Off Topic The "That's interesting"/geek thread

What could go Wong?

 

How the next 'supercontinent' will form
Share using Email


Share on Twitter

Share on FacebookShare on Linkedin


(Image credit: Getty Images)

please log in to view this image

4th April 2022

It might seem that the world's landmasses are fixed, but as Richard Fisher discovers, there are major changes coming.
N
Nearly 500 years ago, the Flemish cartographer Geradus Mercator produced one of the world's most important maps.

It certainly wasn't the first attempt at a world atlas, and it was not particularly accurate either: Australia is absent, and the Americas are only roughly drawn. Since then, cartographers have produced ever-more precise versions of this continental arrangement, correcting for Mercator's errors, as well the biases between hemispheres and latitudes created by his projection. But Mercator's map, along with others produced by his 16th-Century contemporaries, revealed a truly global picture of Earth's landmasses – a perspective that has persisted in people's minds ever since.

Story continues below

please log in to view this image

Mercator's original projection from 1569 (Credit: Wikimedia Commons)

What Mercator didn't know is that the continents have not always been arranged this way. He lived around 400 years before the theory of plate tectonics was confirmed.

When looking at the positions of the seven continents on a map, it's easy to assume that they are fixed. For centuries, human beings have fought wars and made peace over their share of these territories, on the assumption that their land – and that of their neighbours – has always been there, and always will be.


ADVERTISEMENT
From the Earth's perspective, however, the continents are leaves drifting across a pond. And human concerns are a raindrop on the leaf's surface. The seven continents were once assembled in a single mass, a supercontinent called Pangaea. And before that, there's evidence for others stretching back over three billion years: Pannotia, Rodinia, Columbia/Nuna, Kenorland and Ur.

Geologists know that supercontinents disperse and assemble in cycles: we're halfway through one now. So, what kind of supercontinent might lie in Earth's future? How will the landmasses as we know them rearrange over the very long-term? It turns out that there are at least four different trajectories that could lie ahead. And they show that Earth's living beings will one day reside on a very different planet, which looks more like an alien world.

You may also like:

• The missing continent that took 375 years to find
• How to turn yourself into a fossil
• How cities will fossilise

For geologist Joao Duarte at the University of Lisbon, the path to exploring Earth's future supercontinents began with an unusual event in the past: an earthquake that struck Portugal one Saturday morning in November 1755. It was among the most powerful quakes of the past 250 years, killing 60,000 people and sending a tsunami across the Atlantic Ocean. What made it particularly odd was its location. "You should not have big earthquakes in the Atlantic," says Duarte. "It was strange."

Earthquakes of this scale usually happen on or near major subduction zones, where oceanic plates plunge beneath the continents and are melted and consumed in the hot mantle. They involve collision and destruction. The 1755 quake, however, happened along a "passive" boundary, where the ocean plate underlying the Atlantic transitions smoothly into the continents of Europe and Africa.

In 2016, Duarte and colleagues proposed a theory for what might be going on: the stitches between these plates could be unravelling, and a major rupture may be looming. "It could be a kind of infectious mechanism," he explains. Or like the glass splintering between two small holes in a car windscreen. If so, a subduction zone could be poised to spread out from the Mediterranean along western Africa and perhaps all the way up past Ireland and the UK, bringing volcanoes, mountain-building and earthquakes to these regions.

Duarte realised that, if this happens, it could lead to the Atlantic eventually closing. And if the Pacific continued to close too – which is already occurring along the subducting "Ring of Fire" circling it – a new supercontinent would eventually form. He called it Aurica, named because the former landmasses of Australia and the Americas would sit at its centre.

It would look like this:

please log in to view this image

Aurica, the supercontinent that could form if the Atlantic and Pacific closed (Credit: Davies et al)

After Duarte published his proposal for Aurica, he wondered about other future scenarios. After all, his was not the only supercontinent trajectory that geologists had proposed.

So, he began chatting with oceanographer Matthias Green at Bangor University in Wales. The pair realised they needed someone with the computational chops to create digital models. "That person had to be someone a little bit special, who didn't mind studying something that will never happen in human timescales," he explains. That turned out to be his colleague Hannah Davies, another geologist at Lisbon University. "My job was to turn drawings and illustrations from past geologists into something that is quantitative, geo-referenced and in a digitised format," explains Davies. The idea was to create models that other scientists could build on and refine.

