Notes by Dr. Optoglass: The Resolution of the Human Eye
Topics Covered:
The average and maximum resolutions of the human eye
PPI and DPI at various distances
Beauty is all very well at first sight; but who ever looks at it when it has been in the house three days? – George Bernard Shaw
As we have seen earlier, the average visual acuity of the human eye is one arc minute. The maximum possible is 0.4 arc minutes. It would be a very rare human indeed who can beat 0.4 arc minutes!
Therefore, we can safely say that the average resolution of a good eye is between 0.4 and 1 arc minute. Before these figures can be translated to pixels or displays, one needs to realize that the size of the pixel will vary with distance.
What’s the formula?
where
d is the distance in mm
α is the angle in degrees
A very young child can focus at about 2 inches, but the average adult can focus no closer than 4 inches (100 mm). We can assume the lowest value of d to be 100 mm. At this distance, the pixel/dot size p is 0.0116 mm or 11.6 microns – for 0.4 arc minutes. For 1 arc minute, it works out to be 29 microns.
An inch is 25.4mm. So how many of our pixels can fit into an inch? @0.4 arc minutes, it is 2190 ppi (dpi). @1 arc minute, it is 876 ppi (dpi)
Maximum Resolution of the Eye
So this is how it is. If a healthy adult brings any display screen or printed paper or whatever 4 inches (100 mm) from his or her face, the maximum resolution he/she can see at is 2190 ppi/dpi. It doesn’t get any better than this for 99.99% of us, except maybe during pre-kindergarten years.
But the legally accepted norm of 20/20 vision only asks for 876 ppi/dpi at 4 inches!
Let’s have some fun:
Magazines and Fine Art Prints
If the average reading distance is 1 foot (12 inches = 305 mm), p @0.4 arc minute is 35.5 microns or about 720 ppi/dpi. p @1 arc minute is 89 microns or about 300 dpi/ppi. This is why magazines are printed at 300 dpi – it’s good enough for most people. Fine art printers aim for 720, and that’s the best it need be. Very few people stick their heads closer than 1 foot away from a painting or photograph.
Computer Monitors
The average computer monitor viewing distance is about 2.5 feet (762 mm). p@0.4 is 89 microns or about 300 ppi/dpi. p@1 is 222 microns or about 115 ppi/dpi. Now you can understand why most consumer computer monitors are about 100 ppi, and most professional computer monitors are slightly higher, but not by much.
The new iPad (3) has a resolution of 264 ppi, which isn’t as good as 300 dpi print but is much better than the average computer monitor. The new Eizo 36.4″ professional air traffic control 4K monitor is at 128 ppi.
Home television
Assuming the average viewing distance for television is 6 feet (1830 mm), p@0.4 is about 120 ppi and p@1 is about 50 ppi.
Most consumer large screen LCD and LED panels are about 50 ppi to 90 ppi, and average about 72 ppi. Now you know why. If your television gets smaller in size, then the higher ppi doesn’t really help. This is why 1920×1080 (at 100 ppi at 6 feet for a 50″ LCD/LED television panel) is good enough. The eye can’t really resolve a lot more at 6 feet.
Cinema
The width of a cinema screen can vary from 30 to 70 feet (360″ to 840″, 9144 mm to 21,336 mm). The closest viewing distance recommended is about 40 feet (3x height) – 12,192 mm. If one is projecting 2K on these screens, the ppi is about 2.4 ppi to 5.7 ppi. If one is projecting 4K, it is about 5 ppi to 11.4 ppi.
Is this what the eye needs?
p@0.4 works out to be 1.4 mm or 18 ppi.
p@1 works out to be 3.5 mm or 7 ppi.
As you can see, 4K comes very close to what the human eye can fully resolve in a cinema screen at average viewing distances. Obviously, many people sit in the front row, and they’d definitely appreciate higher resolution. Which is why we are moving towards:
8K and UHDTV
A 30 to 70 feet screen at 8K (8192 horizontal) gives me from 9.75 ppi to 22.8 ppi. This resolution beats what the eye can resolve at these distances. The future belongs to 8K.
But, to get 18 ppi (the best possible resolution) for a 70 feet screen, we’ll need a horizontal resolution of 15120 or 16K. This is about 128 Megapixels. Is anybody working on this?
IMAX film is supposed to resolve between 10K to 12K (theoretical maximum)
The Phase One IQ180 digital back is 80 Megapixels.
The Red camera company did announce a 28K camera!
This is as good as it gets in 2012.
Takeaways:
The maximum visual acuity of the human eye is 0.4 arc minutes.
At 4 inches, the maximum the human eye needs is 2190 ppi/dpi.
