Friday, November 18, 2016

8 tools we used to navigate the world around us before GPS and smartphones

 Do you know how the early sailors navigate the oceans?
The technology today makes it real easy to navigate the oceans.
But it's very interesting to know how the early sailors managed to navigate without it.
There's a lot of history on it.

From The Atlantic CityLab by Megan Garber
(from original article The Atlantic)

A new Smithsonian exhibit takes on the history of "getting from here to there."

Type an address into your phone, and up will pop a step-by-step route from where you are to where you want to be.
This is, in its way, magic -- magic that has, at this point, been rubbed and polished into a simple fact of life.
The ease with which we machine-carrying humans make our way through the world, though, is quite new.
And it's the product of a long, painstaking history: of people plotting a course, getting lost, and finally finding their way.
The newest exhibit at the Smithsonian's Air and Space museum, "Time and Navigation: The Untold Story of Getting from Here to There," opened this weekend, shares the story of human route-charting -- in the seas, in the sky, on the street, and in space.
And it's largely a story of failure.
The first spaceships we sent to the moon either missed their destination completely or crashed into it.
Amelia Earhart was very likely lost due to poor navigation.
Columbus and his ships were, famously, misdirected.

 History of Navigation

But the story of navigation is also one of gradual knowledge and readjustment, of looking to the constant objects of the physical world -- the sun, the moon, the stars -- and using them to understand, ever more precisely, how to find our way in the world.
Dead reckoning" (positioning oneself using time, direction, and speed) has now given way to global positioning using satellites.
And that, in turn, is giving way to atomic clocks that can keep time within three billionths of a second -- clocks that may soon make it to our phones.
So it's easy to imagine that, given our tools, we have made getting lost obsolete.
But that's to take the luxury of location-based living for granted. 
"Navigation was the great scientific challenge of our time," an animated 19th-century British "admiral" notes in a video tour of navigation's history.
And it was the challenge on which many more challenges hinged.
As explorers ventured off into distant, unknown lands, they needed above all to know where they were going -- to be, as they say, on the right path. 
Navigation was in many ways a leap of faith.
It's just that the faith in question concerned calculations. 

Now, though, thanks to the man-made stars we navigate by, "the whole world is synchronized." We humans are synchronized.
The problems faced by those early explorers have been solved using that time-honored combination: ingenuity, and math.
"Time and Space" is one of the most ambitious exhibits Air and Space Museum has yet put on -- in part because it involved a collaboration among curators at different Smithsonian institutions (Air and Space as well as American History), but also because the exhibit is so theoretical in its topic and scope.
It's not so much about a particular time or trend, but about, you know, space and time ...
and humans' place between the two.
So one particular challenge the curators faced was to make the story of navigation -- a story, ultimately, about mathematical calculations -- accessible to the range of people who come through the museum every day.
They tackled it well.
The tale is arranged chronologically, but also in sections: navigation in the sea, navigation in the air, navigation in space, navigation in the contemporary world.
We see models of clocks designed by Galileo.
We see Charles Lindbergh's sextant.
We see the updated sextant used by Apollo astronauts to navigate using the stars.
We see a GPS-guided glide bomb.
We see a duplicate of the Mariner 10 space probe, the first craft to reach Mercury.
We see Stanley, the early self-navigating car.
Below, courtesy of the Smithsonian, are some of the artifacts featured in "Time and Navigation." For more, here's the online version of the exhibit.

Bond Chronometer.
This timekeeper was the first American-made marine timekeeper taken to sea.
William Cranch Bond, a 23-year-old Boston clockmaker, crafted it during the War of 1812.
This artifact is part of the National Museum of American History's collection.

 Bygrave Position-Line Slide Rule.
Celestial navigation requires complicated computations.
Performing these calculations in cramped open cockpits with low temperatures and wind speeds of over 160 kilometers (100 miles) per hour was part of what made navigation difficult in the early years of aviation.
Thankfully, Capt. L. C. Bygrave developed this handy slide rule shortly after World War I.
It provided the best shortcut method of speeding up celestial computations at the time.

 Ramsden Sextant.
Navigating in the sea: this sextant was one of the navigation tools invented in the 18th century by British mathematical instrument makers that permitted mariners to find their position much better than ever before.
The sextant became the most essential instrument for celestial navigation, used to find the angle of a celestial body above the horizon.
Jesse Ramsden, who made this sextant, also devised a machine to divide the scale on the sextant very precisely.