But it wasn't straightforward. "What we were nervous about is it's an incredibly blue-sky topic. It's not in the same kind of vein as a regular scientific paper," says Davies. "We wanted to say, 'Okay, we understand this much about plate tectonics after 40 years or 50 years. And we understand this much about mantle dynamics, and all of the other components of the system. How far can we take that knowledge into the future?'"

This led to four scenarios. As well as modelling a more detailed picture of Aurica, they explored three other possibilities, each projecting ahead roughly 200-250 million years from now.

The first was what could happen if the status quo continues: the Atlantic stays open and the Pacific closes. In this scenario, the supercontinent that forms will be called Novopangaea. "It is the most simple, and most plausible based on what we understand right now," says Davies.

please log in to view this image

Novopangaea will form if known tectonic activity today continues with no surprises (Credit: Davies et al)

However, there could also be geological events in the future that lead to different arrangements.

One example is a process called "orthoversion" where the Arctic Ocean closes and the Atlantic and Pacific remain open. This changes the dominant orientations of tectonic spreading, and the continents drift northward, all arranging around the North Pole, except Antarctica.

In this scenario, a supercontinent called Amasia forms:

please log in to view this image

If Amasia forms, it'll be because the continents drifted northwards (Credit: Davies et al)

Finally, it's also possible that the seafloor spreading in the Atlantic could slow down. In the middle of the ocean, there's a giant ridge bisecting two plates, running through Iceland all the way down to the Southern Ocean. Here, new lithosphere is forming, feeding out like a conveyor belt. If this spreading slowed or stopped, and if a new subducting plate boundary formed alongside the east coast of the Americas, you'd get a supercontinent called Pangaea Ultima, which looks like an enormous atoll:

please log in to view this image

Pangaea Ultima is still surrounded by a huge ocean, but has a central sea within it (Credit: Davies et al)

These four digital models now mean that geologists have a base to test other theories. For example, the scenarios could help scientists to understand the effects of different supercontinental arrangement on the tides, as well as the climate of the deep future – what would the weather be like on a world with a massive ocean and giant landmass?

To model the climate of a supercontinent, "you cannot use the IPCC [Intergovernmental Panel on Climate Change] models, full stop, because they are not designed to do that", says Duarte. "You cannot change the variables that you need to change."

The models of Earth's future supercontinents can also serve as a proxy for understanding the climate of exoplanets. "The future Earth is completely alien," says Davies. "If you were in orbit above Aurica, or Novopangaea, you probably wouldn't recognise it as Earth, but another planet that had similar colours."

The presence of life and active plate tectonics may well be entwined
This insight led the trio to collaborate with Michael Way, a physicist at the Nasa Goddard Institute for Space Studies. He and his colleagues seek to study climates on alien worlds by modelling the variations of our own over deep time. "We only have so many examples of what a temperate climate can look like. Well, we have one example to be honest: Earth, but we have Earth through time," says Way. "We have the past scenarios, but by moving to the future and using these wonderful tectonic models for the future, it gives us another ensemble to add to our collection."

You need such models because it can be difficult to know what to look for when analysing potentially habitable exoplanets from afar. Ideally you want to know if a planet has a supercontinent cycle, because the presence of life and active plate tectonics may well be entwined. The continental arrangement could also affect the likelihood of liquid water. Through telescopes, you can't see the continents, and the atmospheric composition can only be inferred. So, models of climate variations could reveal some indirect signature that astronomers could detect.

please log in to view this image

What kind of continental arrangement might rocky alien worlds have? (Credit: Getty Images)

Way's modelling of the supercontinent climates – which took months using a supercomputer – revealed some striking variations between the four scenarios. Amasia, for example, would lead to a much chillier planet than the rest. With land concentrated around the North Pole and the oceans less likely to carry warm currents to cooler latitudes, ice sheets would build up. Aurica, by contrast, would be balmier, with a dry core but coasts akin to Brazil's today, with more liquid water.

All this is helpful to know, because if an Earth-like exoplanet has plate tectonics, we won't know which stage of the supercontinent cycle it is currently in, and therefore we will need to know what to look out for to infer its habitability. We shouldn’t assume that the landmasses will be dispersed, mid-cycle, like our own.

