Astronomer Scott Kardel on top of the 200-inch Hale Telescope at the Palomar Observatory shoveling snow. Image courtesy Scott Kardel.
Ah, the glamorous life of an astronomer. Scott Kardel, public affairs coordinator for the Palomar Observatory, found himself on top of the dome of the 200-inch Hale Telescope — not observing, but shoveling. Snow. Palomar Mountain has been getting its share of the white stuff this winter, and this weekend close to a foot of snow fell in the area. All that snow can cause problems for using the telescope.
“The basic problem is this,” Kardel wrote on his blog, Palomar Skies. “If you open the dome with snow on the top, snow will fall in on the telescope and instrumentation. So a small crew, each secured with a safety harness, is sent up to remove the snow from the dome slit.”
Kardel posted a nice collection of scenic images from his foray on top of the snow-covered dome, adding that, “At Palomar Observatory every day is an adventure.”
Looking for a great vacation spot with those all-important dark skies for astronomical observing? A small island in the English Channel off the French coast of Normandy might be just what you are looking for. The Channel Island of Sark has been officially recognized for the quality of its night sky by the International Dark-sky Association (IDA), who have designated it as the world’s first dark sky island, the latest in a select group of dark sky places around the world.
An aerial view of Sark.
What makes the Sark skies so dark? The island has no public street lighting, there are no paved roads and cars, so effectively, there is no light pollution in the skies. Those who have been there say the night sky is very dark, with the Milky Way stretching from horizon to horizon, meteors streaking overhead, and countless stars on display.
The people who live there have made dark skies one of their priorities. Through a long process of community consultation, a comprehensive lighting management plan was created by Jim Patterson of the Institute of Lighting Engineers, and many local residents and businesses have altered their lighting to make them more dark sky friendly, ensuring that as little light as possible spills upwards where it can drown out starlight.
Roger Davies, president of the Royal Astronomical Society, said, “This is a great achievement for Sark. People around the world are become increasingly fascinated by astronomy as we discover more about our universe, and the creation of the world’s first dark sky island in the British Isles can only help to increase that appetite. I hope this leads to many more people experiencing the wonders of a truly dark sky.”
For more information on Sark, see the island’s website.
Hubble images of the Omega Centauri starfield from 2002, left, and from 2009, right.
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Classification is key to all sciences, but can often cause debate. Within astronomy, fierce debates have raged over the definition of a planet, both on the low-mass end, as well as the high-mass end. A recent paper explores definitions on a larger scale, pondering the definition of a galaxy, particularly, what separates the smallest of galaxies, the dwarf galaxies, from star clusters.
A working definition for dwarf galaxies was proposed in 1994 based on the brightness of the object in question as well as it’s size. For brightness, the cutoff was taken to be an absolute magnitude (MB) of -16. The size would need to be “more extended than a globular cluster.”
As with many definitions, they seem to work initially, but as new technology became available, objects were discovered around the cutoff line, blurring the distinction. These objects, which were first discovered in the late 90’s, are generally referred to with names like “ultra-faint dwarf spheroidals” (dSphs) and “ultra compact dwarfs” (UCDs). Regarding these small fragments, a 2007 study noted that they may “contain so few stars that they can be fainter than a single bright star and contain less stellar mass than some globular clusters”.
To help reconsider the definition of a galaxy, the authors looked at several commonly used criteria that have been applied (often inconsistently) to these questionable cases previously. This included requirements that the system be gravitationally bound, which would keep stellar streams and other ejected objects from being considered galaxies in their own right. Obviously, most galaxies will slowly bleed away stars due to random interactions, giving rise to hypervelocity stars which will leave the galaxy, so the team proposes a threshold that the galaxy have a “relaxation time” greater than the age of the universe. This would allow dSphs and UCDs to be considered galaxies, but would keep out objects that have generally been considered globular clusters.
Another proposed constraint is based on the size of the object. The team proposes a cutoff where the effective radius be greater than or equal to 100 parsecs. This cutoff would exclude dSphs and UCDs.
The types of stars is another consideration proposed since this can be used to achieve somewhat of an understanding of the history of the object. While clusters usually form in a single instance, galaxies are generally considered to have their own, internal machinations leading to complex stellar populations. Thus, the presence of multiple populations of stars. This would include dSphs and UCDs, but may allow some globular clusters to slip in as well since studies have shown that some of our more massive globular clusters in the Milky Way have interacted with gas clouds, triggering star formation which was absorbed by the clusters.
