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Ancient computer found in shipwreck decoded by scientists
A new model of the Antikythera mechanism reveals a "creation of genius."
Today, if you want to know when the next solar eclipse is going to be, you turn to Google. If you lived in ancient Greece, though, you might have used a device now known as the Antikythera mechanism.
Considered the world's first analog computer, this marvel of ancient engineering used dozens of bronze gears to predict the positions of the Moon, Sun, and five planets, as well as the timing of solar and lunar eclipses.
Divers discovered the Antikythera mechanism while exploring a Roman-era shipwreck in 1901, but the ancient computer was in far from pristine condition—only about a third of it had survived the 2,000 years underwater.
Researchers have been trying to understand how the Antikythera mechanism worked ever since—and now, a team from University College London (UCL) may have finally cracked its code.
The Antikythera mechanism
Here's what we knew about the Antikythera mechanism prior to this study.
It had at least 30 gears, housed in a wooden case about the size of a shoebox. On the front of the case was a large circular face with hands, similar to a clock. On its side was some sort of handle or knob that could be used to wind the ancient computer.
The device was found in one big chunk that was later broken into 82 fragments. In 2005, researchers took CT scans of the fragments, revealing text that hadn't been read since before the device landed itself at the bottom of the Aegean Sea.
Using that text—and a Greek philosopher's math theory—the UCL team created a computer model of the part of the Antikythera mechanism that depicts the cycles of the Sun, Moon, and planets.
"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," researcher Tony Freeth said in a press release.
"The Sun, Moon, and planets are displayed in an impressive tour de force of ancient Greek brilliance."
Piecing it together
To create this new model, the UCL team focused on two numbers on the front of the Antikythera mechanism: 462 and 442.
"The classic astronomy of the first millennium BC originated in Babylon," researcher Aris Dacanalis said, "but nothing in this astronomy suggested how the ancient Greeks found the highly accurate 462-year cycle for Venus and 442-year cycle for Saturn."
Re-creating the cycles of those planets (and others) using this one device was further complicated by the fact that the ancient Greeks assumed the Earth—and not the sun—was at the center of the solar system.
The largest surviving piece of the Antikythera mechanism.Credit: National Archaeological Museum, Athens
Using a mathematical method described by ancient Greek philosopher Parmenides as their guide, the UCL team devised an arrangement for the Antikythera mechanism's gears that would cause it to display the correct information about the planets' cycles.
Their solution also minimizes the number of gears needed for the computer to work, ensuring that they'd all be able to fit within the confines of its wooden case.
"Solving this complex 3D puzzle reveals a creation of genius—combining cycles from Babylonian astronomy, mathematics from Plato's Academy, and ancient Greek astronomical theories," the authors wrote in their study.
UCL's computer model of the Antikythera Mechanism.Credit: Tony Freeth
Re-creating an ancient computer
The researchers are confident that their re-creation of the Antikythera mechanism works in theory—but whether the ancient Greeks could have actually constructed the device isn't so certain.
"The concentric tubes at the core of the planetarium are where my faith in Greek tech falters, and where the model might also falter," researcher Adam Wojcik told The Guardian. "Lathes would be the way today, but we can't assume they had those for metal."
The researchers now plan to prove their model's feasibility by attempting to re-create it using ancient techniques.
Even if they're successful, though, other questions about the Antikythera mechanism will remain, including who made it, what did they use it for, and are there others still waiting to be discovered?
The idea of 'absolute time' is an illusion. Physics and subjective experience reveal why.
- Since Einstein posited his theory of general relativity, we've understood that gravity has the power to warp space and time.
- This "time dilation" effect occurs even at small levels.
- Outside of physics, we experience distortions in how we perceive time — sometimes to a startling extent.