 Apollo Sextant and Scanning Telescope.
Navigating in space: to determine position in space, an Apollo astronaut located a specific star using a single-power, wide-field telescope and then took a fix using a sextant.
While this instrument does not look like a traditional sextant, the basic procedure is descended from centuries-old methods used by navigators at sea and in the air.

Dutch Pendulum Clock.
In the 17th century, several inventors were trying to make an accurate clock for finding longitude at sea.
In pursuit of a sea clock, Christiaan Huygens, a Dutch mathematician, changed timekeeping forever when he patented the first working pendulum clock in 1656 and later devised a watch regulator called a balance spring.
Pendulum clocks immediately became the best timekeepers for use on land, but they didn't work accurately on a heaving ship's deck.
Huygens worked with several Dutch clockmakers, including Johannes van Ceulen, who made this table clock around 1680.
It is one of the earliest clocks with a pendulum.

Longines Sidereal Second-Setting Watch.
Before 1927, watches used with sextants for celestial sightings could only be set to the minute.
A watch error of 30 seconds caused a navigational error of up to 12 kilometers (7 miles).
In 1927, P. V. H. Weems devised a watch with an adjustable second hand that could be set using radio time signals.
This was one of his personal navigation watches.
Sidereal refers to the watch running on a celestial day (about 23 hours, 56 minutes), rather than the 24 hour solar day.

Lockheed Vega 5C Winnie Mae.
Wiley Post's Winnie Mae circled the globe two times, shattering previous records.
The first time was in 1931 with Weems associate Harold Gatty as lead navigator.
The second was a solo flight in 1933 assisted by "Mechanical Mike," one of the world's first practical autopilots.

Stanley Autonomous Vehicle.
This autonomous vehicle, named Stanley, was developed by the Stanford Racing Team.
Stanley is a 2005 Volkswagen Touareg modified to navigate without remote control and without a human driver in the seat.
Stanley won the 2005 Grand Challenge, a robot race sponsored by the Defense Advanced Research Projects Agency (DARPA), by successfully navigating 212 kilometers (132 miles) across desert terrain.

Links :

Thursday, November 17, 2016

SpaceX just asked permission to launch 4,425 satellites — more than currently orbit Earth

SpaceX plans Satellite Network for global Internet coverage

From Business Insider by Dave Mosher

SpaceX, the aerospace company founded by the Mars-hungry tech entrepreneur Elon Musk, just made a big move to enshroud the planet in high-speed internet coverage.
On November 15, the company filed a lengthy application with the Federal Communications Commission (FCC) to launch 4,425 satellites.
(We first heard about the filing through the r/SpaceX community on Reddit.)
That is a hell of a lot of satellites.
According to a database compiled by the Union of Concerned Scientists, there are 1,419 active satellites currently orbiting Earth.
There are estimates of roughly 2,600 satellites that no longer work floating in space, but even factoring those in, SpaceX's planned fleet would be larger than everything already in space.
Some of the biggest telecommunications satellites can weigh several tons, be the size of a bus, and orbit from a fixed point about 22,000 miles (35,000 km) above Earth.
After we took a look at SpaceX's FCC application, though, it seems these won't be your typical telecommunications satellites.
Each satellite in SpaceX's planned constellation will weigh about 850 lbs (386 kg) and be roughly the size of a MINI Cooper car.
They will orbit at altitudes ranging from 715 miles (1,150 km) to 790 miles (1,275 km).
From this lofty vantage point, SpaceX says each satellite could cover an ellipse about 1,300 miles (2,120 km) wide.
That's about the distance from Maine to the Florida panhandle.
"The system is designed to provide a wide range of broadband and communications services for residential, commercial, institutional, governmental and professional users worldwide," SpaceX wrote in its application.

SpaceX's filing with the FCC outlines a two-phase launch plan.
To get the party started, SpaceX wants to send up 1,600 satellites at one orbital altitude, then follow up with another 2,825 satellites placed in four shells at different altitudes.
"With deployment of the first 800 satellites, SpaceX will be able to provide widespread U.S. and international coverage for broadband services," SpaceX wrote.
"Once fully optimized through the Final Deployment, the system will be able to provide high bandwidth (up to 1 Gbps per user), low latency broadband services for consumers and businesses in the U.S. and globally."