Dark matter is another criteria that is examined. Since galaxies are proposed to form within dark matter halos and be intrinsically tied into them, the requirement that dark matter be present would fit well with the theory. However, this criteria also poses many difficulties. Firstly, measuring the presence of dark matter in small objects is a challenging task. It is also questionable as to whether or not dSphs and UCDs would contain dark matter as a general rule since their formation is not well understood and the possibility remains that they may have been ejected from our own galaxy during formation and recoalesced, possibly without a dark matter halo.
The last possible criteria is much along the same lines as the nebulous definition for planets that they dominate the local gravitational field. The team considers the possibility that objects would be required to have stellar satellite systems as globular clusters of their own. This would include some dwarf galaxies, but may exclude others.
Even with many of these criteria, classification will still be a treacherous issue. Objects like Omega Centauri may fit some definitions but not others. According to the paper’s lead author, Duncan Forbes, “many amateur astronomers know Omega Cen as massive star cluster, some professional astronomers regard it as a galaxy. This is a stellar system that could be upgraded or downgraded by this exercise, depending on your point of view.”
To help gather opinions on the topic, the authors have set up an online survey to gather opinions on this definition and hope to reach a satisfactory conclusion by collective wisdom. This poll is open to the general public and results will be presented at a future astronomical conferences allowing participants to help take part in the astronomical process. Forbes hopes that this public interaction will help garner public interest in much the same way as the Galaxy Zoo project has.
A radar image of asteroid 2010 JL33, generated from data taken by NASA's Goldstone Solar System Radar on Dec. 11 and 12, 2010. Image credit: NASA/JPL-Caltech
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Intriguing details about the physical properties and characteristics of a recently discovered asteroid have just been unveiled in amazing images obtained using a large radar dish in California. The radar dish serves as a key component of NASA’s Deep Space Network (DSN). The Near Earth asteroid, dubbed 2010 JL33, was imaged by radar on Dec. 11 and 12, 2010 at NASA’s Goldstone Solar System Radar in California’s Mojave Desert when a close approach to Earth offered an outstanding opportunity for high quality science.
Asteroids studies have taken on significantly increased importance at NASA ever since President Obama decided to cancel the Constellation ‘Return to the Moon’ program and redirect NASA’s next human spaceflight goal to journeying to an Asteroid by around 2025.
Update: Orbital diagram added below
A sequence of 36 amazingly detailed images has been assembled into a short movie (see below) by the science team at NASA’s Jet Propulsion Laboratory (JPL) in Pasadena, Calif. The movie shows about 90 percent of one rotation.
The data gathered by radar revealed that the asteroid measures roughly 1.8 kilometers (1.1 miles) in diameter and rotates once every nine hours.
Orbital diagram of Asteroid 2010 JL33 shows location as of Jan 14, 2011. Credit: NASA
click to enlage all images
“Asteroid 2010 JL33 approached within 17 Earth-Moon distances [some 7 million km] in December 2010 and offered an outstanding opportunity to study it with radar,” said Lance Benner, a scientist at JPL who studies asteroids.
“To get detailed radar images, an asteroid must be close to Earth,” Benner told me, for Universe Today.
The object was only discovered on May 6 by the Mount Lemmon Survey in Arizona. The radar observations were led by a team headed by JPL scientist Marina Brozovic.
Video Caption: While safely passing Earth, NASA’s Goldstone Solar System Radar captured the rotation of asteroid 2010 JL33 — an irregular, elongated object roughly 1.8 kilometers (1.1) miles wide. The video consists of 36 frames.
“The radar images we got enabled us to estimate the asteroid’s size, rotation period, and to see features on its surface, most notably, the large concavity that appears as a dark region in the collage,” Benner elaborated.
“It was discovered so recently that little else is known about it.”
The object was revealed to be elongated and irregularly shaped.
70-meter diameter NASA Deep Space Network (DSN) antenna at Goldstone, California.
The 70-meter (230-foot) diameter antenna is the largest, and therefore most sensitive, DSN antenna, and is capable of tracking a spacecraft travelling 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 sq. ft.) surface is maintained within one centimeter (0.4 in.). Credit: NASA
The large concavity is clearly visible in the images and may be an impact crater. It took about 56 seconds for the radio signals from the 70-meter (230-foot) diameter Goldstone radar dish to make the roundtrip from Earth to the asteroid and back to Earth again.
“When we get deeper into our analysis of the data, we will use the images to estimate the three-dimensional shape of the asteroid as well,” Benner added.
