Dropping stones

“I had always wanted to see if there was a way to test what the crow did in Aesop’s fable,” explains Nathan Emery, University of London.

As the 2000-year-old story goes, the crow filled the bucket of water with stones until the level became high enough for him to quench his thirst.

A number of corvids have been found to use tools in the wild, and New Caledonian crows appear to understand the functional properties of tools and solve complex physical problems via causal and analogical reasoning. A 1980s study tells how a rook plugged a hole in its aviary to allow a pool of water to form.

Emery’s experiment includes four captive rooks, presenting them with clear tubes partly filled with water with a bug floating on top, and piles of stones. The tube contained the larvae of a wax moth–the birds’ favorite food–floating near the bottom, just beyond the reach of the rooks’ beaks.

The researchers then placed a small pile of stones next to the tube; in some of the experiments, these varied in size, so the birds had a choice of using either large or small stones. The amount of water in the tube also varied, requiring that the birds drop between one and seven rocks in order to get the prized worm.

Video footage is astonishing: it shows the rook first assessing the water level by peering at the tube from above and from the side, before picking up and dropping the stones into the water. Within a couple of trials the birds had figured out how many stones they needed to bring the bug within reach.

The experiment is a further demonstration of convergent cognitive evolution between the primate and corvid lineages, with both groups having a generalized understanding of the physical world. The rooks are “clearly combining some sort of understanding of the task with an understanding of the tool and are able to solve the task so quickly.” At the very least, adds Emery, the experiments demonstrate the rooks’ talent for “innovation, because they are adapting their previous experience with stones and tubes [in other experiments] to a new problem.”

Wolfram Alpha, the “computational knowledge engine”, is online. The engine is well worth visiting: tons of information nicely presented altogether. From the same guys that brought Mathematica, this engine is already taunted as an adversary to Google and perhaps Wikipedia: with short, descriptive queries and tons of compiled data.

All in all it’s a big hit, so big their servers couldn’t handle. I got this already:

And some Easter eggs have been found already: when querying “to be or not to be”, it responds “that’s the question”.


Tyre was a fortified city occupying a small island off the coast of today’s Lebanon. The geography made it inexpugnable and, as Wallace Bruce Fleming describes in his The History of Tyre, an enticing prize for many superpowers over history.

Some scholars believe the capture of Tyre during the Alexander Campaign was strategically unnecessary. Tyre had offered surrender, but had refused Alexander the right to sacrifice in the temple of Melqart during the great festival in February, because only a native king could perform the necessary religious ceremonies. According to Lucius Flavius Arrianus, in his Anabasis Alexandrinus,

Thence he advanced towards Tyre; ambassadors from which city, despatched by the commonwealth, met him on the march, announcing that the Tyrians had decided to do whatever he might command. He commended both the city and its ambassadors, and ordered them to return and tell the Tyrians that he wished to enter their city and offer sacrifice to Heracles. The reason of this demand was, that in Tyre there existed a temple of Heracles, the most ancient of all those which are mentioned in history. It was not dedicated to the Argive Heracles, the son of Alcmena; for this Heracles was honoured in Tyre many generations before Cadmus set out from Phoenicia and occupied Thebes […]
To this Tyrian Heracles, Alexander said he wished to offer sacrifice. But when this message was brought to Tyre by the ambassadors, the people passed a decree to obey any other command of Alexander, but not to admit into the city any Persian or Macedonian; thinking that under the existing circumstances, this was the most specious answer, and that it would be the safest course for them to pursue in reference to the issue of the war, which was still uncertain. When the answer from Tyre was brought to Alexander, he sent the ambassadors back in a rage.

No Persian king had ever made such an outrageous demand, yet Alexander had felt insulted and had insisted.

Modern military scholars believe Tyre was a strategic coastal base in the war against the Persians. Under attack, the Tyrians were forced to recall the ships that had been fighting in the Aegean sea. Since the other Phoenician towns had already recalled their ships after the towns had surrendered to the Macedonians, the Persian naval offensive in the Aegean sea came to an end.

In January 332 B.C., Alexander’s siege began with a blockaded Tyre. To reach the Tyrian walls, the Macedonians needed a bridge.

A recent study shows a leeward wave shadow generated by this island, allied with high sediment supply after 1000 B.C. and a slowdown in sea-level rise that began around 4000 B.C., culminated in a natural sand bank varying between 1 to 2 meters below sea level.

Swells around Tyre lead to sand bank formations

Swells around Tyre lead to sand bank formations

The formation would probably have been known to sailors, for whom it might have hindered navigation. Alexander’s engineers cleverly exploited this shallow proto-tombolo, using the sandbar as a foundation for the bridge. To reach the Tyrian walls, the Macedonians built a 70-m-wide, 1-km-long causeway using timber, stone, and debris of the abandoned mainland city, destroyed by Nebuchenazzar 250 years earlier.


Approaching Tyre (Ancient Siege Warfare, Duncan B. Campbell)

But the Tyrians still commanded the sea and made the construction extremely difficult. Alexander needed ships to protect the construction, and he was lucky, because Aradus, Tripolis, Byblus, Beirut and Sidon had just recalled their navies. When it was ready, he brought his siege engines along it to the walls.