As for our own planet's future, Davies acknowledges that the four supercontinent scenarios they have modelled are speculative, and there may be unanticipated geological surprises that change the outcome. "If I had a Tardis to go and see, I wouldn't be surprised if, in 250 million years, the supercontinent didn't look anything like any of these scenarios. There are so many factors involved," she says.

However, what can be said for certain is that the landmasses we take for granted will one day rearrange into an entirely new configuration. Countries once isolated from one another will be close neighbours. And if Earth still hosts intelligent beings, they will be able to travel between the ancient ruins of New York, Beijing, Sydney and London without ever seeing an ocean.

 

Tanis: 'First dinosaur fossil linked to asteroid strike'

please log in to view this image

Jonathan Amos
Science correspondent
@BBCAmoson Twitter
Watch: Sir David Attenborough seeks expert help to understand the significance of the fossil leg
Scientists have presented a stunningly preserved leg of a dinosaur.

The limb, complete with skin, is just one of a series of remarkable finds emerging from the Tanis fossil site in the US State of North Dakota.

But it's not just their exquisite condition that's turning heads - it's what these ancient specimens purport to represent.

The claim is the Tanis creatures were killed and entombed on the actual day a giant asteroid struck Earth.

The day 66 million years ago when the reign of the dinosaurs ended and the rise of mammals began.

Very few dinosaur remains have been found in the rocks that record even the final few thousand years before the impact. To have a specimen from the cataclysm itself would be extraordinary.


The BBC has spent three years filming at Tanis for a show to be broadcast on 15 April, narrated by Sir David Attenborough.

• 'Dinosaur asteroid' wrought springtime devastation
• Dinosaurs suffered catastrophic 'winter'
• Dinosaur asteroid's trajectory was 'perfect storm'

please log in to view this image

Image caption,
Sir David examines the inclusions in the impact spherules that rained down on Tanis
Sir David will review the discoveries, many that will be getting their first public viewing.

Along with that leg, there are fish that breathed in impact debris as it rained down from the sky.

We see a fossil turtle that was skewered by a wooden stake; the remains of small mammals and the burrows they made; skin from a horned triceratops; the embryo of a flying pterosaur inside its egg; and what appears to be a fragment from the asteroid impactor itself.

"We've got so many details with this site that tell us what happened moment by moment, it's almost like watching it play out in the movies. You look at the rock column, you look at the fossils there, and it brings you back to that day," says Robert DePalma, the University of Manchester, UK, graduate student who leads the Tanis dig.

Media caption,
Robert DePalma: "Dinosaurs and the impact are two things that are absolutely linked in our minds"
It's now widely accepted that a roughly 12km-wide space rock hit our planet to cause the last mass extinction.


The impact site has been identified in the Gulf of Mexico, off the Yucatan Peninsula. That's some 3,000km away from Tanis, but such was the energy imparted in the event, its devastation was felt far and wide.

The North Dakota fossil site is a chaotic jumble.

The remains of animals and plants seem to have been rolled together into a sediment dump by waves of river water set in train by unimaginable earth tremors. Aquatic organisms are mixed in with the land-based creatures.

please log in to view this image

The sturgeon and paddlefish in this fossil tangle are key. They have small particles stuck in their gills. These are the spherules of molten rock kicked out from the impact that then fell back across the planet. The fish would have breathed in the particles as they entered the river.

The spherules have been linked chemically and by radiometric dating to the Mexican impact location, and in two of the particles recovered from preserved tree resin there are also tiny inclusions that imply an extra-terrestrial origin.

"When we noticed there were inclusions within these little glass spherules, we chemically analysed them at the Diamond X-ray synchrotron near Oxford," explains Prof Phil Manning, who is Mr DePalma's PhD supervisor at Manchester.


"We were able to pull apart the chemistry and identify the composition of that material. All the evidence, all of the chemical data, from that study suggests strongly that we're looking at a piece of the impactor; of the asteroid that ended it for the dinosaurs."

Media caption,
Watch: Prof Phil Manning shows off a section of rock that records the asteroid strike
The existence of Tanis, and the claims made for it, first emerged in the public sphere in the New Yorker Magazine in 2019. This caused a furore at the time.

