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Echoes of Vision


Galileo did not invent the telescope, as is often stated, but when news of an "optical tube" crafted in Holland in 1608 reached him at the University of Padua in Italy, Galileo immediately set to work building his own. By autumn 1609 he had made his first telescope—a tube with two glass lenses, one convex and one concave, which made objects seem three times closer than they were. He turned his marvelous new instrument to the skies and changed our view of the universe.

Galileo wrote about his first observations—of the moon "besprinkled" with spots, of "four planets flying around the star of Jupiter," and of the "inconceivable crowd" of stars in the Milky Way—in Sidereus Nuncias ("Starry Messenger" or "Sidereal Messenger") in 1610. He promised that his 60-page, soon-to-be bestseller would unfold "great and wonderful sights" and display them "to the gaze of everyone." He conceded that his observations were only a beginning: "Perhaps more excellent things will be discovered in time, either by me or by others, with the help of a similar instrument."

When Lyman Spitzer, Jr., proposed a large orbiting telescope 336 years later, he echoed Galileo's vision of exploring the unknown. Spitzer foresaw a telescope with the power to "uncover phenomena not yet imagined." Indeed, the Hubble Space Telescope, just as Galileo's primitive "spyglass," has opened a wondrous universe to all who care to look.

Barbara L. Wyckoff


Human Journey

Scientists who trace modern human origins often talk about a special kind of DNA, mitochondrial DNA (mtDNA). But do you know what mitochondrial DNA is? And do you know what mitochondria do? Mitochondria are tiny structures found within the cell that resemble grains of rice. They produce the energy that cells need to function, and they have their own small complement of DNA, containing just 37 genes in humans. Compare this to the human nuclear genome (the entire set of genetic instructions found within the nuclei of all the cells), which contains some 30,000 genes. But mitochondrial DNA is especially powerful for studying the ancestry of modern humans. While the nuclear genome is reshuffled with each new generation as the father's and mother's DNA recombine, mitochondrial DNA is passed directly from a mother to her children. As a result it preserves patterns of ancient markers that thelp scientists map the path modern humans have taken around the world.

Dharavi


Heptanesia. That was the name Ptolemy, the second-century Greek astronomer and geographer, gave present-day Mumbai. It was an apt name for the seven islands jutting into the Arabian Sea. Centuries later, the local Kolwadi fisherfolk called their villages Mumba, in honor of their patron goddess.

Portuguese explorers, arriving in 1543, named their settlement Bom Bahia—"good bay." The colony was given to King Charles II of England as dowry when he married the Portuguese princess Catherine de Braganza in 1661. A long British presence was established in the emerging city, and the name was anglicized to Bombay. Bombay was the official name for centuries, remaining so even after Indian independence in 1947.

Mumbai is now the official name, established by the Maharashtra state government and its Marathi Hindu leadership in 1995. Harking back to the goddess Mumba, the current name rouses both advocacy and dissension among the city's cosmopolitan population.

And in Dharavi? What do the people of Dharavi call the city in which they live? Dharavi is a diverse enclave, and roots can run deep. Many do call it Mumbai, though it's not unusual to hear Bombay, or even Bombai—somewhere between the two—depending on tradition or family loyalty. Over time, city residents, like the rest of us, are becoming accustomed to saying Mumbai, just as ancient explorers, we imagine, referred to Heptanesia.



What is a virus?

Generally, a living thing is defined as a cellular organism capable of independent metabolic processes and replication. A virus, however, consists of genetic material enclosed by a protein coat and is unable to replicate on its own. Think of a virus as a book of instructions with no one to read the book and start building. It comes to "life" when it invades a host cell and hijacks its machinery, forcing the cell to read and replicate the virus many times. Eventually, the copies of the virus burst forth from the cell, seeking out new hosts.