Turbo speeds 

A speed of 1 Gbps globally would be huge.
The global average for internet speed in late 2015, according Akamai's "State of the Internet" report, was 5.1 Mbps per user — about 200 times slower than SpaceX's target — with most of the higher speeds tied up in cable and fiberoptic connections.
SpaceX also makes the point in its filing's legal statement that, according to a July 2016 report by UNESCO's Broadband Commission for Sustainable Development, "4.2 billion people (or 57% of the world’s population) are offline for a wide range of reasons, but often also because the necessary connectivity is not present or not affordable."
Bathing the planet in internet is one way to get those people online.

Here are some more details directly from SpaceX's filing, which are notable:
  • High capacity: Each satellite in the SpaceX System provides aggregate downlink capacity to users ranging from 17 to 23 Gbps, depending on the gain of the user terminal involved. Assuming an average of 20 Gbps, the 1600 satellites in the Initial Deployment would have a total aggregate capacity of 32 Tbps. SpaceX will periodically improve the satellites over the course of the multi-year deployment of the system, which may further increase capacity.
  • High adaptability: The system leverages phased array technology to dynamically steer a large pool of beams to focus capacity where it is needed. Optical inter-satellite links permit flexible routing of traffic on-orbit. Further, the constellation ensures that frequencies can be reused effectively across different satellites to enhance the flexibility and capacity and robustness of the overall system.
  • Broadband services: The system will be able to provide broadband service at speeds of up to 1 Gbps per end user. The system’s use of low-Earth orbits will allow it to target latencies of approximately 25-35 ms.
  • Worldwide coverage: With deployment of the first 800 satellites, the system will be able to provide U.S. and international broadband connectivity; when fully deployed, the system will add capacity and availability at the equator and poles for truly global coverage.
  • Low cost: SpaceX is designing the overall system from the ground up with cost- effectiveness and reliability in mind, from the design and manufacturing of the space and ground-based elements, to the launch and deployment of the system using SpaceX launch services, development of the user terminals, and end-user subscription rates.
  • Ease of use: SpaceX’s phased-array user antenna design will allow for a low-profile user terminal that is easy to mount and operate on walls or roofs.
  • The satellites will last between 5 years and 7 years and decay within a year after that. 
 Musk is not alone in recognizing the market potential.
Besides investing in Musk’s project, Google is working on a high-altitude balloon-based Internet delivery system called Loon.
Facebook is developing high-altitude, high-endurance drones to deliver Internet capability to remote areas.
Richard Branson’s Virgin Galactic and Qualcomm, meanwhile, are investing in a competing venture called OneWeb, which aims to build a similar network of micro-satellites.
These projects would be similar in concept to the space-based systems, while operating within the Earth’s atmosphere.
Musk first discussed the unnamed satellite constellation project back in January 2015, later filing for an FCC application to test basic technologies that'd support it.

At the time, Musk said during a SpaceX event (our emphasis added):
"The focus is going to be on creating a global communications system. This is quite an ambitious effort. We're really talking about something which is, in the long term, like rebuilding the Internet in space. The goal will be to have the majority of long distance Internet traffic go over this network and about 10% of local consumer and business traffic. So that's, still probably 90% of people's local access will still come from fiber but we'll do about 10% business to consumer direct and more than half of the long distance traffic." 

According to a June 2015 story by Christian Davenport at The Washington Post, Google and Fidelity invested $1 billion into Musk's company, in part to support the project.
So it's a good guess that if and when the network becomes functional, those companies would partly assume control of it.
(Google parent company Alphabet is also working on its own effort to beam internet connectivity from the skies using satellites, balloons and drones.)
The filing comes just two months after a SpaceX rocket exploded during a routine launchpad test.
It was carrying the $200 million AMOS-6 satellite, which Facebook intended to license to beam free internet to parts of Africa.
Business Insider contacted SpaceX for more details on the project, including its projected timeline and how the satellites would be launched (presumably through Falcon 9 and Falcon Heavy rockets), but representatives did not immediately answer our questions.

Links :

Wednesday, November 16, 2016

Uncovered: the mysterious killer triffids that dominate life in our oceans

New videography techniques have opened up the oceans' microscopic ecosystem, revealing it to be both mesmerizingly beautiful and astoundingly complex.
Marine biologist Tierney Thys has used footage from a pioneering project to create a film designed to ignite wonder and curiosity about this hidden world that underpins our own food chain.

