In 1905, when Albert Einstein was twenty-six years old and a technical examiner in the Swiss patent office, he wrote four major papers that would forever influence science. The first, for which he later won the Nobel Prize, was a paper on the photoelectric effect. He described how light could behave as both a wave and a particle. The photoelectric theory laid the foundation for quantum physics.
The second paper proved the existence of atoms and molecules by noting that the jerky, apparently random motions of tiny particles seen in water, called Brownian motion, is caused by the impact of individual atoms.
The third paper is the one that made Einstein famous: it proposed his special theory of relativity. Einstein asked himself a simple question: “If I could travel on a light beam, what would I see?” He established that time and space would appear different for you and for a person not traveling with you. No matter what your speed, you will always measure the speed of light to be a constant, namely about 186,000 miles per second. As a person on a train travels near the speed of light, for example, time slows down for them relative to someone not on the moving train and the train is heavier (mass increase) and appears to be shorter (length contraction).
In his fourth paper, Einstein demonstrated the equivalence of matter and energy. He proved that mass and energy are two sides of the same coin. Even though Einstein never worked on or designed the atomic bomb, his famous E = mc2 equation proved that one was possible. Forty years later, in 1945, the first atomic bomb was detonated in the desert in New Mexico.
What are the practical effects of Einstein’s legacy? His first paper, on the photoelectric effect, gave rise to modern electronics, such as television, fiber optics, solar cells, and lasers. The Global Positioning System, or GPS, takes into account Einstein’s special theory of relativity: clocks on GPS satellites have to be corrected because they do not run at the same speed as clocks here on Earth. The behavior and action of the Sun are explained by E = mc2, as hydrogen is converted to helium and the four million tons of its mass that is lost every second is turned into pure energy.
Einstein was an inventor as well as a theoretician. He was granted twenty-five patents for such things as a hearing aid and a refrigerator that had no moving parts.
Another legacy will be his persona. He’s the man with too large a head, walking around in rumpled clothing, his white hair unkempt, smoking a pipe, playing the violin, sailing in a small boat, and showing up at his naturalization ceremony in shoes but wearing no socks. Einstein is seen as a pure genius, a scientist laboring in relative isolation. He arguably had no equal in the twentieth century, and we are not likely to see his like in the twenty-first century.
Calculus is a powerful tool that helped put men on the Moon, provided “smart weapons” to our military, and made hospital MRIs possible. It allows us to solve science and engineering problems that ordinary algebra can’t handle—specifically, problems involving rates of change. The development of calculus goes back to the Greek era of Democritus and Archimedes. They were using terms such as “an infinite number of cross-sections” and “limits.” They recognized the requirement to compute the areas and volumes of regions and solids by breaking them up into an infinite number of recognizable shapes.
Seventeenth-century giants in math and science, such as René Descartes, Pierre de Fermat, and Blaise Pascal, added much to the development of calculus. Formalization of calculus as a distinct branch of mathematics can be credited to Isaac Newton and Gottfried Leibniz.
Calculus is the math of change and motion. For Isaac Newton, it was change over distance and time. Gravity was the problem for Newton, and calculus was his instrument. He needed a higher form of mathematics to explain gravity, because the pull of gravity varies as the square of the distance between any two objects. So if you are twice as far away from the Earth, the pull of gravity is only one-fourth as much. For more than a century, a debate dragged on over who developed calculus, Newton or Leibniz. A bitter public feud developed between the two mathematical geniuses, with charges and countercharges of plagiarism. Today, both Newton and Leibniz are given credit for the development of calculus.
Newton, born on Christmas Day in 1642, is considered the greatest scientist who ever lived. When the bubonic plague swept through England in 1665, the schools closed and the young teacher returned to the Newton family farm. In a period of eighteen months, he discovered the laws of motion and universal gravitation, found the laws that govern light and color, and formulated a new math, later called calculus. He developed the reflecting telescope in 1668. His book Principia Mathematica, published in 1687, is the foundation of the physical sciences and considered the most influential science book ever written. The unit of force bears Newton’s name. He was the first scientist ever knighted by royalty. His image appeared on the British one-pound note from 1978 to 1988, an honor he shares with the Duke of Wellington and William Shakespeare. Isaac Newton is buried in Westminster Abbey, a place generally reserved for kings and queens.
Escherichia coli, better known as E. coli, is a normal bacterium found in the lower digestive system of mammals. But some strains cause disease. We hear of outbreaks periodically, and several deaths each year.
