Login
New User

Welcome to AOAS.ORG
Sunday, April 20 2014 @ 09:01 PM CDT

Email Article To a Friend View Printable Version

December 2011 Guest Speaker Announced

The Arkansas Oklahoma Astronomical Society is proud to announce our program for the AOAS Annual Holiday Dinner Meeting for 2011!



  
Robert Beauford
  
Craters of the Ozark Plateaus
by Robert Beauford

  
On Earth, where only 178 confirmed examples are known, meteorite impact craters are rarities. For nearly every other rocky body in the solar system, however, they are the predominant surfacing mechanism, defining both general morphology and surface rock lithology. No other features on the Earthís surface can provide us with the insights into our solar system that these few locations offer.

Most of what we know about space science comes from some form of remote sensing or remote analysis. Alongside meteorites, terrestrial hypervelocity impact craters are part of an extremely short list of exceptions to this rule. They are places where we can see and touch, right here on earth, examples of the same processes we are viewing Ďout there.í

Twelve meteorite impact craters are located in the southern and south-central United States. Three of these, Decaturville, Crooked Creek, and Weaubleau are located within a 125 mile stretch of terrain in the center of the Ozarks in Missouri. The Decaturville Crater played a significant role in the historical process of recognizing the presence of meteorite impact craters on earth and in distinguishing these craters from similar structures of volcanic origin. NASA studied the location in the late 60s in order to better understand craters on the Moon. The Crooked Creek crater is one of North Americaís longest recognized but least studied impacts, and the Weaubleau structure is one of the most recently discovered, and is still undergoing the confirmation process. All three offer researchers a remarkable opportunity to visit extraordinarily well preserved terrestrial analogs for our future studies of off-planet impact sites.

Robert Beauford, is a graduate student in the PhD program of the Arkansas Center for Space and Planetary Sciences at the University of Arkansas at Fayetteville, and the Co-Editor of Meteorite Magazine, the International Quarterly Magazine for Meteorites and Meteorite Research. Robert's extensive background in meteorite impact research and passion for mineralogy, lapidary, archaeology, and paleontology makes him an interesting individual and a welcome guest. His presentation should be both interesting and very well received.



Remember, this meeting is also the one where we hold our annual Officer Elections, choosing those who will lead us and serve the AOAS membership for the coming year. Positions open for nominations this year are: President, Vice-President, Secretary, and Treasurer. And, once again, this meeting is preceded by a potluck dinner with a holiday theme. The club is providing the main meat course, so please bring a side dish and/or a dessert, and your favorite non-alcoholic beverages. Dinner starts at 6:30 PM and the main meeting starts at 7:30 PM, December 2 at the Fort Smith Riverpark Event Center - West. Click the link for directions.

Come and enjoy some warm holiday fellowship, fare, and fun with us!
Email Article To a Friend View Printable Version

Space Place Wallpaper Available

NASA Space Place

If you have admired the artwork behind the new Space Place website design, now you can have your own unobstructed view of them right on your computer desktop.  Pick from the home page graphic, or any of the theme backgrounds for space, Sun, Earth, solar system, people and technology, or parents and educators. There’s also the “clubhouse” theme for those more “generic” moods. Go to http://spaceplace.nasa.gov/wallpaper and download any or all in pixel sizes of 1920x1080 or 1920x1200.

 

Distributed by Laura K. Lincoln, on behalf of the Space Place Team.

 

Check out our great sites for kids:

http://climate.nasa.gov/kids

http://scijinks.gov

http://spaceplace.nasa.gov

 

Email Article To a Friend View Printable Version

The Gray Cubicle You Want to Work In

NASA Space PlaceBy Dr. Tony Phillips

  
  
Some of the employees of NASAís Science Mission Directorate may work in gray cubicles, but their jobs are anything but dull. They get to study Earth, the Sun, the Solar System, and the Universe!
It's another day at the office.

You're sitting in a gray cubicle, tap-tap-taping away on your keyboard, when suddenly your neighbor lets out a whoop of delight.

Over the top of the carpeted divider you see a star exploding on the computer screen. An unauthorized video game? No, this explosion is real. A massive star just went supernova in the Whirlpool Galaxy, and the first images from Hubble are popping up on your office-mateís screen.

