory, too. I was blown away in late March when the program's producer and host, Chuck Dovish, sent me an email asking if they could come to Coleman Observatory to film a segment for an upcoming show. I said yes, of course, and we set the date of April 7 to shoot the footage.

I contacted several of our members and asked if they'd consider coming up to be a part of this event, and I was very pleased to see the members listed above that were willing and able to come and participate. May and June are shaping up to be a busy time for AOAS, and this exposure will hopefully garner us increased interest in amateur astronomy, more visitors at our upcoming AOAS/Mulberry Mountain Lodge Star Party, and increased memberships not only for AOAS, but for all Arkansas astronomy clubs as well.

We offer our sincerest thanks to Chuck Dovish and AETN for choosing Coleman Observatory to represent amateur astronomy in Arkansas, and we hope they will visit us again sometime for a full night of observing from our little corner of the Milky Way, and all the wonders of the universe!

This episode of "Exploring Arkansas" will air on AETN on Monday, June 2, 2008, at 6:30 pm. Check with your local cable provider for which channel this show appears, or check your favorite television listings for the channel and time.
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Get Your Gummy Greenhouse Gases!

NASA Space PlaceMaking science edible--and sweet--is a reliable way to attracts kids' interest. The new "Gummy Greenhouse Gases" activity on The Space Place web site makes it fun and easy to learn a bit of chemistry and to find out why too many of these kinds of molecules in the air are likely to cause Earth to get warmer. At http://spaceplace.nasa.gov/en/kids/tes/gumdrops, kids use gumdrops and toothpicks to make simple molecules of ozone, nitrous oxide, carbon dioxide, water vapor, and methane. The curious can go on to http://spaceplace.nasa.gov/en/kids/tes/gases to learn more about the greenhouse effect and about the "good and bad" roles of ozone. A short video shows how new space technology can literally paint a 3-D picture of these gases all around the globe. Afterwards, the ghastly gases can be consumed (mind the toothpicks!), thus helping the environment.
 
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Stellar Compass for Space Explorers

NASA Space Placeby Patrick L. Barry

Compass is built as two separate assemblies, the camera-gyro assembly and the data processor assembly, connected by a wiring harness. The technology uses an active pixel sensor in a wide-field-of-view miniature star camera and micro-electromechanical system (MEMS) gyros. Together, they provide extremely accurate information for navigation and control.
In space, there's no up or down, north or south, east or west. So how can robotic spacecraft know which way they're facing when they fire their thrusters, or when they try to beam scientific data back to Earth?

Without the familiar compass points of Earth's magnetic poles, spacecraft use stars and gyros to know their orientation. Thanks to a recently completed test flight, future spacecraft will be able to do so using only an ultra-low-power camera and three silicon wafers as small as your pinky fingernail.

“The wafers are actually very tiny gyros,” explains Artur Chmielewski, project manager at JPL for Space Technology 6 (ST6), a part of NASA's New Millennium Program.

Traditional gyros use spinning wheels to detect changes in pitch, yaw, and roll—the three axes of rotation. For ST6's Inertial Stellar Compass, the three gyros instead consist of silicon wafers that resemble microchips. Rotating the wafers distorts microscopic structures on the surfaces of these wafers in a way that generates electric signals. The compass uses these signals—along with images of star positions taken by the camera—to measure rotation.

Because the Inertial Stellar Compass (ISC) is based on this new, radically different technology, NASA needed to flight-test it before using it in important missions. That test flight reached completion in December 2007 after about a year in orbit aboard the Air Force's TacSat-2 satellite.

“It just performed beautifully,” Chmielewski says. “The data checked out really well.” The engineers had hoped that ISC would measure the spacecraft's rotation with an accuracy of 0.1 degrees. In the flight tests, ISC surpassed this goal, measuring rotation to within about 0.05 degrees.

That success paves the way for using ISC to reduce the cost of future science missions. When launching probes into space, weight equals money. “If you're paying a million dollars per kilogram to send your spacecraft to Mars, you care a lot about weight,” Chmielewski says. At less than 3 kilograms, ISC weighs about one-fifth as much as traditional stellar compasses. It also uses about one-tenth as much power, so a spacecraft would be able to use smaller, lighter solar panels.

