Lenticular_Murrieta_31325262633_3b5b64dce5_o (1)

Photographer: Mark Ritter

Summary Authors: Mark Ritter; Jim Foster

Featured above are a formation of eye-catching lenticular clouds (Altocumulus lenticularis) seen near sunset, not far from Murrieta, California. Strong airflow over mountain crests, in this case, the Santa Ana Mountains (just off the left edge of the photo), prompted these mid-level, orographic wave clouds to form on the lee side of the range. Since sufficient moisture was available to form clouds, and since the airflow aloft was quite strong, layers of clouds at the wave crest stacked one upon the other. Photo taken on January 5, 2017.

Photo Details:  Camera Model: Canon EOS 5D Mark III; Lens: EF24-105mm f/4L IS USM; Focal Length: 55mm; Aperture: ƒ/7.1; Exposure Time: 0.0063 s (1/160); ISO equiv: 1250; Software: Adobe Photoshop Lightroom 6.8 (Macintosh).

A set of videos, of particular interest to programmers, compliments of Metafilter. Delightful, recommended.

These are lectures/demos of brilliant stupid programmer tricks:

1) A DOS executable that only uses printable bytes. (SLYT, 25:40 (yes, long, but so worth it, and accessible to non-programmers), audio and visual both required)

2) On the Turing Completeness of PowerPoint (SLYT, 5:33, audio and visual both required)

This is a work of art with accompanying making-of:

3) A Mind is Born (article with embedded SLYT, 2:21, primarily audio plus cool but inessential visuals) - a 2+ minute music video that is, in its entirety, a 256 byte program for the Commodore 64. This is now my answer to "can a computer program, in itself, be a serious work of art?" I understand about one word in five of the article; someone on MF said of it, I read most of the how it was done link, and I've been a programmer for 20 years, and I still say the answer is "black magic".

Oh, and a bonus blast from the past – I just got done fixing my broken video links post migration from LJ – 4) Life in Life (SLYT, 1:31, primarily visual, with cool but inessential audio). h/t [personal profile] nancylebov. I originally posted here; I had tagged it "sci", but I dunno, what do we call programming with cellular automata?


Each Sunday we present a notable item from our archives. This EPOD was originally published April 22, 2003.

Provided by: Teena Della, Terry Fox Secondary School

Summary author: Teena Della

The photo above shows a classic example of exfoliation. The U-shaped Coquihalla valley in British Columbia, Canada was carved by glaciers tens of thousands of years ago. As the overlying glacial material was removed, the rocks that had formed underneath the massive ice sheet rose up (isostasy) and tried to expand. Isostasy is also known as glacial rebound. Rocks, of course, aren’t very flexible so instead of expanding, their outer layers are peeling off like onion skins -- the process of exfoliation.

Related Link:

My second venture into the fanzine world was The Tides of Time. I can't find my copy of issue 1, fortunately [personal profile] sir_guinglain has has archived them all. It surprises me that of all the fanzines that have come, and mostly gone, since the 1980s The Tides of Time is one of the few that still produces issues, albeit on an irregular basis.

I've not been involved with it since issue 7, but [personal profile] sir_guinglain is the currently editor and, I believe, possibly looking for contributions...

EPOD_EncoreDeathValleylake bed110502-80lre

Today, and every Saturday Earth Science Picture of the Day invites you to rediscover favorites from the past. Saturday posts feature an EPOD that was chosen by viewers like you in our monthly Viewers' Choice polls. Join us as we look back at these intriguing and captivating images.