From The Conversation by Aditee Mitra

Have you ever wondered where the foam in the ocean comes from?
Or why the sea can look clear on some days and green, brown, or even pink on others?
And how fish get the ingredients to make those omega-fatty acids that we’re told are so good for us?
Well, the single word answer to all of these questions is: “plankton”.
Plankton are organisms that inhabit all water bodies – from lakes and ponds to oceans.
The word plankton is derived from a Greek word – πλαγκτός (planktos) – meaning “I drift”, and so while plankton can move between deeper waters and the surface and vice versa, they cannot swim against the current.
So sometimes we have vast numbers of planktonic jellyfish, fantastic swimmers within the water columns but helpless against the tide, stranded on our beaches.
In size, plankton range from microscopic, single-celled organisms to multi-celled animals such as krills, jellyfish, crab larvae and juvenile fish.

 Little triffids: Mixotrophs at large. Author provided

We often think of the sea as being dominated by fish and whales.
But microscopic, single-celled plankton are, in fact, the main drivers of life in Earth’s oceans.
But how well do we really understand them?
For decades, the accepted view has been that these single-celled microscopic plankton can be divided broadly into two types.
Food producing “phytoplankton” (also known as microalgae) are like tiny marine plants.
Microzooplankton”, on the other hand, eat the phytoplankton and are in turn eaten by bigger zooplankton, such as krills.
This division of microscopic plankton is akin to the plant-animal split in terrestrial ecosystems. However we now know that, beneath the waves, there is another microscopic plankton group – “mixotrophs” that combine features of “plant-like” phytoplankton and “animal-like” microzooplankton.
And their mode of feeding is, but for their microscopic scale, the stuff of horror stories.
They are like miniature triffids, which can engulf living prey, suck out their innards, poison them, harpoon them, make them explode, and steal and reuse body parts.
They can kill whole ecosystems in a matter of hours and alter the colour of the water – and yet they also shape the Earth’s atmosphere and support the growth of larval fish at critical stages of their life cycle.

For decades, these mixotrophs have been considered to be freaks of nature, prospering only when phytoplankton and microzooplankton are disadvantaged.
Over the past five years, however, through a project funded by the Leverhulme Trust, we have established that the mixotrophs are far from freaks; indeed, mixotrophy is the norm rather than the exception.
This has major implications – it means that the base of the oceanic food web doesn’t follow the traditional “plant-animal” pattern.
Instead, it is dominated by the activities of the single-celled mixotrophs, microscopic “triffids” which can photosynthesise like plants and eat like animals – all within the one cell.

 "The Power of Plankton" (Bringing the importance of plankton to life) is an animation movie.
This animation was written and designed by Clare Buckland, SAHFOS Education Officer and is aimed at all age groups of the general public.
The movie promotes the importance of plankton and the long term Continuous Plankton Recorder (CPR) survey.

A new type of life?

Based on our findings, we have proposed a new model for life in our oceans, arguing that the traditional split between the “plant-like” phytoplankton (microalgae) and the “animal-like” microzooplankton used to describe the oceanic food-web is no longer tenable.
This model could overturn a century’s worth of our understanding of marine biology.
Indeed, mixotrophs have the potential to impact all of our lives, not least because they are major contributors to the food webs that support fisheries.
This is especially true for the healthy growth of very young fish, which depend on them for food during the summer months.

Bad news for fish: Phaeocystis bloom on the Loughor Estuary, south Wales.
Author provided

Just like the triffids of John Wyndham’s classic sci-fi novel, however, mixotrophs can be dangerous, too – and to more than just other microplankton.
The release of nitrates and organic nutrients, such as raw sewage or silage slurry, into coastal waters contributes to an imbalance of nutrient loads, which causes mixotrophs to produce toxins and mucus.
The toxins can kill fish and close shell-fisheries.
Muddy-coloured foam in estuaries during summer is the result of plankton secreting excess mucus – and this mucus can clog the gills of fish, effectively drowning them.
Mathematical models are used widely to aid environmental management, to study fisheries and to investigate the impacts of fishing and climate change on them.
But such models do not take into account the presence and activities of the mixotrophs that we now realise comprise more than half of all microscopic plankton.
And this could result in serious flaws.
We have shown that marine food web and climate change models that don’t include mixotrophs could be giving questionable results.
Indeed, based on our modelling studies, we suggest that we start to take mixotrophs more seriously and include their remarkable impacts in mathematical models used to predict climate change and aid environmental management.
They may be microscopic, but we ignore these little triffids at our peril.

