New User

Welcome to AOAS.ORG
Thursday, June 01 2023 @ 03:02 pm EDT

Email Article To a Friend View Printable Version

Early Bird Gets the Worm or "Black Hole Breakfast"

NASA Space Placeby Dr. Tony Phillips

In this artist's concept, a giant black hole is caught devouring a star that ventured too close.
Click image for larger view.
We all know that birds eat worms. Every day, millions of birds eat millions of worms. It's going on all around you! But how often have you awakened in the morning, stalked out in the dewy grass, and actually seen a bird having breakfast? Even though we know it happens all the time, a bird gulping a worm is a rare sight.

Just like a black hole gulping a star…

Every day in the Universe, millions of stars fall into millions of black holes. And that's bad news for the stars. Black holes exert terrible tides, and stars that come too close are literally ripped apart as they fall into the gullet of the monster. A long burp of X-rays and ultraviolet radiation signals the meal for all to see.

Yet astronomers rarely catch a black hole in the act. “It's like the problem of the bird and the worm,” says astronomer Christopher Martin of Caltech. “You have to be in the right place at the right time, looking in the right direction and paying attention.”
Email Article To a Friend View Printable Version

Alone in the Dark; Or, Confessions of a Rank Amateur

Education Outreach
One of our visitors to an outing in 2005 gazes into the eyepiece at the Ringed World, Saturn! It takes time to go from a "rank amateur" to an experienced astronomer. All it takes is practice, practice, practice... Photo by Bob Moody
I guess I'm not the only one who's ever felt this way, but just try to get someone else to admit it. I know, I have tried, and it doesn't work. Everyone is an expert. Everyone seems to know just where all the constellations are on any given night, where all of the Messier objects are, they even know the names of all the stars that make up a constellation. They not only can tell you what planet you're looking at, they can tell you how many moons it has, and all their moon's names, too.

Man is that frustrating or what. There I stand in front of my telescope trying to hide the fact that I've been there an hour and a half and I still can't get the darned thing properly polar aligned, and they're in the background calling off Messier objects and star names and NGC catalog items they've found, and all that in just the last fifteen minutes. What's a person to do?

Well I'll tell ya what I'm gonna do. I'm gonna get me one of those GPS-Locate Where I Am / Find True North / Tell Me What It Is / Tell Me Where It Is / Go Directly To It / Take a Picture Of It By Itself / All-In-One Telescopes. Or, then again, maybe not. Since I don't have an extra few thousand bucks to throw around, maybe I'll just give up and go home. I hate feeling so dumb, but isn't that the price you have to pay when you stand there alone in the dark and are afraid to acknowledge your ignorance about astronomy?

But wait a minute, maybe there's hope after all. Since I've joined the club, I could use my AOAS discount card at Books-A-Million and buy a book, or two, (at 20% off) to help me figure all this stuff out. I mean I may not learn everything about the cosmos from some book, but at least I won't sound like a fool when I ask one of my fellow "amateur" astronomers a question. And maybe then when someone asks me a question I might even be able to have an answer that is not only correct, it may even make it seem like I really do know something. But heck, why bother? It's just a waste of time and money to keep trying to learn this stuff....right?

Email Article To a Friend View Printable Version

Even Solar Sails Need a Mast

NASA Space Placeby Patrick L. Barry

SAILMAST is the thin triangular truss in front of the picture. It is attached to a section of a silver foil solar sail section shown here in a laboratory test. The mast in the picture is 2m (6 ft) long. The Space Technology 8 mission will test the SAILMAST, which is 20 times longer.
Click image for larger view.
Like the explorers of centuries past who set sail for new lands, humans may someday sail across deep space to visit other stars. Only it won't be wind pushing their sails, but the slight pressure of sunlight.

Solar sails, as they're called, hold great promise for providing propulsion in space without the need for heavy propellant. But building a solar sail will be hard; to make the most of sunlight's tiny push, the sail must be as large as several football fields, yet weigh next to nothing. Creating a super-lightweight material for the sail itself is tricky enough, but how do you build a “mast”” for that sail that's equally light and strong?

Enter SAILMAST, a program to build and test-fly a mast light enough for future solar sails. With support from NASA’s In-Space Propulsion Program to mature the technology and perform ground demonstrator tests, SAILMAST’s engineers were ready to produce a truss suitable for validation in space that's 40 meters (about 130 feet) long, yet weighs only 1.4 kilograms (about 3 pounds)!