It's another day at the office … at NASA.

Just down the hall, another office-mate is analyzing global temperature trends. On the floor below, a team of engineers gathers to decode signals from a spaceship that entered “safe mode” when it was hit by a solar flare. And three floors above, a financial analyst snaps her pencil-tip as she tries to figure out how to afford just one more sensor for a new robotic spacecraft.

These are just a few of the things going on every day at NASA headquarters in Washington DC and more than a dozen other NASA centers scattered around the country. The variety of NASA research and, moreover, the variety of NASA people required to carry it out often comes as a surprise. Consider the following:

NASA's Science Mission Directorate (SMD) supports research in four main areas: Earth Science, Heliophysics, Astrophysics, and Planetary Science. Read that list one more time. It includes everything in the cosmos from the ground beneath our feet to the Sun in the sky to the most distant galaxies at the edge of the Universe. Walking among the cubicles in NASAís science offices, you are likely to meet people working on climate change, extraterrestrial life, Earth-threatening asteroids, black holes or a hundred other things guaranteed to give a curious-minded person goose bumps. Truly, no other government agency has a bigger job description.

And itís not just scientists doing the work. NASA needs engineers to design its observatories and build its spacecraft, mathematicians to analyze orbits and decipher signals, and financial wizards to manage the accounts and figure out how to pay for everything NASA dreamers want to do. Even writers and artists have a place in the NASA scheme of things. Someone has to explain it all to the general public.

Clearly, some cubicles are more interesting than others. For more information about the Science Mission Directorate, visit science.nasa.gov. And for another way to reach the Space Place, go to http://science.nasa.gov/kids.

This article was provided by the Jet Propulsion Laboratory, California Institute of Technology, under a contract with the National Aeronautics and Space Administration.
Email Article To a Friend View Printable Version

Unmanned spacecraft? Says who?

NASA Space Place

What’s it like to work right in the middle of an exciting NASA science mission? The Space Place decided to find out by asking NASA scientists and engineers to describe some of their most exciting moments on the job. The result is Mission Chronicles, a blog for parents and teachers—although kids are welcome to read it too. The latest post comes from a mission ACE, more formally called a mission controller. He or she is the one who maintains the human link between spacecraft and Earth as the robotic explorer carries out its mission of discovery in deep space. Check out the ACE’s story at http://spaceplace.nasa.gov/mission-chronicles.

 

Distributed by Laura K. Lincoln, on behalf of the Space Place Team.

 

Check out our great sites for kids:

http://climate.nasa.gov/kids

http://scijinks.gov

http://spaceplace.nasa.gov
Email Article To a Friend View Printable Version

Dark Clues to the Universe

NASA Space PlaceBy Dr. Marc Rayman

  
This Hubble Space Telescope image of Galaxy NGC 4414 was used to help calculate the expansion rate of the universe. The galaxy is about 60 million light-years away. Credit: NASA and The Hubble Heritage Team (STScI/AURA)
Click image for larger view
Urban astronomers are always wishing for darker skies. But that complaint is due to light from Earth. What about the light coming from the night sky itself? When you think about it, why is the sky dark at all?

Of course, space appears dark at night because that is when our side of Earth faces away from the Sun. But what about all those other suns? Our own Milky Way galaxy contains over 200 billion stars, and the entire universe probably contains over 100 billion galaxies. You might suppose that that many stars would light up the night like daytime!

Until the 20th century, astronomers didn't think it was even possible to count all the stars in the universe. They thought the universe was infinite and unchanging.

Besides being very hard to imagine, the trouble with an infinite universe is that no matter where you look in the night sky, you should see a star. Stars should overlap each other in the sky like tree trunks in the middle of a very thick forest. But, if this were the case, the sky would be blazing with light. This problem greatly troubled astronomers and became known as “Olbersí Paradox” after the 19th century astronomer Heinrich Olbers who wrote about it, although he was not the first to raise this astronomical mystery.

To try to explain the paradox, some 19th century scientists thought that dust clouds between the stars must be absorbing a lot of the starlight so it wouldnít shine through to us. But later scientists realized that the dust itself would absorb so much energy from the starlight that eventually it would glow as hot and bright as the stars themselves.

