Popular-Science Magazine for Students and Their Parents
#3 2017 JUNE
oyla-science.com
IN E V I TABLE ANIMATED COVER
FUTURE
FAQ MATH
Why were
logarithms invented?
p. 4
MEGAPROJECT
What’s connection between the Statue of Liberty and the Suez Canal? p. 12
CULTURE
Why did ancient people need art? p. 18
BIOLOGY
How did birds help How do animals survive the rapid changes in our world? the creators of “Lord of the Rings” p. 22 save money? p. 28 What is the sum of all numbers from 1 to 100? Read the story about a boy who earned the title of King of Mathematics p. 9
SCI-FI
Top 5 movies about the future: what has come true? What else is waiting for us down the road? p. 54
ANTHROPOLOGY
p. 58
PHYSICS
Serious science. It’s time to figure out what a black
hole is.
The construction of the Sydney Opera House should have taken 4 years and 7 million AUD. Instead, it took 14 years and $102 million. What is wrong with our predictions
of the future? p. 66 TECHNOLOGY
Ask your parents about their first cell phone. Why won’t your children ask you this question? p. 48
CHEMISTRY
How will people look in a thousand years? Let’s consider the possibilities. p. 36
Bizzare creature that kills palm trees p. 34 MEGAPIXEL
How is oil refined, and what for? p. 76
DOING BUSINESS
How this young guy revolutionized the
computer industry p. 70
7.62, 5.45 and 5.56. Why have these numbers become death sentences for millions of people? p. 84
ECONOMICS
Who wants to be a millionaire? There’s a fast and very risky way. p. 90
Red Palm Weevil Rhynchophorous ferrugineus, or, more commonly, the palm weevil, is one of two species of snout beetle. The beetles are typically between 2–4 centimeters in length and a dark red in colour (the “ferrugineus” part of the biological name literally means “rust-coloured”). Alternative names include the red palm weevil, the Asian palm weevil, and the sago palm weevil. The
2x magnification
insects are a widely known pest in coconut, date, and oil palm plantations around the world, because their larvae bore into the trunks of palm trees. The resulting holes, which can be up to one metre in length, damage the living tissue housed within the trunk of the tree, which causes the crown of palm leaves to wilt. In time, the infestation kills the host plant.
M EG A PI XEL
60x
magnification
YO U S E F A L H A B S H I
PH Y SIC S
Black holes were first discovered… on a piece of paper on which a priest was trying to define the parameters of a star which would be so ‘heavy’ that light would not be able to escape it.
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The apple of knowledge Newton’s Law of Universal Gravitation (LUG) became the cornerstone of classical physics. The law’s simplicity is truly ingenious: to calculate the force with which two point masses are attracted to one another, you only need to know their masses and the distance between them.
F=G
m 1m 2 R2
Although it may be simple, the law of gravitation is far from trivial. It can be used to describe very complex interactions. Here is the simplest example: two unsupported bodies are attracted to each other and begin to be drawn together. What will happen next? The distance between them will shrink, which means that the attractive power will grow until they collide into each other. Considering that point masses are very rarely found in nature, the law of gravitation ceases to be simple. Just look at tides caused by the difference between the forces with which the moon attracts water on the poles and on the equator. Here, “points” — that is, objects without length, width and height — will not be enough. In spite of the fact that LUG describes the interaction of objects quite precisely, the law tells us nothing about the cause of this interaction. As physicists say, LUG is strictly descriptive. However, you should not be too upset by this. Most of school physics operates with theoretical laws without taking a deeper look at things. That was also the case with LUG in the history of physics: the true nature of this law was only understood long after its discovery.
PHYSICS
A relay race of geniuses It took three centuries and a whole constellation of geniuses (Riemann, Laplace, Lagrange, Poincaré, Lorentz, Einstein, and others) to unlock the secrets of universal gravitation. Many fundamental and self-evident concepts had to be revisited for this purpose. And at the forefront (second to Newton, of course) was John Michell, a clergyman in the small community of Thornhill in West Yorkshire. It was John Michell who wrote a letter in 1783 and sent it to the Royal Society of London for Improving Natural Knowledge. For some reason, this message was found only two centuries later, in 1984. The content of the letter was surprising, as it concerned black holes. However, Michell called them “dark stars,” and had no idea of either the theory of relativity or the dual nature of light. He had only the law of universal gravitation and a brilliant mind at his disposal. What was this remarkable scientist’s reasoning? We will try to reconstruct his train of thought, along with that of the famous Marquis de Laplace, who independently obtained similar results.
