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Why the Prime Meridian belongs in the Dustbin of Geography
That picture of you at the Royal Observatory astride the Greenwich Meridian? It's a lie.
That picture of you standing astride the stainless steel Meridian Line in Greenwich? It's a lie: You don't really have one foot in either hemisphere. The real Prime Meridian runs 334 feet (102 m) east, cutting an imaginary north-south line through Greenwich Park. It is marked unceremoniously by a dustbin.
Visiting that dustbin is free (for now), but you paid 10 pounds for the privilege of standing on the exact dividing line between East and West. An article in the Journal of Geodesy describes the science behind the discrepancy. But the error has been knowable since the update to the World Geodetic System (used for GPS technology) in 1984, and actively known about since at least 1998, when the question was raised in the House of Lords.
"Whether the (National Maritime Museum, of which the Royal Observatory Greenwich is part) is liable for prosecution under the Trade Descriptions Act 1968 for selling tickets to the general public purporting to record Greenwich Mean Time on the Prime Meridian, when the time printed is Co-ordinated Universal Time (UTC) on a meridian line 102.5 metres (336 ft) west of the point recognised by the IERS (International Earth Rotation and Reference Systems Service) as from 1 January as the official Prime Meridian for the Millennium."
The Royal Observatory makes no effort to disabuse its visitors of the notion that they are visiting the exact location of the Prime Meridian. Stand astride two hemispheres at the home of Time, says its website — next to the Buy tickets button. But if visitors whip out their GPS-enabled smartphones to verify that they're at Zero Longitude, their screens will read 0°0'5.3”W instead. Staff knows what is going on; Dr. Marek Kukula, public astronomer at the Royal Observatory, has even admitted that “a marker in the park would be brilliant to update the story of the Greenwich Meridian into the 21st century.”
The old meridian, passing through the Observatory (dotted line) and the new one, 334 feet to the east in Greenwich Park. (Image: Journal of Geodesy)
Should the Royal Observatory be prosecuted for false advertising? Refunding that tenner we paid to get in would be a good start. Don't hold your breath on either account. But next time we're in Greenwich, you'll find us 334 feet east of the Royal Observatory, visiting the Dustbin of Geography. How did this happen?
Let's start with a word on latitude and longitude. Latitude defines the north-south position of any point on Earth. Lines of constant latitude are called parallels. The one at the Equator is at 0° latitude. On either pole, latitude is not a line but a single point: 90° latitude North or South. Longitude defines the east-west position of a point. Lines of constant longitude are called meridians. Both latitude and longitude are needed to define any point's exact location on Earth; but unlike latitude, which has the Equator and the poles as its obvious extremities, longitude has no "natural" base line.
At the meridian, but not at zero longitude. (Image: Coventry and Warwickshire Astronomical Society)
This is why many countries devised their own meridians. There used to be separate ones for Warsaw, Florence, Antwerp, Tenerife, and many other places. Until 1884, when an International Meridian Conference was called in Washington, D.C., to establish a Prime Meridian "to be employed as a common zero of longitude and standard of time-reckoning throughout the globe."
Greenwich was an obvious candidate, as Britain's maritime empire then still ruled the waves, ensuring that 72 percent of the world's sea commerce already used charts based on Greenwich. Also, the United States had already based its time zone system on Greenwich. Greenwich won by a large margin: 22 votes in favor, 1 against — the French abstained, no doubt miffed that the Paris Meridian didn't make it.
At zero longitude: the world's soon to be most famous dustbin. (Image: Coventry and Warwickshire Astronomical Society)
The conference settled on the so-called Airy Meridian, calculated in 1851 by Sir George Biddell Airy, the seventh Astronomer Royal. That north-south line runs through the Airy Transit Circle, the telescope at the heart of Greenwich Observatory tracking the movement of "clock stars." These are so called because they never rise or set and transit the meridian twice each day, allowing observers to set time and longitude on their appearance in the telescope crosshairs.
The Airy Meridian was in fact already at least the fourth meridian to be calculated at Greenwich. The Halley Meridian (1721), named after the second Astronomer Royal, runs 43 m west of the Airy Meridian. The Bradley Meridian (1850), established by the third Astronomer Royal, runs six m west of Airy's. It was Great Britain's official Prime Meridian in 1801, when the Ordnance Survey published its first map. The OS still uses Bradley's line as its Zero Meridian. The Pond Meridian (1816), calculated by the sixth Astronomer Royal, is essentially the same as Bradley's. There is no exact data on Meridians of Greenwich calculated before 1721, like the one mentioned by John Flamsteed, the first Astronomer Royal.