Astronomers now realize that the universe is not infinite. A finite universe — that is, a universe of limited size — even one with trillions of stars, just wouldn't have enough stars to light up all of space.

Although the idea of a finite universe explains why Earth's sky is dark at night, other factors work to make it even darker.

The universe is expanding. As a result, the light that leaves a distant galaxy today will have much farther to travel to our eyes than the light that left it a million years ago or even one year ago. That means the amount of light energy reaching us from distant stars dwindles all the time. And the farther away the star, the less bright it will look to us.

Also, because space is expanding, the wavelengths of the light passing through it are expanding. Thus, the farther the light has traveled, the more red-shifted (and lower in energy) it becomes, perhaps red-shifting right out of the visible range. So, even darker skies prevail.

The universe, both finite in size and finite in age, is full of wonderful sights. See some bright, beautiful images of faraway galaxies against the blackness of space at the Space Place image galleries. Visit http://spaceplace.nasa.gov/search/?q=gallery.

This article was provided by the Jet Propulsion Laboratory, California Institute of Technology, under a contract with the National Aeronautics and Space Administration.
Email Article To a Friend View Printable Version

Play Satellite Insight . . . on your iPhone!

NASA Space Place

“Satellite Insight” for iPhone and other iOS devices is now available on iTunes. It’s free! It’s challenging! It’s fun! Colored blocks represent different types of data gathered by GOES-R’s amazing science instruments. The data blocks fall into columns on a grid. Your job is to bundle like data types together and store them safely before the data grid overflows.  It is the very first iPhone app from the National Oceanic and Atmospheric Administration (in partnership with NASA). Check it out at http://itunes.apple.com/us/app/satellite-insight/id463588902?mt=8.

 

"It is engaging and supports a good cause so I suggest you download it." - AppAdvice.com

 

Distributed by Laura K. Lincoln, on behalf of the Space Place Team.

 

Check out our great sites for kids:

http://climate.nasa.gov/kids

http://scijinks.gov

http://spaceplace.nasa.gov
Email Article To a Friend View Printable Version

Diamond Bar G Ranch Star Camp - Oct 21 - 23, 2011

  
Satellite view of Diamond Bar G Ranch
Click image to view in Google Maps
The Arkansas/Oklahoma Astronomical Society would like to invite you all to a weekend of observing and fun at the Diamond Bar G Ranch Star Camp located west of Fayetteville, Arkansas. The Star Camp is scheduled to be held the weekend of Oct 21 - 23. While it may conflict with other star parties this fall, this is the only weekend that the Diamond Bar G Ranch will be available for an event of this type that is not during a full moon. Since the RRAC's Burger Burn events will not be held this year, AOAS thought this might make a nice alternative.

The Diamond Bar G Ranch Star Party is a casual event with no registration fees and no planned schedule, other than a pot luck dinner on Friday evening, Oct 21st. We will not be having speakers or any other type of program. The purpose of the event is to do observing in a fairly dark-sky location without a lot of time devoted to other pursuits.

The observing field is wide so there is a clear view to the south and east, with low tree lines to the north and west. The Diamond Bar G Ranch is located in the Bortle Class 2 (blue) Zone, so light pollution is minimal. There are light domes from both Fayetteville in the NE and Van Buren / Fort Smith in the south but they are not obtrusive, and are usually only visible when there is cloud cover. The Milky Way is easily visible with the naked eye on clear nights.
Email Article To a Friend View Printable Version

Solar System Size Surprise

NASA Space Placeby Dr. Tony Phillips

  
This artist's concept shows NASA's two Voyager spacecraft exploring a turbulent region of space known as the heliosheath, the outer shell of the bubble of charged particles around our sun. Image credit: NASA/JPL-Caltech.
Click image for larger view
News flash: You may be closer to interstellar space than you previously thought.

A team of researchers led by Tom Krimigis of the Johns Hopkins University Applied Physics Laboratory announced the finding in the June 2011 issue of Nature. The complicated title of their article, “Zero outward flow velocity for plasma in a heliosheath transition layer,” belies a simple conclusion: The solar system appears to be a billion or more kilometers smaller than earlier estimates.