The first cosmic velocity (7.9 km/s) is the minimum speed that must be given to the object in order to bring it into geocentric orbit. In other words, this is the speed at which objects will move horizontally above the surface of the planet without falling on it.
Michell’s “dark star” The particle is located in the Newtonian gravitational field; in addition, it has an initial velocity (kinetic energy). According to Michell’s conditions, this whole system is in a state of equilibrium, hence, it is possible to apply the law of conservation of energy:
-
GMm r
+
mv 2
2
=0
which suggests that
v = 2
2GM r
If we suppose that the particle’s velocity is equal to the velocity of light (v = c), the radius r will be equal to:
rg =
2GM c2
Suppose we have a cannon which fires vertically (today we have such weapons, known as anti-aircraft guns). What height could the cannonball reach? Obviously, the height depends on the cannonball’s initial velocity, as well as the Earth’s mass and radius (as it is these parameters that determine the acceleration of gravity). It is possible to come to a similar conclusion independently (which, by the way, is not a bad intellectual exercise). Could the cannon ball fly away entirely and never come back to Earth? It is certainly possible at a certain velocity, which is also confirmed by the calculations carried out by Michell. This velocity, called escape velocity (previously known as the second cosmic velocity), depends only on the mass and radius of the Earth. That’s nice, but that’s it: many other scientists came to similar conclusions. But Michell took another step, which is a testament to his prodigious intellect. He inverted the task, asking: what parameters would not allow the light of the sun or any other star to escape from the gravity of the source?
At the speed of 11.2 km/s an object can leave the Earth’s orbit, which is called the second cosmic velocity or escape velocity. If the speed of the object reaches the third cosmic velocity (16,650 km/s), then it can escape the solar system.
Once escape velocity is achieved, no further impulse must be applied for it to continue in its escape. In other words, given escape velocity, the object will move away from the other body, continually slowing, and will asymptotically approach zero speed as the object’s distance approaches infinity, never to return.
Any object that is within the gravitational radius of a “dark star” must fall on it. Even light is no exception.
According to the general theory of relativity, spacetime near massive bodies is curved. This is clearly illustrated by experiments with a stretched fabric and two massive balls: the consequence of this curvature is their mutual attraction.
It’s hard not to wonder whether the parishioners listening to Michell’s Sunday sermons knew how far ahead of his time he was! And what an enormous contribution might have been made to science if the Reverend Father had chosen another path… We can only ever imagine. John Michell proposed that “dark stars” are almost certainly part of double or triple star systems, forcing their visible neighbours to move in “incorrect” orbits. It is a very reasonable speculation, which is still relevant today.
The geometry of gravity
Dark stars The answer came in the form of the gravitational radius (also known as the Schwarzschild radius), directly proportional to mass of the star and inversely proportional to the square of the velocity of the “escaping” object, whether a stone, cannon ball, satellite or particle of light (the mass of the object is not important). In the case of light, we get a “dark star,” an improbable object tightly “pent-up” in its gravitational field. Laplace, coming to the same conclusion, later wrote, “The gravitation attraction of a star with a diameter 250 times that of the sun and comparable in density to the earth would be so great no light could escape from its surface. The largest bodies in the universe may thus be invisible by reason of their magnitude.”
Unfortunately, dark stars were forgotten for a whole century, dismissed as theoretical curiosities. Besides, the 19th century was an age of the triumph of the wave theory of light, which did not regard gravitation as influencing factor. Moreover, many venerable physicists spoke at the end of the century about the ‘end of science’ altogether: they said that everything had already been discovered and there remained only minor rough patches to be smoothed out, such as confirming the postulated luminiferous aether and working out the kinks of black-body radiation. At the end of the 19th century, the communities of physicists were under the delusion that everything in the world had already been discovered. This state was interrupted by Einstein’s theory of relativity.
