The National Snow and Ice Data Center offers some of our data in the form of images. From these, we have created Google Earth files that enable you to view them on a virtual globe.

Featured Data highlights some of our most requested data, as well as our newest Google Earth files. View Arctic and Antarctic sea ice extents from 1979 through present for the months September (minimum sea ice extents) and March (maximum sea ice extents).Download: Sea Ice: Minimum and Maximum Extents (KMZ)Data Source: Sea Ice Index, Version 3Note: September is the default month when the file is opened.

Tour the globe to view outlines of the three largest glaciers and glacier complexes in each of the 19 glacial regions of the world as defined by the Global Terrestrial Network for Glaciers.Download: Largest Glaciers and Glacier Complexes (KMZ)Data Source: Largest Glaciers and Glacier Complexes in the World, Version 1.

A narrated tour of the snowy and icy regions of the world covering sea ice, glaciers, ice shelves, and permafrost.Download: Climate Change Tour of Cold Places (KMZ)About: A Climate Change Tour for a K-12 AudienceNote: This was a collaborative project between NSIDC and the University of Colorado at Boulder School of Education in 2009.

View Glacier photograph pairs showing how some glaciers have changed over time. Download: Glaciers and Climate Change (KMZ).

Per- and polyfluoroalkyl substances (PFASs) have a wide industrial application and use, from surfactants in aqueous film-forming foams (Moody and Field, 2000), ski wax (Kotthoff et al., 2015), to water-repellent coatings and non-stick surfaces in carpets, clothes, papers and non-stick cookware (Paul et al., 2009).

In the environment, PFASs are ubiquitous organic pollutants that reach remote locations including Polar Regions. Several of the PFAS compounds accumulate in biota with an increasing level up to the food webs, indicating that they are biomagnified (Tomy et al., 2004.

Franklin, 2016). In Antarctic wildlife, PFASs have been quantified in migratory species that are suggested to be exposed outside the Antarctic Circumpolar Current, bringing the PFAS with them to the continent as biovectors (Bengtson Nash et al., 2010.

Roscales et al., 2019). One of these migrating species is the south polar skua (Catharacta maccormicki), which overwinters in tropical or temperate waters outside the Southern Ocean and returns to Antarctica to breed in the austral summer (Weimerskirch et al., 2015).

Munoz et al., 2017. Midthaug et al., 2021), with some of the highest PFAS concentrations recorded in wildlife in sub-tropical and sub-Antarctic waters (Roscales et al., 2019).

Diet is the major source of PFAS in avian wildlife and biomagnification factors (BMFs) reflect the relative change in contaminant concentration from prey to predator (Mackay et al., 2013. Borgå and Ruus, 2019).

Thus, if the contamination load in the predator reflects its local prey, BMFs should be comparable across areas and vary due to physicochemical properties and recalcitrance. Our aim was to investigate if local prey during the breeding season in Antarctica could account for the PFAS occurrence (both the concentrations and pattern) in south polar skuas.

At the inland colony of Svarthamaren, Dronning Maud Land, the south polar skua feeds almost exclusively on Antarctic petrel (Thalassoica antarctica) eggs and chicks (Brooke et al., 1999. Busdieker et al., 2020), whereas they feed mainly on Adélie penguins but also on other prey such as fish in the coastal colony such as in Dumont d’Urville (Young, 1963.

Olsen, 2010. Carravieri et al., 2017.

We analysed Antarctic petrel (Thalassoica antarctica) eggs, blood of chicks, adults, and their stomach samples from Svarthamaren, Dronning Maud Land and blood of Adélie penguin chicks (Pygoscelis adeliae) from Dumont d’Urville, Adélie Land. We also analysed and compared stable isotopes of carbon (δ13C) and nitrogen (δ15N) as dietary markers to assess, respectively, the feeding habitat and relative trophic positions (TPs) of the prey and skuas.

We expected the skua PFAS to reflect their local prey and, thus, the BMFs to be comparable between two colonies, one inland, and one coastal as well as comparable to avian PFAS BMFs from other areas. This study is based on a combination of new data and published PFAS data from skuas at Svarthamaren (Midthaug et al., 2021) and Dumont d’Urville (Munoz et al., 2017) as well as stable isotope data in Adélie penguin chicks (Carravieri et al., 2020).

Svarthamaren is located at 71°53′S, 5°10′E in Dronning Maud Land, 200 km inland from the sea, while Dumont d’Urville is located at 66°39′47′′S, 140°00′10′′E in Adélie Land, close to the ocean (Figure 1). Although the Antarctic petrels are also migratory, they spend most of the inter-breeding period within the Marginal Ice Zone and generally winter south of the Antarctic Circumpolar Current (Descamps et al., 2016.

The Antarctic petrel’s diet is comprised mostly of crustaceans but also includes fish and cephalopods (Lorentsen et al., 1998. Descamps et al., 2016).

Antarctica with the study sites of Svarthamaren in Dronning Maud Land and Dumont d’Urville in Adélie Land marked. Source Google maps.

Wienecke et al., 2000. Cherel, 2008).

At Svarthamaren, whole blood samples were collected from 30 breeding adult south polar skuas, 19 Antarctic petrel chicks in addition to 20 Antarctic petrel eggs during the 2013/2014 breeding season (Supplementary Table 1). During the 2015/2016 breeding season, blood samples were collected from 24 breeding adult Antarctic petrels and 20 breeding adult south polar skuas.

In addition, the stomach contents of six adult petrels in 2015/2016 were collected by lavage according to Wilson (1984) and Descamps et al. (2016).

Few adult petrels did not let us approach too close and were captured with a 1-m noose pole. Adult skuas were captured either with a net attached to a 2-m pole, with a baited trap triggered at a distance or with air propelled net gun.

The samples were kept in a cooler and taken to the camp. The blood samples of petrel chicks from 2013 to 2014 and all the samples from 2015 to 2016 were centrifuged 6–8 h after collection to separate plasma from blood cells.

Skua blood samples from 2013 to 2014 were frozen without centrifugation. The Antarctic petrel eggs were sampled from abandoned nests at the petrel colony or depredated eggs found close to the skua nests.