The recalculation is prompted by data from NASAís Voyager 1 probe, now 18 billion kilometers from Earth. Voyagers 1 and 2 were designed and built and are still managed by NASAís Jet propulsion Laboratory. Aging but active, the spacecraft have been traveling toward the stars since 1977 on a heroic mission to leave the solar system and find out what lies beyond.

To accomplish their task, the Voyagers must penetrate the outer walls of the heliosphere, a great bubble of plasma and magnetism blown in space by the solar wind. The heliosphere is so big, it contains all the planets, comets, and asteroids that orbit the sun. Indeed many astronomers hold that the heliosphere defines the boundaries of the solar system. Inside it is “home.” Outside lies the Milky Way. For 30+ years, the spacecraft have been hurtling toward the transition zone. Voyager 1 is closing in.

Much of Voyager 1ís long journey has been uneventful. Last year, however, things began to change. In June 2010, Voyager 1 beamed back a startling number: zero. Thatís the outward velocity of the solar wind where the probe is now.

“This is the first sign that the frontier is upon us,” says Krimigis.

Previously, researchers thought the crossing was still years and billions of kilometers away, but a new analysis gave them second thoughts. Krimigis and colleagues combined Voyager data with previously unpublished measurements from the Cassini spacecraft. Cassini, on a mission to study Saturn, is nowhere near the edge of the solar system, but one of its instruments can detect atoms streaming into our solar system from the outside. Comparing data from the two locations, the team concluded that the edge of the heliosphere lies somewhere between 16 to 23 billion kilometers from the sun, with a best estimate of approximately 18 billion kilometers.

Because Voyager 1 is already nearly 18 billion kilometers out, it could cross into interstellar space at any time — maybe even as you are reading this article.

“How close are we?” wonders Ed Stone, Caltech professor and principal investigator of the Voyager project since the beginning. “We don't know, but Voyager 1 speeds outward a billion miles every three years, so we may not have long to wait.”

Stay tuned for the crossing.

For more about the missions of Voyager 1 and 2, see http://voyager.jpl.nasa.gov/. Another Voyager project scientist, Merav Opher, is the guest on the newest Space Place Live cartoon interview show for kids at http://spaceplace.nasa.gov/space-place-live.

This article was provided by the Jet Propulsion Laboratory, California Institute of Technology, under a contract with the National Aeronautics and Space Administration.
Email Article To a Friend View Printable Version

New GOES-R to Give More Tornado Warning Time

NASA Space Placeby Dauna Coulter and Dr. Tony Phillips

  
This GOES image shows the storms that spurred the intense April 27 tornado outbreak in the southern U.S. Animation showing the development of weather can be seen at http://earthobservatory.nasa.gov/NaturalHazards/view.php?id=50347.
Click image for larger view
So far this spring, more than 1,400 tornadoes have struck the U.S. Some of them have cut jaw-dropping trails of destruction across the countryside and, tragically, across inhabited communities, too. Hundreds of lives have been lost in the onslaught.

Throughout the season, the National Weather Service has routinely issued tornado alerts. In the case of the Alabama tornadoes of April 27th, forecasters warned of severe weather five full days before the twisters struck. Because they couldnít say precisely where the twisters would strike, however, many of their warnings went unheeded.

“If people get a hurricane warning, they often evacuate the area,” notes NOAA's Steve Goodman. “But we react differently to tornado warnings.”

Perhaps itís because tornadoes are smaller than hurricanes, and the odds of a direct hit seem so remote. Recent pictures from Tuscaloosa, Alabama, and Joplin, Missouri, however, show the perils of playing those odds. Goodman believes that more precise warnings could save lives.

To fine-tune tornado warnings, NOAA will soon launch the first in a series of next-generation weather satellites — GOES-R (Geostationary Operational Environmental Satellites-R series). The spacecraft is brimming with advanced sensors for measuring key ingredients of severe weather including winds, cloud growth, and lightning.

“GOES-R will be the first geostationary spacecraft to carry a lightning sensor,” says Goodman, the GOES-R Program Senior Scientist. “Studies show that sudden changes in the total lightning activity correlate with storm intensity &madash; and with tornadoes.”

