APOD: Fata Morgana: A Possibly Titanic Mirage (2012 Apr 15)

[APOD Robot]

Fata Morgana: A Possibly Titanic Mirage

Explanation: Did this mirage help sink the Titanic? The optical phenomenon called Fata Morgana can make strange shapes or a false wall of water appear above a watery horizon. When conditions are right, light reflecting off of cold water will be bent by an unusual layer of warm air above to arrive at the observer from several different angles. A conceptually comparable mirage can make a setting Sun appear strangely distorted or a distant pavement appear wet. One hundred years ago today, such a Fata Morgana mirage might have obscured real icebergs from the clear view of crew onboard the Titanic. Additional evidence for this distortion hypothesis arises from the nearby vessel SS Californian which reported sightings consistent with Fata Morgana mirages. The above Fata Morgana mirage was taken off the US Pacific coast in 2008.

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[Boomer12k]

Would such a phenomena be visible at 11:40 at night, when the Titanic struck the iceberg?


:---[===] *

[Mila]

Would such a phenomena be visible at 11:40 at night, when the Titanic struck the iceberg?


:---[===] *

Mirages could happen at any time, nighttime or daytime. They do not depend on the sun.
Also this EPOD http://epod.usra.edu/blog/2012/01/flying-dutchmen.html could explain how mirages could obscure a distant object, and make them unrecognizable.

[neufer]

--------------------------------------------------
Moby Dick (1851) - Melville

For an instant, the tranced boat's crew stood still; then turned.
"The ship? Great God, where is the ship?" Soon they through dim,
bewildering mediums saw her sidelong fading phantom,
as in the gaseous FATA Morgana; only the uppermost
masts out of water; while fixed by inFATuAtion,
or fidelity, or FATE, to their once lofty perches, the
pagan harpooneers still maintained their sinking look-outs on
the sea. And now, concentric circles seized the lone boat itself,
and all its crew, and each floating oar, & every lancepole
and spinning, animate & inanimate, all round & round in one
vortex, carried the smallest chip of the Pequod out of sight.
---------------------------------------------
Romeo and Juliet (Quarto 1, 1597)
.
The Prologue.
.
[F]rom forth the FATAll loynes of these two foes,
[A] paire of starre-crost Louers tooke their life:
. {VV}hose misaduentures, piteous ouerthrowes,
[T]hrough the continuing of their Fathers strife,
[A]nd death-markt passage of their Parents rage
--------------------------------------------------
. ON POET-APE [from Ben Jonson's EPIGRAMS]
.
Poor POET-APE , that would be thought our chief,
. Whose works are e'en the frippery of wit,
[F]rom brokage is become so bold a thief,
. As we, the robb'd, leave rage, and pity it.
[A]t first he made low shifts, would pick and glean,
. Buy the reversion of old plays ; now grown
[T]o a little wealth, and credit in the scene,
. He takes up all, makes each man's wit his own :
[A]nd, told of this, he slights it. Tut, such crimes
. The sluggish gaping auditor devours ;
. He marks not whose 'twas first : and after-times
. May judge it to be his, as well as ours.
. Fool ! as if half eyes will not know a fleece
. From locks of wool, or shreds from the whole piece ?
----------------------------------------------------

[JohnD]

The Titanic should be a banned subject; the media have been full of it for weeks, and now it causes not only the APOD to feature a wholly Earthly subject, but the Earth Science Picture of the Day has the SAME SUBJECT! Different pic, but also quoting the Tiatanic as the stimulus. How boring can you get?

IF ANYONE ELSE MENTIONS THE TITANIC I WILL ............. SINK!

JOhn

[nstahl]

I usually defend the choice of topics here, but this one leaves me cold.

[JohnD]

ntx

[RedFishBlueFish]

And what was the "...the nearby vessel SS Californian" doing?

She was lying-to on the edge of an ice flow, perhaps 15 miles away.

She informed Titanic that she was stopped and surrounded by ice. She had previously told Titanic of three large bergs in the area.