Benner belongs to a team that is part of a long-term NASA program to study asteroid physical properties and to improve asteroid orbits using radar telescopes at Goldstone and also at the Arecibo Observatory in Puerto Rico. The 1,000-foot-diameter (305 meters) Arecibo radar dish antenna is operated by the National Science Foundation.
“Each close approach by an asteroid provides an important opportunity to study it, so we try to exploit as many such opportunities as possible to investigate the physical properties of many asteroids. In the bigger picture, this helps us understand how the asteroids formed,” Benner told me.
“Asteroid 2010 JL33 is in an elongated orbit about the Sun. On average, it’s about 2.7 times farther from the Sun than the Earth is, but its distance from the Sun varies from 0.7 to 4.6 times that of the Earth.” That takes the asteroid nearly out to Jupiter at Aphelion. It takes about 4.3 years to complete one orbit around the sun.
But, there’s no need to fret about disaster scenarios. “The probability of impact with Earth is effectively zero for the foreseeable future,” Benner explained.
“On rare occasions it approaches closely to Vesta,” he said. Vesta is the second most massive asteroid and will be visited for the first time by NASA’s Dawn spacecraft later this year.
In addition to the ground based radar imaging, the tiny space rock was investigated by an Earth orbiting telescope.
“This asteroid was also studied by NASA’s Wide-field Infrared Survey Explorer (WISE) spacecraft,” according to Benner. “Our observations will help WISE scientists calibrate their results because we provided an independent means to estimate the size of this object.”
More at this JPL press release. The NASA-JPL Near-Earth Object Program website has an interactive map that allows you to see the asteroid’s position at any time you desire. Go to here
To see the trajectory of any other near-Earth asteroid, go to here
For more information about asteroid radar research, go to here
Check out this awesome pair of inspiring videos about NASA and Space Exploration. They are set to the ever inspiring words of Carl Sagan – reading from his book, “The Pale Blue Dot”. And these beautifully crafted videos were not created by NASA, but rather by people inspired by NASA and Carl Sagan to dream about distant frontiers even in these times of tough budgets for NASA.
The original, highly praised video – see below – was created by Director Michael Marantz, who was inspired by the words of Carl Sagan. Now a completely new version – above – by a fellow going by “damewse”, has been set to the same stirring words and music and the video has gone viral.
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“damewse” posted that he created the new video treatment because he feels NASA’s PR sucks, resulting in massive funding cuts. He pleads with NASA to use social media to relate to the public with videos like these to rekindle public interest in the space program.
Both videos are included here for all to enjoy and compare – moving and thought provoking in their own right.
“damewse” elaborated; “I got frustrated with NASA and made this video. NASA is the most fascinating, adventurous, epic institution ever devised by human beings, and their media sucks.”
“Seriously. none of their brilliant scientists appear to know how to connect with the social media crowd, which is now more important than ever. In fact, NASA is an institution whose funding directly depends on how the public views them.”
Earth: The Pale Blue Dot
The original film and comments by Director Michael Marantz
“Carl Sagan provides the epic narration to this piece. His great ability to convey such overwhelming topics in relatable ways inspired me to make this.”
The Pale Blue Dot. Most distant image of Earth, snapped by the Voyager 1 spacecraft in 1990 at a distance of 6.1 billion kilometers. Credit: NASA
“This piece contains readings from Carl Sagan’s “Pale Blue Dot”. I have edited his words to tell this short narrative.
I took the time lapse images in Mexico and Utah.
The piano is self-composed.
Everything in this video is created by myself except for the words of Carl Sagan.
I hope you enjoy this piece, it has given me hope once again.”
– Michael Marantz
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Well NASA does need to do a more effective job at PR to grab the attention of the public – especially the younger generations – and explaining the agency’s exploration goals in ways that folks will find value in and support. But it’s also true that NASA has embraced many forms of social media. Take a look at almost any NASA Center or Mission homepage and you’ll see buttons for Twitter, Facebook, YouTube, flickr, blogs and more. I’ve found these sources to be invaluable, especially during beaking news events.
It hinges more I think on the quality of the presentation of the content and the organization of outstanding material at those websites. Look here for a thoughtful perspective from Spaceref Canada
The lengthy list of exciting and worthy ideas and lost opportunities for space exploration that have gone unfunded in our lifetimes, is truly sad. Carl Sagan with a model of the Viking Lander that landed on Mars in 1976 in the search for life.