The egg yolk was allocated to PFAS analyses, whereas stable isotopes were analysed in the egg whites. The samples from Svarthamaren were stored in freezers at −20°C.

At Dumont d’Urville, blood samples were collected from the wing of 10 Adélie penguin chicks that were in the moulting phase (Carravieri et al., 2020) as well as from five adult breeding south polar skuas (Munoz et al., 2017) during the 2011/2012 breeding season. These samples were centrifuged and separated into red blood cells and plasma, frozen at −20°C, and transported for further analysis.

The south polar skuas from Svarthamaren collected in 2013/2014 (whole blood) and from Dumont d’Urville in 2011/2012 (plasma) were analysed for PFAS using liquid chromatography/mass spectrometry (LC/MS) as described in Munoz et al. (2017) and Midthaug et al.

These PFAS analyses followed the quality assurance (QA) procedures specified in Grønnestad et al. (2017) for the Norwegian University of Life Sciences (NMBU) and Munoz et al.

The targetted 22 PFAS are given as footnotes to Table 1 and in a separate Supplementary Table 2 in Supporting Information and detailed results from these studies are reported in detail in Munoz et al. (2017) and Midthaug et al.

Table 1. Per- and polyfluoroalkyl substance (PFAS) concentrations (pg/g wet weight) in south polar skuas and food web items.

(2020) for plasma and Warner et al. (2019) for eggs.

At the NILU, approximately, 1 g of egg yolk, 1 g of stomach content, or 200 μl of plasma was extracted with methanol according to Hanssen et al. (2013).

(2013), in the TSQ Vantage LC/MS equipment (Thermo Fisher Scientific, San Jose, CA, United States). The chromatograms were quantified with LCQuan software (version 2.6, Thermo Fisher Scientific Incorporation, Waltham, MA, United States), using the isotopic dilution approach with 13C mass labelled compounds applying an eight-point calibration curve with a concentration range from 0.02 to 50 pg μl–1.

Home > Ministry > Photos. “Google Earth” is a fascinating program from Google.com that you can use to look at much of the earth from space using satellite images.

Use these pictures from Google earth to visit us here in Oryol. The Earth Here’s how an American views the earth.

Turn the Ball From this angle you can see America, Europe, and part of Africa.

North Pole Rotated Now we have America on top and Russia on the bottom.

Europe You can see the outlines of the European countries.

Moscow, Russia is in the upper right, Our town of Oryol, Russia is just below Moscow.

Russia, Belarus, Ukraine In 1994-95, I visited Minsk, Belarus. We lived in Kiev, Ukraine (Kyiv) for over 3 years.

Moscow and Oryol We are 250 miles south of Moscow. Kaluga and Tula are major cities between us and Moscow.

Oryol Province Oryol is the capital city of the Oryol province. The city has 318,000 people, and the entire province has 787,000 people.

City of Oryol The city is narrow, located on both banks of the Oka river, which flows north toward Moscow, and then into the Volga river.

That is the Lenin sports stadium, where the soccer team plays.

That is our apartment building.

You can see the soccer field in the stadium.

Route to Church The green line shows the path from our apartment to the house where we have church. It is about 2 miles away on the other side of the river.

Church House You can’t see much of it in the picture, but the green line ends at the house where we have church services.

But then it kept moving, skittering from its previous location in Nunavut, Canada towards Siberia.

“But since the 1980s, the rate it was moving jumped from 10 kilometers [6.2 miles] per year to 50 kilometers [31 miles].”. Beggan is part of a group of scientists who track the errant pole from year to year.

According to the most recent update of the WMM, magnetic north is still zooming along, though its speed has decreased a bit, to 24.8 miles per year.

Earth’s magnetic field is a sheath of geomagnetic energy that shields the planet from deadly and destructive solar radiation. Without it, solar winds could strip Earth of its oceans and atmosphere.

But the magnetic field and its poles aren’t static. Since scientists discovered the magnetic north pole’s existence in 1831, it has moved 1,400 miles.

Keeping tabs on changes in the magnetic field is imperative for European and American militaries, since their navigation systems rely on it. So, too, do GPS apps and commercial airlines.

The WMM isn’t a static snapshot of what the Earth’s magnetic field looks like every five years. Rather, it’s a list of numbers that allows devices and navigators to calculate what the magnetic field will look like anywhere on Earth at any time during the five years after the model was published.

Recently, however, magnetic north’s gambol around the Arctic accelerated so much that the movement made the WMM inaccurate. The magnetic north pole’s uncharacteristically fast movement over the last five years introduced errors into the 2015 model that became big enough to worry the US military.

“We asked the US Department of Defense if they wanted an early update, and they said yes,” Beggan said. “UK ministry defense wasn’t bothered either way.”.

Then the scheduled update for 2020 was released on December 10.

“Compasses and GPS will work as usual. there’s no need for anyone to worry about any disturbance to daily life,” he said in a press release.

That’s because drilling companies use compasses and the magnetic field to guide drill bits. The DOD, meanwhile, wants as much precision as possible for navigation systems on its planes, submarines, and parachutes.

Earth’s magnetic field exists thanks to swirling liquid nickel and iron in the planet’s outer core, 1,800 miles beneath the surface. Anchored by the north and south magnetic poles (which tend to shift and even reverse every million years or so), the field waxes and wanes in strength, undulating based on what’s going on in the core.

Periodic and sometimes random changes in the distribution of the turbulent liquid metal in the Earth’s core can cause idiosyncrasies in the magnetic field. If you imagine the magnetic field as a series of rubber bands that thread through the magnetic poles and the Earth’s core, changes in the core essentially tug on different rubber bands in various places.

But the turbulence of the outer core can make it hard for researchers like Beggan to predict how it might affect the magnetic field in the future. In the next 10 to 20 years, he said, we might see magnetic north continue toward Siberia, or it could stop moving or go back the other way.

Another theory about why magnetic north has become nomadic is that our magnetic field is undergoing a period of weakening.

That has happened several times in Earth’s history. the latest reversal was 780,000 years ago.

