According to theosophy, the earth is about two billion years old -- a figure in agreement with ancient Hindu teachings. In the west, it was widely believed until the early 19th century that the earth was less than six thousand years old, a belief based on a literal interpretation of the Book of Genesis. In the 1640s, for example, biblical scholar Dr John Lightfoot calculated that the world was created at the autumnal equinox in 3928 BC. A few years later, Archbishop James Ussher of Ireland announced that God created heaven and earth on Saturday evening, October 22, 4004 BC.
In the 19th century, scientists tried to work out the earth's age by assuming that its features had been shaped by the same gradual processes operating today. For example, they calculated the time required for the earth's sedimentary rocks to be deposited, for the oceans to attain their current level of salinity, and for the planet to cool from an original molten state. Because these processes were not fully understood, the resulting estimates of the earth's age differed widely, ranging from 3 million years to 15,000 million years. The discovery of radioactivity in 1896 led to the development of radiometric dating, but it was not until the 1950s that the techniques were considered sufficiently refined to yield reliable dates. This method put an end to the significant level of disagreement among scientists on the age of the earth.
The basic principle of radiometric dating is very simple. A radioactive parent element spontaneously disintegrates, at an apparently constant rate, into a stable daughter element -- e.g. uranium-238 decays to lead-206. By measuring the amounts of the parent and daughter elements in a rock, the time that has elapsed since it solidified can be calculated; the greater the proportion of the daughter element, the older it is. However, there are various complicating factors. Even if it were true that radioactive decay rates never changed, some of the daughter element may have been present in the rock when it crystallized, and some of the parent and daughter elements may have been lost or gained by the rock since it formed. If, after a rock has crystallized, it later undergoes reheating, the radioactive clock will be reset, sometimes to zero. Attempts to take these factors into account are not always successful, resulting in discordant dates. For example, potassium-argon dating has given ages ranging from 160 million to 2.96 billion years for Hawaiian lava flows that occurred in 1800! These anomalous dates were blamed on the presence of 'excess argon'. This is an extreme case, and it would be wrong to dismiss radiometric dating as utterly worthless, since different radiometric techniques frequently give consistent dates for the same rock samples .
The oldest known rocks on earth have been dated radiometrically at 3.96 billion years, and the oldest individual crystals at 4.3 billion years. Scientists believe that the earth is older than this, but that more ancient rocks did not survive the molten conditions that prevailed after the planet's birth. The oldest moon rocks have been dated at about 4.5 billion years, and the oldest meteorites at 4.5 to 4.6 billion years. On the basis of these results, along with calculations concerning lead isotopes in meteorites and in the earth, scientists have concluded that the entire solar system, including earth and all the other planets, formed about 4.55 billion years ago . Radiometric ages of 6 billion years for earth rocks and 5.5 billion years for moon rocks have occasionally been reported, but such results are generally regarded as unreliable . At the other extreme, there are still a number of fundamentalist Christians, or creationists, who believe that the earth -- and in fact the whole universe -- is only a few thousand years old .
According to Hindu philosophy, the age of the earth (to the year 2000) is 1,972,949,101 years . The earth will live for a total of 4.32 billion years -- a 'day of BrahmÔ' -- after which it will die and its lower elements will disintegrate. After a rest-period or 'night of BrahmÔ' of equal length, it will reembody. H.P. Blavatsky stated that these figures were more or less in accordance with the teachings of the Trans-Himalayan Brotherhood, for which she acted as messenger. Has radiometric dating rendered the theosophical age of the earth invalid, and exposed the Brotherhood of Adepts as a bunch of amateurs? Only if we accept the key assumptions on which the method is based -- namely, that radioactive decay began as soon as the earth formed, and that decay rates have remained absolutely constant throughout the earth's history.
Each radioactive atom or isotope has a characteristic half-life, which is the time required for one-half of any given quantity of the atom to decay. Half-lives range from over a billion years to less than a billionth of a second. Experiments have shown that decay rates are not significantly affected by pressure and temperature, chemical reactions, and gravitational, magnetic, and electric fields. This is because radioactivity results mainly from very stable properties of atomic nuclei -- properties which scientists claim to be totally unchanging. However, there is a small measure of uncertainty (of up to 2%) in measured half-lives. This means that extremely slow changes in decay rates could go unnoticed for a very long time. Considering the short period that scientists have been making such measurements, it is premature to conclude that decay rates are absolutely unvarying. It is interesting to note that carefully conducted experiments in psychokinesis have shown that radioactive decay can be influenced by the human mind -- but such results are of course ignored by mainstream science .
In theosophy, the earth's evolution is divided into an arc of descent and an arc of ascent . During the descending arc, which comprises the first half of the earth's life, the earth condensed from its original ethereal condition into an increasingly dense and material state. At the midpoint of human evolution, some 4.5 million years ago , the ascending arc began, during which the earth will gradually become more ethereal again. Radioactive decay is a sign of etherealization, and has only become the dominant trend since the start of the arc of ascent, prior to which there were only temporary episodes of radioactivity . At present there are 118 known chemical elements. All the elements from uranium (atomic number 92) upwards, are very unstable; some do not exist in nature and are known only because they have been artificially created in the laboratory. It is quite likely that several million years ago, when the earth reached its deepest point of materiality, there were more stable elements than there are today. With the commencement of the upward arc, the heaviest elements are the first to become radioactive, but as times goes on, lighter elements will also become unstable, and decay rates will tend to increase.