Amazing Swedish view of Jan 4, 2011 partial solar eclipse, which reached its maximum – about 85%- in this stunner from Stockholm, Sweden. Poor weather and obscuring clouds momentarily relented at just the perfect time. Credit: Peter Rosen
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Millions across Earth enjoyed one of nature’s most awesomely spectacular events during today’s (Jan. 4) partial solar eclipse – the first of four set to occur in 2011. And there was nothing partial about it, for those lucky eyewitnesses where it was visible in parts of Europe, Africa and Central Asia. The eclipse reached its maximum, about 85%, in Sweden. See the maximum stunner above – taken despite pessimistic weather forecasts -by Peter Rosen in Stockholm, Sweden, with more photos from the sequence here at spaceweather.com
Probably the most technically amazing feat is the double solar eclipse captured in one image by renowned astrophotographer Theirry Legault – see below – boasting both the ISS and the Moon on the eclipsed sun’s face. Legault had traveled to the deserts of the Sultanate of Oman, near to the capital of Muscat, for this rare spectacle of nature. The ISS was calculated to be visible in a thin strip barely 11 kilometers wide, according to Astronomie Info news. The ISS transit lasted just about 1 second, speeding by at 28,000 km/sec.
See a global compilation of gorgeous eclipse photos here and comment or send us more. Update 1/6/11: this is a work in progress so please check back again.
New readers photos and eyewitness accounts added below today; as received
Click to enlarge all photos
First up: Double Solar Eclipse by renowned astrophotographer Theirry Legault in Oman
Amazing Double Solar Eclipse with the ISS and the Moon captured in one image in the deserts of the Sultanate of Oman. Credit: Theirry Legault
Check out this exciting gallery of images contributed by eclipse watchers from multiple locations around the world, on Flickr
Composition of 8 different exposures between 8.10 and 9.18 (local) recorded with solar filter and added to a unfiltered picture at the beginning of sequence. Taken with a Sony DSCW-1 with 35mm equivalent focal length. Credit: Marco Di Lorenzo, Pescara, Italy
Here is a collection of images and an eyewitness report sent to me by Marco Di Lorenzo, in Pescara, Italy
Filtered and unfiltered views at 9.11 local time. Credit: Marco Di Lorenzo
Marco writes; Pescara is located at 42.467°N and 14.225°E, about in the center of Italy on the Adriatic sea. I chose my location at the new pedestrian bridge because it is a modern structure which offers a nice foreground and also an open, elevated viewpoint. I used a couple of cameras plus a digital video camera. All the cameras were mounted on a tripod.
The weather was cold and the situation didn’t improve in the mid morning. Illumination was comparable to a slightly foggy day. The frigid temperature didn’t encourage people to go out and check. However some people did venture out. Someone asked me some info on eclipses and how to take pictures of it – very hard indeed, especially if you use a cellular phone ! Combo of 2 pictures taken few seconds apart using solar filter and different exposure; local time was 9.11 AM, near maximum. Marco Di Lorenzo
Urijian Poernick sent these photos and description:
“Colorful Solar Eclipse” at Halley Astronomical Observatory, Heesch, The Netherlands Partial Solar eclipse and flock of birds from Heesch, The Netherlands. Credit: Urijian Poernick
The weather forecast predicted overcast skies with only a few small bright intervals in all parts of The Netherlands. Nevertheless, dozens of members of Halley Astronomical Society and visitors, including many children, challenged the cold winter weather and came together on the flat roof of Halley Astronomical Observatory in The Netherlands.
Partial Solar eclipse from Heesch, The Netherlands. Credit: Urijian PoernickAfter sunrise at 7:44 UT (8:44 local time) they all looked at a narrow opening in the cloud deck near the eastern horizon. At 8:00 UT the sun showed itself: first we saw the left horn of the eclipse and a few moments later the right one.
Due to the clouds and veils it was a very colorful eclipse, with all tints of red and yellow. After twenty minutes the sun and the moon disappeared behind the overcast skies again and they didn’t come back before the end of the eclipse (9:39 UT).
During this short period everyone could watch the eclipse through the telescope and we were all enthusiastic. It was a beautiful spectacle! www.sterrenwachthalley.nl
Gianluca Masi is the National Coordinator of Astronomers Without Borders in Italy and captured this pair of photos from partially overcast Rome, Italy. The clouds contributed to make for a delightfully smoky eclipsed sun Smoky eclipsed sun from Rome, Italy. Credit: Gianluca Masi Credit: Gianluca Masi
Edwin van Schijndel sent me this report from the Netherlands:
I made some pictures in the southwest of the Netherlands. The weather conditions were not so good in the early morning, most places were covered by clouds so we decided to move about 70 miles to the southwest from our hometown. Finally we stopped not far from the city of Bergen op Zoom and were able to see sunrise while most of the sun was covered. It was splendid!