Physics without time<p>In his book "The Order of Time," Italian theoretical physicist Carlo Rovelli suggests that our perception of time — our sense that time is forever flowing forward — could be a highly subjective projection. After all, when you look at reality on the smallest scale (using equations of quantum gravity, at least), time vanishes.</p><p style="margin-left: 20px;">"If I observe the microscopic state of things," writes Rovelli, "then the difference between past and future vanishes … in the elementary grammar of things, there is no distinction between 'cause' and 'effect.'"</p><p>So, why do we perceive time as flowing <em>forward</em>? Rovelli notes that, although time disappears on extremely small scales, we still obviously perceive events occur sequentially in reality. In other words, we observe entropy: Order changing into disorder; an egg cracking and getting scrambled.</p><p>Rovelli says key aspects of time are described by the second law of thermodynamics, which states that heat always passes from hot to cold. This is a one-way street. For example, an ice cube melts into a hot cup of tea, never the reverse. Rovelli suggests a similar phenomenon might explain why we're only able to perceive the past and not the future.</p><p style="margin-left: 20px;">"Any time the future is definitely distinguishable from the past, there is something like heat involved," Rovelli wrote for the <a href="https://www.ft.com/content/ce6ef7b8-429a-11e8-93cf-67ac3a6482fd" target="_blank"><em>Financial Times</em></a>. "Thermodynamics traces the direction of time to something called the 'low entropy of the past', a still mysterious phenomenon on which discussions rage."</p>
The strange subjectivity of time<p>Time moves differently atop a mountain than it does on a beach. But you don't need to travel any distance at all to experience strange distortions in your perception of time. In moments of life-or-death fear, for example, your brain would release large amounts of adrenaline, which would speed up your internal clock, causing you to perceive the outside world as moving slowly.<br></p><p>Another common distortion occurs when we focus our attention in particular ways.</p><p style="margin-left: 20px;">"If you're thinking about how time is <em>currently</em> passing by, the biggest factor influencing your time perception is attention," Aaron Sackett, associate professor of marketing at the University of St. Thomas, told <em><a href="https://gizmodo.com/why-does-time-slow-down-and-speed-up-1840133782" target="_blank">Gizmodo</a></em>.<em> "</em>The more attention you give to the passage of time, the slower it tends to go. As you become distracted from time's passing—perhaps by something interesting happening nearby, or a good daydreaming session—you're more likely to lose track of time, giving you the feeling that it's slipping by more quickly than before. "Time flies when you're having fun," they say, but really, it's more like "time flies when you're thinking about other things." That's why time will also often fly by when you're definitely <em>not</em> having fun—like when you're having a heated argument or are terrified about an upcoming presentation."</p><p>One of the most mysterious ways people experience time-perception distortions is through psychedelic drugs. In an interview with <a href="https://www.theguardian.com/books/2018/apr/14/carlo-rovelli-exploding-commonsense-notions-order-of-time-interview" target="_blank"><em>The Guardian</em></a>, Rovelli described a time he experimented with LSD.</p><p style="margin-left: 20px;">"It was an extraordinarily strong experience that touched me also intellectually," he said. "Among the strange phenomena was the sense of time stopping. Things were happening in my mind but the clock was not going ahead; the flow of time was not passing any more. It was a total subversion of the structure of reality."<br></p><p>It seems few scientists or philosophers believe time is completely an illusion.</p><p style="margin-left: 20px;">"What we call <em>time</em> is a rich, stratified concept; it has many layers," Rovelli told <em><a href="https://physicstoday.scitation.org/do/10.1063/PT.6.4.20190219a/full/" target="_blank">Physics Today</a>.</em> "Some of time's layers apply only at limited scales within limited domains. This does not make them illusions."</p>What <em>is</em> an illusion is the idea that time flows at an absolute rate. The river of time might be flowing forever forward, but it moves at different speeds, between people, and even within your own mind.
The world's 10 most affected countries are spending up to 59% of their GDP on the effects of violence.
- Conflict and violence cost the world more than $14 trillion a year.
- That's the equivalent of $5 a day for every person on the planet.
- Research shows that peace brings prosperity, lower inflation and more jobs.
- Just a 2% reduction in conflict would free up as much money as the global aid budget.
- Report urges governments to improve peacefulness, especially amid COVID-19.
The lush biodiversity of South America's rainforests is rooted in one of the most cataclysmic events that ever struck Earth.
- One especially mysterious thing about the asteroid impact, which killed the dinosaurs, is how it transformed Earth's tropical rainforests.
- A recent study analyzed ancient fossils collected in modern-day Colombia to determine how tropical rainforests changed after the bolide impact.
- The results highlight how nature is able to recover from cataclysmic events, though it may take millions of years.