When such swaps are occurring, the magnetic field drops to about 30% of its full strength, Revenaugh said. Magnetic north loses its strength during these times too, according to Beggan, and sometimes disappears completely for a time.

Then about a millennium later, those local poles would reform into one big magnetic north pole as the reversal process progressed. But a full reversal takes so long that people on Earth would be mostly unaffected.

“So you’d never know if you were living through a reversal, really,” Beggan said.

Google Earth is a unique geomapping and tagging program that uses composite imagery to form a comprehensive, interactive map of the Earth. By stitching together more than a billion satellite and aerial images, the application provides a versatile tool that allows individuals and groups to track climate change, discover unknown geographic and ecological features, and record our history.

By collecting and curating enormous amounts of data, Google has made it possible for conservationists to observe the shifting patterns of flora and fauna on a global scale, for governments to observe the growth of cities worldwide, and for individuals to tell their personal stories in a unique way. The underlying technology for Google Earth was originally developed by Intrinsic Graphics, a gaming company that built visual databases.

Launched in 2005, Google Earth was the first widely available, interactive composite map of our world. In 2015, the development team started planning a revamped version that focused on accessibility and availability.

Google Earth features 3D reconstructions, annotation tools and satellite imagery provided by NASA dating back all the way back to 1984, allowing users to virtually travel back in time. As new images become available via satellite and aerial imagery, the map is constantly updated to reflect our ever-changing world.

According to Gopal Shah, Google Earth’s product manager, the development team consists of four to five user experience designers, and around 30 engineers who are mostly focused on improving the app’s ability to send data. “Even if you’re a kid in rural India on a 2G network, we want you to be able to access Google Earth in a meaningful way,” Shah told Live Science.

“When you open Google Earth for the first time, that image is composed of trillions of pixels from NASA satellite photos,” Shah said. “When you see that image, it’s showing you springtime on every area of the planet.

Many areas also have also been rendered in 3D, created from thousands of aerial photos of the same place from different angles. To gather these pictures, a plane flies overhead in a tight pattern, “like mowing a lawn in the sky,” Shah said.

For most people, Google Earth is a novel way to explore cities and landscapes from above, allowing us to view our world within the greater context of itself.How Google Earth is used. “Probably around 99% of first-time users visit their neighborhood first,” Shah said.

[7 Amazing Places to Visit with Google Street View]. Saroo Brierley, an orphan from India who was raised in Australia, was able to reconnect with his birth family after being separated for 25 years, by following geographic markers on Google Earth.

New features have provided conservation groups and researchers with the tools to keep track of our changing world. “One of our new features—Earth Engine—has allowed researchers to visualize global deforestation patterns, map waterway changes, and discover as-yet-unknown areas all over the world,” Shah said.

“Any time you see a major news network zooming in and out of a region to show context, that’s Earth Studio,” Shah said. Allowing people to better understand current events in a geospatial context improves our ability to recognize the issues of our day in a more holistic way.

“A conservation group was able to view illegally fished and overfished areas off the Indonesian coast, and the government there has stepped up enforcement and implemented policy to maintain a healthy coastline.” Another conservation group has also discovered an “uncharted, untouched rainforest atop a plateau in Mozambique,” Shah said.

“If you want to see how coastlines and geographic features change when global temperatures rise, you can do that.”. Educational tools are one of the biggest areas of focus for the Google Earth team right now.

“Voyager can best be described as a magazine for Google Earth,” Shah said. Google has partnered with “Sesame Street,” “Carmen Sandiego” and National Geographic to develop interactive games, tours and stories to help people get a better perspective of our world.

Now, kids are able to be taken on guided cultural tours of different regions across the world, led by that place’s special ‘Sesame Street’ guide.” Additionally, people have been using Voyager to tell their own stories. By annotating areas where their own life events have taken place, individuals are able to record their personal histories, to share with others and preserve for posterity.

The polar regions, also called the frigid zones or polar zones, of Earth are Earth’s polar ice caps, the regions of the planet that surround its geographical poles (the North and South Poles), lying within the polar circles. These high latitudes are dominated by floating sea ice covering much of the Arctic Ocean in the north, and by the Antarctic ice sheet on the continent of Antarctica and the Southern Ocean in the south.

The Arctic has various definitions, including the region north of the Arctic Circle (currently Epoch 2010 at 66°33’44” N), or just the region north of 60° north latitude, or the region from the North Pole south to the timberline. The Antarctic is usually defined simply as south of 60° south latitude, or the continent of Antarctica.

The two polar regions are distinguished from the other two climatic and biometric belts of Earth, a tropics belt near the equator, and two middle latitude regions located between the tropics and polar regions.

The axial tilt of the Earth has the most effect on climate of the polar regions due to its latitude.

Polar regions are characterized by extremely cold temperatures, heavy glaciation wherever there is sufficient precipitation to form permanent ice, short and still cold summers, and extreme variations in daylight hours, with twenty-four hours of daylight in summer, and complete darkness at mid-winter.

There are many settlements in Earth’s north polar region. Countries with claims to Arctic regions are: the United States (Alaska), Canada (Yukon, the Northwest Territories and Nunavut), Denmark (Greenland), Norway, Finland, Sweden, Iceland, and Russia.

As such, the northern polar region is diverse in human settlements and cultures.

McMurdo Station is the largest research station in Antarctica, run by the United States. Other notable stations include Palmer Station and Amundsen–Scott South Pole Station (United States), Esperanza Base and Marambio Base (Argentina), Scott Base (New Zealand), and Vostok Station (Russia).

While there are no indigenous human cultures, there is a complex ecosystem, especially along Antarctica’s coastal zones. Coastal upwelling provides abundant nutrients which feeds krill, a type of marine Crustacea, which in turn feeds a complex of living creatures from penguins to blue whales.

This colorful and intricately detailed map from 1587 is more than nine feet by nine feet when fully assembled. For the last 430 years, its 60 individual sheets were bound together as an atlas, but now they have finally been put together—digitally—to reveal a complete picture of the world as it was understood at the time.