Engineers at Draper Laboratory, the Cambridge, Massachusetts, company that built the ISC, are already at work on a next-generation design that will improve the compass's accuracy ten-fold, Chmielewski says. So ISC and its successors could soon help costs—and spacecraft—stay on target.

Find out more about the ISC at nmp.nasa.gov/st6. Kids can do a fun project and get an introduction to navigating by the stars at spaceplace.nasa.gov/en/kids/st6starfinder/st6starfinder.shtml.

This article was provided by the Jet Propulsion Laboratory, California Institute of Technology, under a contract with the National Aeronautics and Space Administration.
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What Lurks Behind the Light?

Deep SkyWhen the familiar becomes the unfamiliar, it can either be a little unnerving, or, it can make us marvel as if we're seeing things for the very first time. That's how I felt when the image of the Sombrero Galaxy (M-104) began coming up on my screen from the March 8th Astronomy Picture of the Day.
This remarkable image shows details in the spiral arms of the Sombrero well into the central region. Just look and see how the spiral arms wind all the way in. This image is possible through a new image processing technique called, High Dynamic Range Wavelet Transform algorithm (HDRWT) and you can read more about the process, and see many other impressive images by clicking on this link. And, Just to see how much different this image is from the "regular" or "normal" image of M-104 we're all familiar with, just click here

And it keeps getting better.....the APOD image for March 22nd shows the otherwise familiar Cat's Eye Nebula located in the northern polar constellation Draco in greater detail than the original 1994 image of the same. Otherwise known by its New General Catalog number NGC-6543, the Cat's Eye Nebula is a planetary nebula, possibly resembling what our own star Sol may look like in 5 billion years or so, give or take a few hundred million years. (LOL)

In 1999, an APOD image from September 16th, is a neat little shot that combines TWO images taken 3 years apart that clearly show the nebula e x p a n d i n g !! The images shift between 1994 and 1997, and if you watch closely, you can actually SEE the nebula expanding and contracting. But in this newest image, notice the greater detail in the "knots" of material around the thicker portions of the nebula, as well as in the whispy streaks, too. It would be cool to once again create a two or even three image "blinking" effect to see more continued expansion of the material in the Cat's Eye.

Undoubtedly, this new way of getting more information from already established and well-known astronomical objects by using High Dynamic Range Wavelet Transform algorithms (HDRWT) will soon become a preferred way of processing images, possibly for some of today's up-and-coming crop of new astronomers. What I wouldn't give to be one of them! Perhaps just as importantly, though, what new technologies will be developed and presented on the APOD website next?
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Challenge Yourself with Weather Slyders

NASA Space Place
The Dust Bowl. Hot, loopy solar gases. Killer Katrina. Combining dramatic images of Earth and space weather with the challenge of an old-fashioned slider puzzle, the new "Slyder" game on the SciJinks Weather Laboratory website will capture the attention of any middle-schooler--and maybe even their parents and teachers. Players pick from a rich variety of captioned images, including photos from the ground, photos from space, and artist's renderings. After picking a difficulty level (3x3, 4x4, 5x5 grids), the player slides the scrambled tiles around to make a whole picture again. Go to http://scijinks.gov/weather/fun/slyder to become the newest Slyder buff!
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Invisible Spiral Arms

NASA Space Placeby Patrick Barry

In this image of galaxy NGC 1512, red represents its visible light appearance, the glow coming from older stars, while the bluish-white ring and the long, blue spiral arms show the galaxy as the Galaxy Evolution Explorer sees it in ultraviolet, tracing primarily younger stars. (Credit: NASA/JPL-Caltech/DSS/GALEX).
At one time or another, we've all stared at beautiful images of spiral galaxies, daydreaming about the billions of stars and countless worlds they contain. What mysteries—and even life forms—must lurk within those vast disks?

Now consider this: many of the galaxies you've seen are actually much larger than they appear. NASA's Galaxy Evolution Explorer, a space telescope that “sees” invisible, ultraviolet light, has revealed that roughly 20 percent of nearby galaxies have spiral arms that extend far beyond the galaxies' apparent edges. Some of these galaxies are more than three times larger than they appear in images taken by ordinary visible-light telescopes.