Of all those various meridians, it was Airy's that became the benchmark for global systems of time and place measurement. It divides the world in eastern and western hemispheres, and defines Greenwich Mean Time (now superseded by UTC) as the basis for global timekeeping. This is where the Third Millennium officially started. Tourists throng to the Meridian Line marker at the Royal Observatory in such numbers that the stainless steel attraction is showing signs of wear and tear. For this is as close to the crossroads of time and space as anyone is ever likely to get.
In all its glory. (Image: Coventry and Warwickshire Astronomical Society)
Where Airy went wrong was using a basin filled with mercury to ensure his telescope was aligned in absolute perpendicularity between the clock stars and the Earth. It would have worked, if the Earth were uniformly round. But it isn't, and the resulting gravitational anomaly affected Airy's measurements.
The error wasn't spotted until satellites using GPS technology were able to make measurements independent of local variations in gravity. The updated system is known as WGS 84 (World Geodetic System 1984) and ITRF (International Terrestrial Reference Frame). Scientists maintain the anomaly is limited to Greenwich, and doesn't affect the complex fabric of space and time built up around it. "Despite the lateral offset of the original and current zero longitude lines at Greenwich, the orientation of the meridian plane used to measure Universal Time has remained essentially unchanged,” the article in the Journal of Geodesy states.
That sounds a little too convenient. Imagine the alternative: a world of property, local, state and international borders assigned to the Dustbin of Geography, 334 feet to the east.
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Certain water beetles can escape from frogs after being consumed.
- A Japanese scientist shows that some beetles can wiggle out of frog's butts after being eaten whole.
- The research suggests the beetle can get out in as little as 7 minutes.
- Most of the beetles swallowed in the experiment survived with no complications after being excreted.
In what is perhaps one of the weirdest experiments ever that comes from the category of "why did anyone need to know this?" scientists have proven that the Regimbartia attenuata beetle can climb out of a frog's butt after being eaten.
The research was carried out by Kobe University ecologist Shinji Sugiura. His team found that the majority of beetles swallowed by black-spotted pond frogs (Pelophylax nigromaculatus) used in their experiment managed to escape about 6 hours after and were perfectly fine.
"Here, I report active escape of the aquatic beetle R. attenuata from the vents of five frog species via the digestive tract," writes Sugiura in a new paper, adding "although adult beetles were easily eaten by frogs, 90 percent of swallowed beetles were excreted within six hours after being eaten and, surprisingly, were still alive."
One bug even got out in as little as 7 minutes.
Sugiura also tried putting wax on the legs of some of the beetles, preventing them from moving. These ones were not able to make it out alive, taking from 38 to 150 hours to be digested.
Naturally, as anyone would upon encountering such a story, you're wondering where's the video. Thankfully, the scientists recorded the proceedings:
The Regimbartia attenuata beetle can be found in the tropics, especially as pests in fish hatcheries. It's not the only kind of creature that can survive being swallowed. A recent study showed that snake eels are able to burrow out of the stomachs of fish using their sharp tails, only to become stuck, die, and be mummified in the gut cavity. Scientists are calling the beetle's ability the first documented "active prey escape." Usually, such travelers through the digestive tract have particular adaptations that make it possible for them to withstand extreme pH and lack of oxygen. The researchers think the beetle's trick is in inducing the frog to open a so-called "vent" controlled by the sphincter muscle.
"Individuals were always excreted head first from the frog vent, suggesting that R. attenuata stimulates the hind gut, urging the frog to defecate," explains Sugiura.
For more information, check out the study published in Current Biology.
The design of a classic video game yields insights on how to address global poverty.
Poverty can be a self-sustaining cycle that might require an external influence to break it. A new paper published in Nature Sustainability and written by professor Andrew Bell of Boston University suggests that we could improve global anti-poverty and economic development systems by turning to an idea in a video game about a race car-driving Italian plumber.
A primer on Mario Kart
For those who have not played it, Mario Kart is a racing game starring Super Mario and other characters from the video game franchise that bears his name. Players race around tracks collecting power-ups that can directly help them, such as mushrooms that speed up their karts, or slow down other players, such as heat-seeking turtle shells that momentarily crash other karts.
The game is well known for having a mechanism known as "rubber-banding." Racers in the front of the pack get wimpy power-ups, like banana peels to slip up other karts, while those toward the back get stronger ones, like golden mushrooms that provide extra long speed boosts. The effect of this is that those in the back are pushed towards the center, and those in front don't get any boosts that would make catching them impossible.
If you're in last, you might get the help you need to make a last-minute break for the lead. If you're in first, you have to be on the lookout for these breakouts (and the ever-dreaded blue shells). The game remains competitive and fun.
Rubber-banding: A moral and economic lesson from Mario Kart
In the real world, we see rubber-banding used all the time. Welfare systems tend to provide more aid to those who need it than those who do not. Many of them are financed by progressive taxation, which is heavier on the well-off than the down-and-out. Some research suggests that these do work, as countries with lower levels of income inequality have higher social mobility levels.