The map is packed with fantastical creatures, from unicorns in Siberia to mermen frollicking in the Southern Ocean and a terrifying bird flying off with an elephant in its talons. The map reflects the geographical knowledge (and misconceptions) of its time, but in some ways it’s surprisingly advanced.

“It’s unique in many ways,” says G. Salim Mohammed, the head and curator of the David Rumsey Map Center at Stanford University, which recently added the map to its collection.

Monte included a portrait of himself at age 43 (left) and later updated it at age 45 by pasting a new portrait over it (right). Little is known about the mapmaker, Urbano Monte.

It was, after all, an exciting age of discovery, writes Katherine Parker, a historian of cartography, in a recent essay about Monte’s map: “Their world was growing each day and Monte wanted to understand all of it.”. Monte appears to have been quite geo-savvy for his day.

Thanks to his connections in high places, Monte met with the first official Japanese delegation to visit Europe when they came to Milan in 1585. Perhaps as a result, his depiction of Japan contains many place names that don’t appear on other Western maps of the time.

Animals roam the land, and his oceans teem with ships and monsters. King Philip II of Spain rides what looks like a floating throne off the coast of South America, a nod to Spanish prominence on the high seas.

A more unusual feature of Monte’s map, however, is the projection—that is, the method he uses to flatten the globe onto a map. Monte’s map is circular, with the North Pole at the center and lines of longitude radiating outward from there—what modern cartographers call a polar azimuthal projection, a very unusual choice for his time.

“I think Monte was really trying to show the circular nature of the Earth,” says David Rumsey, the map collector who bought the map and donated it to the center he founded last year at Stanford. The polar projection has the advantage of accurately portraying the continents of the northern hemisphere.

“Most cartographers thought it had to be massive to counterbalance the large landmasses to the north,” he says—a misguided but influential idea dating back to the ancient Greeks. Rumsey purchased the Monte map in September, and his nephew Brandon did most of the work to scan each page and stitch the images together.

The individual sheets and composite are now online, as is a version of the map aligned with the modern globe in Google Earth: MONTE’S 1587 GLOBE.

Making the new digital version freely available should make it easier for scholars to learn more about Monte and his map. For the rest of us, it’s a chance to explore an extremely rare map that happens to be one of the most spectacular of its time.

For more about David Rumsey and Stanford’s cutting-edge map center, see our post about its opening.

If you’re out exploring British Columbia’s wilderness for fun or for work, GeoBC has just added a useful tool to add to your mobile mapping kit. GeoBC’s topographical maps are now available in a high-resolution electronic format, making it easy to view on mobile devices.

If your mobile is GPS-enabled, the map will pinpoint your location, useful if you are exploring and want to keep track of your movements on the maps. I checked it out on my computer browser and on my iPhone and here is a step-by-step walk through of how it worked:

Go to the GeoBC website’s 1:20K Topographic Maps.

Click on download KMZ on right hand side. 3.

Click on the area where you want a topographical map.

Click on the map link to open the topographical map.

GeoBC has 7,027 maps at the 1:20,000 scale available online, covering every area of B.C.

Google Maps Moon likely uses a Simple Cylindrical projection for storing their map data. This is fine for the majority of the globe, but there are problems at the poles.

The data is prone to discontinuities because it has the entire top or bottom edge of the rectangular projection converging on one point. The poles of the Moon have areas in permanent darkness, and always has a significant portion of the surface in shadow.

Due to high incidence angles with respect to the sun, the lit portions of the surface are not nearly as bright as a sunlit spot on the surface closer to the equator. Furthermore, your non-Google Maps Moon images are likely hillshade, meaning the shading of the landscape is derived from height data (usually based on LIDAR) instead of imagery.

The sun is always very close to the horizon. There are some crater floors at the poles that never see sunlight.

Likewise there are polar plateaus and mountain tops that enjoy nearly constant sunlight. Shadows cast across these plateaus are always long though.

I suspect that might account for the radial burst appearance when they try to patch many polar images together. The strong distortions and star-like stripes are an artifact of Googles’ image processing.

I increased the contrast to make the artifacts more visible – the ice itself just has less contrast than the rocky features of the Moon.

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Coordinates: 85°48′N 176°9′E Location: Arctic Ocean. Also referred to as the Arctic pole of inaccessibility, the northern pole of inaccessibility was initially thought to be located 214km (133mi) from the current position and several expeditions have been made to cross it.

He eventually achieved the feat in 1928.

Herbert was awarded an Arctic bar – added to his previously achieved Polar Medal – and received awards from the Royal Geographical Society as well as other institutions. The problem was he’d gone to the wrong place.

The new coordinates were published in 2013. The northern pole of inaccessibility is located in the Arctic Ocean equidistant from the islands of Ellesmere (Canada), Komsomolets (Russia) and Henrietta (Russia).

Despite renewed attempts to reach the new location, the current northern pole of inaccessibility remains unconquered.

When talking to job candidates, give them the full picture: tell them where they stand in the hiring pipeline, and walk them through the interview process step-by-step. Be candid about the realities of working at your company, sharing both the upsides and the challenges.

Keeping things open, clear, and compliant is key.

You might phrase it like this: “As part of our standard procedure, I have to ask every candidate about their work authorization in the U.S. Are you legally authorized to work in the United States.

” This structure keeps the question concise and underscores the necessity of consistency to uphold non-discriminatory practices.

Then, take the time to deeply explore and identify your core values. This self-awareness is key to leading authentically and effectively.

To keep tech recruits thriving, offer exciting career paths, mentorship, and continuous learning opportunities. Challenge them with diverse projects, support their tech passions, and recognize their achievements.

Do what you say you’ll do. Maintain your commitments and meet deadlines consistently.

Transforming promises into tangible actions reinforces a culture of accountability and high standards.

The Mercator projection (/mərˈkeɪtər/) is a cylindrical map projection presented by Flemish geographer and cartographer Gerardus Mercator in 1569. It became the standard map projection for navigation because it is unique in representing north as up and south as down everywhere while preserving local directions and shapes.

As a side effect, the Mercator projection inflates the size of objects away from the equator. This inflation is very small near the equator but accelerates with increasing latitude to become infinite at the poles.