Thus, theosophy does not just say that decay rates have been slower in the past, but that most of the earth's history to date has been characterized by the concretion of matter -- the opposite of radioactivity. On the upward arc, heavier elements tend to disintegrate into lighter elements, whereas on the downward arc lighter elements tended to integrate into heavier elements. Radiometric dating currently makes no allowance for this. In the uranium-lead dating method, for instance, it is generally assumed that all the uranium in a rock has been present from the time it formed, and that the lead has been produced mainly by the decay of the uranium; the possibility that the uranium was partly produced by the materialization of lead is not considered. Due to the flawed assumptions on which radiometric dating is based, it results in ages that are far too old; at best, it gives only relative dates, not absolute dates.
Scientists recognize that light elements can turn into heavier ones by means of nuclear fusion, but the prevailing belief is that this can take place only at temperatures of millions of degrees, such as are thought to exist in stars. However, biologist Louis Kervran and a number of other researchers have demonstrated that, in both living organisms and the mineral world, some common elements are transmuted into heavier elements without the need for extremely high temperatures and pressures, and some are transmuted into lighter elements . Orthodox science does not bother to study these subtle, alchemical processes because it is already convinced that they cannot exist. 'Cold fusion' is another anomalous phenomenon that has largely been shunned and sidelined by the scientific establishment . The term covers a variety of poorly understood nuclear reactions but, in contrast to 'hot' fusion, these take place at low temperatures and in relatively simple devices, instead of in reactors costing millions of dollars. Clearly, mainstream scientists are in no position to decree what is or is not possible in nature!
The earth's history is divided into a series of geological periods, whose boundaries are often marked by geological convulsions, biological extinctions, and the sudden development of new species. According to theosophy , sedimentation in the present, fourth round of the earth's evolution began in the Laurentian period, towards the close of the Precambrian era, about 320 million years ago (corresponding 'scientific' date: about 640 million years). This was followed by the Paleozoic era (the age of trilobites and fishes), which began with a rapid and unprecedented proliferation of marine organisms (the 'Cambrian explosion'), and ended with the greatest extinction event in earth history. It was followed by the Mesozoic era (the age of reptiles), and then the Cenozoic era (the age of mammals). The main theosophical and scientific dates are given below:
Paleozoic: began about 240 million years ago (science: 540 million)
Divided into: Cambrian, Silurian, Ordovician, Devonian, Carboniferous, Permian
Mesozoic: began about 44 million years ago (science: 245 million)
Divided into: Triassic, Jurassic, Cretaceous
Cenozoic: began about 8 million years ago (science: 66.4 million)
Divided into: Tertiary (subdivisions: Paleocene, Eocene, Oligocene, Miocene, Pliocene);
Quaternary (subdivisions: Pleistocene, Holocene)
The Quaternary period began with the Pleistocene ice age, about 870,000 years ago (science: 1.6 million), which ended with the extinction of many species of large mammals around 10,000 years ago, during the transition to the Holocene or Recent epoch.
Most scientists have so much faith in the radiometric timescale that independent verification of it is no longer considered necessary. There are, however, indications that it might be wrong. For instance, by counting the fine rhythmic layers making up the 3800-metre-thick Tertiary deposits of Burma, L.D. Stamp concluded that the duration of the Oligocene and half of the Miocene was about 2.5 million years . This figure is consistent with estimates based on measurements of present-day sedimentation rates. It is also exactly equal to the theosophical figure. The corresponding figure based on radiometric dating, on the other hand, is 22 million years.
Although the main reason for the discrepancies between the scientific and theosophical timescales is the false assumptions underlying radiometric dating, another relevant factor is the length of the earth-year. In theosophical dates, a year simply means one revolution of the earth around the sun, however long it may take. Radioactive half-lives and the dates derived from them, on the other hand, are based on the length of the earth-year as it is at present. If a year was much longer in the past, this would account for part of the chronological differences. Scientists do in fact claim that there were more days in a year in the distant past, but they say that this is because the earth used to rotate more rapidly, not because it took longer to orbit the sun. Growth rings in fossil corrals supposedly confirm that there used to be about 425 days in a year in the early Paleozoic, but this interpretation of the rather contradictory data has been challenged by some scientists . According to theosophy , the number of days in a year averages 360 over the course of the earth's lifetime -- i.e. the earth rotates on its axis an average of 360 times during each revolution around the sun; at times, such as at present, there are slightly more days in a year and at other times slightly less. The absolute length of the year is likewise said to both lengthen and decrease, and it therefore probably plays no more than a minor role in explaining the discordances between scientific and theosophical dates.
Scientists seek to reconstruct the earth's history by examining the distribution and sequence of rock strata, their physical characteristics, and the fossils preserved in them. The ages assigned to these strata are of secondary importance. When correlating scientific findings with the information on the earth's history provided by theosophy, it is therefore important to focus on geological periods rather than years. For instance, theosophy says that the first apes arose in the Miocene, beginning about 4 million years ago, as a result of cross-breeding between undeveloped humans and simians. According to science, the primitive ape-like hominids known as the australopithecines also appeared around 4 million years ago. Given the difference between the theosophical and scientific timescales, the fact that these dates are the same clearly indicates that they do not refer to the same event! The 4-million-year date assigned by science to the earliest australopithecines places them in the late Pliocene -- millions of years after the appearance of their distant ancestors, whose fossils are found in Miocene strata; it is to the latter event that the theosophical date refers.
The Quaternary is sometimes called the 'age of man'. From a theosophical viewpoint, while it is true that our own fifth root-race or humanity rose to dominance during this period, recognizably human beings, with self-conscious minds, emerged over 18 million years ago in the Mesozoic, and the beginning of human evolution in the fourth round dates as far back as the mid-Paleozoic, when humans had huge ethereal forms. Our journey through the human kingdom on this planet embraces vast, unimaginable periods of time. However, it is not so much the attaining of some far-off goal of relative spiritual perfection that is important, but how we handle the challenges and adventures we meet along the way.