Photographer: Marli Bryant Miller

Summary Author: Marli Bryant Miller

November 2011 Earth Science Picture of the Day Viewer's ChoiceThe Mesquite Flat dune field, part of which is shown above, is the largest and most accessible of five dune fields in Death Valley National Park. Like all dune fields, it requires three conditions to form: 1) a steady supply of sand, which here is supplied by nearby alluvial fans, 2) plenty of wind to move the sand, and 3) a natural windbreak so the wind will actually deposit the sand. Most of the dune fields of Death Valley lie in windbreaks afforded by irregularities in the adjacent mountain front. The fine-grained, mud-cracked deposits in the foreground underlie many of the interdune areas of the dune field. They're sediments of a former lake, which covered the area when the climate was wetter. The mountains in the background, the Grapevine Mountains, were uplifted relative to the valley floor along an active fault zone. They consist mostly of Paleozoic limestone, dolomite, and sandstone. Photo taken on May 2, 2011.

Photo Details: Camera Model: Canon EOS 5D Mark II; Lens: EF17-40mm f/4L USM; Focal Length: 19.0mm; Aperture: f/10.0; Exposure Time: 0.020 s (1/50); ISO equiv: 100; Software: Adobe Photoshop Lightroom.

To count poetic feet requires but
A little time. Not much; and yet within
The mire of... despair sounds foetid, and
depression's worse. Let's say the mire of
the forty-fifth. (It's not his fault I'm stuck,
Not acting, but, if honest with myself,
I'm glad to blame him for all sins. Sore throat?
Tortilla burnt? My wrist is sore? It's Trump's
America. Perforce, my staring, blank,
At laptop screens is D.T.'s fault, as well.)

Relief is mine that [personal profile] petra's taken up
The pen -- the keyboard? were it me I'd say
The microphone! -- to celebrate the week
Of blank verse blogs
. She's posted thrice, huzzah!
While I have scarcely managed once. Yay, P!
([syndicated profile] epod_feed Apr. 21st, 2017 03:01 am)

Constellation Leo and the chinese guardian lions (1)

Photographer: Jeff Dai

Summary Author: Jeff Dai

The constellation Leo the Lion is shown here rising above guardian lions in the Inner Mongolia region of China. Lions aren't native to China. But with increased trade during the Han dynasty and cultural exchanges through the Silk Road, lions were introduced into China from the ancient states of Central Asia and India. The Buddhist version of the lion was originally introduced to China as the protector of dharma. These lions have been depicted in religious art as early as 208 BC. Gradually, they were incorporated as guardians of the Chinese Imperial dharma. Apparently, lions seemed appropriately regal beasts to guard the gates and have been used as such ever since.

Evidence suggests that like lions the 12 zodiacal constellations were introduced to China from India. The ancient Chinese had their own independent astronomy, but the zodiacal constellations are still widely noted in art and literature. For example, numerous ancient Chinese books mention the names of the zodiacal constellations. Photo taken on December 27, 2016.

Tame Layman had sufficiently fond memories of The Talons of Weng Chiang that the Teenager was summoned to watch it with us. She indulged us, but I don't think she was really sold on it. She quite liked Leela and could take or leave the rest.

She prefers The Avengers, I think, which is possibly fair enough.

More under the cut )

Tame Layman and I had a lot of fun watching Talons and felt we were reminded what a great companion Leela was, but the Teenager's relative indifference makes me think that this is not a classic with real staying power. It is a bit too long for the material to sustain, it relies a little too much on tropes from stories that are no longer in vogue, and Leela (out of context) is not as refreshing and different as she appears to older eyes.
([syndicated profile] epod_feed Apr. 20th, 2017 03:01 am)

Optics in My Home Garden copy

Photographer: Menashe Davidson

Summary Author: Menashe Davidson

One advantage of keeping a garden is the opportunity to understand nature better. As Albert Einstein said, "Look deep into nature, and then you will understand everything better."

After it rains, I always check its effect on the plants of my terrace garden in Rishon LeZion, Israel. The above photos were taken after a recent rain and demonstrate the optical phenomena of a mirror and a lens nicely. On the top photo (taken on December 17, 2016) notice the rain that had accumulated in the little metal basin holding the Cyclamen flower pot, in the foreground. Like a flat mirror, the light rays were reflected (specular reflection) resulting in the upside-down image of the tall building adjacent to my apartment. On the second photo, water drops are adhering to Adenium (Desert Rose) flower tubes. These drops functioned as a lens, refracting light through the drops to produce the inverted image of the same tall building that appears in the top photo.