Next: Airy Disk and Pixel Density of the Eye
Previous: Focal Lengths of the Human Eye
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Related posts:
Notes by Dr. Optoglass: Focal Lengths of the Human Eye
Notes by Dr. Optoglass: Eye Geometry
Notes by Dr. Optoglass: Angle of View and Aspect Ratio
Notes by Dr. Optoglass: The Human Eye – Part II
Notes by Dr. Optoglass: The Human Eye – Part III
July 21, 2012
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Vimal Gopal Apr 11, 2013
Under the "Home Television" section, you mentioned that a 1920x1080, 50" display is 100 dpi. But, according to pxcalc.com, that combination only gets you to 38.4 dpi. How are you getting 100 dpi?? Thanks.
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Sareesh Sudhakaran moderatorApr 11, 2013
@Vimal Gopal The formula is available, Vimal. What results are you getting?
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Too many Pixels? |SamMobile says:
February 17, 2013 at 1:01 am
[...] with perfect 20/20 vision would theoretically be able to see individual pixels at a density of 2190ppi on a screen just 4” (~100mm) from their eyes, and for the average person with 20/20 vision, it’s about 876ppi. The [...]
Too many Pixels? | The Smartphone World says:
February 17, 2013 at 8:25 pm
[...] with perfect 20/20 vision would theoretically be able to see individual pixels at a density of 2190ppi on a screen just 4” (~100mm) from their eyes, and for the average person with 20/20 vision, it’s about 876ppi. The [...]
MICROSOFT SURPRISED NO ONE on
Tuesday when it announced that it picked up Nokia's devices unit and
licensed some of its software for a cool £4.6bn in cash. While many see
the deal as two struggling companies merging for a final shot at
success, we think the deal should have Apple and Google worried.
First off, Nokia pretty much is Windows Phone. Ask somebody
in the street to name a Windows Phone maker and they're unlikely to
mention Samsung or HTC, with the Finnish phone firm accounting for
around 85 percent of Windows Phone handsets sold and its Nokia Lumia 520
smartphone ranking as the best selling phone running the Microsoft
mobile operating system yet. With Microsoft taking Nokia under its wing,
it's hard to see Samsung, HTC or even Huawei or ZTE continuing to
develop Windows Phone devices, despite Microsoft claiming that the deal
will "help the market" for its other OEM partners.
This could be a worry for Google. When the firm bought handset maker
Motorola last year, Google reassured Android OEMs that it would not
favour the company in any way. However, after Microsoft's buyout of
Nokia, perhaps other Windows Phone makers can't feel quite so assured.
So why is this bad for Google? Samsung and HTC are unlikely to want
to rely on only the Android mobile operating system, and could avoid
throwing all of their eggs into one basket by branching out elsewhere.
This, for example, could see Samsung focusing more heavily on its Tizen
mobile operating system and distancing itself from Android somewhat,
which could spell bad news for the Android ecosystem, given that the
firm accounts for 95 percent of profits in the Android smartphone market.
There have been some rumours recently that HTC could be planning to
launch its own mobile operating system, and Microsoft's acquisition of
Nokia devices could see the firm looking to focus on this to avoid
reliance on Android.
That's not the only reason Google should be worried, and Apple should
be too, as the buyout finally sees Windows Phone becoming an exciting
third player in the smartphone market, looking to end the duopoly
currently held by iOS and Android. The pairing of the two companies
might be just what Microsoft's mobile operating system needs to extend
its reach beyond the present 9.2 percent marketshare it holds in the UK. In fact, Microsoft has already said that it wants to see its market share triple by 2018 following its purchase of Nokia.
The deal sees Microsoft taking back control of the Windows Phone
market, with Steve Ballmer already voicing that he wants to use the
buyout to boost the number of big-name apps in the Windows Store,
including apps like Instagram. Up until now, apps have been Windows
Phone 8's main downfall. We've long praised the Windows Phone interface
as one of the best on the mobile market and we've rarely had complaints
relating to Nokia's hardware, so if Microsoft can stick to its promise
here it could see Windows Phone getting a lot more competitive in the
apps market.
In fact, we could go on. There are a number of factors that should
have Google and Apple worried: Nokia bringing its distribution reach to
Microsoft, the amount of money Microsoft can pump into Nokia, and the
fact that Microsoft now owns Nokia's extensive patent portfolio, which
could see Microsoft going after its rivals in other ways.
Today's deal also effectively writes off Blackberry as a major player
in the smartphone market, as Microsoft picking up Nokia sees the firm
combining the Finnish firm's hardware division with its software and is
likely to make Microsoft the number one choice in the enterprise market.