“Astronomers have been observing some of these galaxies for many, many years, and all that time, there was a whole side to these galaxies that they simply couldn't see,” says Patrick Morrissey, an astronomer at Caltech in Pasadena, California, who collaborates at JPL.

The extended arms of these galaxies are too dim in visible light for most telescopes to detect, but they emit a greater amount of UV light. Also, the cosmic background is much darker at UV wavelengths than it is for visible light. “Because the sky is essentially black in the UV, far-UV enables you to see these very faint arms around the outsides of galaxies,” Morrissey explains.

These “invisible arms” are made of mostly young stars shining brightly at UV wavelengths. Why UV? Because the stars are so hot. Young stars burn their nuclear fuel with impetuous speed, making them hotter and bluer than older, cooler stars such as the sun. (Think of a candle: blue flames are hotter than red ones.) Ultraviolet is a sort of “ultra-blue” that reveals the youngest, hottest stars of all.

“That's the basic idea behind the Galaxy Evolution Explorer in the first place. By observing the UV glow of young stars, we can see where star formation is active,” Morrissey says.

The discovery of these extended arms provides fresh clues for scientists about how some galaxies form and evolve, a hot question right now in astronomy. For example, a burst of star formation so far from the galaxies' denser centers may have started because of the gravity of neighboring galaxies that passed too close. But in many cases, the neighboring galaxies have not themselves sprouted extended arms, an observation that remains to be explained. The Galaxy Evolution Explorer reveals one mystery after another!

“How much else is out there that we don't know about?” Morrissey asks. “It makes you wonder.”

Spread the wonder by seeing for yourself some of these UV images at http://www.galex.caltech.edu. Also, Chris Martin, principle scientist for Galaxy Evolution Explorer—or rather his cartoon alter-ego— gives kids a great introduction to ultraviolet astronomy at http://spaceplace.nasa.gov/en/kids/live#martin.

This article was provided by the Jet Propulsion Laboratory, California Institute of Technology, under a contract with the National Aeronautics and Space Administration.
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Asteroid 2007 TU24 WILL MISS Earth....but not by much

Lunar & PlanetaryA relatively large asteroid, estimated to be at least 500 feet in diameter, but possibly as much as 2000 feet in diameter, will pass close to Earth on the evening of January 29, 2008 at an estimated distance of only 334,000 miles away! Here's what you need to know.

Don't worry, this asteroid WILL NOT hit Earth, but it provides a great segue into the science involved in the phenomena of asteroid and comet impacts, and how they can completely change the Earth and its thriving civilizations of humankind. I'll get into that later, but for now, look at AOAS Interim Vice President Leonard Lynch's article Earth Impact Craters, my past article on Japan's asteroid mission Hayabusa - The Japanese Asteroid Sample Return Mission, and then here's the NASA article regarding this event, a link to the NASA site where its located, and a second link to the JPL site of Near-Earth Object searches and their article on this upcoming event.

NASA Scientists Get First Images of Earth Flyby Asteroid

http://www.nasa.gov/topics/solarsystem/features/asteroid-20080125.html

Scientists at NASA's Jet Propulsion Laboratory in Pasadena, Calif., have obtained the first images of asteroid 2007 TU24 using high-resolution radar data. The data indicate the asteroid is somewhat asymmetrical in shape, with a diameter roughly 250 meters (800 feet) in size. Asteroid 2007 TU24 will pass within 1.4 lunar distances, or 538,000 kilometers (334,000 miles), of Earth on Jan. 29 at 12:33 a.m. Pacific time (3:33 a.m. Eastern time).

"With these first radar observations finished, we can guarantee that next week's 1.4-lunar-distance approach is the closest until at least the end of the next century," said Steve Ostro, JPL astronomer and principal investigator for the project. "It is also the asteroid's closest Earth approach for more than 2,000 years."

Scientists at NASA's Near-Earth Object Program Office at JPL have determined that there is no possibility of an impact with Earth in the foreseeable future.

Asteroid 2007 TU24 was discovered by the NASA-sponsored Catalina Sky Survey on Oct. 11, 2007. The first radar detection of the asteroid was acquired on Jan. 23 using the Goldstone 70-meter (230-foot) antenna. The Goldstone antenna is part of NASA's Deep Space Network Goldstone station in Southern California's Mojave Desert. Goldstone's 70-meter diameter (230-foot) antenna is capable of tracking a spacecraft traveling more than 16 billion kilometers (10 billion miles) from Earth. The surface of the 70-meter reflector must remain accurate within a fraction of the signal wavelength, meaning that the precision across the 3,850-square-meter (41,400-square-foot) surface is maintained within one centimeter (0.4 inch).