There is some controversy over the origins of the Mercator. German polymath Erhard Etzlaub engraved miniature “compass maps” (about 10×8 cm) of Europe and parts of Africa that spanned latitudes 0°–67° to allow adjustment of his portable pocket-size sundials.

However, given the geometry of a sundial, these maps may well have been based on the similar central cylindrical projection, a limiting case of the gnomonic projection, which is the basis for a sundial. Snyder amended his assessment to “a similar projection” in 1993.

Joseph Needham, a historian of China, speculated that some star charts of the Chinese Song Dynasty may have been based on the Mercator projection. however, this claim was presented without evidence, and astronomical historian Kazuhiko Miyajima concluded using cartometric analysis that these charts used an equirectangular projection instead.

Portuguese mathematician and cosmographer Pedro Nunes first described the mathematical principle of the loxodrome and its use in marine navigation. In 1537, he proposed constructing a nautical atlas composed of several large-scale sheets in the equirectangular projection as a way to minimize distortion of directions.

In 1569, Gerhard Kremer, known by his trade name Gerardus Mercator, announced a new projection by publishing a large planispheric map measuring 202 by 124 cm (80 by 49 in) and printed in eighteen separate sheets. Mercator titled the map Nova et Aucta Orbis Terrae Descriptio ad Usum Navigantium Emendata: “A new and augmented description of Earth corrected for the use of sailors”.

Mercator never explained the method of construction or how he arrived at it. Various hypotheses have been tendered over the years, but in any case Mercator’s friendship with Pedro Nunes and his access to the loxodromic tables Nunes created likely aided his efforts.

English mathematician Edward Wright published the first accurate tables for constructing the projection in 1599 and, in more detail, in 1610, calling his treatise “Certaine Errors in Navigation”. The first mathematical formulation was publicized around 1645 by a mathematician named Henry Bond (c.

However, the mathematics involved were developed but never published by mathematician Thomas Harriot starting around 1589.

However, it was much ahead of its time, since the old navigational and surveying techniques were not compatible with its use in navigation. Two main problems prevented its immediate application: the impossibility of determining the longitude at sea with adequate accuracy and the fact that magnetic directions, instead of geographical directions, were used in navigation.

Despite those position-finding limitations, the Mercator projection can be found in many world maps in the centuries following Mercator’s first publication. However, it did not begin to dominate world maps until the 19th century, when the problem of position determination had been largely solved.

The criticisms leveled against inappropriate use of the Mercator projection resulted in a flurry of new inventions in the late 19th and early 20th century, often directly touted as alternatives to the Mercator. Due to these pressures, publishers gradually reduced their use of the projection over the course of the 20th century.

Today, the Mercator can be found in marine charts, occasional world maps, and Web mapping services, but commercial atlases have largely abandoned it, and wall maps of the world can be found in many alternative projections. Google Maps, which relied on it since 2005, still uses it for local-area maps but dropped the projection from desktop platforms in 2017 for maps that are zoomed out of local areas.

As in all cylindrical projections, parallels and meridians on the Mercator are straight and perpendicular to each other.

Because the linear scale of a Mercator map increases with latitude, it distorts the size of geographical objects far from the equator and conveys a distorted perception of the overall geometry of the planet. At latitudes greater than 70° north or south the Mercator projection is practically unusable, because the linear scale becomes infinitely large at the poles.

see the transverse Mercator projection for another application).

with the help of a parallel ruler.

Both have extreme distortion far from the equator and cannot show the poles. However, they are different projections and have different properties.

As on all map projections, shapes or sizes are distortions of the true layout of the Earth’s surface.

Because of great land area distortions, critics like George Kellaway and Irving Fisher consider the projection unsuitable for general world maps. Because it shows countries near the Equator as too small when compared to those of Europe and North America, it has been supposed[by whom.

Mercator himself used the equal-area sinusoidal projection to show relative areas. However, despite such criticisms, the Mercator projection was, especially in the late 19th and early 20th centuries, perhaps the most common projection used in world maps.

Atlases largely stopped using the Mercator projection for world maps or for areas distant from the equator in the 1940s, preferring other cylindrical projections, or forms of equal-area projection. The Mercator projection is, however, still commonly used for areas near the equator where distortion is minimal.

Because of its common usage, the Mercator projection has been supposed[by whom. ] to have influenced people’s view of the world.

Arno Peters stirred controversy beginning in 1972 when he proposed what is now usually called the Gall–Peters projection to remedy the problems of the Mercator, claiming it to be his own original work without referencing prior work by cartographers such as Gall’s work from 1855. The projection he promoted is a specific parameterization of the cylindrical equal-area projection.

Practically every marine chart in print is based on the Mercator projection due to its uniquely favorable properties for navigation. It is also commonly used by street map services hosted on the Internet, due to its uniquely favorable properties for local-area maps computed on demand.

Heim Your post this week brought back some old Air Force flying memories. In the late 1950s and early 60s my Squadron flew up the 75th W Longitude to the North Pole.

As a Navigator (well before GPS) this was my favorite mission. The aircraft was headed straight North toward the Pole but passing 80+ degrees N the pilots compass pointed East.

Steering by Gyro, the Navigator wasn’t confused but the pilots were and frequently checked on my health and welfare. 60 years ago the Magnetic North was in Eastern Canada about 300 miles South of the Pole.

Thanks for the flashback. P.S.

Hudson Bay was plotted but some places the shoreline was off by 50 miles. Understandable as the lines of Longitude converge.

Thanks for the feedback. You can find a nice map of that wandering magnetic pole in this Sky Lights post: Comments are closed.

In the competition for Earth’s coldest pole, the South Pole in Antarctica wins. The South Pole is found over icy land, rather than over sea ice, helping to make it colder.

Both the North and South Pole are very cold because they get very little direct sunlight throughout the year. This has to do with where the poles are located on the sphere-shaped Earth.

When you connect the poles with an imaginary line, it is called Earth’s axis. Looking at Earth as it travels, or orbits, around the Sun, the axis is not straight up and down.