Eclipsed sunrise from Bergen op Zoom, the Netherlands. Credit: Edwin van Schijndel
Unfortunately there came more clouds so the rising sun disappeared and we drove 20 miles to the north just before Rotterdam and the sky was more clear at this place. Again we took some pictures but the maximum covering of the sun had been a few minutes before. After all this wasn’t really a pity, we were very lucky to have seen the rising of the sun and be able to make some nice pictures of the partial eclipse. Many people in the Netherlands saw less or even nothing.
Credit: Edwin van Schijndel Credit: Edwin van Schijndel
Send us or comment more solar eclipse photos to post here. ken : [kremerken at yahoo.com]
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More Readers Photos and Eyewitness Accounts. Beautiful, Thanks ! ken
Story and Photos sent me by Stefano De Rosa. Turin, Italy
Early in the morning, I moved to a site close to Turin (Italy) where the forecast was not so bad as in my city to try to observe and photograph the partial solar eclipse. Unfortunately, when I arrived it was cloudy and foggy and so decided to go back home. Technical details: Canon Eos 1000d, F/22; 150-500mm lens @ 500mm; ISO. 1/1600 sec Turin, Italy. Credit: Stefano De Rosa
Suddenly, as I was sadly driving on the motorway, close to the city of Alessandria, noticed a little break on the clouds from my rearview mirror: I stopped the car and, after a quick set up, managed to capture the crescent Sun!
http://ofpink.wordpress.com Well, I hope you carefully looked back before hitting the brakes ! – ken Turin, Italy. Credit: Stefano De Rosa
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Story and Photos sent me by Roy Keeris, Zeist, The Netherlands
Middelkerke, The Netherlands. Credit: Roy Keeris
Me and a friend (Casper ter Kuile) wanted to see the eclipse from The Netherlands. If clouds should intervene, we planned to drive a little (max. a couple of hours) to a place with a better chance for a clear sky. During the night we checked weather forecasts and satellite images. We were pretty unsure if we would succeed in seeing the eclipse, because it was pretty cloudy, and especially the low clouds tend to be quite unpredictable. In the end we chose to drive to Middelkerke (near Oostende) in Belgium because of a clear spot approaching from the North Sea.
Middelkerke, The Netherlands. Credit: Roy Keeris
We arrived at the Belgian coast just in time before sunrise. There we witnessed the eclipse from the top of a dune. About 25 minutes after sunrise the sun appeared from behind the lower clouds, just when the eclipse was at its maximum. It was magical!
First we saw the right ‘horn’ and then the left one appeared. From then on we watched the rest of the eclipse and took many pictures. [no pics from Casper ??]
Later we heard that despite the clouds, many people in The Netherlands were able to see the eclipse. There was a long stretch with a clear zone in the clouds- near the border of Germany.
Middelkerke, The Netherlands. Credit: Roy Keeris
If they had a clear horizon, people could look underneath the clouds and were just able to see the sunrise. I could even have seen it at home from my apartment on the 13th floor! But the trip was fun. It’s always nice to hunt for the right place to be at these events.
Here are some pictures I took from Middelkerke. They were shot with a Canon 400D in combination with a Meade ETS-70 telescope and a Tamron 20-200mm lens.
Thanks – Yes the hunt is half the fun. ken
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Story and Photos sent me by Igal Pat-El, Director, Givatayim Observatory, Tel Aviv, Israel
We took some images of the Jan. 4 Solar Eclipse from the Givatayim Observatory, just near Tel-Aviv, Israel. We were pleased to have Prof. Jay Passachoff as a guest during the eclipse. We had a live broadcast in plan but we had to cancel it due to heavy rain from the first contact, therefore we closed the dome’s shutter and went to the balcony trying to take some quick photos of the eclipse.
Tel Aviv, Israel. All Photos Credit: Igal Pat-El, Givatayim Observatory.
Collage assembled by Ken Kremer
We had the portable PST Coronado CaK telescope with a Ca filter On a Alt-Az mount (we could not do any alignment due to the rain). We took about 5 images against all odds in this very dim filter, using the Orion SS II Planetary imager, all of them through the haze and clouds.
Thanks, Igal. Another good lesson learned. Take a chance. You never know what you’ll get till you try !