PHYSICS
The theoretical possibility of the existence of black holes follows from certain solutions of the Einstein equations The aphorism of Stanisław Jerzy Lec, the Polish satirist, comes to mind: “In reality, it wasn’t the same as how it actually happened.’ The slender tower of physics that was erected with such difficulty by the scientists of previous generations was in fact just a little annex to the grand labyrinthine palace of the universe, whose corridors we roam to this day. A full-fledged theory on black holes needed the new understanding of gravitation that was set forth in Einstein’s theory of relativity. This theory systematically revised almost all postulates of classical mechanics, seeing as they entered into obvious contradiction with daily experience. It’s no accident that school programs in physics, while examining in detail the key points of science as of the early 20th century, are rarely concerned with relativistic (much less quantum) physics, i.e., related to interactions at speeds approaching the speed of light. Even the simplest principle of velocity addition seems to be incorrect when applied to light. For example, let two vehicles move towards each other at 50 kilometers per hour. What velocity do they move at relative to each other? The answer is elementary and perfectly clear: it could not be anything other than 100 kilometers per hour. Now let’s replace the vehicles with rays of light (whose velocity is 300,000 kilometers per second). Has anything
fundamentally changed? Probably not, and yet the result is completely different: the relative velocity will be equal not to 600,000 kilometers per second, but to the same 300,000. And this is the simplest foundation of relativistic physics! There’s no telling about truly complex topics, like the curvature of spacetime caused by gravitational masses! It is difficult even to imagine. Nevertheless, the mathematical model of the theory of relativity (both special and general) is thoroughly developed enough, and more importantly, it has been repeatedly and reliably confirmed by the results of different experiments. In its most elementary presentation, the gist of the general theory of relativity could be summarized as follows: the key action of gravity is the curvature of space, distorting the trajectory of the straight, uniform motion of any objects with energy (since in some sense, energy and mass are equivalent). This new theory of gravitation of Einstein’s sparked a flurry of interest just as much as Newton’s law of gravitation had in its time. The consequences of the theory are paradoxical in many ways, and were immediately rigorously tested. Take, for example, the expedition organized in 1919 by a by Arthur Eddington, the prominent astronomer, whose goal was to verify the effect of light beam deflection in strong gravitational fields.
v 1 + v 2 = 100
v 1 + v 2 ≠ 2c
v 1 = 50
for macro objects
v 2 = 50
v 1= c
for quantum objects
v2 =c
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For all his British conservatism and scepticism, Eddington discovered that the position of stars near the sun (observed during a total solar eclipse from the island of Principe off the coast of West Africa) were displaced by exactly the value predicted by Einstein — 0.8 arcseconds at a distance of two solar radii. Eddington’s experiment played a decisive role in recognizing the General Theory of Relativity as the only correct theory of gravity
The actual position of the star
Observed position of the star
Sun
light trajectory straight line
Earth
An unbelievable solution The modern model of black holes, worked out in the course of analyzing the consequences of general relativity, was developed in 1916 by Karl Schwarzschild , an outstanding astronomer and physicist. Schwarzschild tried to calculate the radius of a hypothetical sphere on whose boundary the gravitational pull would approach infinity for the given mass of the object. For example, the mass of Earth is equal to 6×1024 kg, and its Schwarzschild radius is equal to 10-2 m. As we can see, the sizes of the object and Schwarzschild radius do not always coincide. But if
If we reduce the radius of the Earth to its Schwarzschild radius (if we maintain its mass), then we will end up in a black hole.
the object “contracts” into a size less than the Schwarzschild radius, then light or particles of this body will not be able to overcome the field of gravitation, and we will get a black hole. The Schwarzschild radius is a unique threshold of nonexistence, on which the escape velocity equals the speed of light. An external observer cannot be affected by the events in the sphere of this radius (although he can influence them by sending something heavy toward the cosmic target). Therefore the surface of sphere is called the event horizon. A rational inhabitant of the interior of a black hole (if we are willing to consider such a wild idea) is in a slightly different position. In theory, he is the possessor of all matter pulled into the hole, which includes not only substances such as atoms, molecules, and a great number of elementary particles, but also fields, whose action and interaction anchors everything that exists in the universe. In some sense the hole pulls in both all possible information about the surrounding space, and all events that have happened (and will happen) in the neighboring areas of space. However, it has no method of using this information to change anything on the outside. So the phrase “knowledge is power” here, at least, is incorrect. It is believed that once inside a black hole, a substance is compressed to a staggering density. Actually, there is a natural limit, which is the intranuclear density arrived at through the dense packing of nucleons (protons and neutrons), equal to 100 million (!) tons per one cubic centimeter. Based on modern views on the structure of matter, it would be impossible to exceed this, and that is why the fear that our planet will turn into a black hole (as the overzealous press threatened before the launch of the Large Hadron Collider) is highly irrational. The Schwarzschild radius for Earth is a less than centimeter, and its mass in the grand scheme of outer space is insignificant, but the density of such a microplanet would have to exceed the nuclear density by several orders of magnitude. Another matter is black holes in the centers of galaxies, like the colossus in the galaxy of NGC 1600, recently discovered as part of the project MACS (MAssive Cluster Survey), launched in 2014 to study 100 neighboring (that is, within 350 million light-years) galaxies with masses not less than 300 billion solar masses. This celestial “monster” is 17 billion times heavier than the sun (for comparison, that’s the ratio in mass between a grain of sand and a 25-meter diplodocus, one of the largest dinosaurs). But its density, according to calculations, is comparable to the density of… air! And who knows what’s going on inside, beyond the event horizon?