It is a little more difficult to use rubber-banding in real life than in a video game, of course. While in the game, it is easy to decide who is doing well and who is not, things can be a little more muddled in reality. Furthermore, while those in a racing game are necessarily antagonistic to each other, real systems often strive to improve conditions for everybody or to reach common goals.
As Bell points out, rubber-banding can also be used to encourage sustainable, growth programs that help the poor other than welfare. They point out projects such as irrigation systems in Pakistan or Payments for Ecosystems Services (PES) schemes in Malawi, which utilize positive feedback loops to both provide aid to the poor and promote stable systems that benefit everyone.
Rubber-banding feedback loops in different systems. Mario Kart (a), irrigation systems in Pakistan (b), and PES operations in Malawi (c) are shown. Links between one better-off (blue) and one worse-off (red) individual are highlighted. Feedback in Mario Kart (a), designed to balance the racers, imprAndrew Bell/ Nature Sustainability
In the Malawi case, farmers were paid to practice conservation agriculture to reduce the amount of sediment from their farms flowing into a river. This immediately benefits hydroelectric producers and their customers but also provides real benefits to farmers in the long run as their soil doesn't erode. By providing an incentive to the farmers to conserve the soil, a virtuous cycle of conservation, soil improvement, and improved yields can begin.
While this loop differs from the rubber-banding in Mario, the game's approach can help illustrate the benefits of rubber-banding in achieving a more equitable world.
The task now, as Bell says in his paper, is to look at problems that exist and find out "what the golden mushroom might be."
Satellite imagery can help better predict volcanic eruptions by monitoring changes in surface temperature near volcanoes.
- A recent study used data collected by NASA satellites to conduct a statistical analysis of surface temperatures near volcanoes that erupted from 2002 to 2019.
- The results showed that surface temperatures near volcanoes gradually increased in the months and years prior to eruptions.
- The method was able to detect potential eruptions that were not anticipated by other volcano monitoring methods, such as eruptions in Japan in 2014 and Chile in 2015.
How can modern technology help warn us of impending volcanic eruptions?
One promising answer may lie in satellite imagery. In a recent study published in Nature Geoscience, researchers used infrared data collected by NASA satellites to study the conditions near volcanoes in the months and years before they erupted.
The results revealed a pattern: Prior to eruptions, an unusually large amount of heat had been escaping through soil near volcanoes. This diffusion of subterranean heat — which is a byproduct of "large-scale thermal unrest" — could potentially represent a warning sign of future eruptions.
Conceptual model of large-scale thermal unrestCredit: Girona et al.
For the study, the researchers conducted a statistical analysis of changes in surface temperature near volcanoes, using data collected over 16.5 years by NASA's Terra and Aqua satellites. The results showed that eruptions tended to occur around the time when surface temperatures near the volcanoes peaked.
Eruptions were preceded by "subtle but significant long-term (years), large-scale (tens of square kilometres) increases in their radiant heat flux (up to ~1 °C in median radiant temperature)," the researchers wrote. After eruptions, surface temperatures reliably decreased, though the cool-down period took longer for bigger eruptions.
"Volcanoes can experience thermal unrest for several years before eruption," the researchers wrote. "This thermal unrest is dominated by a large-scale phenomenon operating over extensive areas of volcanic edifices, can be an early indicator of volcanic reactivation, can increase prior to different types of eruption and can be tracked through a statistical analysis of little-processed (that is, radiance or radiant temperature) satellite-based remote sensing data with high temporal resolution."
Temporal variations of target volcanoesCredit: Girona et al.
Although using satellites to monitor thermal unrest wouldn't enable scientists to make hyper-specific eruption predictions (like predicting the exact day), it could significantly improve prediction efforts. Seismologists and volcanologists currently use a range of techniques to forecast eruptions, including monitoring for gas emissions, ground deformation, and changes to nearby water channels, to name a few.
Still, none of these techniques have proven completely reliable, both because of the science and the practical barriers (e.g. funding) standing in the way of large-scale monitoring. In 2014, for example, Japan's Mount Ontake suddenly erupted, killing 63 people. It was the nation's deadliest eruption in nearly a century.
In the study, the researchers found that surface temperatures near Mount Ontake had been increasing in the two years prior to the eruption. To date, no other monitoring method has detected "well-defined" warning signs for the 2014 disaster, the researchers noted.
The researchers hope satellite-based infrared monitoring techniques, combined with existing methods, can improve prediction efforts for volcanic eruptions. Volcanic eruptions have killed about 2,000 people since 2000.
"Our findings can open new horizons to better constrain magma–hydrothermal interaction processes, especially when integrated with other datasets, allowing us to explore the thermal budget of volcanoes and anticipate eruptions that are very difficult to forecast through other geophysical/geochemical methods."