Science usually demands the initial presentation of new discoveries is made in the pages of a scholarly journal. A few peer-reviewed papers have now been published, and the dig team promises many more as it works through the meticulous process of extracting, preparing and describing the fossils.

To make its TV programme, the BBC called in outside consultants to examine a number of the finds.

Prof Paul Barrett from London's Natural History Museum looked at the leg. He's an expert in ornithischian (mostly plant-eating) dinosaurs.

"It's a Thescelosaurus. It's from a group that we didn't have any previous record of what its skin looked like, and it shows very conclusively that these animals were very scaly like lizards. They weren't feathered like their meat-eating contemporaries.

"This looks like an animal whose leg has simply been ripped off really quickly. There's no evidence on the leg of disease, there are no obvious pathologies, there's no trace of the leg being scavenged, such as bite marks or bits of it that are missing," he tells me.

"So, the best idea that we have is that this is an animal that died more or less instantaneously."

please log in to view this image

Image caption,
Artwork: The thinking is that a water surge buried all the creatures at Tanis
The big question is whether this dinosaur did actually die on the day the asteroid struck, as a direct result of the ensuing cataclysm. The Tanis team thinks it very likely did, given the limb's position in the dig sediments.

If that is the case, it would be quite the discovery.

But Prof Steve Busatte from Edinburgh University says he's still somewhat sceptical - for the time being.

He's acted as another of the BBC's outside consultants. He wants to see the arguments presented in more peer-reviewed articles, and for some palaeo-scientists with very specific specialisms to go into the site to give their independent assessment.

Prof Busatte says it's possible, for example, that animals that had died before the impact were exhumed by the violence on the day and then re-interred in a way that made their deaths appear concurrent.

"Those fish with the spherules in their gills, they're an absolute calling card for the asteroid. But for some of the other claims - I'd say they have a lot circumstantial evidence that hasn't yet been presented to the jury," he says.

"For some of these discoveries, though, does it even matter if they died on the day or years before? The pterosaur egg with a pterosaur baby inside is super-rare; there's nothing else like it from North America. It doesn't all have to be about the asteroid."

please log in to view this image

Image caption,
A pterosaur embryo is an exceptional find, especially for North America
There's no doubting the pterosaur egg is special.

With modern X-ray technology it's possible to determine the chemistry and properties of the egg shell. It was likely leathery rather than hard, which may indicate the pterosaur mother buried the egg in sand or sediment like a turtle.

It's also possible with X-ray tomography to extract virtually the bones of the pterosaur chick inside, to print them and reconstruct what the animal would have looked like. Mr DePalma has done this.

The baby pterosaur was probably a type of azhdarchid, a group of flying reptiles whose adult wings could reach more than 10m from tip to tip.

Mr DePalma gave a special lecture on the Tanis discoveries to an audience at the US space agency Nasa's Goddard Space Flight Center on Wednesday. He and Prof Manning will also present their latest data to the European Geosciences Union General Assembly in May.

Dinosaurs: The Final Day with Sir David Attenborough will be broadcast on BBC One on 15 April at 18:30 BST. A version has been made for the US science series Nova on the PBS network to be broadcast later in the year.

please log in to view this image

 

James Webb telescope's MIRI instrument goes super-cold

please log in to view this image

Jonathan Amos
Science correspondent
@BBCAmoson Twitter

Published
3 hours ago
Share

please log in to view this image

IMAGE SOURCE,ESA
Image caption,
Conceptual studies on what would become MIRI began in the late 1990s
It is perhaps the very definition of cool. The Mid-Infrared Instrument on the James Webb Space telescope is now at its super-low operating temperature.

The UK-assembled instrument has reached a decidedly chilly -267C, or just six degrees above "absolute zero".

This unimaginably low temperature is not far short of the point where all atoms are supposed to stop jiggling.

MIRI's frigid status will allow the Webb observatory to see the distant Universe in unprecedented detail.

The temperature milestone, confirmed by the US space agency Nasa on Wednesday, was hailed by the instrument's British co-principal investigator, Prof Gillian Wright.

"The cooldown process has been a validation of our thermal design," she told BBC News.

"When you plan these things, you always have contingencies. There are 'what ifs?'; how will you react if this happens or that happens? But it's been done in a single, straight shot. It's a really fantastic achievement."