In spite of its light weight, this truss is surprisingly rigid. “It's a revelation when people come in and actually play with one of the demo versions—it’s like, whoa, this is really strong!” says Michael McEachen, principal investigator for SAILMAST at ATK Space Systems in Goleta, California.
Email Article To a Friend View Printable Version

Last Night's Sky

Book ReviewsIt's here, and it's official.....this will be the last ever issue of Night Sky magazine. With the first issue from May/June 2004, Night Sky gave experienced amateur astronomers lots of new ideas for easier ways to help explain myriad things in the night sky to anyone just entering this hobby we love so much. I know of a few people who actually started subscriptions to Night Sky, our own AOAS founding member Dale Hall among them. Even I was quickly taken in by the way this new astronomy magazine did its job, getting the rawest of novices outside to see things never seen before.

Yet, the subscriptions for Night Sky never really did catch on. As a letter inside the front pages of this last issue announces, "ultimately we couldn't attract nearly enough [beginning astronomer] like-minded people to sustain the effort profitably. I'm sorry to tell you that this issue of Night Sky will be the last." Kelly Beatty, Editor.

I hate to see it go so soon, but I understand why they're doing it. You can't keep pouring more and more money into any effort that never reaches a level of at least breaking even. Now all we have are our back-issues to help us with invaluable ways to explain the abstract, the mundane, and the sublime, to all our new recruits to astronomy. We MUST hold on to these past issues for that very reason. Night Sky will live on, even if its as dead as a door nail.
The final issue of Night Sky magazine. In only three short years the magazine was becoming a welcome aid to many newbie amateur astronomers. But low subscription levels were slowly doing it in. Now we'll make sure that we keep a valuable resource available to our members by creating as many complete sets of every issue that we possibly can.

I heard it through the Night Sky Network with an email about 3 months ago. Night Sky was closing up shop and doomed to fade away like a dimming supernova. I had become a real fan and I eagerly awaited the next issue. As members of the Night Sky Network, we were part of a campaign to help put Night Sky into the hands of as many visiting individuals as we could whenever we had an observing event, school visit, or a club meeting. They allowed us up to 40 issues each printing for free to give away at those opportunities, and I'll really miss that, too. I made sure that I started keeping one copy of every issue to start a collection that we'd be able to refer to for as long as the paper held together. That way, I reasoned, we'd always have those great tips found in the magazine to be made available to anyone that I thought might benefit from them. Now that its finally official, I want to ask everyone reading this to do one of two things...1) send or bring me all the past issues of Night Sky magazine as you have, or, 2) donate the issues you have to your nearest, or favorite astronomy club in your area. Why, you ask? Well, I'd at least hope that everyone would recognize how the past issues are able to instruct and inspire newcomers to our hobby in learning so much from such a great resource.

What I want to do for our AOAS library is to make up as many complete sets of the magazine as I can assemble, put these sets in individual magazine cases, and make them available to every paid member of AOAS to use whenever they ask for them. In order to accomplish this, I want to ask EVERYONE who has back issues of Night Sky magazine to find a way to get them to me. You can bring them to me at our next observing event (Feb 16th at Hackett), club meeting (set for March 2nd at UAFS MS-UC room 211 at 7pm) or at any other function or outing where you might find me. If you want to send them via snail-mail, it's a little more expensive than I'd want to spend just to donate some magazines to us, but that's your choice.

Please consider donating your back issues of Night Sky to us so we can assemble several sets of every copy ever published. I know you might be missing an issue, or maybe several issues, but if everyone were to do this, we might be able to create 4 or 5, maybe even more complete sets of every issue. I may be the only one who thinks this is an idea worth doing, (I HOPE I'm not alone in this, however) but if only a couple of people use this as a resource in the next few years, it will have been worth the effort as far as I'm concerned. Help me make this humble effort possible if you can, and thank you in advnce for doing so. Bob
Email Article To a Friend View Printable Version

