That water clarity is an engineering decision, and the math behind it is wilder than the video.
Roman aqueducts ran on gravity alone. No pumps, no pressure systems. Engineers carved channels with a gradient so shallow it borders on absurd. The Pont du Gard in southern France drops 2.5 centimeters over 275 meters. That's roughly the thickness of a coin over the length of three football fields. They surveyed that accuracy with plumb lines and wooden leveling instruments.
The clarity you're seeing is a direct product of flow velocity. Too steep and the water erodes the channel walls, picks up sediment, turns brown. Too flat and it stagnates. Roman engineers targeted a slope of about 20 centimeters per kilometer, which kept the water moving fast enough to stay fresh but slow enough to stay clear. Before the water reached the city, it passed through multi-chamber settling tanks where velocity dropped near zero. Suspended particles sank. Clean water flowed out the top into the next chamber. Repeat three or four times.
Pliny specified the minimum slope in writing. Vitruvius published the exact mortar ratio for hydraulic cement: one part lime to two parts volcanic ash for underwater work. The pozzolana from Pozzuoli reacted with water to form a calcium-aluminum-silicate compound that actually gets stronger the longer it sits submerged. Modern concrete degrades in water. Roman concrete bonds with it.
Scale the whole system and it gets harder to process. Eleven aqueducts fed Rome at its peak. Combined output: roughly 1 million cubic meters of water per day. That works out to about 250 gallons per person for a city of one million. Modern New York delivers about 125 gallons per person per day. Ancient Rome had access to double the per capita water supply of the largest city in the United States, running entirely on slope and stone.
The Trevi Fountain in Rome is still fed by one of them. Two thousand years, same source, same gravity, same water.
People don’t realize how completely, mind-blowingly absurd this is.
A camera.
On a robot.
On Mars.Built by humans on a blue planet 140 million miles away.
Blasted into space on a roaring rocket.
Lowered gently onto the surface by a freaking sky crane.
Now cruising across an ancient alien desert, grinding over rocks billions of years old, and snapping photos so sharp you can count every pebble and grain of sand.Just 100 years ago, your great-grandparents stared in awe at the first rickety airplanes and called it the greatest miracle of their lifetime.
Mars...
@tokyoXmo@jaredCmitchell I get it. Our daughter will be 6 months old on Friday! Time flies and is an absolute thief. Enjoy the newborn scrunch as long as possible
Bruce Springsteen began his concert in Austin on Sunday night by acknowledging Saturday's assassination attempt at the White House Correspondent's Dinner and offering a "prayer of thanks that our President, nor anyone in the administration, nor anyone attending, was injured."
"We can disagree. We can be critical of those in power, and we can peacefully fight for our beliefs, but there is no place in any way, shape, or form for political violence of any kind in our beloved United States."
📸: Jeff Kravitz/FilmMagic
Germie Bernard can do it ALL on the football field. A Deebo-type player but with better route running & WR traits 👀 Steelers fans y’all got a good one with Mr. Bernard #herewego#nfldraft
How cool is this?! The Wyndham in downtown #Pittsburgh is lit up with graphics for the Draft, and it looks SO much better than what I had in my head! After the event tonight I ran up to Mt. Washington and the West End to capture it, and these are some of my favorites.
Clearest image of Moon ever captured...
You may think moon is colourless but this is what it really looks like in true color.
Its so detailed you can even see individual crater and spots in color.
Every oncologist and cancer researcher should watch this interview with @BenSasse:
https://t.co/PeTl9Eg1g8
Daraxonrasib, a “super poison for cancer,” shrank his metastatic pancreatic tumors by 76%, even though he says his skin feels and looks “nuclear.” When I learned of his diagnosis, I wanted him to get this drug (oral RAS ON inhibitor), which is poised to become first-line therapy in pancreatic cancer. I hope his experience on a clinical trial encourages more patients to enroll in studies, and pushes clinicians and researchers to keep advancing new therapies.
PLANET OF THE APES was released 58 years ago today. Regarded as one of the great science fiction films and a movie with one of the great plot twists, the behind the scenes story is like talking a walk through The Forbidden Zone…
1/50
Well now I’m seething. My son’s laptop is literally splitting open from a swollen battery and Amazon denied my claim because it “matches its description”. IT WAS SOLD WITH AN EXPIRED WARRANTY.
This is a safety hazard and a misrepresented product
@AmazonHelp@amazon@Dell please take a closer look. This is unacceptable.