The E. coli bacterium was discovered in human feces in 1885 by a German doctor, Theodor Escherich, and the genus is named for him; the species name, coli, means that it inhabits the colon. We actually need E. coli to develop properly; these bacteria supply many needed vitamins, such as vitamin B complex and vitamin K. E. coli is often in the news as a food-borne pathogen, but the vast majority of E. coli strains are harmless. About 0.1 percent of all bacteria in our intestine are E. coli.
Immediately after we are born, we acquire all kinds of bacteria, which live symbiotically with us—we help them to live and they help us to live. Just as there are human beings who are not very nice, indeed downright dangerous, so there are different strains of E. coli bacteria that can harm us.
At some point, an E. coli cell was infected by a virus. The virus had the ability to put its own DNA into the bacteria’s chromosomes without harming the bacteria, and the DNA was then able to remain there. Every time the bacterium cell divides, the virus’s DNA is passed on to every descendant cell, so now we have E. coli O157:H7, one of those dangerous strains. This strain of E. coli produces a toxin that causes severe damage to the cell wall of the intestine. The damage is so massive that blood vessels are destroyed, with nasty bleeding, or hemorrhaging. Symptoms usually start in three or four days, but they can begin anytime between one and ten days after eating the contaminated food. The person has cramps, becomes dehydrated, and experiences bloody diarrhea. The condition can be fatal for children, who can’t tolerate much fluid and blood loss. Elderly people are also more vulnerable.
We can prevent E. coli infections by thoroughly cooking ground beef, not drinking unpasteurized milk and juices, rinsing produce thoroughly, keeping meat and its juices away from other foods while cooking, and washing our hands carefully in between handling them. Because E. coli lives in the intestines of animals, meat can become contaminated during slaughter. This can lead to infection in people who eat the beef; the risk is higher in ground beef, because meat from many different animals is mixed together, increasing the chance that one of them carries E. coli.
When these E. coli outbreaks occur, they create headline news. Most cases involve eating undercooked and contaminated ground beef. Most people recover without any medication. However, severe cases can lead to kidney damage and even death. And a disturbing new trend is the existence of some strains of E. coli becoming resistant to certain types of antibiotics.
The five planets closest to the Sun, other than Earth, can be seen with the naked or unaided eye. So Mercury, Venus, Mars, Jupiter, and Saturn were known since the first time humans looked up to the heavens. These planets seemed to move about among the background stars. The word “planet” is rooted in the Greek word for “wanderer.”
Uranus was the first planet to be discovered by telescope. In 1781, English astronomer William Herschel noted a “bigger than normal” star in the constellation of Gemini, the Twins. That big object turned out to be a planet.
Newton’s laws allowed the prediction of the existence of Neptune even before the planet was discovered, making it the first planet to be discovered by mathematics. Something was tugging, or pulling, on the orbit of Uranus. Calculations done in 1846 showed that the gravitational effects of a nearby object perturbed the path of Uranus. Astronomers trained their telescopes on the exact spot where such a planet should be, and Neptune showed up!
Pluto was the first planet (although since demoted to “dwarf planet”) discovered using a photograph. In February 1930, astronomer Clyde Tombaugh, working at the Lowell Observatory in Arizona, noticed that two images on different photographs had shifted slightly. From our distance, stars do not appear to move relative to each other—at least not over a period of weeks or months.
Pluto was “kicked out” of the family of nine planets in August 2006 by the International Astronomical Union that met in the Czech Republic. They placed Pluto in the family of dwarf planets, of which there are more than forty-four known. They said that Pluto does not dominate its moon Charon. Charon is half the size of Pluto and planets are much, much bigger than their companion moons. Also, Pluto has a highly elliptical orbit rather than the more sedate circular orbit enjoyed by the remaining eight “real” planets. Adding insult to injury, Pluto’s orbit path is inclined steeply to the plane of the other planets, marking it as a true renegade.
Now astronomers can search for planets orbiting stars other than our Sun, or exoplanets. This is not an easy task. The light from stars is so bright that the glare overwhelms the light reflected from surrounding planets. It’s like trying to see a birthday candle placed right in front of a searchlight. Astronomers have developed a few work-arounds to this problem. For example, they try to measure the gravitational effect of planets on stars. A planet tugs on the star as it orbits, causing the star’s motion to change slightly. Also, if a planet’s orbit takes it between its star and Earth, it will block some of the light, so astronomers can look for variations in the brightness of stars. Since 1990, over 880 planets have been discovered that orbit around other stars.