Emily Krieger

Sea Monsters

To aid in capturing prey, some ancient marine reptiles evolved features such as supersize eyes, fearsome teeth, or extremely long necks. Thalassomedon's 20-foot (6-meter) neck helped it ambush schools of fish from below. With 62 vertebrae, the neck stretched about 14 feet (4 meters) longer than a modern giraffe's, which has only seven vertebrae. But while Thalassomedon may seem like a blueprint for the Loch Ness monster, scientists say its neck probably couldn't have risen too far above the surface; buoyant underwater, its head and neck would not easily be supported in thin air. Also, writes paleontologist Michael Everhart in Oceans of Kansas: A Natural History of the Western Interior Sea, "since the eyes of a plesiosaur are located on top of the skull and are generally directed upward, the plesiosaur would almost have to turn its head upside down to look down at the water in search of prey from above the surface." Plesiosaurs like Thalassomedon had ample food below the surface, where they likely feasted on fish such as Apsopelix, which were abundant some 95 million years ago, during the late Cretaceous period. Easing into a school from below, Thalassomedon would turn its head to the side, snapping its jaws on the quarry.

Michael Klesius and Kathy Maher

Biofuels


Henry Ford thought that biofuels were the "fuel of the future." Ford's vision of mass biofuel consumption began with his Model T Ford. Starting in 1908, the Model T propelled Ford Motor Company to become the largest producer of automobiles at the time. By 1918 over half the cars in America were Model T's, giving Ford little reason to change the car's design in its nearly 20 years on the road.

From the original design, the Model T ran on ethanol as well as petroleum. Ford believed ethanol would become the most commonly used fuel source, and as early as 1925 envisioned an America that would grow its own fuel, making it out of everything from potatoes to sawdust. With more people willing to consume agricultural goods, he believed, farmers' produce would have more market value. Forces were beyond his control, however, and the economic crisis affecting farming only increased with the onset of the Great Depression.

In 1927, in order to compete with General Motors, a new up-and-coming car company, Ford issued his first new car model since the Model T: the Model A. After that new cars rolled out of Ford Motor Company's doors on a more regular basis, and with them came the phasing out of the classic Model T–and Ford's vision for ethanol use in the near future.


Space at 50


According to NASA, each day presents a one-in-a-trillion chance of a person getting hit by a falling piece of space junk. In 1968, the Baltimore Sun reported that a piece of U.S. space debris landed in a Cuban pasture, killing two Guernsey cows. Since 1957, human-made space junk has been falling back to Earth on a regular basis. Everything humankind has ever thrown into orbit, haphazardly or otherwise, will eventually make its way back to Earth. The only question is, when.
For Lottie Williams, the cosmic lottery hit a jackpot on a cool Tulsa, Oklahoma, morning in 1997. Soon after witnessing a satellite breaking up in the atmosphere during her early morning walk, Williams entered the history books as the first, and only, person on record to be hit by falling space junk. The feather-light piece of scalded shielding from what is believed to be a Delta rocket booster lightly tapped her shoulder with no ill effect.

Nearly all the clutter of space travel now hangs above us at distances as far as 22,500 miles (36,200 kilometers) and as near as 150 miles (240 kilometers) from Earth, and some of it has long outlived its usefulness. The oldest known object is the 1958 Vanguard I research satellite, which ceased all functions in 1964 and has since orbited the globe nearly 194,000 times. Orbital debris, the technical term for nonfunctional and human-made space junk, includes not only whole, abandoned satellites, but also pieces of broken satellites, deployed rocket bodies, human waste, and other random objects, like the glove lost by astronaut Ed White during his historic 1965 spacewalk. The newest jettisoned junk is a fridge-size ammonia reservoir released into its own orbit on July 23, following a NASA decision that no other disposal options were feasible.

The United States Space Surveillance Network catalogs about 12,000 pieces of debris larger than about four inches (ten centimeters) in diameter, and tracks their speedy march around the globe to help protect larger satellites, shuttles, and the International Space Station. (Small, undetectable pieces number in the millions, and pose a potentially lethal and largely unpredictable threat to human operations in space.) So, how often does orbital debris make its way back home? NASA estimates that, on average, one piece of cataloged debris reenters the lower atmosphere and falls to Earth every day.

Pyramid of death

Aliens did not design Teotihuacan, nor is it related to the lost city of Atlantis. Ever since the first aerial photographs of Teotihuacan were taken in the 1960s, the city's specific and precise layout has confounded scientists and scholars. The entire city is organized in a rigid grid system based on its central avenue, the Street of the Dead. This main street, however, is not oriented on a true north-south axis, but is offset by an exact 15.5º east of true north, a curiosity that has perplexed scholars and led to a variety of explanations throughout the years.