This means that sometimes the top of the planet (North Pole) is pointed more at the Sun and sometimes it is pointed away. Earth’s axis does not appear straight up and down, but rather is tilted.

This tilt is the reason for seasons. When the North Pole is pointed toward the Sun, it is summer there.

As Earth travels around the Sun, the poles switch seasons. Earth’s tilted axis creates seasons.

When it is pointing away, there is less sunlight, leading to winter. As the poles are on opposite ends of Earth, they experience opposite timing for the seasons.

At both poles, the Sun is always low on the horizon. This helps keep the poles cold even in the summer when the Sun is up all day.

So the days are just like the nights — cold and dark. Even though the North Pole and South Pole are at opposite ends of the planet, they both get the same amount of sunlight over the year.

What do you see.

The South Pole is a lot colder than the North Pole in both seasons. Why.

Let’s compare. The North Pole sits in the middle of the Arctic Ocean.

A map of Earth while looking down on the North Pole. The white are areas are places normally covered in ice.

There is also land ice over Greenland. Credit: NASA/JPL-Caltech.

That means that the North Pole sits in the middle of sea ice. Since sea ice floats over water, it acts differently than ice over land.

Plus, the temperature of the water below the sea ice changes. These limit how thick the sea ice can grow.

Now we have land surrounded by ocean. A map of Earth while looking down on the South Pole.

Credit: NASA/JPL-Caltech. The continent of Antarctica is dry and high.

This ice sheet forms a huge plateau — a flat surface like a tabletop — that sits high above sea level. Antarctica’s ice and snow also sits on top of mountains that are very tall and rise high above sea level.

This 3D topographical view of Antarctica gives an idea of its high elevations and mountains with ice that covers them. A topographical map shows the elevation and other features of a land surface in greater detail.

Another reason that the South Pole is so much colder than the North Pole is because of the strength of the winds blowing around it. Antarctica is surrounded by water on all sides.

Without land to slow down the winds, they can become very strong. These winds can stop the warmer air from warmer places — north of Antarctica — from mixing with the cold, polar air.

Winds also blow around the North Pole and Arctic, but they are not as strong most of the time. This is because there is land around the Arctic Ocean that can slow down winds as they travel around the Arctic.

This is another reason why the Arctic is warmer. The Arctic may be warmer, but it’s still cold.

And maybe go when it’s summer.

1✉ Laboratory of Synecology, Severtsov Institute of Ecology and Evolution, Russian Academy of Sciences, Moscow 119071, Russia.

Tracing the trends in the faunal composition and ecology of certain larger groups along a latitudinal gradient, up to its northern range limit in polar desert landscapes, is of special interest (Chernov 2002). There are only a few publications where the ”extreme” set of species has been analyzed for higher arthropod taxa (McAlpine 1965.

Makarova 2002a, b. Makarova et al.

Chernov and Makarova 2008. Krasheninnikov and Gavrilo 2014.

Most of the polar desert areas are insular territories situated far from mainland areas (Figure 1A), thus being hardly accessible for researchers. This is why the invertebrate fauna of the Franz Josef Land (FJL) Archipelago, the northernmost in the Old World, has remained scarcely known (Coulson et al.

Figure 1. Location of Franz Josef Land Archipelago (A) and sites where mites were collected in this study (B).

Bulavintsev, A.B. Babenko, A.A.

Krasheninnikov.

The first information on the invertebrates living here came from the Jackson-Harmswoth-Expedition of 1896 and referred to a spider, Erigone psychrophila Thorell, 1871 found on the Northbrook Isl. (Pickard-Cambridge 1898).

Besides the remoteness, the islands became closed to foreigners from the early 1930’s to the beginning of 1990’s (\urlbib{ They were visited by Russian biologists very rarely, mainly as members of military or topographic expeditions. Quite surprising, the next information on terrestrial arthropods was published only in 1983 (Bulavintsev and Babenko 1983).

2014). In 1994, the FJL was declared a wildlife sanctuary and since 2010 it has become part of the ”The Russian Arctic” National Park ( ).

As a result, we have obtained acarological material that originated from seven islands and collected by four researchers during five expeditions (Figure 1B). The objective of this contribution is to discuss the taxonomic composition and geographic distributions of FJL free-living mites, as well as the structure of their assemblages in the Tikhaya Bay (Hooker Island) and Cape Flora (Northbrook Island).

So, in particular, I test here the following hypotheses: (1) the mite diversity of FJL is the smallest among the known High Arctic faunas of the Palaeartic (cf. Makarova 2002a.

2020). (2) the number of Arachnida species is higher than that of Insecta (cf.

Makarova 2002a. Chernov 2004).

Makarova 2015. Makarova et al.

Seeman and Nahrung 2018). The Franz Josef Land is the northernmost archipelago in the Eastern Hemisphere (Figure 1A).

The highest elevations reach 600−700 meters above sea level. Extremely cold conditions are responsible for the 85% glaciation of the territory (Boyarskiy 2013).

The climate of the FJL is classified as Marine Arctic. Landscapes of the archipelago are characterized by an extremely low heat supply with the annual temperature averaging from –10.9 to –12.7 °C (data from four stations) and a very short vegetation season, usually less than 50 days (Boyarskiy 2013).

Mid-July temperatures vary from +0.2 to +1.2 °C (with extremes up to +16 °C), the average temperatures of January-March (March being the coldest month) are between –20 and –24 °C (–50 °С is the absolute minimum). During the whole year, icy events are possible on grounds.

The average annual precipitations vary between 295 and 305 mm (Boyarskiy 2013). The terrestrial vegetation of the FJL is scarce, frost boiled soils often being common on plains and plateaus where the vegetation cover regularly does not exceed 10–50% (Kuliev 2013.

2020). The biota of the islands is very poor, including from 51 species (Matveyeva et al.

2020) of vascular plants, 18 species of nesting birds, and two species of terrestrial mammals (Gavrilo 2013). Yet these are archaic higher taxa (mosses, lichens, algae, nematodes, and collembolans) that maintain their high diversity levels (Matveyeva et al.

Babenko 2018. V.

Elshishka, pers. communication, 11 May 2018).