Of course, we could also list many risks that both Microsoft and
Nokia face, and Stephen Elop said on Tuesday that there is both
"ambiguity and concern" among employees because neither firm knows what
the future holds.
Done right, however, the future could present a shot at success in the mobile market for both companies. µ
Several new versions of the flu vaccine are debuting this year —
more powerful, more protective, even a version for those with egg
allergies — but they are so new they are not yet widely available.
Health
experts, however, say you still will be able to get the traditional flu
shot this year, which you should if you are at least 6 months old.
The
U.S. Centers for Disease Control and Prevention and the state
Department of Health both are urging people to get a flu shot as soon as
it's available.
"It's not too early to get it," said Dr. Carrie DeLone, the state's physician general.
Pharmacies
are now giving the shot, as are local physician offices. Hospitals will
start to vaccinate employees next month, and the state health
department is rolling out its clinics.
Limited supplies of the new types of flu vaccines will be available locally, including:
n A high-dose vaccine for people age 65 and older.
The
new vaccine contains additional amounts of vaccine that stimulate the
production of antibodies to marshal a stronger defense against the flu
in the elderly, who are the most at risk for a severe illness or death
from the flu.
n A quadrivalent form of the vaccine, which protects against two A strains of flu and two B strains of flu.
Traditional
flu vaccines are trivalent, protecting against two A strains and one B
strain. It is the A strain that causes severe illness, but the B strain
also can sicken people.
n An egg-free version of the vaccine.
Up until now, people who were allergic to eggs could not get a flu vaccine because the vaccine is made using eggs.
Local
hospitals say they will not be offering the high-dose or quadrivalent
forms of the vaccine on a wide basis. The two new versions were not
available when they ordered their vaccines in the spring.
State
health department clinics will offer the quadrivalent vaccine, in both a
nasal spray version and an injectable version. But only about 115,000
of the quadrivalent vaccines will be available, compared to about
400,000 of the trivalent vaccines.
DeLone said the CDC does not
recommend the quadrivalent vaccine for any particular type of patient so
whoever can get it, and wants it, can take it.
People who are uninsured or underinsured and are looking for a flu shot at a state health clinic can call 1-877-PA HEALTH.
At
pharmacies, the quadrivalent vaccine is available on a limited basis,
and will cost about $10 more than the trivalent version.
Pharmacies also are offering the high-dose vaccine for the 65-and-over crowd.
Some
soon-to-be-published reports show that the high-dose vaccine does
appear to be effective among senior citizens, said Dr. Neil A. Greene,
chief of the infectious disease division at Lancaster General Hospital.
If the high-dose vaccine continues to prove to be effective, it likely will become more widely available next year, he said.
While
nobody knows how bad the upcoming flu season will be, last year's
outbreak still is fresh in the minds of many local caregivers.
The worst season in at least a decade, the 2012-13 flu killed 10 people here and sickened more than 1,800.
"After
last year, I think more people will be willing to roll their sleeve
up," said Peg Holland, infection control coordinator at Ephrata
Community Hospital. "It was rough."
Last year, LGH required its employees to get the flu vaccine to protect its patients and staff. Ephrata is doing so this year.
Heart
of Lancaster and Lancaster Regional Medical Centers do not require
their employees to get the shot. But they do require them to a submit a
reason if they do not get the vaccine, and to wear a mask around
patients and other employees during flu season, said Marla Konas,
infection control nurse.
Even employees with an egg allergy may
not have an iron-clad reason not to get the shot anymore, as this year a
new egg-free shot became available.
Egg allergies are rare —
only 20 to 30 people out of the 8,000 or so Lancaster General Health
employees last year got deferments for the allergy, Greene said.
In
addition to getting vaccinated, you can do other things to protect
yourself from contracting or spreading the flu, DeLone said.
Wash
your hands often. Cover your mouth when you cough. Don't go to work or
send your children to school if flu symptoms develop.
And if you
do develop the flu, get to your physician as soon as possible for
anti-viral medications, which can lessen the severity of the illness,
Greene said.
Assad allegedly hiding troops, weapons among civilians
Two
young Syrian soldiers ride a motorcycle past a huge poster bearing a
portrait of President Bashar al-Assad next to a painting of a Syria's
national flag in the Christian town of Marmarita in the central Homs
region, about 200 kms northwest of the capital Damascus, on August 19,
2013. /Getty Images
BEIRUT As the Obama administration tries to prod Congress into backing armed action against Syria, the regime in Damascus is hiding military hardware and shifting troops out of bases into civilian areas.
Politically, President Bashar Assad has gone on the offensive, warning in a rare interview with Western media that any military action against Syria could spark a regional war.