• A $10bn machine in search of the end of darkness
• 'Fully focused' Webb telescope beats expectations
• Astronomers spot 'most distant galaxy' on record

please log in to view this image

MIRI is one of four instruments on Webb, which is the successor to the venerable Hubble Space Telescope and expected to be no less revolutionary.


ADVERTISEMENT


A key difference, though, is that Webb will be tuned to see the Universe at longer wavelengths, in the infrared.

This means it must be protected from all heat sources, including its own hardware, which would otherwise glow in that same portion of the light spectrum it wants to detect.

To this end, Webb deployed a giant sunshield shortly after it was launched on 25 December.

This tennis court-sized membrane put all the important parts of the telescope in the shade.


Media caption,
Gillian Wright: "The technologies on James Webb took years to develop"
This was enough in the environment of space to passively cool three of the instruments on Webb to their target temperatures of just under -233C, or to use the more scientific temperature scale: 40 kelvin.

But this isn't nearly cold enough for MIRI, which will work with the longest infrared wavelengths in Webb's sensitivity range.

"Our detectors have to be at less than 7K, or they swamp themselves with what we call 'dark current'," said Prof Wright.

"If we're higher than this temperature the inherent motions of the atoms inside the detectors create a charge and that's what they would be measuring above 7K. The optics, or mirrors, inside MIRI need to be less than 12K," the director of the UK Astronomy Technology Centre in Edinburgh explained.

please log in to view this image

Achieving an even colder regime has required an active cooling unit, or cryo-cooler, developed by engineers at Nasa's Jet Propulsion Laboratory in California.

The unit is a network of pumps, valves and piping that drives helium gas at various pressures across the telescope to absorb excess heat inside MIRI and then dump it well away from the instrument.


With the operating temperature now achieved, the MIRI team can get on with preparing for observations.

This involves first ensuring the focusing of Webb's huge, 6.5m-wide mirror works for MIRI just as well as it does for the telescope's other instruments.

Then there is calibration work - confirming MIRI is delivering the data from its camera and spectrographs in a way that's expected and understood.

All this is likely to take a couple of months.

please log in to view this image

IMAGE SOURCE,MPIA
Image caption,
Filter wheel: Mechanisms inside MIRI will need to work for perhaps 20 years
MIRI's camera will eventually give us great vistas of the cosmos, much like Hubble has done; the spectrographs will reveal the chemistry, temperature, density and velocity of many of the objects in view.

James Webb has a number of goals that include searching for the very first stars to shine in the Universe and to study in detail the formation and evolution of galaxies.

MIRI will be involved in all of this.

Among its smart technologies are four coronagraphs. These are small discs placed across the field of view for use in high-contrast imaging. They will permit Webb to block out the glare of a star to study only its orbiting planets.

The coronagraphs are on a wheel of different imaging filters developed by the Max Planck Institute for Astronomy (MPIA) in Heidelberg, Germany.

This mechanism, like the detectors and optics in MIRI, will have to keep working in the super-cold conditions inside the instrument for what could be the next 20 years.

MIRI was produced in a partnership between a European consortium, led from the UK, and Nasa. Components were brought from all over Europe and America to be assembled and tested in the UK before being shipped to the US for integration into the telescope.

Conceptual studies on what would become MIRI began in the late 1990s. It's now almost ready to begin picturing and analysing the Universe.

 

Our Super Massive Black Hole!


Black hole: First picture of Milky Way monster

please log in to view this image

Jonathan Amos
Science correspondent
@BBCAmoson

please log in to view this image

This is the gargantuan black hole that lives at the centre of our galaxy, pictured for the very first time.

Known as Sagittarius A*, the object is a staggering four million times the mass of our Sun.

What you see is a central dark region where the hole resides, circled by the light coming from super-heated gas accelerated by immense gravitational forces.

For scale, the ring is roughly the size of Mercury's orbit around our star.

That's about 60 million km, or 40 million miles, across.

Fortunately, this monster is a long, long way away - some 26,000 light-years in the distance - so there's no possibility of us ever coming to any danger.

The image was produced by an international team called the Event Horizon Telescope (EHT) collaboration.

please log in to view this image

It's their second such image after releasing in 2019 a picture of the giant black hole at the heart of another galaxy called Messier 87, or M87. That object was more than a thousand times bigger at 6.5 billion times the mass of our Sun.