Titanic replied "Shut up, Shut up, I’m working Cape Race (ed: a radio station on shore)"

Not too many minutes later, Californian secured her wireless, and about ten minutes after that Titanic hit the iceberg whilst still making twenty knots or more.

So, to answer the question posed - "Did this mirage help sink the Titanic?" - the answer can only be it it did, it was an insignificant associated factor.

What sank Titanic was hubris.

[Beyond]

IF ANYONE ELSE MENTIONS THE TITANIC I WILL ............. SINK!

TITANIC



Here's a lifepreserver......

[Mila]

The Titanic should be a banned subject; the media have been full of it for weeks, and now it causes not only the APOD to feature a wholly Earthly subject, but the Earth Science Picture of the Day has the SAME SUBJECT! Different pic, but also quoting the Tiatanic as the stimulus. How boring can you get?

IF ANYONE ELSE MENTIONS THE TITANIC I WILL ............. SINK!

JOhn

Instead of getting bored, you could try to figure out why Titanic lookouts noticed the iceberg only, when it was about .2 miles from the ship.
In his testimony to British Wreck Commissioner Sir Ernest Shackleton said that even at night time icebergs could be seen at "about five miles" or in a dead calm sea conditions at "three mile" http://www.titanicinquiry.org/BOTInq/BO ... eton01.php
So, what prevent Titanic lookouts from noticing the iceberg earlier?

[Scabulus]

I live in the California high desert and have seen many mirages. As the text says, it allows an object to be seen from many different angles. That makes an object bigger, not smaller. I've seen city lights about 6 to 8 miles distant expanded to appear as 3, 4 and even 5 lights vertically. I've seen mountains 70 miles away expanded vertically to appear twice their size. I've seen objects 10 to 20 miles away split in two vertically where one image of the object will hang unattached above the other. In all cases making an object appear bigger. No, a fata morgana would not hide an iceberg, it would make it visibly larger vertically. To steer a boat to avoid an object, seeing it 10 to 20 miles away allows avoidance maneuvers to be initiated in time. Having an iceberg appear bigger, helps. A fata morgana would certainly hide an object behind the expanded object, but that would be something over the visible horizon, maybe a cloud or star. We see mirages in astronomy too where a gravitationally significant object will bend the light of a more distant object - the gravitational lens. It allows us to see objects further than we can otherwise see. Again, visibly larger object, not smaller.

[neufer]

What sank Titanic was hubris.

<<Hubris means extreme pride or arrogance. Hubris often indicates a loss of contact with reality and an overestimation of one's own competence or capabilities, especially when the person exhibiting it is in a position of power. In ancient Greek, hubris (Ancient Greek ὕβρις) referred to actions that shamed and humiliated the victim for the pleasure or gratification of the abuser. Hubris was considered the greatest crime of ancient Greek society. Icarus' flying too close to the sun, despite his father's warning, has been interpreted by ancient authors as hubris, leading to swift retribution. In the Odyssey, the behaviour of Penelope's suitors is called hubris by Homer, possibly still in a broader meaning than was later applied. The blinding and mocking of Polyphemos called down the nemesis of Poseidon upon Odysseus; Poseidon already bore Odysseus a grudge for not giving him a sacrifice when Poseidon prevented the Greeks from being discovered inside the Trojan Horse. Specifically, Odysseus' telling Polyphemos his true name after having already escaped was an act of hubris.

Hubris against the gods is often attributed as a character flaw of the heroes in Greek tragedy, and the cause of the "nemesis", or destruction, which befalls these characters. Herodotus made it clear in a passage, “Seest thou how God with his lightning smites always the bigger animals, and will not suffer them to wax insolent, while those of a lesser bulk chafe him not? How likewise his bolts fall ever on the highest houses and the tallest trees? So plainly does He love to bring down everything that exalts itself. Thus ofttimes a mighty host is discomfited by a few men, when God in his jealousy sends fear or storm from heaven, and they perish in a way unworthy of them. For God allows no one to have high thoughts but Himself.">>

<<The Space Shuttle Challenger disaster occurred on January 28, 1986, when Space Shuttle Challenger broke apart 73 seconds into its flight, leading to the deaths of its seven crew members. The spacecraft disintegrated over the Atlantic Ocean, off the coast of central Florida at 11:38 EST. Disintegration of the entire vehicle began after an O-ring seal in its right solid rocket booster failed at liftoff.

