Telescopes and Microscopes—Advances From Yesterday to Our Day
OBSERVATORY telescopes today are virtual behemoths compared to Galileo’s 1 3/4-inch-diameter (4.4 cm) models. His primitive devices were refracting telescopes. A large convex lens on one end formed the image and a small concave lens at the other end, later modified to be also convex, magnified the image. Remarkably, his instrument could magnify objects up to 33 times, allowing him to view such distant wonders as Jupiter’s four moons and Venus’ moon-shaped phases.
Today’s reflecting telescopes use immense, bowl-shaped mirrors (up to 236 inches [600 cm] across!) to collect light from faraway heavenly bodies. They are thus able to detect objects ten million times fainter than those that can be seen with the naked eye. Why, it is claimed that one telescope in Australia could detect a candle flame a thousand miles (1,600 km) away!
Interestingly, though, astronomers today still run into the same problem Galileo faced. He noticed that when magnified the stars increased in number but not in size. Galileo reckoned that the stars must be incredibly distant to remain mere points of light under magnification. Though today’s astronomers seemingly know just how far away these celestial objects are, they still, even with their precision lenses and polished mirrors, see stars as pinpricks of light. As The Observer’s Book of Astronomy declares: “The stars are so remote that no telescope yet built will show them as anything except points of light.”
This, though, does not stop scientists from trying to get a closer look at the stars. For example, in 1986, the National Aeronautics and Space Administration (U.S.A.) plans to launch a large space telescope that will orbit above the earth’s atmosphere. Scientists believe it will detect objects 50 times fainter than earthbound telescopes can detect.
Fortunately, there are other ways to see the universe. Some time ago it was discovered that certain heavenly bodies emit radio waves. By the time these signals reach earth they can be fainter than one trillionth of a watt. Hence, large radio telescopes have been developed to pull in and amplify these signals. In this way astronomers have been able to see quasars, pulsars and other intriguing phenomena.
Astronomers, therefore, no longer spend hours squinting through a telescope’s eyepiece, as did Galileo. The Encyclopædia Britannica explains: “Almost all astronomical research is done photographically or photoelectrically, rather than visually . . . Objects can be photographed that are many times fainter than can be seen by looking through the eyepiece. One photographic plate may contain a vast amount of information . . . 1,000,000 star images and 100,000 galaxian images on it.”
Scientists can do remarkable things with such photographs. The magazine Sky and Telescope once explained that a technique called speckle interferometry can reveal the disks of some red supergiants, though the rest of the stars—even the closest ones—remain mere points of light.
The closest star to our sun, as seen by the naked eye, turns out to be three when viewed through a telescope. One is Proxima Centauri. The other two are a pair of stars that revolve around each other every 80 years and are known as Alpha Centauri. Except for the sun, these three are the nearest of all the stars, and yet they are 4.3 light-years (over 25 trillion miles; 40 trillion kilometers) from earth! Observes the book Astronomy: “If the size of the sun is represented by one of the periods on this page, the sun’s nearest neighbor among the stars, the double star Alpha Centauri, would be shown on this scale by two dots 16 kilometers [9.6 mi] away.”
Crossing the south celestial pole are what appear to be two patches of cloud. In the 15th century, Portuguese navigators called them Clouds of the Cape. Later they were named after the famous explorer Ferdinand Magellan. Telescopes reveal that both are vast external galaxies. The Large Magellanic Cloud alone contains an estimated five thousand million stars.
Man thus comes full circle. Though his telescope has put to rest superstitious notions about the universe, he nevertheless finds himself gazing upward with a renewed sense of awe!
Seeing the Hidden World
The world of the microscopically small is no less fascinating. Driven by insatiable curiosity, Leeuwenhoek used to study just about anything he could fit under his lens. Once he took some saliva from his mouth and examined it under his microscope. To his surprise he saw “many very little living animalcules [little animals], very prettily a-moving.” He then sent a description and drawing of these mouth bacteria to the Royal Society of London in 1683. “What if one should tell,” later exclaimed Leeuwenhoek, “that there are more animals living in the scum on the teeth in a man’s mouth, than there are men in a whole kingdom?” Modern estimates of the number of microorganisms living in the human mouth run into the billions.
Indeed, scientists peering into that hidden world have discovered things that would have astounded even Leeuwenhoek. They can now, for instance, see that a simple drop of blood may contain some 35 million red cells. Each cell, in turn, may contain more than 280 million hemoglobin molecules. “Imagine the task of mapping the 10,000 atoms of just one hemoglobin molecule,” exclaimed Dr. Coppedge in his book Evolution: Possible or Impossible?
Microorganisms—Good or Bad?
Many of us naturally recoil at the very thought of germs. And it is true that some microorganisms cause sickness and death. However, this appears to be the exception rather than the rule.
For example, do you enjoy a glass of milk? Well, it takes trillions of microorganisms in a cow’s stomach to enable it to digest fodder and produce milk. Benign germs also dwell in a human’s intestines. Says the textbook Elements of Microbiology: “Many intestinal bacteria can synthesize the major B vitamins and vitamins E and K. Vitamins so produced make a significant contribution to the vitamin requirements of the host.”
Tiny microorganisms even act as an efficient sanitation department. “If microbes did not deal with dead and waste matter,” wrote science writer Ludovici, “it would pile up to such an extent that we should die for lack of space. It really is no exaggeration to say our existence depends on microbes, on an invisible world that comes into view with the help of the microscope.”
With improved equipment, biologists can even get a closer look at the microorganisms themselves. These, too, are amazingly complex. Some microorganisms possess a whiplike tail called a flagellum. It is fascinating to look through a microscope and watch them darting about in a mere drop of water! One kind of bacterium (called Spirillum serpens) even has tails that spin like electric propellers. (It has been clocked at 2,400 rpm!) And if this minisubmarine needs to change directions, it simply switches on at the opposite end!
Microscopes—The State of the Art
Leeuwenhoek’s homemade devices could, amazingly enough, magnify objects 250 times or more. Optical microscopes today, however, can magnify objects about a thousand times. “The common housefly magnified to the same extent would appear to be more than 30 ft [9 m] long,” explains the book Elements of Microbiology.
In 1931 the electron microscope was invented. By aiming a stream of electrons at an object, a visual image can be produced in which objects are magnified about a million times. There is one serious drawback: It cannot be used to study living specimens. A new device, however, which combines the optical microscope with television cameras and computer memory, now makes it possible for scientists actually to observe the biological activity of living cells! Reported The New York Times: “Ducts, or microfilaments, only a millionth of an inch in diameter, can be seen transporting such particles as food and waste in opposite directions at the same time.”
Telescopes and microscopes are thus potent tools. They have given man a startling insight into the world—and universe—in which he lives. But does this new insight enhance—or in some way do away with—the need for faith?
[Blurb on page 4]
An estimated 200 globular clusters are in our Milky Way galaxy, each with thousands to hundreds of thousands of stars
[Picture on page 5]
Telescopes have revealed a universe filled with billions of galaxies, each with billions of stars
[Pictures on page 6]
A small drop of blood contains millions of red cells, each cell contains millions of hemoglobin molecules, each molecule contains 10,000 atoms
A small spoonful of soil may teem with billions of microorganisms
[Picture on page 7]
The flagella of this microscopic bacterium rotate like propellers. Some turn at speeds up to 2,400 rpm