Stars in the Natural State

Education Outreach
Orion, the Giant Hunter - The brightest and most recognized of all constellations, Orion is seen in winter skies, rising in the east at sunset in January and dropping behind the western horizon in the first week of May. Orion is home to the magnificent emission nebula known as M-42, roughly estimated to be 17 light-years across lying approximately 1,500 light-years away. Image by Akira Fujii used by permission from David Malin Images.
The AOAS 2007 public observing events kick off on Friday evening, February 9, 2007, with the first of four scheduled public viewing events at the Janet Huckabee River Valley Nature Center. We call these special events in cooperation with the Nature Center our "Stars in the Natural State" and the public is invited to attend. Our other three events at the Nature Center for 2007 will be held on May 11, Sept 14, and Dec 14. Make plans to attend all four events, and you will experience four different quadrants of the night sky, and have an opportunity to see all 50 or so northern hemisphere constellations.

AOAS is very proud to announce a year-long collaboration with the Janet Huckabee River Valley Nature Center located at 8300 Wells Lake Rd in Barling, AR. Borrowing from the Arkansas State motto, we call these public nights our "Stars in the Natural State" viewing events, all of which as always begin at dusk no matter which of the four seasons in which they'll be held.

Setting four events with one for each season gives our visitors a unique opportunity to see all the northern hemisphere constellations by simply attending each of these events. With this first event, you'll watch mighty Orion as he fends off the mythical attack of Taurus the Bull, while slowly switching from the eastern sky to the western sky between this first event and the May 11 event. Of course by that time the eastern sky is seeing an entirely new set of constellations rise and take their turn at making the same stately trek across the vault of the night sky, this time bringing with it a giant number of distant galaxies scattered through the constellations of Coma Berenices, or, Bernices Hair; Canis Venatici, the Hunting Dogs; and Virgo, the Virgin.
The Great Nebula in Orion - This object is the showpiece object of the northern winter sky. It's beauty hides violent, turbulent processes as new stars are formed from the gas and dust visible in this colorful HST/SST image. More than 3,000 stars have been identified using a combination of visible (Hubble Space Telescope) and infrared (Spitzer Space Telescope) space-based observations. Photo from Hubble Heritage Project
Literally hundreds of faint small galaxies are within the reach of medium or large backyard telescopes, and a dozen or more galaxies are bright enough to view in even small telescopes.

Our observing events are learning experiences. Seeing several dozen constellations are a favorite request from our guests, as are the inevitable questions of "What planets are out?", and "Where are the Black Holes?", or "Can you see the [American] flag on the moon?" Our members are very happy to show whoever might ask them ANY THING they want to see, up to a point, that is.

The flag is NOT visible to any telescope, ground-based or space-based, period! We simply do not have the technology to see something that small on the moon. Will it always be that way? I wouldn't want to bet on that. And Black Holes? Well, by definition, they're black, and they can NOT be seen directly. We know they exist due to the evidence we see in objects where something unseen exhibits some gravitational influence on a separate visible object and thereby revealing itself. Thanks to our club's membership in the Night Sky Network, we receive periodic toolkits containing simple components which are very effective at helping us explain such difficult, or abstract ideas.

Come and visit us at one or more of our dozen-plus planned events this year. You are guaranteed to see things you've never seen before and even things that you may never have known you even COULD see.
Email Article To a Friend View Printable Version

Explore Our Solar System Program

Education OutreachThe following information may be of great interest to K-8 teachers: EXPLORE OUR SOLAR SYSTEM. This workshop for K-8 teachers will be held at the McDonald Observatory in Fort Davis, TX. The $525 fee includes room & board, materials, and instruction. Teachers will practice their new astronomy skills under the observatory's dark skies and partner with trained and nationally recognized astronomy educators. APPLY BY MAY 1, 2007, at http://mcdonaldobservatory.org/teachers/profdev

Chuck Larson, Ed.D.
Email Article To a Friend View Printable Version

Cogno Science Challenge Program

Education OutreachInformation to classroom teachers - COGNO SCIENCE CHALLENGE: Each week share with your students a thought-provoking science puzzler, drawn from the award-winning Cogno science board games. You'll receive a weekly e-mail with a fully illustrated one-pager, ready to be photocopied for students. The e-mail message includes the answer and explanation, allowing you to facilitate as much or as little discussion as you like. Students will learn about astronomy, forces and motion, and life sciences. Scientist at NASA and the SETI Institute have reviewed all the content. For more informatiion and to register, see www.congo.com/challenge.