Links :

Tuesday, November 15, 2016

‘We couldn’t believe our eyes’: A lost world of shipwrecks is found

An image of the well-preserved medieval ship found at the bottom of the Black Sea, one of more than 40 wrecks discovered.
Photogrammetry, a process using thousands of photographs and readings, produced a rendering that appears three-dimensional.
Credit Expedition and Education Foundation/Black Sea MAP

From New York Times by William J. Broad

The medieval ship lay more than a half-mile down at the bottom of the Black Sea, its masts, timbers and planking undisturbed in the darkness for seven or eight centuries.
Lack of oxygen in the icy depths had ruled out the usual riot of creatures that feast on sunken wood.
This fall, a team of explorers lowered a robot on a long tether, lit up the wreck with bright lights and took thousands of high-resolution photos.
A computer then merged the images into a detailed portrait.
Archaeologists date the discovery to the 13th or 14th century, opening a new window on forerunners of the 15th- and 16th-century sailing vessels that discovered the New World, including those of Columbus.
This medieval ship probably served the Venetian empire, which had Black Sea outposts.
Never before had this type of ship been found in such complete form.
The breakthrough was the quarterdeck, from which the captain would have directed a crew of perhaps 20 sailors.

“That’s never been seen archaeologically,” said Rodrigo Pacheco-Ruiz, an expedition member at the Center for Maritime Archaeology at the University of Southampton, in Britain.
“We couldn’t believe our eyes.”

 A photogrammetric image of a ship from the Ottoman era that most likely went down between the 17th and 19th centuries.
The discoverers nicknamed it the Flower of the Black Sea because of its ornate carvings, including two large posts topped with petals.
Credit Expedition and Education Foundation/Black Sea MAP

Remarkably, the find is but one of more than 40 shipwrecks that the international team recently discovered and photographed off the Bulgarian coast in one of archaeology’s greatest coups.
In age, the vessels span a millennium, from the Byzantine to the Ottoman empires, from the ninth to the 19th centuries.
Generally, the ships are in such good repair that the images reveal intact coils of rope, rudders and elaborately carved decorations.
“They’re astonishingly preserved,” said Jon Adams, the leader of the Black Sea project and founding director of the maritime archaeology center at the University of Southampton.
Kroum Batchvarov, a team member at the University of Connecticut who grew up in Bulgaria and has conducted other studies in its waters, said the recent discoveries “far surpassed my wildest expectations.”
Independent experts said the annals of deepwater archaeology hold few, if any, comparable sweeps of discovery in which shipwrecks have proved to be so plentiful, diverse and well preserved.

 A photogrammetric image of the stern of the Ottoman-era ship showing coils of rope and a tiller with elaborate carvings.
A lack of oxygen at the icy depths of the Black Sea left the wrecks relatively undisturbed.
Credit Expedition and Education Foundation/Black Sea MAP

“It’s a great story,” said Shelley Wachsmann of the Institute of Nautical Archaeology at Texas A&M University.
“We can expect some real contributions to our understanding of ancient trade routes.”
Goods traded on the Black Sea included grains, furs, horses, oils, cloth, wine and people.
The Tatars turned Christians into slaves who were shipped to places like Cairo.
For Europeans, the sea provided access to a northern branch of the Silk Road and imports of silk, satin, musk, perfumes, spices and jewels.
Marco Polo reportedly visited the Black Sea, and Italian merchant colonies dotted its shores.
The profits were so enormous that, in the 13th and 14th centuries, Venice and Genoa fought a series of wars for control of the trade routes, including those of the Black Sea.
Brendan P. Foley, an archaeologist at the Woods Hole Oceanographic Institution on Cape Cod, Mass., said the good condition of the shipwrecks implied that many objects inside their hulls might also be intact.
“You might find books, parchment, written documents,” he said in an interview.
“Who knows how much of this stuff was being transported? But now we have the possibility of finding out. It’s amazing.”