Photo Details: Top - Camera Model: NIKON D7100; Focal Length: 22mm (35mm equivalent: 33mm); Aperture: ƒ/22.0; Exposure Time: 0.0063 s (1/160); ISO equiv: 2000; Software: Windows Photo Editor 10.0.10011.16384. Bottom - same except:  Lens: 18.0-200.0 mm f/3.5-5.6; Focal Length: 200mm (35mm equivalent: 300mm); Aperture: ƒ/16.0; Exposure Time: 0.0020 s (1/500); ISO equiv: 500; Software: Adobe Photoshop CS5 Windows.

denise: Image: Me, facing away from camera, on top of the Castel Sant'Angelo in Rome (Default)
([staff profile] denise posting in [site community profile] dw_maintenance Apr. 19th, 2017 11:02 pm)
Our content importer has mostly caught up with its backlog; almost everything that's still listed as being "in the queue" are jobs that were tried, failed once or more with a temporary failure, and are waiting to try again. (The importer tries a few times, at successively longer intervals, when it gets a failure it thinks might be temporary/might correct itself later on.) This means that new imports scheduled now should complete in hours (or even minutes), not the "several days" it's been taking.

If you tried to schedule a second import while the first one was still running, at any time in the past 10 days or so, you may have confused the poor thing. If you think your import should be finished by now and it isn't, and you're seeing "Aborted" on the Importer Status part of the Importer page, feel free to open a support request in the Importer category and we'll look into it for you. (It may take a little bit before you get a response; those of us who have the access to look into importer problems have been really busy for the past two weeks or so, and I at least need a few days to catch my breath a bit before diving back into the fray! But we'll do what we can.)

I hope all y'all are continuing to settle in well to your new home!
purplecat: Texture by simpleandclean (LiveJournal) (Doctor Who)
([personal profile] purplecat Apr. 19th, 2017 08:34 pm)
"Oh dear, this looks cheap," Tame Layman said as the opening shot swept along the corridors of Terra Alpha.

I acknowledge the truth of this under the cut )

"That was really rather good," Tame Layman said at the end, showing that a good script and fine performances can lift Doctor Who well above what you might expect its budget to allow.
sophie: A cartoon-like representation of a girl standing on a hill, with brown hair, blue eyes, a flowery top, and blue skirt. ☀ (Default)
([personal profile] sophie posting in [site community profile] dw_dev Apr. 19th, 2017 09:31 am)
As mentioned in my last post, I will be taking the Dreamhack server down for maintenance in 30 minutes! I'll edit this post once it starts and again when it's back up.

10:04am BST: I have restricted logins to admins and am beginning the maintenance now. This will involve a reboot and some diagnostics before opening it back up.

10:58am BST: The maintenance is done, and logins are unrestricted again!
([syndicated profile] epod_feed Apr. 19th, 2017 03:01 am)

BuffaloFalls (2)

Photographer: Rod Benson

Summary Author: Rod Benson

A big part of the history of humanity is the story of cultures figuring out how to make a living using what nature has given them. Buffalo Falls, located 25 mi (40 km) west of Great Falls, Montana, provides an interesting example of this. Volcanic activity during the late Cretaceous period, several miles southwest of here, caused several dikes, laccoliths and sills to form. Note that Buffalo Falls is the edge of a sill, and Birdtail Butte (in the background) is a laccolith. Since igneous rock is more durable than the sandstone that it intruded, the edge of the sill was exposed as a cliff.

Centuries before the arrival of horses, Native Americans in the area took advantage of this resource, using it as a bison kill site. Two rows of evenly spaced rock cairns about two mi (3.2 km) long formed a V that funneled the stampeding bison to the cliff where they fell to their death. Those not killed by the fall were finished off by hunters positioned below. Evidence such as arrowheads indicates that Shoshone, Salish and Blackfeet peoples probably all used the site during different time periods. Several tipi rings located in the narrow valley just below the cliff show where the groups camped as the meat and other materials were harvested and processed.