The Siege of Tyre (The Department of History, United States Military Academy)

The Siege of Tyre (The Department of History, United States Military Academy)

The citizens now fought desperately, and the Greeks were repeatedly driven back. But after seven months the city was running out of food and, after a seven month siege, the town was attacked from three sides: the Phoenician fleet destroyed the Tyrian fleet in the “Egyptian port”; Macedonian ships attacked the walls with siege engines; and marines from Cyprus landed in the “Sidonian port” and forced their way into the city. Tyre fell.

Alexander was so furious that this one city had halted his progress for so long, that he gave the city over to plunder and his soldiers sacked it without mercy. Macedonians lost 400 men, but 8,000 Tyrians were killed in the fighting, 30,000 were enslaved. Alexander indulged in his anger: he ordered 2,000 Tyrians to be crucified on the beach. The king and a few of his retinue were pardoned:

Alexander gave an amnesty to all those who fled for refuge into the temple of Heracles; among them being most of the Tyrian magistrates, including the king Azemilcus, as well as certain envoys from the Carthaginians, who had come to their mother-city to attend the sacrifice in honour of Heracles, according to an ancient custom. The rest of the prisoners were reduced to slavery; all the Tyrians and mercenary troops, to the number of about 30,000, who had been captured, being sold. Alexander then offered sacrifice to Heracles, and conducted a procession in honour of that deity with all his soldiers fully armed. The ships also took part in this religious procession in honour of Heracles. He moreover held a gymnastic contest in the temple, and celebrated a torch race.

More interesting though, the siege of Tyre had a lasting effect: the mole stayed, silted up, and today Tyre is connected to the mainland. Alexander, in his drive to conquer, permanently changed the face of the land.

Tyre today, from satellite

Tyre in 332BC x Tyre today

After the victory at Tyre, the causeway irreversibly changed the flow patterns in the water surrounding the former island: long-shore currents were interrupted, and at both north and south of this causeway two bays were formed, slowly silting up.

Tyre peninsula formation

Around 7.5 million square feet (700,000 square meters) of new land were created, forming the broad peninsula that can be seen today.

Tyre in 332BC x Tyre today

* * *
Almost 800 years later, during the First Crusade in 1111-12, Tyre would be under siege yet again, this time by King Baldwin I. The fighting, which also included siege towers, was chronicled by Ibn Al-Qalanisi, a contemporary scholar from Damascus.

Former future President of the United States

Former future President of the United States

At a hearing at the Senate Committee on Foreign Relations, Sen. James Risch (R-Idaho) asked Al Gore (minute 150:00 on the video):

“What does your modeling tell you about how long we’re going to be around as a species?”

Be glad for representative democracy.

Moon, as seen by Galileo

Moon, as seen by Galileo

In 1610 Galileo published the astonishing report of his first telescope observations, containing detailed drawings of the moon surface and his discovery of four “planets” orbiting around Jupiter.

Almost three years later he wrote about even more precise observations, including more than a hundred drawings of their relative daily positions. This fantastic animation depicts the relative motions in detail.

The notion that Galileo got in trouble with the Vatican because he supported the Copernican system is an oversimplification. The heliocentrical model wasn’t considered heretic anymore per se; but Galileo used the Copernical model to draw theological conclusions conflicting with Rome’s teachings. In a letter to the Grand Duchess Christina, he actually interpreted a problematical biblical passage in the book of Joshua to conform to a heliocentric cosmology. He was meddling with theology, a space reserved for and guarded by the Vatican.

Moon, as seen by you

Moon, as seen by you

Galileo’s problem was more about the way the approached the situation: arrogant, he collected enemies during his debates with Church scientists, despite having some friends in important places. The most important of them was Maffeo Barberini, former Bishop of Spoleto, who later became Pope Urban VIII.

In 1624, Galileo was assured by Pope Urban VIII that he could write about Copernican theory as long as he treated it as a mathematical proposition. He was fond of Galileo’s wit, but at the same time had to protect Church’s interests.

Dialogue Concerning the Two Chief World Systems

Dialogue Concerning the Two Chief World Systems

With the printing of the Dialogue Concerning the Two Chief World Systems, Galileo was called to Rome in 1633 to face the Inquisition again. It seems the Pope never forgave Galileo for putting the argument of God’s omnipotence (the argument he himelf had put to Galileo in 1623) in the mouth of Simplicio, the staunch Aristotelian whose arguments had been systematically destroyed in the previous 400 pages.

Galileo was found guilty of heresy for his Dialogue, and was sent to his home near Florence where he was to be under house arrest for the remainder of his life. In 1638, the Inquisition allowed Galileo to move to his home in Florence, so that he could be closer to his doctors. By that time he was totally blind. In 1642, Galileo died at his home outside Florence.

Out of Many, One:

Definitely a must-read.

The Edge released the results of its annual World Question Center 2009. 150 contributors, among writers, philosophers, psychologists, biologists, astronomers and physicists, trying to answer this question: “What game-changing scientific ideas and developments do you expect to live to see?”

The results are very interesting. From new teaching-and-learning technologies to scientific breakthroughs, from technological jumps in robotics and AI to green tech advancements, from bright ideas (“a very very good battery”) to dark nuclear clouds. They are all very good.

But my favorite is still the one from Stefano Boeri, architect, teaching at Politecnico of Milan:

“Discovering that someone from the future has already come to visit us.”

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