"But this new image is special because it's our supermassive black hole," said Prof Heino Falcke, one of the European pioneers behind the EHT project.

"This is in 'our backyard', and if you want to understand black holes and how they work, this is the one that will tell you because we see it in intricate detail," the German-Dutch scientist from Radboud University Nijmegen told BBC News.

https://www.bbc.co.uk/news/science-environment-61412463

 

Hmmm … “we see it in intricate detail” said Prof Heino Falcke - I think he needs to go to specsavers, that is definitely a fuzzy pic in any book

 

The clearest photo of Mercury ever taken NASA

please log in to view this image

 

Pentaquarks: scientists find new "exotic" configurations of quarks

Scientists have found new ways in which quarks, the tiniest particles known to humankind, group together.

The new structures exist for just a hundred thousandth of a billionth of a billionth of a second but may explain how our Universe is formed.

Atoms contain smaller particles called neutrons and protons, which are made up of three quarks each.

"Exotic" matter discovered in recent years is made up of four and five quarks - tetraquarks and pentaquarks.

Scientists at the Large Hadron Collider in Switzerland have discovered one new pentaquark and two tetraquarks. This takes the total number discovered there to 21. Each is unique, but researchers are excited about the qualities of the three new finds.


https://www.bbc.co.uk/news/science-environment-62027238

 

The ejector seats that fire through the floor




(Image credit: Fred Tanneau/AFP/Getty Images)

please log in to view this image

Lockheed F-104 "Starfighter", the first US jet fighter capable of flying at more than twice the speed of sound. It was at the furthest limits of aircraft design at the time.

After flying to 30,000ft, a malfunction with the ailerons (the hinged back sections of the wing which help a plane turn) caused Simpson's Starfighter to pitch straight down and tumble wildly, high above the ground. Simpson knew he had to get out quickly and pulled the ejector seat handle at 27,000ft (8.1km).

"I can still remember the powerful, full force of rushing air, pinning me to my seat – like going downhill in the front seat of a mile high roller coaster," Simpson recounted to Flight Journal in an interview in 1998. "Only this blast was instantaneous; it hit me at about 450mph (725km/h)."

Simpson's parachute opened safely and he survived the mishap with little more than bumps and bruises. But what's remarkable about his ejection is that he wasn't spat out of the aircraft through the Starfighter cockpit canopy, but through the floor. The young test pilot is one of a handful who successfully escaped a doomed plane on an ejector seat which fired down, not up.

***

As military aviation developed during World War Two, the increasing speed of aircraft had created a dramatic problem – it was much more difficult to escape them if something went wrong.

Older, slower aircraft were much easier for a parachute-equipped pilot to jump out of, but a fighter plane travelling 450mph (724km/h) or more created almost insurmountable problems – the plane would be moving so quickly that a pilot wouldn't have time to clear the tail.

You might also like:

• The rocket-powered rise of the ejector seat
• The other fighter which saved Britain
• The plane too ahead of its time

It was another design by Lockheed – the twin-engined P-38 "Lightning" fighter – which had helped spur the development of the ejector seat during World War Two. The P-38 had a novel design, with the two engines housed in long booms connecting to the tail and a small central section housing the pilot and armament. The two rail rudders at the rear of the plane were connected by a thick horizontal tail plane. This made the P-38 very difficult to escape if it was damaged. The pilot's manual tried to gloss over this with a series of step-by-step guides to successfully exit a damaged P-38, perhaps forgetting that a pilot might be coming under fire at the time.

"The gyrations that a pilot had to do to get out of a P-38 in an emergency situation were almost laughable," says Alex Spencer, a curator at the National Air and Space Museum in Washington DC. "You know, get out, get on the wing, slide down and make sure you're away from the airplane. While the plane's moving around, and you don't know what it's going to do once you get out of it."

please log in to view this image

The F-104’s high tail was a danger to upward-firing seats (Credit: Keystone/Getty Images)

As jet fighters replaced propellor-driven ones, a safe way to escape a plane at high speeds became even more pressing, especially once aircraft broke the speed of sound.