If the U.S. opts for missile strikes, Assad's reaction could have a major effect on the trajectory of Syria's civil war.
Neighboring countries could get dragged into a wider conflict, or it
could be back to business as usual for a crisis that has claimed the
lives of more than 100,000 people over 2.5 years.
The
main Western-backed opposition group says that during the buildup last
week to what seemed like an imminent U.S. attack, the army moved troops
as well as rocket launchers, artillery and other heavy weapons into
residential neighborhoods in cities nationwide. Three Damascus
residents, speaking on condition of anonymity for fear of reprisals,
confirmed such movements.
One man said two members of the
elite Republican Guards broke into an empty house he owns and showed
him an official document stating they were authorized to do so because
Syria is at war. A woman in another area said soldiers moved into a
school next to her house.
That trend is likely to continue in the coming days after the regime won a reprieve following President Barack Obama's decision to seek congressional approval for military action.
"The
Syrian regime knows there are 30-40 potential targets for U.S.
airstrikes, and they have had ample time to prepare," said Hisham Jaber,
a retired Lebanese army general and director of the Middle East Center
for Studies and Political Research in Beirut. "Half of them, if not
more, have been evacuated, moved or camouflaged. This is the natural
thing to do."
Obama said last week that he believes the U.S. should strike Syria for what the administration says was a deadly chemical weapons attack by Assad's forces
on rebel-held suburbs of Damascus. The administration has stressed,
however, that any operation would be limited and not aimed at tipping
the balance of power in Syria's civil war.
In an
interview published Monday with the French newspaper Le Figaro, Assad
refused to say how Syria would respond to Western strikes, but warned
that "the risk of a regional war exists."
The regime has a
range of options if the U.S. does bomb. It could retaliate with rockets
against U.S. allies in the region. It could unleash allies like
Hezbollah against Western targets abroad. Or it could do nothing — and
score propaganda points by portraying itself as victim of U.S.
aggression.
Syrian Deputy Foreign Minister Faisal Mekdad told CBS News' Elizabeth Palmer over the weekend the regime could use all options if the U.S. attacks, and that the "Middle East will be on fire."
"We
have an army, we have our people, we have our capabilities, we have our
friends, and all these means will be used to stop such an aggression,"
said Mekdad, adding the U.S. "cannot control what will happen" in the
aftermath of an attack.
The regime's choice, analysts
say, will probably depend on the magnitude of the American military
action: The bigger and more sustained the strikes, the more likely the
government in Damascus will feel compelled to respond.
If Washington follows through with calibrated strikes, analysts say, Assad may reach for a political card, not a military one.
"His
first option is propaganda value," said Salman Shaikh, director of the
Brookings Doha Center. Assad could try to foster the notion "that the
West is again attacking a Middle Eastern state, an Arab state, without
the right international legitimacy. And he can bolster that dynamic,
that narrative, by showing that it's had a cost on innocent civilians."
One way to achieve that would be to show the world images of civilians purportedly killed by American strikes.
"If
he's able to score points from this, he will feel that he's actually
won without actually engaging in a military response," Shaikh said.
Assad charted a similar course after Israeli airstrikes in May
that targeted advanced weapons destined for Lebanon's Shiite militant
group Hezbollah. His regime portrayed the attacks as proof of the
rebels' collusion with Israel, denounced the strikes as a violation of
Syrian sovereignty and dispatched an obscure militant group to threaten
retaliation.
In terms of military responses, Assad could
launch rockets at U.S. allies Turkey, Jordan or Israel. But that could
touch off a prolonged military engagement with an outside power at a
time when the regime is already in a bloody fight for its survival.
An
attack against NATO-member Turkey could trigger a response from the
entire military alliance, while Jordan hosts about a dozen U.S. F-16
jets, a Patriot missile battery and around 1,000 American troops.
As
for Israel, the Assad regime could launch rockets at the Jewish state,
or turn to Hezbollah to do so. The militant group, which fought Israel
to a standstill in a 34-day war in 2006, is believed to have a
well-stocked arsenal of missiles capable of hitting the country's major
cities. While Iran has directly threatened to strike at Israel should
the U.S. attack Syria, the Assad regime has been noncommittal about what
would happen in regards to the Jewish state.
But
analysts say Syria is unlikely to pursue an aggressive course against
Israel unless the U.S. strikes pose an immediate threat to Assad's grip
on power.
Hezbollah would have a lot to lose. The group
is already facing flak at home for fighting alongside Syrian government
troops against the rebels. A full-on confrontation with Israel on behalf
of Syria would probably be a tough sell to its Shiite constituents at
home, let alone the broader Lebanese public.