I’ve combined Igal’s photos into a collage for an enhanced view. ken
See more photos and a video in comments section below
Today, we take it for granted that the Sun produces energy via nuclear fusion. However, this realization only came about in the early 1900’s and wasn’t confirmed until several decades later (see the Solar Neutrino Problem). Prior to that, several other methods of energy production had been proposed. These ranged from burning coal to a constant bombardment of comets and meteors to slow contraction. Each of these methods seemed initially plausible, but when astronomers of the time worked out how long each one could sustain such a brightness, they came up against an unlikely opponent: Charles Darwin.
In a “Catholic Magazine and Review” from 1889, known as The Month, there is a good record of the development of the problem faced in an article titled “The Age of the Sun and Darwinism”. It begins with a review of the recently discovered Law of Conservation of Energy in which they establish that a method of generation must be established and that this question is necessarily entangled with the age of the Sun and also, life on Earth. Without a constant generation of energy, the Sun would quickly cool and this was known to be unlikely due to archaeological evidences which hinted that the Sun’s output had been constant for at least 4,000 years.
While burning coal seemed a good candidate since coal power was just coming into fashion at the time, scientists had calculated that even burning in pure oxygen, the Sun could only last ~6,000 years. The article feared that this may signal “the end of supplies of heat and light to our globe would be very near indeed” since religious scholars held the age of the Earth to be some “4000 years of chronological time before the Christian era, and 1800 since”.
The bombardment hypothesis was also examined explaining that the transference of kinetic energy can increase temperatures citing examples of bullets striking metal surfaces or hammers heating anvils. But again, calculations hinted that this too was wrong. The rate with which the Sun would have to accumulate mass was extremely high. So much so that it would lead to the “derangement of the whole mechanism of the heavens.” The result would be that the period of the year over the past ~6,000 years would have shortened by six weeks and that the Earth too would be constantly bombarded by meteors (although some especially strong meteor showers at that time lent some credence to this).
The only strong candidate left was that of gravitational contraction proposed by Sir William Thomson (later Lord Kelvin) and Hermann von Helmholtz in a series of papers they began publishing in 1854. But in 1859, Darwin published the Origin of Species in which he required an age of at least two billion years. Thomson’s and Helmholtz’s hypothesis could only support an age of some tens of millions of years. Thus astronomy and biology were brought head to head. Darwin was fully aware of this problem. In a letter to a friend, he wrote that, “Thomson’s views of the recent age of the world have been for some time one of my sorest troubles”.
To back the astronomers was the developing field of spectroscopy in which they determined that the sun and other stars bared a strong similarity to that of nebulae. These nebulae could contract under their own gravity and as such, provided a natural establishment for the formation of stars, leading gracefully into the contraction hypothesis. Although not mentioned in the article, Darwin did have some support from geologists like Charles Lyell who studied the formation of mountain ranges and also posited an older Earth.
Some astronomers attempted to add other methods in addition to gravitational contraction (such as tidal friction) to extend the age of the solar system, but none could reach the age required by Darwin. Similarly, some biologists worked to speed up evolutionary processes by positing separate events of abiogenesis to shave off some of the required time for diversification of various kingdoms. But these too could not rectify the problem.
Ultimately, the article throws its weight in the camp of the doomed astronomers. Interestingly, much of the same rhetoric in use by anti-evolutionists today can be found in the article. They state, “it is not surprising to find men of science, who not only have not the slightest doubt about the truth of their own pet theories, but are ready to lay down the law in the realms of philosophy and theology, in science which with, to judge from their immoderate assertions, their acquaintance is of the most remote? Such language is to be expected from the camp-followers in the army of science, who assurance is generally inversely proportional to their knowledge, for many of those in a word who affect to popularize the doctrine of Natural Selection.”
In time, Darwin would win the battle as astronomers would realize that gravitational contraction was just the match that lit the fuse of fusion. However, we must ask whether scientists would have been as quickly able to accept the proposition of stellar fusion had Darwin not pointed out the fundamental contradiction in ages?
Donate your used astronomy books to the Astro Book Drive!
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Astronomy is one of the oldest sciences, and one of the most popular amateur hobbies around the world. In fact, there are thousands of astronomy clubs and groups across the globe, but in many developing countries they don’t have the resources to help educate their their members, as well popularize astronomy for students and the public.
“The enthusiasm of most of these groups are vast but they always come across the lack of resources to conduct programs,” said Thilina Heenatigala, from the Sri Lanka Astronomical Association, who has been instrumental in organizing astronomy book drives for fledgling astronomy clubs in developing countries the past few years.
Astro Book Drive is a project that works on helping improve astronomy education in developing countries by sharing resources. Right now, Astro Book Drive is gathering books and other resources for an astronomy club in Indonesia.
So, c’mon – you know you have some astronomy books, pamphlets and other items that you’d like to donate!