The first ejector seats basically followed a similar pattern – an explosive charge would break the canopy above the pilot, and explosive rockets would launch the seat and pilot clear of the aircraft. In a conventional aircraft design, this worked well. But the early jet age saw a great deal of experimentation and novel design, as engineers had to adapt to new aerodynamic challenges beyond the sound barrier. This led to several early jet designs featuring a "T-tail", with the tail planes placed higher up on the tail fin, which can reduce drag and improve airflow over the tail's moving surfaces. One of the first jet fighters to enter service, the RAF's Gloster Meteor, had just such a configuration. It was also one of the first aircraft to feature an ejector seat, but didn't fly fast enough for its tail to be an issue.

That soon changed.

Testing these seats required live crew, in the absence of sophisticated test dummies
"If you look at the aircraft that had the downward-ejecting seats… the engineers don't have many options for getting the crew out of them," says Spencer. "It's not the ideal situation – at all – but it's probably the only option they had to save the crew in an emergency situation."

In the 1950s, aircraft such as the F-104 and the US Air Force's B-47 bomber tail planes meant designers now had think outside the conventional ejection box. In the B-47's case, the crew of three were housed in two pressurised pods inside the aircraft. The pilot and co-plot ejected normally, but the navigator, housed in the pod much closer to the tail, had to eject downwards.

Testing these seats required live crew, in the absence of sophisticated test dummies. The first aviator to test the downward seat was Colonel Arthur Henderson of the US Air Force in October 1953, who later recounted the historic plunge in a 1955 article for the magazine Popular Mechanics. "'Swish' is the easiest way of describing the sensation of downward ejection from an airplane," he wrote. "There is no jolt, nor is there the sickening feeling one experiences rapidly descending elevators. You're sitting there relaxed and then, instantly, when you fire the seat you're gone. A kaleidoscopic scene of colour unfolds before your eyes. There is no blackout or redout, but merely a few moments of confusion. By the time you can move your head to look at the belt, the seat is gone. You are free-falling through emptiness…"

please log in to view this image

Before engineers were able to fit more powerful seats, the first versions of the F-104 had to have a seat which fired through the cockpit floor (Credit: Lockheed Martin)

Henderson had been strapped into his seat with shoulder harness and seatbelt before take-off. "I could do nothing for about 30 minutes but sit over the open hatch and be with God and my thoughts."

Henderson's first ejection proceeded perfectly, the colonel landing in the water of Chochawtachee Bay in Florida. Later tests – there were seven in all – found that if aircrew held on to the d-ring to fire the seat at speeds higher than 440mph (708km/h), the windspeed caused their arms to flail around, and two suffered arm fractures.

The Starfighter's configuration was especially problematic – in order to reach its maximum speed, the fighter resembled a rocket more than an aircraft. To cut drag, the leading edges of the short, stubby wings and tailplanes were so sharp they could cut paper. Ground crew had to fit protective caps while servicing them to avoid injury. Lockheed decided that a downwards escape route was necessary.

The aircraft suffered so many fatal crashes that crews nicknamed it "Man Eater"
The down-firing seats on the early versions of the B-47 and F-104 had one major problem, however. While they prevented crew colliding with the aircraft tail, they needed a minimum height below the aircraft of at least 500ft (150m). Aircrew would have been aware that the seats were less than ideal for take-off and landing – the times when aircraft accidents are most common. In the F-104's case, upward firing seats became an absolute necessity as from the 1960s, many Nato air forces used it as a low-level fighter – with some training at heights below 100ft (30m).

While most downward-firing seats have been replaced, there is one aircraft that will soldier on with them perhaps until the middle of this century. The US Air Force's Boeing B-52 "Stratofortress" bomber, which first entered service in the 1950s, features downwards-firing seats for the navigator and radar navigator. This is not so much because of the aircraft's tail (the tailplanes are set low down and the B-52 is relatively slow) but because the two crew members sit on a lower deck, beneath the other crew.