Each of the two Space Shuttle Solid Rocket Boosters (SRBs) that comprised part of the Space Transportation System was constructed of six sections joined in three factory joints and three "field joints". The factory joints had asbestos-silica insulation applied over the joint, while the field joints—assembled in the Vehicle Assembly Building at Kennedy Space Center (KSC)—depended on two rubber O-rings, a primary and a secondary (backup), to seal them. The seals of all of the SRB joints were required to contain the hot high-pressure gases produced by the burning solid propellant inside, forcing it out the nozzle at the aft end of each rocket. As originally designed by Morton Thiokol, the O-ring joints in the SRBs were supposed to close more tightly due to forces generated at ignition. However, a 1977 test showed that when pressurized water was used to simulate the effects of booster combustion, the metal parts bent away from each other, opening a gap through which gases could leak. This phenomenon, known as "joint rotation," caused a momentary drop in air pressure. This made it possible for combustion gases to erode the O-rings. In the event of widespread erosion, an actual flame path could develop, causing the joint to burst—which would have destroyed the booster and the shuttle.

Engineers at the Marshall Space Flight Center wrote to the manager of the Solid Rocket Booster project, George Hardy, on several occasions suggesting that Thiokol's field joint design was unacceptable. For example, one engineer suggested that joint rotation would render the secondary O-ring useless. However, Hardy did not forward these memos to Thiokol, and the field joints were accepted for flight in 1980.

Evidence of serious O-ring erosion was present as early as the second space shuttle mission, STS-2, which was flown by Columbia. However, contrary to NASA regulations, the Marshall Center did not report this problem to senior management at NASA, but opted to keep the problem within their reporting channels with Thiokol. Even after the O-rings were redesignated as "Criticality 1"—meaning that their failure would result in the destruction of the Orbiter—no one at Marshall suggested that the shuttles be grounded until the flaw could be fixed.

[b][color=#0000FF]Ice on the launch tower hours before Challenger launch[/color][/b]

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By 1985, Marshall and Thiokol realized that they had a potentially catastrophic problem on their hands. They began the process of redesigning the joint with three inches of additional steel around the tang. This tang would grip the inner face of the joint and prevent it from rotating. However, they did not call for a halt to shuttle flights until the joints could be redesigned. Rather, they treated the problem as an acceptable flight risk. For example, Lawrence Mulloy, Marshall's manager for the SRB project since 1982, issued and waived launch constraints for six consecutive flights. Thiokol even went as far as to persuade NASA to declare the O-ring problem "closed". Donald Kutyna, a member of the Rogers Commission, later likened this situation to an airline permitting one of its planes to continue to fly despite evidence that one of its wings was about to fall off.

Forecasts for January 28 predicted an unusually cold morning, with temperatures close to −1 °C, the minimum temperature permitted for launch. The low temperature had prompted concern from Thiokol engineers. At a teleconference on the evening of January 27, Thiokol engineers and managers discussed the weather conditions with NASA managers from Kennedy Space Center and Marshall Space Flight Center. Several engineers—most notably Roger Boisjoly, who had voiced similar concerns previously—expressed their concern about the effect of the temperature on the resilience of the rubber O-rings that sealed the joints of the SRBs, and recommended a launch postponement. They argued that if the O-rings were colder than 12 °C, they did not have enough data to determine whether the joint would seal properly. This was an important consideration, since the SRB O-rings had been designated as a "Criticality 1" component, meaning that there was no backup if both the primary and secondary O-rings failed, and their failure would destroy the Orbiter and its crew.

Thiokol management initially supported its engineers' recommendation to postpone the launch, but NASA staff opposed a delay.

During the conference call Hardy told Thiokol:
[list] "I am appalled. I am appalled by your recommendation."[/list]
Mulloy said: "My God, Thiokol, when do you want me to launch — next April?"