"I can't see
a situation whereby they would accept an order from Assad to, say,
attack Israel or attack some domestic enemies. I think that would be too
damaging for their position," said Chris Phillips, a Syria specialist
at Queen Mary University in London.
Israeli defense
officials also say the odds of retaliation by Syria or Hezbollah are
very low. Still, Israel has deployed Iron Dome anti-missile batteries in
the Tel Aviv area and toward its northern frontier with Syria.
Between
these two extremes lies a middle path for Assad, which would involve an
attack such as a car bombing carried out by a sympathetic militant
group.
"Something to indicate to the outside world that
it's dangerous to mess with the Assad regime, that they have levers that
can cause damage elsewhere, while also plausibly denying that they've
had direct impact," Phillips said.
As an example,
Phillips pointed to a double car bombing earlier this year in Turkey
that killed more than 50 people. Turkey blames Syria, while Syria denies
any role.
Most muslims don't understand the sacrifices make by US. Hopefully this article will summarise it all in one emotional letter. Muslims should't expect other people to defend their interests.
See the letter to Obama from A.J. Spiker and David Fischer of the Iowa GOP
An Open letter to President Obama from A.J. Spiker and David Fischer Chairman and Co-Chairman of the Republican Party of Iowa.
President Obama: We oppose the president beginning another war by bombing Syria.
As fathers we believe our children’s lives are worth far more than the
price you’ll pay for admitting you’re wrong when it comes to dragging us
into war in Syria.
We believe the prosperity of America’s next generation is worth more
than profits for defense contractors and the bump in the polls you and
your fellow politicians may receive from portraying yourselves as
wartime leaders.
We’ve been at war for over ten years now, costing
us trillions of dollars and resulting in the death of thousands of
American soldiers and untold numbers of civilians. Many of those who
survive come home with debilitating injuries, strained families, and
emotional scars.
Our troops have been called up again and again as
we continue to engage in wars that pose no threat to American security,
fighting to control the borders of other countries while our own
borders at home remain unsecured. We proclaim to set the standard for
freedom and liberty, yet we trample our Constitution, spy on our
citizens, engage in nation building, and continue to police other
countries whether the people of that country want us there or not. What
we have to show for all these military engagements is death,
destruction, more enemies, and a broken economy, with a national debt
that is over $17,000,000,000,000 and climbing. Syria
is mired in a dangerous civil war and while the news of the conflict
there is troubling, it does not present a threat to American security.
In fact, American intervention is likely to make things worse and create
new enemies. Some intelligence reports even indicate the rebel forces
you’re contemplating helping may actually be made up of Al-Qaeda itself.
There are few things in politics that actually bring Amerians together, but 90% of Americans oppose a war in Syria.
Yet somehow, Mr. President, you and some of our other so-called leaders
are gearing up to take us into an unwanted, undeclared,
unconstitutional war in Syria. It’s time to put an end to this nonsense and mind the store here at home.
Together
with our wives we have five children aged 10 and under. They have never
known a world in which the United States was not at war. It’s marked
their childhood and surrounded them with a pervasive “War on Terror”
culture that benefits politicians who are ready to support this
narrative, particularly at election time. America’s children inherit the
bills for this recklessness and an economy so damaged they will
struggle to achieve the prosperity enjoyed by their parents’ generation.
For
some the cost of yet another war will be the economic drain, as
countless billions of taxpayer dollars are diverted from productive
uses. But for others, the cost will be the loss of sons and daughters,
brothers and sisters, and (hitting closest to home for us) fathers of
children who just want their dads to come home and won’t understand why a
President who pledged to end unnecessary wars sent their fathers to
fight in a country that posed no threat to American security.
Even
if you somehow support using money we don’t have to unnecessarily send
our troops into harms way again, the decision to take the country to war
rests with the Congress, not the President. It wasn’t long ago that as a
U.S. Senator you stated, “The President does not have power under the
Constitution to unilaterally authorize a military attack in a situation
that does not involve stopping an actual or imminent threat to the
nation.” We couldn’t agree more, Mr. President, and if you want to take
us to war you need to honor your oath to the Constitution and go to the
peoples’ representatives in Congress for a declaration of war.
As
fathers we work to help our children achieve the American dream of
freedom, prosperity, and peace. But if that dream will include a
lifetime of debt and endless wars, then we will have to tell our
children that the elected officials who took an oath to defend the
Constitution have failed them. For the sake of our troops, our economy,
and most importantly our children, we need to look for opportunities to
end wars, not start new ones.
Sharks and Nature Cooperate for Solo Cuba-to-Florida Swim
Andy Newman/Florida Keys News Bureau, via Associated Press
Kayakers helped escort Diana
Nyad about two miles off of Key West, Fla., on her way to becoming the
first swimmer to cross the 110-mile Florida Straits without the
protection of a shark cage.