Chuck Larson, Ed.D.
Email Article To a Friend View Printable Version

A Great Big Wreck

NASA Space Placeby Dr. Tony Phillips

This GALEX UV image of the colliding Antennae Galaxies shows areas of active star formation, which is not in the tidal tails as one might expect.
People worry about asteroids. Being hit by a space rock can really ruin your day. But that's nothing. How would you like to be hit by a whole galaxy?

It could happen. Astronomers have long known that the Andromeda Galaxy is on a collision course with the Milky Way. In about 3 billion years, the two great star systems will crash together. Earth will be in the middle of the biggest wreck in our part of the Universe.

Astronomer John Hibbard isn't worried. “Galaxy collisions aren't so bad,” he says. A typical spiral galaxy contains a hundred billion stars, yet when two such behemoths run into each other “very few stars collide. The stars are like pinpricks with lots of space between them. The chance of a direct hit, star vs. star, is very low.”

Hibbard knows because he studies colliding galaxies, particularly a nearby pair called the Antennae. “The two galaxies of the Antennae system are about the same size and type as Andromeda and the Milky Way.” He believes that the Antennae are giving us a preview of what's going to happen to our own galaxy.

The Antennae get their name from two vast streamers of stars that resemble the feelers on top of an insect's head. These streamers, called “tidal tails,” are created by gravitational forces—one galaxy pulling stars from the other. The tails appear to be scenes of incredible violence.

But looks can be deceiving: “Actually, the tails are quiet places,” says Hibbard. “They're the peaceful suburbs of the Antennae.” He came to this conclusion using data from GALEX, an ultraviolet space telescope launched by NASA in 2003.

The true violence of colliding galaxies is star formation. While individual stars rarely collide, vast interstellar clouds of gas do smash together. These clouds collapse. Gravity pulls the infalling gas into denser knots until, finally, new stars are born. Young stars are difficult to be around. They emit intensely unpleasant radiation and tend to “go supernova.”

GALEX can pinpoint hot young stars by the UV radiation they emit and, in combination with other data, measure the rate of star birth. “Surprisingly,” Hibbard says, “star formation rates are low in the tidal tails, several times lower than what we experience here in the Milky Way.” The merging cores of the Antennae, on the other hand, are sizzling with new stars, ready to explode.

So what should you do when your galaxy collides? A tip from GALEX: head for the tails.

To see more GALEX images, visit www.galex.caltech.edu. Kids can read about galaxies and how a telescope can be a time machine at spaceplace.nasa.gov/en/educators/galex_puzzles.pdf.

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

Space Weather for Air Travelers

NASA Space PlaceBy Dr. Tony Phillips

The shortest airline routes from the Eastern U.S. to popular destinations in Asia go very near the magnetic North Pole, where space weather is of greatest concern.
At a time when much of the airline industry is struggling, one type of air travel is doing remarkably well: polar flights. In 1999, United Airlines made just twelve trips over the Arctic. By 2005, the number of flights had grown to 1,402. Other airlines report similar growth.

The reason for the increase is commerce. Business is booming along Asia's Pacific Rim, and business travel is booming with it. On our spherical Earth, the shortest distance from Chicago to Beijing or New York to Tokyo is over the North Pole. Suddenly, business travelers are spending a lot of time in the Arctic.

With these new routes, however, comes a new concern: space weather.

“Solar storms have a big effect on polar regions of our planet,” explains Steve Hill of NOAA's Space Weather Prediction Center in Boulder, Colorado. Everyone knows about the Northern Lights, but there's more to it than that: “When airplanes fly over the poles during solar storms, they can experience radio blackouts, navigation errors and computer reboots — all caused by space radiation.”

In 2005, United Airlines reported dozens of flights diverted from polar routes by nasty space weather. Delays ranged from 8 minutes to nearly 4 hours, and each unplanned detour burned expensive fuel. Money isn't the only concern: Pilots and flight attendants who fly too often over the poles could absorb more radiation than is healthy. “This is an area of active research — figuring out how much exposure is safe for flight crews,” says Hill. “Clearly, less is better.”