In 2014, NASA plans to launch the Terrestrial Planet Finder (TPF) an array of four optical telescopes and a combiner instrument. The light from the four telescopes will be combined in such a way as to cancel out the bright glare from the star. Hopefully, finding other planets will take a giant leap forward with this new technology.
Stonehenge is an impressive site, almost mystical in nature. One of the most famous prehistoric sites in the world, Stonehenge sits atop a low hill and is surrounded by a near-treeless plain with cattle grazing nearby. Stonehenge, a ring of immense stones, is on the Salisbury Plain about one hundred miles west of London.
Stonehenge marks the seasons. At summer solstice, the Sun rises over the Heel Stone as seen from the Altar Stone. Construction started around 3000 BC, and the last known construction was around 1600 BC. The Heel Stone is a large block of sarsen stone outside the Stonehenge earthwork, close to the main road. It is sixteen feet tall and eight feet thick. The Altar Stone is seven feet tall and weighs an estimated six tons.
There is no general agreement on why Stonehenge was built. Some argue that it was a place of worship, or church, if you will. Others claim it was strictly an observatory to mark the seasons. Archeologists continue to study and ponder this magnificent structure.
Work went on by prehistoric people for a period of about fifteen hundred years. The twenty-five- to fifty-ton sarsen stones we see today came from quarries in Marlborough Down, a distance of twenty-five miles. They were set upright in a circle and topped with a ring of stone lintels. The four-ton bluestones, placed during the third phase of construction, came from Wales, over 150 miles away. What an amazing feat of transportation!
My wife, Ann, and I visited Stonehenge in August 2006. Walking around the massive stones, I was thinking of those ancient people who built this edifice. What would their language sound like, what did they eat, how did they gather food, how did they stay warm, what kind of games did they play, and how did they govern themselves? And what induced these people to build anything on this lonely, windy plain near Salisbury?
There are some good books on the subject. One of the best is Stonehenge: The Secret of the Solstice, by George Terence Meaden. Another is The Making of Stonehenge, by Rodney Castleden. Yet another excellent work is Stonehenge—A New Understanding, by Mike Parker Pearson. The Internet is an excellent resource for some gorgeous pictures. If you ever have the opportunity to be in England, go see Stonehenge.
Ole Rømer, a Danish astronomer, made the first estimate of the speed of light in 1676. Using a telescope, he observed the motion of Io, one of four large Galilean moons of Jupiter. Io would alternately move in front of Jupiter, and then go behind Jupiter. It took 42.5 hours for Io to go around Jupiter when the Earth was closest to Jupiter. He recorded that as Earth and Jupiter moved farther apart, Io’s eclipse by Jupiter would come later than predicted. He estimated that it took twenty-two minutes for light to cross the diameter of the orbit of Earth. His calculation for the speed of light came out to 136,000 miles per second. Not bad for a first crude measurement. The accepted value today is about 186,000 miles per second.
Armand-Hippolyte-Louis Fizeau made the first successful measurement of the speed of light on Earth in 1849. He directed a beam of light at a mirror a few miles away. The beam passed through a rotating cog wheel. At a particular rate of rotation, the beam would pass through one gap on the way out and another on the way back. By knowing the distance to the mirror, the number of teeth in the cog wheel, and the rate of rotation, Fizeau could calculate the speed of light. He got a result of 195,732 miles per second, closer to the true value.
An American, Albert Michelson, measured the speed of light in 1926. He set up a rotating mirror system to measure the time for light to make a round trip from Mount Wilson to Mount San Antonio in southern California, a distance of about twenty-two miles. Michelson’s precise measurements yielded a value of 186,285 miles per second, or 299,796 kilometers per second. He was awarded the Nobel Prize in 1907 for teaming up with Edward Morley, also an American, to try to measure the so-called ether.
Light is an electromagnetic wave and travels at the same speed as radio or television waves. Light takes 1.2 seconds to go from the Earth to the Moon. Sun to Earth time is 8.5 minutes. Sun to Pluto is 5.5 hours. The light of the nearest star is 4.3 years away, and light takes one hundred thousand years to cross our Milky Way Galaxy. We humans live in a very big house!
Dinosaurs roamed planet Earth for 160 million years; then suddenly they died off, 65.5 million years ago. There have been a half dozen prominent theories and as many less plausible theories to explain the dinosaur’s sudden demise.