PHYSICS
What Чтоelse ещёshould следует you знать know оabout «чёрных black дырах»? holes?
What color are black holes? Are they really black? Black holes do not emit light, they only absorb it. Consequently, there’s no real point talking about their color. But things aren’t that simple. When interacting with other objects, for example, against the background of a satellite star, we can actually see a black object, and the light from the star will be heavily distorted as a result of gravitational lensing. And if a black hole begins to ‘suck in’ a star, then we will see a glowing accretion disk.
The protagonist of the film Interstellar, entering a black hole, appeared in a fourth dimension, where he could see and touch time. How much truth is there in all this? We will start with the question of landing in a black hole, particularly crossing the event horizon. Depending on the size of the hole you can have two scenarios, but both will end the same — you will be torn into atoms. The size of the hole only determines the speed at which it will happen: either very quickly, or very, very quickly.
There are a vast number of exotic theories with detailed mathematical calculations about what happens in black holes. Among them, there are some that suggest the creation of a time machine using a black hole, or travel to parallel universes, and many others. Do not forget that the idea of a black hole was mere fantasy just 150 years ago.
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Not everyone believes in the existence of black holes We should start with the fact that the question of the existence of black holes is closely related to how true the theory of gravitation is that suggests their existence. This, in turn, is best confirmed experimentally within the framework of the general theory of relativity. It should be noted that there are alternative theories which can suggest the existence of black holes. At the moment, scientists presume to have recorded about 10,000 black holes or objects very similar to them.
Could the Large Hadron Collider create a black hole?
Can our sun become a black hole?
In theory, yes, but it would be so little that it would immediately evaporate due to Hawking radiation.
According to the theory of the appearance of black holes, they are born as a result of the collapse of massive stars. The size of our sun is not large enough to form a black hole — to be large enough, it would need to be 30 times greater than its current size.
Black holes last forever Stephen Hawking, the English scientist, asserts that at the quantum level, the claim that a black hole radiates nothing and only absorbs is not quite true. A black hole emits radiation named after the scientist: Hawking radiation takes with it some of the hole’s energy, as if the hole is boiling. A detailed description of this process would require an in-depth understanding of quantum physics. This idea is only theoretical; it has not yet been successfully proven through experiment.
E RU DI T ION
The ancient Greek naturalist Dioscorides wrote: “There is a kind of coalesced honey, found in reeds in India and Eudaimon Arabia, similar in consistency to salt.” What is it?
What books did the famous mystery writer Georges Simenon collect to help him choose names for his characters?
A comic strip depicts a baby animal standing next to a hedgehog. The baby animal’s mother stands in front of them and says: “No, son, your friend may not sleep over at our place!” Name the animal.
American designer Jack Ryan was married five times, and each time he suggested his wives get plastic surgery to make their figures match the ideal he’d once invented: 99-46-84. What was the name of that ideal?
According to legend, when Scottish writer Robert Louis Stevenson sailed to the US, his ship was run by two captains, one of whom was very spiteful, and the other of whom good. What are their names?
The 30th U.S. President Calvin Coolidge was known for his taciturnity. One day a guest at a dinner party argued with friends that he could get Coolidge to utter at least three words. Calvin Coolidge heard this and said: “You …”. Finish his sentence.
ANSWERS
Sugar
Telephone directories
Kangaroo
Barbie
Jekyll, Hyde
Lose