To help airlines avoid bad space weather, NOAA has begun equipping its GOES weather satellites with improved instruments to monitor the Sun. Recent additions to the fleet, GOES 12 and 13, carry X-ray telescopes that take spectacular pictures of sunspots, solar flares, and coronal holes spewing streams of solar wind in our direction. Other GOES sensors detect solar protons swarming around our planet, raising alarms when radiation levels become dangerous.

“Our next-generation satellite will be even better,” says Hill. Slated for launch in 2014, GOES-R will be able to photograph the Sun through several different X-ray and ultra-violet filters. Each filter reveals a somewhat different layer of the Sun's explosive atmosphere — a boon to forecasters. Also, advanced sensors will alert ground controllers to a variety of dangerous particles near Earth, including solar protons, heavy ions and galactic cosmic rays.

“GOES-R should substantially improve our space weather forecasts,” says Hill. That means friendlier skies on your future trips to Tokyo.

For the latest space weather report, visit the website of the Space Weather Prediction Center at http://www.sec.noaa.gov/. For more about the GOES-R series spacecraft, see http://goespoes.gsfc.nasa.gov/goes/spacecraft/r_spacecraft.html. For help in explaining geostationary orbits to kids — or anyone else — visit The Space Place at http://spaceplace.nasa.gov/en/kids/goes/goes_poes_orbits.shtml.

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

Martian Devils

NASA Space Placeby Dr. Tony Phillips

The top half of this image is part of a series of images of a passing dust devil on Mars caught by Spirit. In the bottom half, the image has been filtered to remove everything that did not change from one image to the other. Notice the faint track left by the dust devil. Credit NASA/JPL/Mark T. Lemmon, Univ. of Arizona Lunar and Planetary Laboratory.
Admit it. Whenever you see a new picture of Mars beamed back by Spirit or Opportunity, you scan the rocks to check for things peeking out of the shadows. A pair of quivering green antennas, perhaps, or a little furry creature crouched on five legs…? Looking for Martians is such a guilty pleasure.

Well, you can imagine the thrill in 2004 when scientists were checking some of those pictures and they did see something leap out. It skittered across the rocky floor of Gusev Crater and quickly disappeared. But it wasn't a Martian; Spirit had photographed a dust devil!

Dust devils are tornadoes of dust. On a planet like Mars which is literally covered with dust, and where it never rains, dust devils are an important form of weather. Some Martian dust devils grow almost as tall as Mt. Everest, and researchers suspect they're crackling with static electricity — a form of “Martian lightning.”

NASA is keen to learn more. How strong are the winds? Do dust devils carry a charge? When does “devil season” begin — and end? Astronauts are going to want to know the answers before they set foot on the red planet.

The problem is, these dusty twisters can be devilishly difficult to catch. Most images of Martian dust devils have been taken by accident, while the rovers were looking for other things. This catch-as-catch-can approach limits what researchers can learn.

No more! The two rovers have just gotten a boost of artificial intelligence to help them recognize and photograph dust devils. It comes in the form of new software, uploaded in July and activated in September 2006.

“This software is based on techniques developed and tested as part of the NASA New Millennium Program's Space Technology 6 project. Testing was done in Earth orbit onboard the EO-1 (Earth Observing-1) satellite,” says Steve Chien, supervisor of JPL's Artificial Intelligence Group. Scientists using EO-1 data were especially interested in dynamic events such as volcanoes erupting or sea ice breaking apart. So Chien and colleagues programmed the satellite to notice change. It worked beautifully: “We measured a 100-fold increase in science results for transient events.”

Now that the techniques have been tested in Earth orbit, they are ready to help Spirit and Opportunity catch dust devils — or anything else that moves — on Mars.

“If we saw Martians, that would be great,” laughs Chien. Even scientists have their guilty pleasures.

Find out more about the Space Technology 6 “Autonomous Sciencecraft” technology experiment at nmp.nasa.gov/st6/TECHNOLOGY/sciencecraft_tech.html, and the use of the technology on the Mars Rovers at nmp.nasa.gov/TECHNOLOGY/infusion.html. Kids can visit spaceplace.nasa.gov/en/kids/nmp_action.shtml and do a New Millennium Program-like test at home to see if a familiar material would work well in space

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

User Functions

Lost your password?

What's New


No new stories

COMMENTS last 2 days

No new comments

LINKS last 2 weeks

No recent new links

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.