The reputable accounts over the past two centuries have been these:
Last, there’s the asteroid theory, which is the most popular and widely accepted theory today. A large asteroid or comet struck the Earth about 65.5 million years ago. The father-son team of Luis and Walter Alvarez discovered a very distinct layer of iridium in rocks at a depth that corresponds to that time. Iridium is found in abundance only in meteorites and asteroids. Their initial discovery was in Italy in 1980. Since that time, that same kind of very thin layer of iridium has been found in various parts of the world at the same depth.
In 1991, geologists found the huge Chicxulub Crater (named after a nearby village) at the tip of Mexico’s Yucatán Peninsula. The crater dated back to the time of dinosaur extinction. The meteor or asteroid crater was 110 miles across. Scientists estimate the asteroid was six miles in diameter and struck the Earth at 45,000 mph, with a force two million times the energy of the most powerful nuclear bomb ever detonated.
The heat from this asteroid or comet impact boiled the ocean’s waters, ignited forest fires worldwide, and plunged the Earth into darkness as the debris blocked sunlight from reaching Earth. This dropped the Earth’s temperature into the freezing range, killing most plants and animals. Plant-eating animals died a few months after the vegetation died. Only small animals that burrowed underground survived.
Even though the asteroid theory is the one held by most scientists today, a number of the other theories continue to find some support. There is evidence, for example, of a gigantic volcanic eruption occurring in India about 65.5 million years ago that sent a gaseous volcanic plume into the atmosphere. The reasoning is that this volcanic eruption was enough to trigger significant climate change, which the dinosaurs failed to adapt to.
Other scientists hold to the idea that there may have been more than one cause of dinosaur demise. They believe that both an asteroid impact and volcanic eruptions caused dinosaurs to die off. Or they hold to the possibility that an asteroid impact triggered volcanic eruptions and that the combination was deadly for dinosaurs, other animals, and plant life.
Dinosaur extinction was not the first massive die-off in history; the biggest was the Permian-Triassic extinction event, called the Great Dying, happened 251 million years ago. Over 70 percent of land vertebrates, and 96 percent of water species, were wiped out.
Ice ages occur when the Earth has notably colder climate conditions. During an Ice Age, the polar regions are cold and there is a heightened difference in temperature between the equator and the north and south poles. The winters in the north regions are more extreme, allowing a lot of snow to accumulate, and the summers are cool enough that the snows of previous winters do not melt completely away. When this process continues for centuries, ice sheets begin to form.
The thinking right now is that the most likely cause of ice ages is the amount of radiation put out by the Sun. Variations in its intensity and timing are caused by changes in radiation of heat from the Sun; according to most scientists, these variations are responsible for the glacial cycles, and it may turn out that more than one cause responsible for ice ages. Ours is a very dynamic planet, and ice ages are most likely a result of complicated interactions among several of the below.
While the exact causes of ice ages are unknown and controversial, there is general agreement about possible causes. They are:
Several of these factors can have reciprocal effects. For example, an increase in atmospheric carbon dioxide gas may alter the climate, and then the climate change may alter the composition of the gases in the atmosphere.
The last glaciers melted and receded from our area around Wisconsin about eleven thousand years ago. It’s estimated that the next ice age will reach its peak in eighty thousand years, but nobody knows for sure when it will start. There have been ten periods of spreading ice sheets and falling seas in the last million years. Evidence comes from ice core samples from all over the globe.
Sometimes we forget about the time frame for planet Earth. All of human history is in our current warming period, called the Holocene. So it’s hard to picture most of the United States and Europe buried under fifty feet of ice. Interglacial phases like the one we are experiencing right now are mere blips in between long periods of extreme cold.
These climate swings of big freezes interspersed with warming periods are rooted in changes in Earth’s orbit and the tilt of its axis. Even though these changes are tiny, they have a huge impact on how much solar heat hits our planet. Right now we are in a warming period.
How does the knowledge of an upcoming ice age fit in with the current global warming? It might seem that human-caused global warming would fend off or delay the next ice age. But that may not be true, and it may even hasten one. Global warming could help bring on another ice age more quickly by melting the freshwater ice caps and shutting down the heat-carrying ocean currents that keep northern climates warm.
Most climatologists say that there is an extremely complex interplay of greenhouse gases, orbital shifts of the Earth’s rotation, ocean currents, and output of the Sun, which is not well understood.