In the Soviet Union, the supersonic Tupolev Tu-22 "Blinder" bomber was another design which necessitated downward firing seats, thanks to its two massive engines mounted on the tail. The Tupolev's seats were even more restrictive than the US models, and could not be used lower than 1,000ft (300m). This was particularly sobering for "Blinder" crews because the bomber had dangerously high landing speeds and took great physical effort to control, making it very susceptible to landing accidents. The aircraft suffered so many fatal crashes that crews nicknamed it "Man Eater" – its unconventional ejection seat set-up might have been partly to blame.

please log in to view this image

The Stratojet’s downward-firing seat could only be used if the aircraft was above 1,000ft (300m) (Credit: Museum of Flight/Corbus/ Getty Images)

As ejector seat technology improved, the seats made by the likes of Martin-Baker became more powerful and able to clear aircraft in plenty of time. Downward-firing seats were no longer needed. But there were still incidents where conventional seats failed. One of the most infamous involved Kara Hultgreen, the US Navy's first female fighter pilot. In 1994, Hultgreen's F-14 Tomcat stalled as she was approaching the aircraft carrier USS Abraham Lincoln. The aircraft flipped over just as she ejected, with the seat firing straight into the water. She was killed instantly.

A few years before, the world had been shown a solution to such tragedies. In 1989, Soviet test pilot Anatoly Kvochur carried out a much-anticipated aerial display at the Paris Air Show in a new MiG-29 fighter, still something of a mystery in the West. Towards the end of its display, a bird was sucked into one of its engines, causing it to roll towards the ground. Kvochur stayed with the aircraft as long as possible to ensure it missed the huge crowd. He ejected less than three seconds before the MiG crashed into the ground, with the plane's cockpit pointed downwards toward the ground. Despite landing less than 100ft (30m) from the MiG's burning wreckage, Kvochur suffered little more than a cut from his oxygen mask.

Then when they saw the seat come out and shoot straight up by the rockets changing the thrust vectors, boy that made a huge difference - Alex Spencer
The crash took place in front of TV cameras and even today his safe ejection seems little less than miraculous. His remarkable escape was thanks to a special ejector seat the Soviets had devised for its new fighter planes. Fitted with an auto gyro system, the Zvezda K-36 had a system of rockets which would fire the seat clear of the ground, whichever direction it was pointed.

"And then when it happened, everybody witnessed this autocorrection take place and the pilot survived. At that point they didn't even know the Soviets had this capability," says Spencer.

please log in to view this image

The Tu-22 was one Soviet aircraft which also used downward-firing seats; these may have contributed to its poor reputation among crews (Credit: Wojtek Laski/Getty Images)

"It shocked the crowed when it happened, from the angle the pilot got out of that plane at, with the ejection seats at that time it would have shot him almost straight down into the ground. Then when they saw the seat come out and shoot straight up by the rockets changing the thrust vectors, boy that made a huge difference. Western engineers didn't even know that the Soviets had such technology, and they got to work very quickly to have that on our own seats.

"I would have liked to have been in the meeting room at Martin-Baker the day after, when they figured out how they were going to try and keep up with that."

Martin-Baker's own seats now employ similar technology, and jet pilots no longer have to worry about whether a downward-fitting seat has enough height to operate properly.

Attack helicopters are flying so low that by the time you make the decision to eject and move to take action, you're probably dead anyway – Roger Connor
But spare a thought for helicopter pilots. Though aircraft designers have dreamed of similar escape systems for rotary craft, only two helicopters made by the Russian company Kamov currently carry ejector seats. The Ka-50 and 52 attack helicopters feature explosive bolts which release the rotor blades before the seats fire, thus avoiding any risk of collision.

It's not something US helicopter makers are likely to copy, however, Smithsonian National Air and Space Museum curator Roger Connor tells BBC Future. "Attack helicopters are flying so low that by the time you make the decision to eject and move to take action, you're probably dead anyway, so why add the weight, complexity, vulnerability, cost of an escape system that's almost never likely to be used."

--

 

Awesome

 

hmmm

French scientist apologies after photograph of star turns out to be image of chorizo

please log in to view this image

GB News on YouTube http://bit.ly/3vAYaw0

please log in to view this image

gbnews.uk
French scientist apologies after photograph of star turns out to be image of chorizo
Etienne Klein posted the image on Twitter, but has now claimed it to be a 'prank

 

I took this incredible photo of two black holes mating with my old Polaroid.

please log in to view this image

 

Thought this would be better on the geek thread....

 

It's stuff like this that the oil companies want to bury....governments world wide should be piling into innovations like this is and getting us all to have this put on our roofs (not that I get much sun up here).

 

Or Hamsters.