Because of NASA's opposition, Thiokol management reversed itself and recommended that the launch proceed as scheduled. Despite public perceptions that NASA always maintained a "fail-safe" approach, Thiokol management was influenced by demands from NASA managers that they show it was not safe to launch rather than prove conditions were safe. It later emerged in the aftermath of the accident that NASA managers frequently evaded safety regulations to maintain the launch manifest.

The temperature on the day of the launch (−2.2 to −1.6 °C) was far lower than had been the case with previous launches; previously, the coldest launch had been at 12 °C. Rockwell engineers watching the pad from their headquarters in Downey, California, were horrified when they saw the amount of ice. They feared that during launch, ice might be shaken loose and strike the shuttle's thermal protection tiles, possibly due to the aspiration induced by the jet of exhaust gas from the SRBs. Rocco Petrone, the head of Rockwell's space transportation division, and his colleagues viewed this situation as a launch constraint, and told Rockwell's managers at the Cape that Rockwell could not support a launch. Houston-based mission manager Arnold Aldrich to go ahead with the launch. Aldrich decided to postpone the shuttle launch by an hour to give the Ice Team time to perform another inspection. After that last inspection, during which the ice appeared to be melting, Challenger was finally cleared to launch at 11:38 am EST.>>

The Space Shuttle Columbia disaster occurred on February 1, 2003, when shortly before it was scheduled to conclude its 28th mission, STS-107, the Space Shuttle Columbia disintegrated over Texas and Louisiana during re-entry into the Earth's atmosphere, resulting in the death of all seven crew members. Debris from Columbia fell to Earth in Texas along a path stretching from Trophy Club to Tyler, as well as into parts of Louisiana.

Approximately 82 seconds after launch from Kennedy Space Center's LC-39-A, a suitcase-size piece of thermal insulation foam broke off from the External Tank (ET), striking Columbia's left wing reinforced carbon-carbon (RCC) panels. As demonstrated by ground experiments conducted by the Columbia Accident Investigation Board, this likely created a 6-to-10-inch diameter hole, allowing hot gases to enter the wing when Columbia later reentered the atmosphere. At the time of the foam strike, the orbiter was at an altitude of about 20 km, traveling at Mach 2.46.

The Left Bipod Foam Ramp is an approximately three-foot aerodynamic component made entirely of foam. The foam, not normally considered to be a structural material, is required to bear some aerodynamic loads. The shuttle's main fuel tank is covered in foam as an insulator, to avoid ice forming on it when full of liquid hydrogen and oxygen, which itself could damage the shuttle when shed during lift-off. The bipod ramp was originally designed to reduce aerodynamic stresses around the bipod attachment points at the external tank, but it was proven unnecessary in the wake of the accident and was removed from the external tank design for tanks flown after STS-107.

Bipod Ramp insulation had been observed falling off, in whole or in part, on four previous flights: STS-7 (1983), STS-32 (1990), STS-50 (1992) and most recently STS-112 (just two launches prior to STS-107). Ironically, STS-112 had been the first flight with the "ET Cam", a video feed mounted on the ET for the purpose of giving greater insight to the foam shedding problem. Post-107 analysis revealed that (STS-52 and -62) also had bipod ramp foam loss that went undetected. In addition, Protuberance Air Load (PAL) ramp foam has also shed pieces, plus spot losses from large-area foams. At least one previous strike caused no serious damage. NASA management came to refer to this phenomenon as "foam shedding." As with the O-ring erosions that ultimately doomed the Space Shuttle Challenger, NASA management became accustomed to these phenomena when no serious consequences resulted from these earlier episodes. This phenomenon was termed "normalization of deviance" by sociologist Diane Vaughan in her book on the Challenger launch decision process.

