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New model reveals display of 2,000 year-old mechanical device used by the ancient Greeks to predict astronomical events.
An ancient Greek hand-powered mechanical device for predicting astronomical events has been recreated, offering a fresh understanding of how it worked.
The 2,000-year-old Antikythera Mechanism is considered the world’s first analogue computer, used to forecast positions of the sun, moon and the planets, as well as lunar and solar eclipses.
It was first discovered in a Roman-era shipwreck in 1901 by Greek sponge divers near the Mediterranean island of Antikythera.
Only 82 fragments have survived – about a third of the entire astronomical calculator – leaving researchers baffled about its true form and capabilities.
The back of the mechanism was solved by previous studies but the gearing system at the front has remained a mystery, until now.
Scientists from University College London (UCL) believe they have finally cracked this complex 3D puzzle using computer modelling, pushing research a step closer to understanding the full power of the Antikythera Mechanism and how accurately it was able to predict astronomical events.
Lead author, Professor Tony Freeth, said: “Ours is the first model that conforms to all the physical evidence and matches the descriptions in the scientific inscriptions engraved on the Mechanism itself.
“The sun, moon and planets are displayed in an impressive tour de force of ancient Greek brilliance.”
The largest surviving fragment, called Fragment A, displays features of bearings, pillars and a block. Another, known as Fragment D, shows an unexplained disk, 63-tooth gear and plate.
Inscriptions on the back cover include a description of the cosmos display, with the planets moving on rings and indicated by marker beads, which scientists set out to reconstruct.
Using previous X-ray data and an ancient Greek mathematical method, they were able to explain how the cycles for Venus and Saturn were derived, as well as recovering the cycles of all the other planets, where the evidence was missing.
Their findings were published in the Scientific Reports journal. [Reply]
So, there's actually a pretty significant threat to the modern banana right now. To the point that the extinction of the modern banana is actually a possibility. As I've posted about previously, the modern banana is a completely sterile species. Called triploid hybrids. It has no seeds, and the only way to make new bananas is to cut living pieces of existing bananas. The current Cavendish banana genome strain(technically not the only banana strain) is the only real commercially viable strain of banana right now. It's being decimated by a fungus called TR4. One of the only potential fixes is genetic engineering...
In the British Drama, Years and Years, they imagine the very near future. I do wonder what someone from 2010 would have thought about a tv show accurately depicting 2020. In any case, one of the throw-away lines of the show was that there are no more bananas. The writers did their research – that the Cavendish banana will disappear sometime in the 2020’s is extremely likely. It is being threatened by a fungus called Tropical Race 4 (TR4), which a century ago wiped out the previous commercial dessert banana, the Gros Michel (it’s not extinct, but cannot be grown commercially anymore).
TR4 is now on every continent that grows bananas. It is literally just a matter of time before the entire commercial Cavendish market is wiped out. TR4 and similar funguses also threaten other banana varieties (more like plantains) that provide a staple source of nutrition for large segments of the world (about 400 million people). So this is not just about no longer having access to a favorite dessert fruit – this can create a serious threat to food security in parts of the world.
Part of the problem is that all Cavendish banana plants are clones. The plants are triploid hybrids, which is why they don’t produce seeds. This also makes them sterile. They are reproduced by taking new shoots that grow off the underground bulb (or corm). For this reason the entire Cavendish industry is basically comprised of clones. This is the ultimate monoculture – which leaves them particularly susceptible to disease, such as TR4.
One solution is to do what they did after the Gros Michel crop was lost – cultivate a new banana that is resistant to TR4. But few cultivars have all the traits necessary for a commercial banana. It has to ripen slowly, so it ships well, and has to taste good. Cavendish bananas, apparently, are a pale comparison to their tastier predecessor, and many were concerned they would not be accepted. There are many local varieties of dessert bananas, some are quite tasty (I have tried a few, like apple bananas, which are good). But these varieties don’t ship as well as the Cavendish, which is why they are mostly available locally.
The other solution is to breed or genetically engineer the Cavendish (or the Gros Michel, for that matter) to be highly resistant to TR4. Then we could at least get another century out of the banana, hopefully. A research group in Australia is working on a CRISPR edited version of the Cavendish that is resistant to TR4. Fortunately, nature already has a partial solution – some wild type bananas have a gene, RGA2, that provides resistance to TR4. In fact, the RGA2 gene is already present in the Cavendish, it is just expressed 10% of that of the resistant varieties. So all the scientists have to do is activate the expression of the already present RGA2 genes in the Cavendish. They have done this and are already in field trials, which are showing enhanced resistance.
There is also a gene from a nematode, the Ced9, which confers resistance to TR4. This is not being used by the Australian group, but is another path to resistant bananas. We may end up needing this gene as well at some point.