MIAMI — This time, nature tipped its hat, and Diana Nyad finally
conquered the 110-mile passage from Cuba to Florida that had bedeviled
her for 35 years.
Spectators in Key West, Fla., cheered Ms. Nyad at the end of her 53-hour swim from Havana.
Sharks steered clear, currents were friendly, and storms took most of the Labor Day weekend off.
The 64-year-old endurance swimmer emerged dazed and sunburned from the
surf on Smathers Beach in Key West, Fla., just before 2 p.m. on Monday
after nearly 53 hours in the ocean, a two-day, two-night swim from her
starting point in Havana. She had survived the treacherous Florida
Straits, a notorious stretch of water brimming with sharks, jellyfish,
squalls and an unpredictable Gulf Stream. And she became the first
person to do so unaided by the protection of a shark cage.
It was her fifth attempt, coming after four years of grueling training,
precision planning and single-minded determination. Her face scorched
and puffy from so many hours in the salt water, she leaned on one of her
friends and said from the beach:
“I have three messages. One is we should never, ever give up. Two is you
never are too old to chase your dreams. Three is it looks like a
solitary sport, but it takes a team.”
Coming at an age when few people try to set endurance records, Ms.
Nyad’s swim lit up Twitter and Facebook with postings about perseverance
and grit, including a tweet from President Obama: “Congratulations to
Diana Nyad. Never give up on your dreams.”
Ms. Nyad’s success was built on her failures — the first in 1978, when
she was 28, and the most recent last year at age 62. After each attempt,
she improvised, learning what to adjust, whom to consult and which new
protective protocol to consider.
“Diana did her homework,” said Bonnie Stoll, Ms. Nyad’s friend and chief
handler, shortly after Ms. Nyad completed her swim.
Two summers ago, she was felled midswim by a long asthma attack, her
first ever. This year, she added a pulmonologist to her 35-member
support team, Ms. Stoll said.
Box jellyfish, which are especially venomous, have been a constant
source of danger; Ms. Nyad was stung so badly on previous swims she had
to stop. To break that cycle, she found an expert on box jellyfish this
year to help her contain the threat.
In the evenings, Ms. Nyad donned a special suit with long sleeves and
pant legs to protect her. She slathered “sting stopper” gel to form a
barrier to keep out the venom. On Saturday night, she also wore a
special mask that covered her face. But the mask proved uncomfortable,
cutting her mouth and tongue so badly, and impeding her breathing, that
she discarded it after the first night.
The course was mostly clear of box jellyfish this time. When she finally
encountered a cluster, it was on her approach to Key West. The shark
divers swam ahead of Ms. Nyad to disperse the swarm.
In 2011, Ms. Nyad decided to use a team of shark divers who carried
special zappers to ward off the predators. Trial and error also
presented new options. She learned which wet suits were more forgiving
on her skin in saltwater and which special drinks and nutrition gels
best fueled her. (She ingested them, sometimes through a tube, while
treading water.)
But there were two things Ms. Nyad could not control: the weather and the current. This time, both cooperated.
“I think that Mother Nature said, ‘You know what? Let her go,’ ” Ms. Stoll said.
Unlike past swims derailed by squalls that pushed her off course, only
one storm hit this weekend. It came on Sunday night and lasted a little
under 90 minutes, Ms. Stoll said. Ms. Nyad followed her protocol and
swam through it, accompanied by shark divers.
Sharks, always a menace, were nowhere to be seen this time.
The favorable currents carried her along so swiftly that Ms. Nyad
finished her swim a day earlier than expected, Ms. Stoll said. On
average, Ms. Nyad swims about 1.6 miles an hour. With the current
propelling her, she cruised at 5 m.p.h. during one stretch, Ms. Stoll
said, adding, “Everything was in our favor.”
To help her focus, Ms. Nyad relied, as she always has, on her favorite
songs. Over and over, she hums them in her head, her strokes falling in
time with the music’s cadence: “Ticket to Ride” by the Beatles echoed on
one stretch, “Paperback Writer” on another.
“Swimming is the ultimate form of sensory deprivation,” Ms. Nyad said in
the month before her 2011 swim. “You are left alone with your thoughts
in a much more severe way.”
Through the years, others have tried to swim from Cuba to Key West and
failed. In June, an Australian, Chloe McCardel, swam 11 hours and 14
miles before jellyfish stings forced her to stop.
In 2012, another Australian, Penny Palfrey, swam 79 miles until strong
currents waylaid her. In 1978, Walter Poenisch, an Ohio man, said he
made the swim using flippers and a snorkel, but he lacked independent
documentation to verify it.