Video taken during lift-off of STS-107 was routinely reviewed two hours later and revealed nothing unusual. The following day, higher-resolution film that had been processed overnight revealed the foam debris striking the left wing, potentially damaging the thermal protection on the Space Shuttle. Damage-prediction software was used to evaluate possible tile and RCC damage. The tool for predicting tile damage was known as "Crater", described by several NASA representatives in press briefings as not actually a software program but rather a statistical spreadsheet of observed past flight events and effects. The "Crater" tool predicted severe penetration of multiple tiles by the impact if it struck the TPS tile area, but NASA engineers downplayed this. The engineers believed that results showing that the model overstated damage from small projectiles meant that the same would be true of larger Spray-On Foam Insulation (SOFI) impacts. The program used to predict RCC damage was based on small ice impacts the size of cigarette butts, not larger SOFI impacts, as the ice impacts were the only recognized threats to RCC panels up to that point. Under 1 of 15 predicted SOFI impact paths, the software predicted an ice impact would completely penetrate the RCC panel. Engineers downplayed this, too, believing that impacts of the less dense SOFI material would result in less damage than ice impacts. In an e-mail exchange, NASA managers questioned whether the density of the SOFI could be used as justification for reducing predicted damage. Despite engineering concerns about the energy imparted by the SOFI material, NASA managers ultimately accepted the rationale to reduce predicted damage of the RCC panels from possible complete penetration to slight damage to the panel's thin coating.

Ultimately the NASA Mission Management Team felt there was insufficient evidence to indicate that the strike was an unsafe situation, so they declared the debris strike a "turnaround" issue (not of highest importance) and denied the requests for the Department of Defense images.>>

[Case]

A fata morgana would not hide an iceberg, it would make it visibly larger vertically.

NatGeo did a show (I think it was “Titanic: case closed”), about how a mirage could bring up the distant horizon, which could hide an iceberg for a long time, as that wouldn't show a silhouette against the clear starry night. Many people on ships in that area can confirm that such mirages can happen under the right weather circumstances.

Click to view full size image

[Mila]

I live in the California high desert and have seen many mirages. As the text says, it allows an object to be seen from many different angles. That makes an object bigger, not smaller. I've seen city lights about 6 to 8 miles distant expanded to appear as 3, 4 and even 5 lights vertically. I've seen mountains 70 miles away expanded vertically to appear twice their size. I've seen objects 10 to 20 miles away split in two vertically where one image of the object will hang unattached above the other. In all cases making an object appear bigger. No, a fata morgana would not hide an iceberg, it would make it visibly larger vertically. To steer a boat to avoid an object, seeing it 10 to 20 miles away allows avoidance maneuvers to be initiated in time. Having an iceberg appear bigger, helps. A fata morgana would certainly hide an object behind the expanded object, but that would be something over the visible horizon, maybe a cloud or star. We see mirages in astronomy too where a gravitationally significant object will bend the light of a more distant object - the gravitational lens. It allows us to see objects further than we can otherwise see. Again, visibly larger object, not smaller.

The research does not claim the object (the iceberg) was smaller, it speculates it was obscured.
See how the ship is obscured in the left, upper frame of this image? So a mirage could have obscured the visibility of the iceberg, but on the other hand any mirage disappears when an observer (Titanic in our case) is getting closer to the miraged object (the iceberg in our case). So why lookouts did not see it even after the mirage did not effect the iceberg any more? Well, Tim Maltin, the author of the research, believes that a haze associated with a superior mirage could have been a problem. Please take a look at this image

See the white band above the horizon? Could have a similar kind of band (haze) obscured the iceberg by lowering its contrast against the sky? Well, I do not know. It depends on many things, but it is just another interesting theory.

[Mila]

A fata morgana would not hide an iceberg, it would make it visibly larger vertically.

NatGeo did a show (I think it was “Titanic: case closed”), about how a mirage could bring up the distant horizon, which could hide an iceberg for a long time, as that wouldn't show a silhouette against the clear starry night. Many people on ships in that area can confirm that such mirages can happen under the right weather circumstances.

Yes, and this APOD was used in the documentary you're talking about.

[Beyond]

Now, Fata Morgana isn't a problem. Radar to the rescue!

[neufer]

Now, Fata Morgana isn't a problem. Radar to the rescue!