There is a bit of news in that Del Monte has agreed to fund the Australian group developing the Cavendish with enhanced RGA2. Hopefully this will help bring the resistant banana to market in time to save it. And of course, there are anti-GMO activists who against this banana – for no legitimate reason. They just oppose everything GMO for misguided ideological reasons.
Clearly we are in an arms race against infectious disease. This extends beyond the banana – our entire farming infrastructure is a constant battle with pests and diseases. We need to use a multi-pronged defense, something called “integrated pest management”, for example. We need to maintain output to feed the world, but at the same time adjust our practices to minimize the threat of crop disease. This will be a never-ending battle. Also, we will need every tool we have, including genetic engineering, in order to keep up. Without genetic modification, the banana industry is going away. Other crops are similarly threatened – genetic engineering has already saved the papaya industry in Hawaii. Citrus greening threatens our citrus industries.
I do wonder what this will be like in 50, 100, or 500 years. Can we get into a sustainable loop, where we abandon certain crops for resistant ones, but eventually can return to them once the diseases that were specific to them wane (similar to antibiotic resistance)? Or perhaps we will need to develop farmland on the Moon or Mars, or in orbiting stations, that are entirely sterile except for the crops themselves and beneficial bacteria in the soil – but no pests. They could be run by robots, and entirely sealed off from any possible contamination.
Another benefit to off-worlding our food production is that more of the Earth’s surface can be returned to natural ecosystems. Right now about half of the world’s habitable land is used for agriculture. This is perhaps the biggest negative effect on other species, the loss of habitat due to agriculture. This, of course, is a far future (at least a few centuries) solution, but I do wonder if this will be an ultimate solution.
In the meantime, genetic engineering is probably our best chance to keep one step ahead of the worst pathogens like TR4.
The US Federal Aviation Administration has ordered Boeing 787 operators to switch their aircraft off and on every 51 days to prevent what it called "several potentially catastrophic failure scenarios" – including the crashing of onboard network switches.
The airworthiness directive, due to be enforced from later this month, orders airlines to power-cycle their B787s before the aircraft reaches the specified days of continuous power-on operation.
The power cycling is needed to prevent stale data from populating the aircraft's systems, a problem that has occurred on different 787 systems in the past.
According to the directive itself, if the aircraft is powered on for more than 51 days this can lead to "display of misleading data" to the pilots, with that data including airspeed, attitude, altitude and engine operating indications. On top of all that, the stall warning horn and overspeed horn also stop working.
This alarming-sounding situation comes about because, for reasons the directive did not go into, the 787's common core system (CCS) stops filtering out stale data from key flight control displays. That stale data-monitoring function going down in turn "could lead to undetected or unannunciated loss of common data network (CDN) message age validation, combined with a CDN switch failure".
Solving the problem is simple: power the aircraft down completely before reaching 51 days. It is usual for commercial airliners to spend weeks or more continuously powered on as crews change at airports, or ground power is plugged in overnight while cleaners and maintainers do their thing. [Reply]
A new material made from carbon nanotubes can generate electricity by scavenging energy from its environment.
MIT engineers have discovered a new way of generating electricity using tiny carbon particles that can create a current simply by interacting with liquid surrounding them.
The liquid, an organic solvent, draws electrons out of the particles, generating a current that could be used to drive chemical reactions or to power micro- or nanoscale robots, the researchers say.
“This mechanism is new, and this way of generating energy is completely new,” says Michael Strano, the Carbon P. Dubbs Professor of Chemical Engineering at MIT. “This technology is intriguing because all you have to do is flow a solvent through a bed of these particles. This allows you to do electrochemistry, but with no wires.” [Reply]
Originally Posted by BigRedChief:
Tiny Particles Power Chemical Reactions
A new material made from carbon nanotubes can generate electricity by scavenging energy from its environment.
MIT engineers have discovered a new way of generating electricity using tiny carbon particles that can create a current simply by interacting with liquid surrounding them.
The liquid, an organic solvent, draws electrons out of the particles, generating a current that could be used to drive chemical reactions or to power micro- or nanoscale robots, the researchers say.
“This mechanism is new, and this way of generating energy is completely new,” says Michael Strano, the Carbon P. Dubbs Professor of Chemical Engineering at MIT. “This technology is intriguing because all you have to do is flow a solvent through a bed of these particles. This allows you to do electrochemistry, but with no wires.”
Do you have a source? Trying to figure out what is meant by current with no indication of routing. Current generally connotes movement from one place to another with work usually done en route. And this is unclear where the current if flowing from and to and work can be done with it, with a substance [carbon structure] placed in another medium [solvent]. [Reply]
Originally Posted by Baby Lee:
Do you have a source? Trying to figure out what is meant by current with no indication of routing. Current generally connotes movement from one place to another with work usually done en route. And this is unclear where the current if flowing from and to and work can be done with it, with a substance [carbon structure] placed in another medium [solvent].