Susie Maroney did complete the swim in 1997, but she did so inside a
shark cage that was being pulled by a boat, providing a draft that made
swimming much easier. The first time Ms. Nyad attempted the swim, in
1978, she also used a shark cage. She did not use a shark cage this
time.
Whenever Ms. Nyad scrambled, heartbroken and exhausted, onto a boat
after a failed attempt, she vowed it would be her last. “It was a fairy
tale,” she said after her second attempt, in August 2011, “but the fairy
tale didn’t come true.”
After last summer, Ms. Stoll said she was convinced that the Florida
Straits were unswimmable. “I thought it wasn’t humanly possible or she
would have done it,” Ms. Stoll said. “I was glad to be wrong.”
This article has been revised to reflect the following correction: Correction: September 2, 2013
An
earlier version of this story incorrectly stated the time of Diana
Nyad’s arrival from Cuba on a beach in Key West, Fla. The swimmer
arrived just before 2 p.m. on Monday, not at 1:20 p.m.
WASHINGTON — The White House’s aggressive push for Congressional
approval of an attack on Syria appeared to have won the tentative
support of one of President Obama’s most hawkish critics, Senator John
McCain, who said Monday that he would back a limited strike if the
president did more to arm the Syrian rebels and the attack was punishing
enough to weaken the Syrian military.
Representative Gerald E. Connolly of Virginia before a security briefing on Syria on Sunday.
In an hourlong meeting at the White House, said Mr. McCain, Republican
of Arizona, Mr. Obama gave general support to doing more for the Syrian
rebels, although no specifics were agreed upon. Officials said that in
the same conversation, which included Senator Lindsey Graham, the South
Carolina Republican, Mr. Obama indicated that a covert effort by the
United States to arm and train Syrian rebels was beginning to yield
results: the first 50-man cell of fighters, who have been trained by the
C.I.A., was beginning to sneak into Syria.
There appeared to be broad agreement with the president, Mr. McCain and
Mr. Graham said, that any attack on Syria should be to “degrade” the
Syrian government’s delivery systems. Such a strike could include
aircraft, artillery and the kind of rockets that the Obama
administration says the forces of President Bashar al-Assad used to
carry out an Aug. 21 sarin attack in the Damascus suburbs that killed
more than 1,400 people.
The senators said they planned to meet with Susan E. Rice, Mr. Obama’s
national security adviser, to discuss the strategy in greater depth.
“It is all in the details, but I left the meeting feeling better than I
felt before about what happens the day after and that the purpose of the
attack is going to be a little more robust than I thought,” Mr. Graham
said in an interview.
But Mr. McCain said in an interview that Mr. Obama did not say
specifically what weapons might be provided to the opposition or discuss
in detail what Syrian targets might be attacked.
“There was no concrete agreement, ‘O.K., we got a deal,’ ” Mr. McCain
said. “Like a lot of things, the devil is in the details.”
In remarks to reporters outside the West Wing, he called the meeting
“encouraging,” urged lawmakers to support Mr. Obama in his plan for
military action in Syria and said a no vote in Congress would be
“catastrophic” for the United States and its credibility in the world.
Mr. McCain said he believed after his conversation with the president
that any strikes would be “very serious” and not “cosmetic.”
Although the words from Mr. McCain and Mr. Graham were a positive
development for Mr. Obama and a critical part of the administration’s
lobbying blitz on Syria on Monday, the White House still faces a tough
fight in Congress. Many lawmakers entirely oppose a strike, and others
favor a resolution that would provide for more limited military action
than what is in a draft resolution that the White House has sent to
Capitol Hill. The conflict of opinion underscores Mr. Obama’s challenge
in winning votes in the House and Senate next week and avoiding personal
defeat.
A Labor Day conference call with five of Mr. Obama’s highest-ranking
security advisers drew 127 House Democrats, nearly two-thirds their
total number, after 83 lawmakers of both parties attended a classified
briefing on Sunday. Pertinent committees are returning to Washington
early from a Congressional recess for hearings this week, starting
Tuesday with the Senate Foreign Relations Committee, which will hear
from Secretary of State John Kerry, Defense Secretary Chuck Hagel and
Gen. Martin E. Dempsey, the chairman of the Joint Chiefs of Staff.
“The debate is shifting away from ‘Did he use chemical weapons?’ to
‘What should be done about it?’ ” said Representative Adam B. Schiff, a
California Democrat on the House Intelligence Committee, in an interview
after the Monday conference call.
The push in Washington came as reaction continued around the world to
the president’s abrupt decision over the weekend to change course and
postpone a military strike to seek authorization from Congress first.