[b][color=#0000FF]Corporal “Radar” O’Reilly laughing at [/color][/b][url=http://www.npr.org/2011/12/07/143296020/harry-morgan-m-a-s-hs-col-potter-dies-at-96]Harry Morgan(a)[/url] [b][color=#0000FF]because B.J put black lip stick on the end of his binoculars.[/color][/b]

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<<Corporal “Radar” O’Reilly is a fictional character in the M*A*S*H novels, film and television series. The character was portrayed by Gary Burghoff in both the film and on television — the only actor from the film to reprise his role on television, aside from G. Wood as General Hammond.

The novel establishes that Radar was from Ottumwa, Iowa and literally dreamed of joining the Army right after high school. He seemed to have extra-sensory perception, appearing at his commander's side before being called and finishing his sentences. He also had exceptionally good hearing, able to hear incoming helicopters before anyone else. It was these abilities that earned him the nickname "Radar." The character was inspired by real-life company clerk Don Shafer, who was also born in Ottumwa and nicknamed "Radar" by his compatriats, and who served alongside Hornberger in Korea.

While Radar's full name is never given in the original novel or film, on the TV series it is Walter Eugene O'Reilly. O'Reilly started off worldly and sneaky, a clerk who carried with him at all times a pocketful of passes for any potential scam that might arise; he also had a racket of selling tickets for spying through a peephole into the nurses shower and was not adverse to taking pictures of the nurses showers with a camera. At one point, he mailed home a Jeep, piece by piece. (Hawkeye commented that once Radar's mailman found out, he'd have a retroactive hernia.); another time he cons nearly every member of MASH 4077 into buying mail order shoes. He was known for his tremendous appetite for heaping portions of food. He was also not averse to drinking Col. Blake's brandy and smoking his cigars when the colonel was off-duty, and he occasionally drank the moonshine liquor that Hawkeye and McIntyre made in their still. He was very briefly promoted to 2nd Lieutenant as the result of a poker game, but soon became disillusioned with the rank and persuaded Hawkeye and B.J. to get him demoted back to Corporal. As the series progresses, this worldly version of Radar was apparently not wholly to the writers' liking, and Radar evolved into a naïve farm boy. Cigars and strong liquor made him ill or dizzy, and despite numerous references to him losing his virginity in earlier episodes, he appeared to have regained it later in the series. His favorite beverage was Nehi Brand Grape Soda. A running gag is that Radar sleeps with a teddy bear-which ended up in the MASH time capsule episode. >>

[Beyond]

Gee neufer, you're fast! I wasn't expecting something like this for at least another hour or so.

[Case]

Despite a century of technological gains, ships rely heavily on the human eye to detect icebergs (Source: Oskar Henriksson/stock.xchng)

---

Saving ships from Titanic's fate

We've painted them, tagged them, bombed them, monitored them with radar and watched them from space - but icebergs like the one that sank the Titanic are still a threat to ships today. Formed in 1913, the year after the Titanic's demise, the International Ice Patrol (IIP) patrols 1.7 million square kilometres of the northwest Atlantic.
According to the Ship Iceberg Collision Database held by Canada's NRC, there has been a steady decline in incidents since 1913. There were 57 iceberg collisions in the northern hemisphere from 1980 to 2005, an average of 2.3 per year - down from 170 hits or 6.8 per year in the 25 years up to 1912.

Could happen again
The last passenger ship to sink with fatalities after hitting an iceberg was the Hans Hedtoft, which went down off southern Greenland in January 1959 with 95 people on board. In November 2007, the cruise ship MV Explorer sank after hitting an iceberg off the Antarctic Peninsula's northern tip. All 100 passengers and 54 crew were saved. Human error means a disaster on the scale of the Titanic can happen again. "There are still icebergs, there are still ships. Despite all warnings that you give, ship captains are out there still trying to make the shortest possible crossing, trying to keep to the schedules."