Ostro and his team plan further radar observations of asteroid 2007 TU24 using the National Science Foundation's Arecibo Observatory in Puerto Rico on Jan. 27-28 and Feb. 1-4.

The asteroid will reach an approximate apparent magnitude 10.3 on Jan. 29-30 before quickly becoming fainter as it moves farther from Earth. On that night, the asteroid will be observable in dark and clear skies through amateur telescopes with apertures of at least 7.6 centimeters (three inches). An object with a magnitude of 10.3 is about 50 times fainter than an object just visible to the naked eye in a clear, dark sky.

Scientists working with Ostro on the project include Lance Benner and Jon Giorgini of JPL, Mike Nolan of the Arecibo Observatory, and Greg Black of the University of Virginia.

NASA detects and tracks asteroids and comets passing close to Earth. The Near Earth Object Observation Program, commonly called "Spaceguard," discovers, characterizes and computes trajectories for these objects to determine if any could be potentially hazardous to our planet. The Arecibo Observatory is part of the National Astronomy and Ionosphere Center, a national research center operated by Cornell University, Ithaca, N.Y., for the National Science Foundation. JPL is a division of the California Institute of Technology in Pasadena.

For more information, visit http://neo.jpl.nasa.gov.

Here is the link to the NASA story which includes the picture taken by radar of this asteroid

http://www.nasa.gov/topics/solarsystem/features/asteroid-20080125.html

Click on the above TITLE of this article for more info, including a link to the JPL article, and more
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Is Time Travel Possible?

NASA Space PlaceEvery science fiction fan has pondered the weird implications of time travel. Can you travel into the future and find out the winning Super Lotto number -- then come back and buy a ticket? Would doing so be cheating the laws of physics (to say nothing of ethics?) Astrophysicist Marc Rayman toys with such ideas in this Space Place Musings Podcast. Go to http://spaceplace.jpl.nasa.gov/en/educators/podcast/ to subscribe to these Podcasts. Or listen now to this and the previous Podcasts on your computer or read the transcripts.
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No Mars Rock Unturned

NASA Space Placeby Patrick L. Barry

Are these rocks of any scientific interest? With the new AEGIS software, the Mars Rovers, Spirit and Opportunity, will be able to judge for themselves whether a scene is worth a high-resolution image. (Artist’s rendering.) Photo courtesy NASA/JPL
Imagine someday taking a driving tour of the surface of Mars. You trail-blaze across a dusty valley floor, looking in amazement at the rocky, orange-brown hillsides and mountains all around. With each passing meter, you spy bizarre-looking rocks that no human has ever seen, and may never see again. Are they meteorites or bits of Martian crust? They beg to be photographed.

But on this tour, you can't whip out your camera and take on-the-spot close-ups of an especially interesting-looking rock. You have to wait for orders from headquarters back on Earth, and those orders won't arrive until tomorrow. By then, you probably will have passed the rock by. How frustrating!

That's essentially the predicament of the Spirit and Opportunity rovers, which are currently in their fourth year of exploring Mars. Mission scientists must wait overnight for the day's data to download from the rovers, and the rovers can't take high-res pictures of interesting rocks without explicit instructions to do so.

However, artificial intelligence software developed at JPL could soon turn the rovers into more-autonomous shutterbugs.

This software, called Autonomous Exploration for Gathering Increased Science (AEGIS), would search for interesting or unusual rocks using the rovers' low-resolution, black-and-white navigational cameras. Then, without waiting for instructions from Earth, AEGIS could direct the rovers' high-resolution cameras, spectrometers, and thermal imagers to gather data about the rocks of interest.

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Become a card-carrying member of AOAS. Paying dues gives you several advantages over other registered users, including a subscription to the club newsletter, an AOAS.ORG e-mail address, use of club materials, including books and telescopes, and access to the Coleman Observatory facilities. On top of all that, you also qualify for a 20% discount on all books at any Books-A-Million location.

To get your membership application, click here.