According to the Office of Historic Preservation (Montana), archeologists have identified over 300 bison kill sites in Montana, and there are likely more that haven't been found or reported. We know them as buffalo jumps, however, most are not cliffs, but rather places where bison were driven into natural or artificial enclosures, or into bogs or snow-banks and then finished off with weapons. No two are the same, but they often contain a wealth of evidence, including bison bones, arrowheads, tools, roasting pits, and fire-cracked rock. The use of buffalo jumps started to decline in the 1700s with the arrival of the horse - an animal that brought many big changes to the Indian way of life. Photo taken on June 13, 2015.

Photo Details: Camera Maker: Panasonic; Camera Model: DMC-LX7; Focal Length: 4.7mm (35mm equivalent: 24mm); Aperture: ƒ/2.8; Exposure Time: 0.0008 s (1/1300); ISO equiv: 80; Software: QuickTime 7.6.6.

kareila: (runaways)
([personal profile] kareila Apr. 18th, 2017 07:52 am)
It's been a stressful few days. Heather's father-in-law passed away late last week after a brief hospitalization, and the funeral was yesterday afternoon. And the day before that was Easter, with all the musical and family obligations that entails. Everything went well, though. I got to meet H's wonderful mother-in-law for the first time, and on Easter I got to see my favorite uncle for the first time in probably a year. (I was supposed to see him at Thanksgiving, but he was bedridden with stomach flu.)

We watched Harvey at my mom's house on Sunday afternoon, which is a classic black and white film starring Jimmy Stewart as an affable guy whose best friend happens to be a six foot tall invisible rabbit. So that was interesting. And Mom and I had planned to go this morning to a matinee of Going in Style, the new crime caper comedy with Michael Caine and Morgan Freeman. I'll probably still go, although right now I feel like I'd rather just curl up with an overdue library book.

The kids seemed to have a good holiday. In addition to the usual candy, Will got Math Fluxx and Connor got Exploding Kittens. We got another Lego Dimensions character, too, although I haven't found the time to play recently. Still pouring most of my available hours into Dreamwidth stuff.
Voice-hearers and clinicians: the World Hearing Voices Congress is being held in the US for the first time, Aug 16-18, 2017, in Boston, at BU.

([syndicated profile] epod_feed Apr. 18th, 2017 03:01 am)

Bayside-sea slippers and barnacles

Photographer: Rob Sheridan

Summary Author: Rob Sheridan

A number of invasive invertebrates have disrupted New England’s intertidal ecosystems in recent decades, but three old stalwart natives remain common. All three form amazing but different marine adhesives. The Blue Mussel (Mytilus edulis), shown in my hand, is a bivalve mollusk that adheres to rocks and to each other with strong slightly elastic byssal threads. These fine filaments are secreted by byssal glands along the foot of the mussel, forming as soon as the final planktonic stage finds a resting place and anchoring the maturing mussel for life.

The Atlantic Slipper Limpet (Crepidula fornicata) is a gastropod mollusk that has evolved a mucous based glue that prevents vertical removal (by predators) while permitting lateral motion, allowing the mobile animal to graze on algae. They're the whitish, rounded objects on the of the mussel's shell. Interestingly, the New England native Atlantic Slipper Limpet has become a difficult invasive in European waters, interfering with oyster production.

The Northern Rock Barnacle (Balanus balanoides), the objects with holes at the center of their shells, is a crustacean, like lobsters and crabs, rather than a mollusk. It's oriented with its head glued down by cement, excreted by glands at the base of its first antennae. After this cementing process, the barnacle then forms a calcium carbonate enclosure. It's the only crustacean that remains fixed in one spot for life. When covered with water, barnacles open their enclosure and extend feathery modified leg appendages (cirri) that filter nutritional organic matter from the water and function as gills.

