Looking Deeper Into the Heavens
By Awake! correspondent in Australia
HOW long has it been since you took more than just a casual glance at the stars at night? If you do so occasionally, you realize that you do not need binoculars or a telescope to be mentally stunned at the vastness, complexity and grandeur of it all. Almost 3,000 years ago, King David of Israel expressed what many of us sometimes feel. He wrote: “When I see your heavens, the works of your fingers, the moon and the stars that you have prepared, what is mortal man that you keep him in mind?”—Psalm 8:3, 4.
David was talking about the stars visible to his unaided eye. But since the days of Galileo, man’s natural vision has been enhanced by the telescope, and he has learned how much more immense the heavens are than he suspected. He has learned that many of the twinkling stars he can see are in reality huge suns, some much bigger than our own sun. It is only distance that makes them look so small. He has learned also that throughout space there are billions of vast, rotating clusters of suns called galaxies.
The galaxy that our sun belongs to contains billions of other suns. Some galaxies are so huge that it takes light, travelling at nearly 300,000 kilometres (186,000 mi) each second, half a million years to travel from one end of a galaxy to the other. However, most other galaxies, despite their containing innumerable stars as bright or brighter than our sun, are too far away to be seen by the unaided eye.
Not a Star at All!
In recent decades the optical telescope has been supplemented by another instrument, the radio telescope, which tunes in to radio waves reaching the earth from outer space. Armed with this, astronomers have broadened even further our understanding of “the moon and the stars.” On occasion they have discovered stellar bodies they never before knew existed. For example, in 1963, with the help of the radio telescope, astronomers using the Mount Palomar optical telescope in California, U.S.A., suddenly found a new, quite unexpected and absolutely incredible object in the heavens.
At that time, in the early 1960’s, radio astronomy was just growing up. Although there were radio waves coming from sources in the sky, scientists had problems identifying accurately the exact source of the transmissions. In 1963 the situation changed dramatically when it was predicted that a certain radio source from outer space might be blocked off temporarily as the moon passed in front of it. Since the position of the moon is clearly known, it should be possible to use this coincidence to determine exactly where that transmission was coming from. The observations were carried out successfully by the Parkes radio telescope in Australia, and the source of the radio waves was found to be a dim, bluish star.
This star was then examined more carefully, using the huge, 200-inch optical reflecting telescope at Mount Palomar. It was discovered, to everyone’s surprise, that the object was not a star at all! Hence, it came to be called a quasar, short for “quasi-stellar radio source.” It was calculated to be so far away that light from it takes two billion years to reach us. Indications are that it is relatively small, yet it pours out an unbelievable amount of light.
Many more quasars are now known. It is estimated that at least ten million are visible with a large telescope. They are believed by all but a few astronomers to be at vast distances from the earth, from 2 to 15 billion light-years away.* Dr. Edward R. Harrison, an astronomer and physicist, describes them this way: “Imagine that a large room represents the size of the Galaxy; on this scale the highly luminous quasar is no more than a mere speck of dust floating in the air.” Yet each of these ‘specks of dust’ pumps out, on an average, a hundred times more energy than all the billions of stars in our galaxy put together!
What are these quasars? No one knows, but there are theories. Here is an intriguing one. The light from the most distant quasars takes 15 billion years to reach us. That means we see them as they were 15 billion years ago. No known quasar is farther than 15 billion light-years away; hence, they represent something that started happening 15 billion years ago.
According to the currently popular theory, the universe got started with a “big bang” about 18 to 20 billion years ago. Hence, quasars came into existence when the universe was “only” from 3 to 5 billion years old. According to the theory, that is about the time when galaxies would have started to form. Hence, quasars may be galaxies in the process of being born.
And Then the Pulsars
In 1967 astronomers were startled again when they discovered an object so bizarre that they thought it was some extraterrestrial intelligence trying to contact the earth.
Members of the Mullard Radio Astronomy Observatory at Cambridge, England, were carrying out routine surveys when a new kind of signal was noticed. It was a radio signal that flashed on and off, pulsated, in a regular rhythm. Radio astronomy, as you can imagine, is plagued by interference from local sources such as passing automobiles. Hence, at first, these strange signals were ignored. However, a more systematic examination showed that they were coming, not from traffic noise, but from outer space!
From where in outer space? This time the sources seemed to be stars located within our galaxy. They came to be called pulsars because of their strange, pulsating light and radio emissions. However, pulsars are not like ordinary stars. To emit their distinctive signals they must be rotating, rather like a lighthouse beacon. And since they pulsate every second or so—there is one that pulsates 30 times each second—they must be very small and spinning like a top. Astronomers now believe that pulsars may be only 24 kilometres (15 mi) across, but so dense that a cubic inch would weigh millions of tons. They also feel they must be very hot and have a huge gravitational field. Strange objects indeed!
Our Near Neighbors
The past few decades have seen some startling changes in our understanding of some of our closer neighbors too. As you know, our earth is only one of at least nine planets orbiting the sun. Robot spaceships have travelled through the emptiness of space, passed by the other planets and sent back pictures. Our neighbors turned out to be awe inspiring but not inviting.
Venus is a searing world permanently surrounded by clouds of sulfuric acid with surface temperatures higher than molten lead. Mars is a cold, lifeless world, with not a trace of the fabled Martians. Jupiter seems to be mainly a ball of gas. It radiates energy (but not enough to qualify as a sun) and is surrounded by a miniature solar system of 16 moons. Saturn, the next in line, lost its distinction of being the only planet surrounded by a ring system when rings were detected around Jupiter and Uranus too. But Saturn’s rings are still incomparably the most beautiful.
In 1979 the Voyager I spaceship discovered that active volcanoes are not confined to the earth. As the small spacecraft passed by Io, a large moon of Jupiter, it photographed a volcano in the act of erupting. It was further found that earth’s highest mountain, Everest, is not really in the big leagues where big mountains are concerned. Olympus Mons, for example, a volcanic cone on Mars, rises 24,000 metres (80,000 ft) above the general surface level of the planet.
It is impossible to consider the universe without using some very large numbers. Our own earth, for example, is about 12,900 kilometres (8,000 mi) in diameter. Compare that with the sun, which is 1,392,000 kilometres (865,000 mi) in diameter and could hold more than a million earths. The surface temperature of the sun is almost 6,000 degrees Celsius (11,000° F.), and at the core this is believed to rise in excess of 15,000,000 degrees Celsius (27,000,000° F.).
However, in comparison with a star examined in 1981 by the Explorer satellite, our sun is quite small. This hot, blue star, known only as R136a, is ten times hotter than our sun, 2,500 times more massive, one million times bigger and a hundred million times brighter! Can you comprehend all of that?
Undoubtedly many of the theories advanced to explain these extraordinary sights will be revised from time to time. But one thing is sure, we live in a wonderful universe, and as we probe farther and farther into space, we find ourselves more and more in agreement with King David. “Mortal man” is truly insignificant in comparison with “the moon and the stars”!
Nevertheless, while underlining our own puniness, our broadening understanding of the heavens has served to deepen our appreciation of and wonder at Jehovah God, the dynamic source of all these marvels. The Bible extends the invitation: “Raise your eyes high up and see. Who has created these things? It is the One who is bringing forth the army of them even by number, all of whom he calls even by name. Due to the abundance of dynamic energy, he also being vigorous in power, not one of them is missing.”—Isaiah 40:26.
A light-year is the distance that light travels in a year, about 9,460 billion kilometres (5,880 billion mi).
[Picture on page 17]
Saturn still has the most beautiful set of rings in the solar system