In France, the only nation to offer vigorous support for an American
attack, there were rising calls for a parliamentary vote like the one
last week in Britain, where lawmakers jolted the White House with a
rejection of a British military attack. But the French government, in an
effort to bolster its case, released a declassified summary of French
intelligence that it said ties Mr. Assad’s government to the use of
chemical weapons on Aug. 21.
In Russia, Foreign Minister Sergey V. Lavrov dismissed as unconvincing
the evidence presented by Mr. Kerry of chemical weapons use by the
Syrian government. “We were shown certain pieces of evidence that did
not contain anything concrete, neither geographical locations, nor
names, nor evidence that samples had been taken by professionals,” Mr.
Lavrov said in a speech at the Moscow State Institute of International Relations.
In Israel, President Shimon Peres offered strong support for Mr. Obama’s
decision to seek the backing of Congress, saying he had faith in the
president’s “moral and operational” position. “I recommend patience,”
Mr. Peres said in an interview on Army Radio. “I am confident that the
United States will respond appropriately to Syria.”
In Washington, the White House’s “flood the zone” effort, as one
official called it, will continue. Classified briefings will be held for
all House members and senators on Tuesday, Thursday and Friday.
On Tuesday, Mr. Obama has invited the Republican and Democratic leaders
of the House and Senate defense, foreign affairs and intelligence
committees to the White House. But that night, he will depart on a
long-planned foreign trip, first to Sweden and then to Russia for the
annual Group of 20 summit meeting of major industrialized and developing
nations, a forum that is sure to be dominated by talk of Syria, and
bring Mr. Obama face to face with Mr. Assad’s chief ally and arms
supplier, President Vladimir V. Putin of Russia.
House Democrats on the conference call with administration officials,
which lasted 70 minutes, said Mr. Kerry, who has been the most
aggressive and public prosecutor for military action, took the lead.
Democrats said he had portrayed not only the horrors of chemical weapons
inflicted on Syrian civilians in the Aug. 21 attacks outside Damascus,
but also the potential threat, if left unanswered, that such weapons
posed to regional allies like Israel, Jordan and Turkey.
Mr. Kerry argued that inaction could embolden Iran or nonstate
terrorists to strike those allies, and further encourage Iran and North
Korea to press ahead with their nuclear programs.
“One of the important propositions that Kerry put to members was, are
you willing to live with the consequences of doing nothing?” said
Representative Gerald E. Connolly, a Virginia Democrat.
The secretary of state addressed lawmakers’ concern that the United
States should have international support. “The United States will not go
it alone,” he said at one point, according to a senior Democrat who
declined to be identified. Offers of “military assets” have come from
France, Saudi Arabia, Turkey and the United Arab Emirates, he said,
without identifying the assets, and more are expected.
In the week since the Obama administration began moving toward a
military strike on the Assad government, Mr. Kerry said, the Syrian
military has had about 100 defections, including 80 officers.
General Dempsey reviewed the range of possible targets and how the
Pentagon is planning strikes that would minimize risk to civilians.
Despite reports that Syrian commanders were moving troops and equipment
into civilian neighborhoods, General Dempsey told lawmakers, as he had
assured Mr. Obama, that delaying military action would not weaken the
effectiveness of any military attack. He suggested that military
officials would adjust their targets to address changes on the ground.
The general acknowledged that the United States could not prevent the
Assad government from using chemical weapons again, but said the
military had “additional options” should a first missile strike not
deter a retaliatory strike by Mr. Assad, including in defense of
critical allies, presumably Israel, Jordan and Turkey. That possibility,
however, describes just the escalating conflict some opponents fear.
“My constituents are skeptical that a limited effort will not mushroom
into a full-blown boots on the ground,” said Representative Elijah E.
Cummings, a Maryland Democrat.
Mr. McCain, who has been arguing for two years that the United States
should support a moderate Syrian opposition, said he strongly urged the
president on Monday to provide anti-tank and antiaircraft systems to the
opposition and to attack the Syrian Air Force.
Mr. Obama indicated that “he favorably viewed the degrading of Bashar
al-Assad’s capabilities as well as upgrading the Free Syrian Army,” Mr.
McCain said in an interview.
Administration officials have told Congress that the C.I.A.’s program to
arm the rebels would be deliberately limited at first to allow a trial
run for American officials to monitor it before ramping up to a larger,
more aggressive campaign. American officials have been wary that arms
provided to the rebels could end up in the hands of Islamic extremists
with ties to Al Qaeda.
David M. Herszenhorn contributed reporting from Moscow, Jodi Rudoren from Jerusalem, and Scott Sayare from Paris.