Experts said the success in Bulgarian waters might inspire other nations that control portions of the Black Sea to join the archaeological hunt.
They are Georgia, Romania, Russia, Turkey and Ukraine.
Dr. Foley, who has explored a number of Black Sea wrecks, said the sea’s overall expanse undoubtedly held tens of thousands of lost ships.
“Everything that sinks out there is going to be preserved,” he added.
“They’re not going away.”
For ages, the Black Sea was a busy waterway that served the Balkans, the Eurasian steppes, the Caucasus, Asia Minor, Mesopotamia and Greece.
It long beckoned to archaeologists because they knew its deep waters lacked oxygen, a rarity for large bodies of water.
The great rivers of Eastern Europe — the Don, the Danube, the Dnieper — pour so much fresh water into the sea that a permanent layer forms over denser, salty water from the Mediterranean.
As a result, oxygen from the atmosphere that mixes readily with fresh water never penetrates the inky depths.
In 1976, Willard Bascom, a pioneer of oceanography, in his book “Deep Water, Ancient Ships,” called the Black Sea unique among the world’s seas and a top candidate for exploration and discovery.

A photogrammetric image of a Byzantine wreck, dating perhaps to the ninth century.
Superimposed is an image of one of the expedition’s tethered robots that photographed the lost ships. 
Credit Expedition and Education Foundation/Black Sea MAP

“One is tempted,” he wrote, “to begin searching there in spite of the huge expanse of bottom that would have to be inspected.”
In 2002, Robert D. Ballard, a discoverer of the sunken Titanic, led a Black Sea expedition that found a 2,400-year-old wreck laden with the clay storage jars of antiquity. One held remnants of a large fish that had been dried and cut into steaks, a popular food in ancient Greece.
The new team said it received exploratory permits from the Bulgarian ministries of culture and foreign affairs and limited its Black Sea hunts to parts of that nation’s exclusive economic zone, which covers thousands of square miles and runs up to roughly a mile deep.
Although the team’s official name is the Black Sea Maritime Archaeology Project, or Black Sea MAP, it also hauls up sediments to hunt for clues to how the sea’s rising waters engulfed former land surfaces and human settlements.
Team members listed on its website include the Bulgarian National Institute of Archaeology, the Bulgarian Center for Underwater Archaeology, Sodertorn University in Sweden, and the Hellenic Center for Marine Research in Greece.

An illustration of what the research team believes the medieval ship found in the Black Sea looked like during its heyday.Credit Jon Adams/University of Southampton/Black Sea MAP

The project’s financial backer is the Expedition and Education Foundation, a charity registered in Britain whose benefactors want to remain anonymous, team members said.
Dr. Adams of the University of Southampton, the team’s scientific leader, described it as catalyzing an academic-industry partnership on the largest project “of its type ever undertaken.”

Nothing is known publicly about the cost, presumably vast, of the Black Sea explorations, which are to run for three years.
The endeavor began last year with a large Greek ship doing a preliminary survey.
This year, the main vessel was the Stril Explorer, a British-flagged ship bearing a helicopter landing pad that usually services the undersea pipes and structures of the offshore oil industry.

Instead, archaeologists on the ship lowered its sophisticated robots to hunt for ancient shipwrecks and lost history.
In an interview, Dr. Pacheco-Ruiz of the University of Southampton said he was watching the monitors late one night in September when the undersea robot lit up a large wreck in a high state of preservation.
“I was speechless,” he recalled.
“When I saw the ropes, I couldn’t believe my eyes. I still can’t.”

Dr. Pacheco-Ruiz said the vessel hailed from the Ottoman Empire, whose capital was Constantinople (today Istanbul), and most likely went down sometime between the 17th and 19th centuries.
He said the team nicknamed it “Flower of the Black Sea” because its deck bears ornate carvings, including two large posts with tops that form petals.
In an interview, Dr. Batchvarov of the University of Connecticut said most of the discoveries date to the Ottoman era.
So it was that, late one night, during his shift, he assumed that a new wreck coming into view would be more of the same.
“Then I saw a quarter rudder,” he recalled, referring to a kind of large steering oar on a ship’s side. It implied the wreck was much older.
Then another appeared. Quickly, he had the expedition’s leader, Dr. Adams, awakened.
“He came immediately,” Dr. Batchvarov recalled.
“We looked at each other like two little boys in a candy shop.”
Dr. Batchvarov said the wreck — the medieval one found more than a half-mile down — was part of a class known by several names, including cocha and “round ship.”
The latter name arose from how its ample girth let it carry more cargo and passengers than a warship.