“Even though we are much advanced in technology and internet has a vast amount of resources,” Heenatigala told Universe Today, “most of the groups from developing countries are lacking resources to conduct astronomy programs and educate people. As coming from a developing country myself, I can tell you that one of the most basic, yet powerful ways to bring astronomy to developing countries is through the simple gift of books.”
If you’re like me, you probably have a surplus of astronomy materials lying; these materials are valuable to groups from developing countries.
“This is a global effort and anyone/group welcome to donate what they have, even one book can make big difference,” said Heenatigala. “I’m hoping to keep the book drive running from December through February 2011.”
The group from Indonesia, langitselatan (LS) – Southern Skies – is an astronomy communication and educator media in Indonesia run by young group of astronomy enthusiasts with the vision of getting astronomy in the local media, astronomy education and awareness throughout the country. Heenatigala said LS has been working tirelessly over the years to achieve these by conducting star parties, telescope training, teachers training, hands on activities, story telling session, astronomy discussion and talk shows and astro-presentation.
To expand their efforts, LS hopes to build a small library which will be used by the members, students and the local community. Through the library project, they hope to increase the reading habits of young students and teachers as well. To achieve their dream of setting up a library to improve astronomy education in Indonesia, Astro Book Drive calls the international community to donate Astronomy reading materials.
There are other book drives as well, and will probably be more coming up in 2011. The Astro Book Drive project was started in 2009 as part of the International Year of Astronomy.
“Usually the procedure is to get a group/institutes from a wealthy country to run a book drive for a group in developing country, where they donate from 3 – 10 boxes of books. But for the Indonesian book drive, I had to put an open call since it’s an effort to set up an Astro Library there.”
For more information on specifically the book drive for Indonesia, see this link
Some colours just can’t keep up with the others! Well, that’s probably the simplest way to put it. But when scientists talk about the characteristics of light, it would be more accurate to say that different colours of light propagate at different speeds, orhave different wavelengths, and therefore refract differently. A well-known example of this is the prism effect, where a beam of white light is broken into a rainbow of colours. The result of this is that when objects are viewed through a simple lens, light will refract (bends) at different angles, meaning that it will not image all in the same place. A distortion results in which “fringes” of color appear along the boundaries that separate dark and bright parts of the image. This effect, known as Chromatic Aberration, can be a real pain for astronomers, surveyors, photographers, or just about anyone who wants to view an object (or objects) through a lens and needs to do so clearly!
Sir Isaac Newton was the first to demonstrate this effect some two-hundred years ago when he discovered that light was composed of multiple wavelengths. These colours refract unevenly, with blue-appearing light refracting at shorter wavelengths and red-appearing light refracting at longer, with green refracting in the middle. Since that time, scientists, astronomers and opticians have come to identify two basic kinds of aberration. The first is axial (or longitudinal) where different wavelengths are focused at a different distance because the lens in unable to focus different colours in the same focal plane. The second is transverse (or lateral) aberration, where different wavelengths are focused at different positions in the focal plane and the effect is a sideward displacement of the image. In the former case, distortion occurs throughout the image whereas in the latter, distortion is absent from the centre but increases towards the edge.
There are many ways to remedy Chromatic Aberration. During the 17th century, telescopes had to be very long in order to correct for colour distortions. Sir Isaac Newton remedied this problem by creating the comparably compact, reflecting telescope in 1668 that used curved mirrors to get around this problem. The achromatic lens (or achromatic doublet) is another; a double lens that uses two kinds of glass that focuses all white light coming in at the same point on the other side of the lens. Many types of glass, known as low dispersion glasses, have been developed to reduce chromatic aberration, the most notable being glasses that contain fluorite.
The discovery of Chromatic Aberration and the development of corrective lenses were major steps in the development of the optical microscope, the telescope; which in turn was a boon for astronomers and biologist who were able to gain a greater understanding of the universe and the natural world as a result.
We have written many articles about chromatic aberration for Universe Today. Here’s an article about optical aberration, and here’s an article about achromatic lens.
FU Orionis and its associated nebula. Image cedit: ESO
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In 1937, an ordinary 16th magnitude star in the constellation Orion began to brighten steadily. Thinking it was a nova, astronomers were astounded when the star just kept getting brighter and brighter over the course of a year. Most novae burst forth suddenly and then begin to fade within weeks. But this star, now glowing at 9th magnitude, refused to fade. Adding to the puzzle, astronomers could see there was a gaseous nebula nearby shining from the reflected light of this mysterious star, now named FU Orionis. What was this new kind of star?