(Excerpt)

[Mila]

Despite a century of technological gains, ships rely heavily on the human eye to detect icebergs (Source: Oskar Henriksson/stock.xchng)

---

Saving ships from Titanic's fate

We've painted them, tagged them, bombed them, monitored them with radar and watched them from space - but icebergs like the one that sank the Titanic are still a threat to ships today. Formed in 1913, the year after the Titanic's demise, the International Ice Patrol (IIP) patrols 1.7 million square kilometres of the northwest Atlantic.
According to the Ship Iceberg Collision Database held by Canada's NRC, there has been a steady decline in incidents since 1913. There were 57 iceberg collisions in the northern hemisphere from 1980 to 2005, an average of 2.3 per year - down from 170 hits or 6.8 per year in the 25 years up to 1912.

Could happen again
The last passenger ship to sink with fatalities after hitting an iceberg was the Hans Hedtoft, which went down off southern Greenland in January 1959 with 95 people on board. In November 2007, the cruise ship MV Explorer sank after hitting an iceberg off the Antarctic Peninsula's northern tip. All 100 passengers and 54 crew were saved. Human error means a disaster on the scale of the Titanic can happen again. "There are still icebergs, there are still ships. Despite all warnings that you give, ship captains are out there still trying to make the shortest possible crossing, trying to keep to the schedules."

(Excerpt)

Click to view full size image

Yes, good old Explorer. I took this image of a cruise ship navigation along an iceberg from Explorer, but it was a few years before Explorer sunk.

[krp]

I'm wondering what kind of mirage this is: http://www.flickr.com/photos/28183637@N ... 8546697103 It's a picture I took of Lake Michigan on a cold December day.

[Mila]

I'm wondering what kind of mirage this is: http://www.flickr.com/photos/28183637@N ... 8546697103 It's a picture I took of Lake Michigan on a cold December day.

It is an inferior mirage like this one http://upload.wikimedia.org/wikipedia/c ... mirage.jpg for example. Inferior mirage is much more common than a superior mirage.

[neufer]

I'm wondering what kind of mirage this is:

http://www.flickr.com/photos/28183637@N ... 8546697103
It's a picture I took of Lake Michigan on a cold December day.

An "Inferior (“oasis-in-a-desert”) Mirage" over relatively warm Lake Michigan water
(as opposed to a "Superior (“Arctic”) Mirage" over relatively cold Lake Superior water).

[b][color=#0000FF]Image forms ABOVE the actual location of source Produced when warm air lies over cold air (temperature inversion) Difference in air denisty bends horizon light downwards Creates visual distortions and/or makes objects located below the horizon visible[/color][/b]

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[b][color=#0000FF]Image forms BELOW actual location of source Produced when cool air lies over very hot air Difference in air density bends horizon light upwards Creates ‘water on the roadway’ effect Adapted from: Mirages: A Primer, The Weather Doctor at http://www.islandnet.com/~see/weather/ (accessed March 2007). [/color][/b]

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What produced the light we saw glowing over, on, and in Lake Superior last October?
May 2007 by Sea Grant Staff

“It was as if a small town was floating on Lake Superior,” witnesses said. Looking across the lake from Grand Marais, Minn., two, then eventually three, patches of whitish-yellow light illuminated the distant horizon for many hours during the night of October 23, 2006.

“I’ve lived on the lake for 14 years and seen lots of stars and moonshine, boats and northern lights, but never anything like this,” said Grand Marais resident Julie Anderson. “There didn’t seem to be any source for the glowing. We looked through powerful binoculars but there were no ships on the lake or any visible structure at all. The lights never moved or blinked. They were still in the same spots at 2 a.m., but there was a third patch of light by then, and one had gotten significantly bigger. I haven’t seen them again, though I look at the lake every night.”

Another Grand Marais resident said, “At first I thought it was a ship, except the lights were so huge and farther out than usual ship traffic. The main light was elliptical and they were all of the same intensity. To the east, smaller glows made it appear like something was coming up from the bottom, like a huge
underwater spotlight.”

Sea Grant’s hunt for a scientific explanation for the Lake Superior lights included discussions with people from the U.S. Coast Guard, the National Weather Service, and the American Meteorological Society.