One of the more popular hypotheses suggests that the setting sun is at a 90º angle to the Street of the Dead on the days of the zenith (when the sun passes directly overhead). Some scholars, however, dismiss this hypothesis, stating that the math just doesn't add up. In the early 1970s, Colgate University astronomer and archaeologist Anthony Aveni suggested that a point 90º west of the Street of the Dead marked the setting position of the Pleiades, a star cluster linked to the Mesoamerican calendar, at about the time Teotihuacan was founded. However, Vincent Malmstrom, professor emeritus at Dartmouth College, argued a few years later that a point 90º west of the Street of the Dead marks the spot where, twice a year–on April 30 and August 13–the sun sets directly opposite the Pyramid of the Sun. Malmstrom believes this to be significant because the latter date is the day the ancient Maya believed the world began.

No conclusive explanation of why the founders of Teotihuacan oriented their city in such a specific way exists. Scientists and scholars are baffled and will, without a doubt, continue to look for clues to this one mystery among many that Teotihuacan holds.


Coral Reef Color


The simplest types of light receptors are known as ocelli—they are so basic that they cannot even be called eyes. Ocelli are light-sensitive regions in single-celled organisms or light-sensitive cells in animals. They usually detect whether the animal's surroundings are light or dark, although some more advanced types can sense the direction of a light source. Corals and sea anemones have simple ocelli—usually of alternating pigment and sensory cells—that are scattered over the animals' entire body surfaces. Some corals and sea anemones cannot perceive color, but others have ocelli containing pigments that specifically absorb certain wavelengths of light. These are usually the blue-green wavelengths that penetrate farthest through water, ensuring that the animals capture the maximum amount of light available.

Some active swimmers, such as jellyfish, have pigmented ocelli. These ocelli contain two different types of pigmented cells: some that shade and some that are light-sensitve. This type of ocellus allows an animal to not only perceive the direction of a light source, but also, because of its multicellular nature, to detect an object moving past it—the shadow is detected by one cell after another as it moves across the ocellus.

Seismographs Through Time

Throughout human history we have tried to learn more about the workings of earthquakes through various types of tools and gadgets. The first person to create a seismoscope, an earthquake recording instrument, was a Chinese philosopher named Chang Heng. In a.d. 132, Heng invented what he called an "earthquake weathercock," which could measure the occurrence of an earthquake and from which direction it came. The instrument—technically a seismoscope—looked like a ceramic urn with eight dragons attached to its sides, each representing one of the eight compass directions. Every dragon held a small bronze ball in its mouth. When an earthquake occurred, one of the balls would fall out and into one of eight toads sitting below. The dragon with the empty mouth would be located in the direction opposite from which the earthquake came. Although no one knows what was inside the jar, most scientists assume it held a pendulum that would trigger a specific dragon with its motion.

The 17th and 18th centuries saw the invention of more seismoscopes. In one invention by Luigi Palmieri in 1855, an earthquake would cause mercury to spill out of a bowl and into a particular container, depending on the direction of the quake. Contact with this container would stop a clock, indicating the exact time, and start recording ground motion onto a drum.

In the late 1800s the earliest seismograph (also known as a seismometer) was invented. A seismograph can provide more information about the intensity and other details of an earthquake than a seismoscope can. This first seismograph was later improved by British researchers in Japan, among them a man named John Milne, who invented the horizontal pendulum seismograph. Pendulum designs became more advanced throughout the 19th and 20th centuries.

The typical seismograph we see today uses pendulum technology and is made by securing a bar deep into the ground on one end and adding a weight to the other end. A pen is attached to the weight and is held against a rotating drum that has paper wrapped around it. In periods of inactivity, the pen draws straight lines with little ticks that indicate each passing minute. Any small wiggles in the lines are usually caused by outside noise, such as a truck rumbling by. When an earthquake happens, everything moves except the weight and the pen. The spiky lines recorded by the pen show the ground motion made by the earthquake. The paper containing these lines is called a seismogram and can be analyzed by a seismologist to find the epicenter, time, focal depth, cause, and even magnitude of the earthquake.

Although these types of seismographs are still used today, most scientists have switched to digital means of recording earthquakes. Computers that are linked together at different sites quickly process the information collected by digital seismographs during an earthquake and send it out over the Internet. What used to take days, weeks, or even months to analyze can now be done in a matter of minutes, allowing the media and rescue workers to react as quickly as possible.