Chernov and Makarova 2008. Chernov et al.

Matveyeva et al. 2015).

Most of the sampling efforts thus focused on slopes. Permanent slides with microarthropods mounted from numerous samples collected on different FJL islands were obtained from V.I.

Most of the data received from that material were treated earlier and elsewhere (Bulavintsev and Babenko 1983). Even though many of those earlier microscopic slides were in very bad condition (now partly remounted), some mite species could still be reliably identified.

Table 1. Material studied (extracted samples, * − pitfall traps), Franz Josef Land Archipelago, 1981−2016.

Table 2. Free-living mites of the Franz Josef Land, their occurrence in nearest archipelagos, Severnaya Zemlya and Svalbard, and characteristics of their geographic distributions (Makarova 2002a, 2013, with a few additions.

present data). Notes: * (first record of species or genus in the FJL).

(no data). Lg (longitudinal characteristics of distribution): C (cosmopolitan), H (Holarctic), P (Palaearctic), WP (West Palaearctic).

1) (recorded only from the 1981 material). 2) (in the High Arctic, only two Ameronothrus species have been found [Schulte 1975], both recorded from Svalbard [Seniczak et al.

3) (included in accordance with published data [Bulavintsev and Babenko 1983. Krivolutsky and Kalyakin 1993]).

excluded).

Babenko (also IPEE RAS) during the voyage of the Floating University on board of the research vessel ”Professor Molchanov” in July 2015 (Figure 1B, Table 1). The trip was organized by the Northern Arctic Federal University, Arkhangelsk.

In 2016, that material was supplemented by the samples collected by A.A. Semikolennykh (Lomonosov State University, Moscow) for the analysis of the impacts of a bird colony on arctic soils.

Additional mite specimens were obtained from A.B. Krasheninnikov (Perm State University) who collected arthropods on Salm Island and Hooker Island using pitfall traps in the summer of 2016.

Babenko and A.A. Semikolennykh originated from the most favorite sites of the archipelago with the greatest floristic diversity and the richest vegetation, namely, the Tikhaya Bay and Cape Flora (Kuliev 2013.

2015). Both sampling plots were situated on nearly south-faced slopes under the bird colonies enriching the underlying soils.

We roughly distinguished polar desert-like, bog-like and tundra-like communities, as well as bird rookeries. Bird colonies of the FJL belong to the High-Arctic type and are usually dominated by the little auk (Alle alle), with Brünnich′s guillemo.

The Richat Structure also known as the “eye” of the Sahara in Mauritania is a deeply eroded geological structure of exposed layers of sedimentary rock that appear as concentric rings. Because of its shape, some believe it to be the remains of Plato’s Atlantis.

Wondering if this feature like the Richat Structure could be evidence of a previous civilization in this part of the world, Scott discovered an interesting article in the November and December 1903 issue of The American Antiquarian. The article entitled “Elephant Remains in Mexico” begins with the following introduction:

Nicholas Leon, archaeologist of the National Museum of Mexico. The signature would justify the belief that proper investigation of the facts related has been made.

Many massive walls have been found, but they are covered with a mass of deposited earth, sixty feet in thickness. And mingled in this earth are human skeletons, the tusks of elephants, etc., distributed in a way which indicates that the overflow of water and mud was sudden, giving no time for escape.

Leon, who was one of the most respected archaeologists in Mexico at this time, joined the National Museum in Mexico City in 1900 and became head of the Department of Anthropology. The article continues:

We cannot vouch for its accuracy, and simply present the report: Portions of buildings, so far unearthed, show that the city — at least the largest of the cities were covered by the debris of the flood, there being at least three cities destroyed— was very extensive.

According to the estimates of the scientists under whose directions the excavations are now being made, the city in question had a population of at least 50,000. The destruction which was brought by the flood was complete.

Skeletons of the human inhabitants of the cities and of the animals are strewn all through the debris, from a depth of three feet from the surface to a depth of sixty feet, showing that all the debris was deposited almost at once. Measurements show that the debris is on an average, sixty feet-deep where the largest of the cities stood.

Never before in the history of Mexico has it been ascertained positively that elephants were ever in the service of the ancient inhabitants. The remains of the elephants that have been found at Paredon show plainly that the inhabitants of the buried cities made elephants work for them.

Upon many of the tusks that have been found were rings of silver. Most of the tusks encountered so far have an average length, for grown elephants, of three feet, and an average diameter at the roots of six inches.

Several editorial comments follow that leave with reader with some doubt about the credibility of Dr. Leon’s report:

It is true that the tusks and bones of mastodons are frequently found in the swamps of Michigan, Ohio, and Indiana, but they are supposed to belong to the same species which are found in the frozen mud of Siberia and the gravels of the Northwest coast. A species covered with hair and adapted to the cold climate, and quite different from any-that would be found as far south as Mexico.

Other animals, such as the buffalo and bison, have over run portions of this continent, since the days of the mastodon, but none of them reached as far south as Mexico. The discovery of hundreds of mammoth skeletons recovered at an airport construction site north of Mexico City in 2020 suggests the bones unearthed by Dr.

As we saw in the previous article, if we accept the possibility of crustal displacements as a working hypothesis, according to Hapgood’s theory, if the North Pole were in Hudson Bay during the North American ice age, most of the places mammoth remains have been found would have been in the temperate zone relative to the former pole.

The discovery of mammoth remains near Mexico City suggests this region extended into Northern Mexico.

If the elephant remains found by Dr. Leon were those of mammoths, then this portion of his report becomes extremely interesting:

Many massive walls have been found, but they are covered with a mass of deposited earth, sixty feet in thickness. And mingled in this earth are human skeletons, the tusks of elephants, etc., distributed in a way which indicates that the overflow of water and mud was sudden, giving no time for escape.

Where the Richat Structure is an isolated formation in the Sahara, the “eye” of Mexico, exists along with other similar features in a region that lies between the mountains to the west and the coastal plain to the east.

Besides volcanism, domes can also form as the result of a process known as diapirism in which less dense materials rise to the surface, and from horizontal stresses resulting in the formation of a system of basins and domes, a process known as refolding. If a crustal displacement shifted the North Pole from Hudson Bay to the Arctic, the line of maximum displacement would have been only about 1400 miles to the east.