Dr. Adams said the remarkable color images of the lost ships derived from a process known as photogrammetry.
It combines photography with the careful measurement of distances between objects, letting a computer turn flat images into renderings that seem three-dimensional.
He said tethered robots shot the photographic images with video and still cameras.
The distance information, he added, came from advanced sonars, which emit high-pitched sounds that echo through seawater.
Their measurements, he said, can range down to less than a millimeter.
A news release from the University of Southampton refers to the images as “digital models.”
Their creation, it said, “takes days even with the fastest computers.”
Filmmakers are profiling the Black Sea hunt in a documentary, according to the team’s website.
Another part of the project seeks to share the thrill of discovery with schools and educators.
Students are to study on the Black Sea, the website says, or join university scientists in analyzing field samples “to uncover the mysteries of the past.”
The team has said little publicly on whether it plans to excavate the ships — a topic on which nations, academics and treasure hunters have long clashed.
Bulgaria is a signatory to the 2001 United Nations convention that outlaws commercial trade in underwater cultural heritage and sets out guidelines on such things as artifact recovery and public display.
Dr. Pacheco-Ruiz said the team had so far discovered and photographed 44 shipwrecks, and that more beckoned.
Which was the most important?
Dr. Adams said that for him, a student of early European shipbuilding, the centerpiece was the medieval round ship.
He said it evoked Marco Polo and city states like Venice.
The ship, he added, incorporated a number of innovations that let it do more than its predecessors had and paved the way for bigger things to come.
“It’s not too much,” he said, “to say that medieval Europe became modern with the help of ships like these.”

Links :

Monday, November 14, 2016

We’re about to see a record-breaking supermoon - the biggest in nearly 70 years

From Science Alert

If you only see one astronomical event this year, make it the November supermoon, when the Moon will be the closest to Earth it’s been since January 1948.
During the event, which will happen on the eve of November 14, the Moon will appear up to 14 percent bigger and 30 percent brighter than an average full moon.
This is the closest the Moon will get to Earth until 25 November 2034, so you really don’t want to miss this one.

So how do you get a supermoon?

As NASA explains, because the Moon has an elliptical orbit, one side - called the perigee - is about 48,280 km (30,000 miles) closer to Earth than the other side (the apogee).
When the Sun, the Moon, and Earth line up as the Moon orbits Earth, that’s known as syzygy (definitely something you want to keep in your back pocket for your next Scrabble match).
When this Earth-Moon-Sun system occurs with the perigee side of the Moon facing us, and the Moon happens to be on the opposite side of Earth from the Sun, we get what’s called a perigee-syzygy.
That causes the Moon to appear much bigger and brighter in our sky than usual, and it’s referred to as a supermoon - or more technically, a perigee moon.
Supermoons aren’t all that uncommon - we just had one on October 16, and after the November 14 super-supermoon, we’ll have another one on December 14.

But because the November 14 Moon becomes full within about 2 hours of perigee, it’s going to look the biggest it has in nearly seven decades.
"The full moon of November 14 is not only the closest full moon of 2016, but also the closest full moon to date in the 21st century," says NASA.
"The full moon won’t come this close to Earth again until 25 November 2034."
Depending on where you're viewing it from, the difference between a supermoon and a regular full moon can be stark, or difficult to tell.
If the Moon is hanging high overhead, and you have no buildings or landmarks to compare it to, it can be tricky to tell that it's larger than usual.
But if you're viewing from a spot where the Moon is sitting closer to the horizon, it can create what's known as 'moon illusion'.
"When the moon is near the horizon, it can look unnaturally large when viewed through trees, buildings, or other foreground objects," says NASA.
"The effect is an optical illusion, but that fact doesn’t take away from the experience."

If you're planning on viewing the November 14 supermoon, be sure to get somewhere nice and dark, away from the lights of the city, if you can.
You'll have some awesome opportunities to take pictures with your phone overnight, but if you want to see it at its absolute biggest, it's expected to reach the peak of its full phase on the morning of November 14 at 8:52am EST (1352 GMT).
For those of you in Australia, you'll need to wait until November 15 to see it, and the Moon will hit its full phase at 12:52am AEST.

Links :

Sunday, November 13, 2016

The importance of Maritime Surveillance

The Swordfish MPA is a high-end, multi-role safeguard platform
that offers strategic ISR capabilities over both sea and land.