FU Ori has remained in this high state, around 10th magnitude ever since. Because this was a form of stellar variability never seen before and there were no other examples of this behavior, astronomers were forced to learn what they could from the only known example, or wait for another event to provide more clues.
Finally, more than 30 years later, FU Ori-like behavior appeared again in 1970 when the star now known as V1057 Cyg increased in brightness by 5.5 magnitudes over 390 days. Then in 1974, a 3rd example was discovered when V1515 Cyg rose from 17th magnitude to 12th magnitude over an interval lasting years. Astronomers began piecing the puzzle together from these clues.
FU Orionis stars, commonly called FUOrs, are pre-main sequence stars in the early stages of stellar development. They have only just formed from clouds of dust and gas in interstellar space, which occur in active star- forming regions. They are all associated with reflection nebulae, which become visible as the star brightens.
This artist's concept shows a young stellar object and the whirling accretion disk surrounding it. NASA/JPL-Caltech
Astronomers are interested in these systems because FUOrs may provide us with clues to the early history of stars and the formation of planetary systems. At this early stage of evolution, a young stellar object (YSO) is surrounded by an accretion disk, and matter is falling onto the outer regions of the disk from the surrounding interstellar cloud. Thermal instabilities, most likely in the inner portions of the accretion disk, initiate an outburst and the young star increases its luminosity. Our Sun probably went through similar events as it was developing.
One of the major challenges in studying FU Orionis stars is the relatively small number of known examples. Although approximately 20 FU Orionis candidates have been identifed, only a handful of these stars have been observed to rise from their pre-outburst state to their eruptive state.
Now, in the last year, several new FUOrs have been discovered. In November 2009, two newly discovered objects were announced. Patrick Wils, John Greaves and the Catalina Real-time Transient Survey (CRTS) collaboration had discovered them in CRTS images.
The first of these objects appeared to coincide with the infrared source IRAS 06068-0641 in Monoceros. Discovered on Nov. 10, it had been continuously brightening from at least early 2005, when it was magnitude 14.8, to its present 12.6 magnitude. A faint cometary reflection nebula was visible to the east. A spectrum taken with the SMARTS 1.5-m telescope at Cerro Tololo, on Nov. 17, confirmed it to be a YSO. The object lies inside a dark nebula to the south of the Monocerotis R2 association, and is likely related to it.
Also inside this dark nebula, a second object, coincident with IRAS 06068-0643, had been varying between mag 15 and 20 over the past few years, much like UX-Ori-type objects with very deep fades. This second object is also associated with a variable cometary reflection nebula, extending to the north.
Light curves, spectra and images can be found here.
Then, in August 2010, two new eruptive, pre-main sequence stars were discovered in Cygnus. The first object was an outburst of the star HBC 722. The object was reported to have risen by 3.3 magnitudes from May 13 to August 16, 2010. Spectroscopy reported by Ulisse Munari on August 23rd, support this object’s classification as an FU Ori star. Munari and his team reported the object at 14.04V on Aug 21, 2010.
The second object, coincident with another infrared source, IRAS 20496+4354, was discovered by K. Itagaki of Yamagata, Japan, on August 23, 2010. The object appears very faint, approximately magnitude 20, in a Digital Sky Survey image taken in 1990. Subsequent spectroscopy and photometry of this object by Munari showed that this object also has the characteristics of an FU Ori star. Munari reported the object at 14.91V on August 26, 2010.
Both these objects are now the subjects of an AAVSO observing campaign announced October 1, 2010 in AAVSO Alert Notice 425. Dr. Colin Aspin, University of Hawai’i, has requested the help of AAVSO observers in performing long-term photometric monitoring of these two new YSOs in Cygnus. AAVSO observations will be used to help calibrate optical and near-infrared spectroscopy to be obtained during the next year.
Since these stars are newly discovered, very little is known about their behavior. Their classification as FU Ori variables is based on spectroscopy, but establishing a good optical light curve and maintaining it, over the next several years, will be crucial to understanding these stars. This kind of long-term monitoring is one of the things at which amateur astronomers excel.
So after a very slow start, discoveries of new YSOs and our understanding of the dusty disk environments around them are starting to heat up. With new tools and new examples to study we are peering into the early stages of stellar and planetary formation and finding some of our models have been pretty close to the truth. We expect to find more and similar objects as new all-sky surveys begin to cover the sky, but these objects will still be relatively rare and therefore interesting, because this period in a star’s evolution is short-lived and only takes place in the active star forming regions of galaxies.