Evidently, Dr. Leon never published a detailed account of his findings in a scientific paper:

D.—about 500 years ago. If any were built earlier, they are in ruins, but no remains of elephants have been discovered among the ruins, in fact no semblance of the elephant has been recognized in the sculpture, except in a few cases, where what resembles an elephant’s trunk, or the trunk of a tapir, is found on the sculptured columns at Copan.

One has to wonder if Dr. Leon’s field notes still exist in some form, in some place, say in the basement of the National Institute of Anthropology and History (INAH) in Mexico City, and if so, do they provide sufficient detail to tell us where his finds are located.

Just look at the path on the sphere. Here it is in Google Earth:

The path on your map is strongly curved because your map uses a projection with lots of distortion. (The distortion grows without bound towards the poles and this path is getting close to the north pole.).

More can be said that is at once useful, informative, and elegant. See whether you agree.

Its salient qualities are that it is. Cylindrical: in particular, meridians are vertical lines on the map,.

Loxodromic: any route of constant bearing (on the earth) is rendered as a straight line segment on the map. These properties make it easy to read some critical information directly off the map.

(These are the bearings measured from the north.) For instance, the path depicted in the question starts in Canada, around 54 degrees latitude, making an angle of about 30 degrees with its meridian. What we also need to know about a point at 54 degrees latitude is that it is closer to the earth’s axis than points along the equator.

(This is essentially the definition of the cosine. It helps to have some familiarity with cosines, so you understand how they behave, but you don’t really need to know any other trigonometry at all.

Well, one more thing: the sine of an angle is the cosine of its complement. E.g., sin(32 degrees) = cos(90-32) = cos(58).).

This lets us invoke Clairaut’s beautiful. Theorem (1743): On a path in any smooth surface of revolution, the product of the distance to the axis with the sine of the bearing is constant if and only if the path is locally geodesic.

How does this help. Well, consider what would happen if the path were to continue approximately straight on the map.

Using Clairaut’s theorem we can solve for the bearing at this latitude: This says that by the time we reach a latitude of 73 degrees, we must be traveling due east.

(Of course I found the value 73 degrees by solving the equation cos(latitude) = cos(latitude) * sin(90) = cos(54) * sin(60). To do this yourself you would have to know that (a) sin(90) = 1 (because sin(90) = cos(90-90) = cos(0) = 1) and (b) most calculators and spreadsheets have a function to solve cosines.

I hope you don’t view this little detail as breaking my earlier promise about no more trig..). After doing a few calculations like this you develop an intuition for what Clairaut’s Theorem is saying.

Because there is a limit on how perpendicular one can get–90 degrees is it. –there is a limit to how close to the axis you can get.

Here are some easy implications of Clairaut’s Theorem. See whether you can prove them all:

All meridians are geodesics. No line of latitude, other than the equator (and the poles, if you want to include them), can be a geodesic.

Loxodromes (aka rhumb lines), which are lines of constant bearing, cannot be geodesics unless they are meridians or the equator. Not even a small part of such a loxodrome can be geodesic.

Point 4 says if you fly from the Canadian Rockies at an initial bearing of 30 degrees east of north, you must appear, relative to north, to be constantly turning (to the right) in order to fly straight. you will never go north of 73 degrees latitude.

Of course the details–73 degrees and Poland and 150 degrees–are obtained only from the quantitative statement of Clairaut’s Theorem: you can’t usually figure out that sort of thing just using your intuitive idea of geodesics. It is noteworthy that all these results hold on a general spheroid (a surface of revolution generated by an ellipse), not just on perfect spheres.

(The sci fi author Larry Niven wrote a novel in which a small artificial torus-shaped world is featured. The link includes an image from the novel’s cover depicting part of this world.).

Just a quick addition:. Also, planes from Asia to US would travel almost over North Pole.

In the other direction they will indeed fly over/close to the poles.

The Mercator projection distorts at the poles more info Tissot’s Indicatrix. So the steepness is more acute in the latter poles.

The explain-it-to-a-5-year-old version: “On a globe, shortest paths are flat, and navigation lines are curvy. Mercator made a map where navigation lines are straight.

It is due to the projection of a 2D plane onto a polorised 2 spheres surface, as the line moves past the poles, it becomes distorted as far as observers of the 2D plane are concerned because the straight line to the destination appears to be a curved ark of a Great Circle, which is a term in mathematics that relates to the greatest circle that can be sliced from a sphere, as long as the circle passes through the center of the sphere.

I think some similar concept Is behind Gravitational forces, but I’m not a physicist so I couldn’t say.

The closer to the Poles a point gets, the less deformed it appears to be when rendered onto a Flat 2D surface, although it still is by a tiny amount. It also depends on the Projection method used, and there are some that are focused on making the quickest route between two points appear to be flat and then round back on the full spherical view.

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The authors gratefully acknowledge Richard Wagener (for the AERONET sun-photometric measurements conducted at Barrow), Ihab Abboud and Vitali Fioletov (for the AERONET sun-photometric measurements conducted at Resolute Bay and Eureka-0PAL), Norm O’ Neill (for the AERONET sun-photometric measurements conducted at Eureka-0PAL), Piotr S.

Stone (for the NOAA/GMD sun-photometric measurements conducted at Barrow and Alert), Stephan Nyeki (for the PMOD/WRC sun-photometric measurements conducted at Summit, in Greenland), Andreas Herber (for the AWI measurements conducted at Ny-Ålesund), Kerstin Stebel (for the NILU/PFR measurements conducted at Ny-Ålesund), Veijo Aaltonen (for the FMI/PFR sun-photometric measurements conducted at Sodankylä), and Sergey M.

Holben and A. Smirnov would like to thank Dr.

Steven Platnick from EOS Project Science Office for their support of AERONET. A.

Manfred Wendisch and Andre Erlich are grateful for the funding provided by the Deutsche Forschungsgemeinschaft (DFG, German Research Foundation) – Project–ID 268020496 – TRR 172.