After ruling out…

moonlight
aurora borealis
boating traffic
Coast Guard live-fire training exercises
alien activity
UFOs (unidentified FLYING and FLOATING objects)
diamond dust (ice crystals in the air refracting light)

…the most logical explanation is that a temperature inversion made Ontonagon, Mich. — a city about 120 km (75 miles) across the lake and well below the geometric horizon — visible for the night. This type of optical phenomenon is known as an arctic mirage.
The Tricks of Temperature and Light

The two main types of mirages involve different atmospheric conditions.

Arctic mirages are not only confined to areas north of 60 degrees latitude. In Rainbows, Haloes and Glories, author Robert Greenler reported that one April night the residents of Grand Haven, Mich. looked across Lake Michigan and saw city lights and a flashing red beacon. Their sightings were later confirmed to have been the city of Milwaukee, Wisc. Like Grand Marais and Ontonagon, these two cities were also about 120 km (75 miles) apart. Similarly, Clevelanders have clearly spotted Canadian trees and buildings across Lake Erie.

Not to be confused with the more familiar inferior mirages (think “oasis-in-a-desert”), arctic mirages, or superior mirages, are created by atmospheric conditions that alter the appearance of the Earth’s horizon. Know as the hillingar in Icelandic, arctic mirages are made possible by uniform and widespread temperature inversions, where warm air quietly lies over a layer of colder air. Climate data confirm that conditions were favorable for a temperature inversion over Lake Superior during the time when the lights were visible.

Arctic mirages are only one type of superior mirage. Aside from making objects from beyond the horizon visible, superior mirages can make things appear bigger, closer, distorted, suspended in air, or flipped upside down. The temperature inversions causing the various superior mirages can be common over cold water and snow surfaces, particularly at night. Lake Superior’s coldish waters provide ideal conditions for creating and viewing superior mirages. Sometimes an ore boat can appear to float above the water, or travel upside down. Frequently, the Bayfield Peninsula seems to loom from the horizon when viewed from the shoreline between Duluth and Beaver Bay.

Air’s ability to bend the path of light depends on its density. Warm air is less dense and is less able to refract (bend) light than denser, colder air. When warm air blankets a layer of cool air adjacent to the Earth, light rays bend downwards creating an arc toward the observer. If the temperature warms 11ºC over 100 m (6ºF/100 ft), the Earth’s horizon appears to flatten out. If the inversion becomes stronger, the horizon will appear to rise vertically. Under intense arctic mirage conditions, sailors have reported seeing landforms about 320 km (200 miles). A bluff rising about 3.7 m (12 ft) above the sea can be seen at a distance of 19.2 km (12 miles) through a clear, normal atmosphere.

Historians believe that superior mirages, particularly arctic mirages, encouraged the Vikings to sail from Iceland to Greenland, and to explore lands to the west leading them to North America. Some of the legends told by the inhabitants of northern Europe are also rooted in the bizarre sights created by superior mirages.

Inexplicable lights have dazzled humans throughout history and throughout the world. The optic phenomena are physical, as evidenced by photographs and film. But our interpretation of them can be psychological. Although it is tempting to weave stories of magic and mystery to explain the unknown, mundane explanations are typically the most factually accurate. Some unusual lights…and some oases…are certainly mirages, tricks of our eyes, our brains, and our atmosphere.>>

[Moonlady]

Would such a phenomena be visible at 11:40 at night, when the Titanic struck the iceberg?


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Miragescould happen at any time, nighttime or daytime. They do not depend on the sun.[/b]
Also this EPOD http://epod.usra.edu/blog/2012/01/flying-dutchmen.html could explain how mirages could obscure a distant object, and make them unrecognizable.

I red MIGRAINE and I thought, yes, it does not depend on timing cycle

[RedFishBlueFish]

Science is seeing wonderful new questions, where others see only boring old answers.

The interplay of machine, human nature, and the sea manifest in the Titanic disaster has fascinated me since childhood.

There is always something to be learned: Prior to this APOD I had not known of La Fata Morgana's mirage.

Mes amis, cela n'a pas été "ennuyeux" du tout.