All three species share a somewhat similar reproductive strategy. They adhere to hard substrates, including boat hulls and larger animals and to each other. Having female and male animals in proximity promotes reproduction; timing release of their gametes to facilitate commingling in the water. Fertilized eggs in all three species are initially planktonic before fixing on a stable surface for life, with their amazing adhesives. Scientists are actively pursuing these adhesives for a variety of medical uses. Photo taken on September 22, 2008.

Photo Details: Camera Model: Canon PowerShot SD1000; Focal Length: 5.8mm; Aperture: ƒ/2.8; Exposure Time: 0.0031 s (1/320); ISO equiv: 80. 

Hi all,

I'm going to need to schedule some maintenance for the Dreamhack server as I've just discovered that the quota settings haven't taken effect. I'm therefore going to schedule maintenance for Wednesday 2017-04-19, 10am BST (5am EDT, 2am PDT) (about 36 hours from now) for up to 2 hours. (It shouldn't actually take that long, but I'm reserving it just in case.)

This maintenance will involve a reboot of the Dreamhack server. I will also be restricting logins until the maintenance is done, as the nature of the maintenance means that it will need as little data modification done as possible.

I'll post again once the maintenance starts, and edit that post when it ends.
purplecat: Hand Drawn picture of a Toy Cat (Default)
([personal profile] purplecat Apr. 17th, 2017 11:00 am)

The first batch of Star Wars crochet figures.

B. somehow managed to mistake C3PO for Chewbacca. He claims it was incorrect choice of yarn colour on my part (TBH, it isn't really golden enough, but choosing yarn colours on the internet is non-trivial and it was called "gold").

Mila_Mirage_sunset (2)

Photographer: Mila Zinkova

Summary Author: Mila Zinkova

Most everyone has seen a sunset where the round disk of the Sun slowly sets and eventually disperses below the horizon. As seen from San Francisco, the setting Sun is rarely round, as shown above, and sometimes it's rising instead of setting! Click here to see a video of one such rare and amazing sunset.

On this video, at first the Sun isn't really going down but is rather getting flatter. Then at around the 1:02 mark you'll see a thin red line at the sea's horizon. At this point, the real Sun is already below the horizon. What you're seeing is a mirage of the Sun. You'll notice that multiple images of the miraged Sun start appearing above each other. After a few more seconds, the Sun looks more like a nuclear explosion than our home star. Continue watching the video and you'll observe that the lower images of the Sun are connected to each other and take on a rectangular shape. At the 4:16 mark the lowermost images of the Sun begin to show the Novaya Zemlya effect, first commented on by polar explorers.

The miraged Sun isn't really setting; rather it's melting into the sky. Yet it's reluctant to disappear. Notice how some of the images of the Sun that seemed to have disappeared actually reappear again a split second later. For example, at 5:58 it seems that only the uppermost image of the Sun is still present, but at 5:59, the image of the Sun below it is reappearing and in addition is getting brighter. Also, note the weird clouds at upper right (they're much better seen after the 4:16 mark). They look odd because they're miraged as well -- a fata morgana in the clouds. This mesmerizing sunset was delayed by more than 6 minutes based on the ephemeris time for sunset in San Francisco.

So what's going on here? As with all mirages, temperature gradients are involved. However, in this case, a complex temperature profile over the sea, including a thermal inversion, wildly distorted the shape of the Sun as it set.

sophie: A cartoon-like representation of a girl standing on a hill, with brown hair, blue eyes, a flowery top, and blue skirt. ☀ (Default)
([personal profile] sophie posting in [site community profile] dw_dev Apr. 16th, 2017 10:19 am)
Apologies again for the delay on this - Dreamhack applications are now officially open again!

As I explained in my previous post (which you should read if you haven't already - there's a lot of info in there), anybody who wants a Dreamhack should apply through this form, even if you already had one before. I will, as a one-time thing, email everybody who had an account before to let them know that the service is back up and that they'll need to re-apply.

My apologies once again for the delay! If you find any issues with the service, please feel free to let me know.