The lightning mapper will detect and map not only cloud-to-ground lightning, but also bolts within and between clouds. The kind of cloud-to-ground lightning we see from our front yards accounts for only 15-20 percent of total lightning. To get a clear idea of a storm's intensity, meteorologists need to know about all the lightning — a view GOES-R can provide.

All by itself, the lightning mapper will provide 7 minutes more lead time in tornado warnings, according to Goodman. GOES-Rís state-of-the-art instruments will also improve long-range forecasts.

“The satellite's Advanced Baseline Imager (ABI), for instance, will provide a much clearer picture of clouds,” says NOAA research meteorologist Tim Schmit. Compared to lesser instruments already in orbit, ABI can better detect super-cold “overshooting tops,” evidence of enormous energy and upward velocity that correlate with subsequent severe weather.

“Accurate advanced notice of high-risk tornadic conditions can cue officials to close schools and businesses even before tornadoes are actually detected,” says Schmit.

Forecasters doubt tornadoes can ever be predicted with 100% accuracy. The twisters are just too capricious. GOES-R, however, is a step in the right direction.

Find out more about GOES-Rís unprecedented capabilities at http://www.goes-r.gov. Young people can learn more about tornadoes and all kinds of other weather at http://scijinks.gov.

This article was provided by the Jet Propulsion Laboratory, California Institute of Technology, under a contract with the National Aeronautics and Space Administration.
Email Article To a Friend View Printable Version

Finding Planets among the Stars

NASA Space Placeby Dr. Tony Phillips

  
Exoplanets are easier to see directly when their star is a dim, red dwarf.
Click image for larger view
Strange but true: When it comes to finding new extra-solar planets, or exoplanets, stars can be an incredible nuisance.

Itís a matter of luminosity. Stars are bright, but their planets are not. Indeed, when an astronomer peers across light years to find a distant Earth-like world, what he often finds instead is an annoying glare. The light of the star itself makes the star's dim planetary system nearly impossible to see.

Talk about frustration! How would you like to be an astronomer who's constantly vexed by stars?

Fortunately, there may be a solution. It comes from NASA's Galaxy Evolution Explorer, an ultraviolet space telescope orbiting Earth since 2003. In a new study, researchers say the Galaxy Evolution Explorer is able to pinpoint dim stars that might not badly outshine their own planets.

“We've discovered a new technique of using ultraviolet light to search for young, low-mass stars near the Earth,” said David Rodriguez, a graduate student of astronomy at UCLA, and the study's lead author. “These M-class stars, also known as red dwarfs, make excellent targets for future direct imaging of exoplanets.”

Young red dwarfs produce a telltale glow in the ultraviolet part of the electromagnetic spectrum that Galaxy Evolution Explorer can sense. Because dwarf stars are so numerous — as a class, they account for more than two-thirds of the stars in the galaxy — astronomers could reap a rich bounty of targets.

In many ways, these stars represent a best-case scenario for planet hunting. They are close and in clear lines-of-sight, which generally makes viewing easier. Their low mass means they are dimmer than heavier stars, so their light is less likely to mask the feeble light of a planet. And because they are young, their planets are freshly formed, and thus warmer and brighter than older planetary bodies.

Astronomers know of more than five hundred distant planets, but very few have actually been seen. Many exoplanets are detected indirectly by means of their “wobbles” — the gravitational tugs they exert on their central stars. Some are found when they transit the parent star, momentarily dimming the glare, but not dimming it enough to reveal the planet itself.

The new Galaxy Evolution Explorer technique might eventually lead to planets that can be seen directly. That would be good because, as Rodriguez points out, “seeing is believing.”

And it just might make astronomers feel a little better about the stars.

The Galaxy Evolution Explorer Web site at http://www.galex.caltech.edu describes many of the other discoveries and accomplishments of this mission. And for kids, how do astronomers know how far away a star or galaxy is? Play “How Old do I Look” on The Space Place at http://spaceplace.nasa.gov/whats-older and find out!

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

What's New

STORIES

No new stories

COMMENTS last 2 days

No new comments

LINKS last 2 weeks

No recent new links

Who's Online

Guest Users: 8

User Functions






Lost your password?

Want It ALL?

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.