Ancient Earth

One slightly surprising question that has popped up since this web site went online is: how do I know that the Sun and Earth are billions of years old, as as I say they are -- as opposed to being just a few thousand years old, as some people claim?

Young Earth Calendars

Some modern creationists (though by no means all) fall into the Young Earth camp, believing that a literal interpretation of the Bible proves that the Earth can't be more than about 10,000 years old at most. Since this is the view that comes most into conflict with my statements, for example, about the age of the Sun, this is what I shall explore in this page.

The dating of the Earth based on interpretations of genealogical lists in the Bible goes back a few centuries, and has produced varying, though broadly consistent, results. For instance, Archbishop Ussher calculated that the Earth was created in the 6 days beginning at nightfall on October 22, 4004 BC; other scholars placed the creation in 3929 BC (John Lightfoot), or 3949 BC (Scaliger), or 3952 BC (Bede). This was coupled with a general supposition that the Earth was scheduled to last for 6,000 years before the end of the world; which would have happened in 1996, by Ussher's calendar.

These calendars obviously came into conflict with the developing scientific view of the world -- evolution is often cited as the problem, but in fact the scientific view was based on many separate strands of thought from biology, astronomy, and geology -- and also came under heavy fire from theologians. Science produced more and more evidence which pointed to an Earth billions of years old; and with the major Christian churches eventually adopting the "ancient Earth" view, Ussher's calendar, and the others like it, were essentially abandoned until the rise of the Young-Earth Creationist movement in the 20th century.

Young-Earth Creationists (as opposed to other Creationists, many of whom have no problem with the ancient Earth, or with evolution) hold to a literal interpretation of the bible as a history of the Earth, and many of them have adopted Ussher's calendar as being at least an approximately accurate timeline of the Earth's history. Such people have a problem with statements that the Earth is 4.5 billion years old, or that the Sun is 5 billion years old, and have asked me to explain how I can be so sure; since no-one was around to observe and record the Sun billions of years ago, how can we know that it is really that old?

The rest of this page is my attempt to explain that.

The Scientific Evidence

The first thing to mention is that I didn't come up with this age for the Sun and Earth -- that was done by expert astronomers and physicists (backed up by biologists, chemists, geologists, etc...) the world over. Since I'm not any kind of professional scientist, or any kind of expert at all, I don't have the background to put the case behind the results in detail; but I will attempt to explain what I know of the theory as best I can. I'll probably make some mistakes, but hopefully I can convey at least the size and shape of the scientific case. For more details, there is any amount of literature available on all the fields I will touch on below.

We know how big the Sun is, and we know (from measurements, for example of different types of radiation emitted from the centre, vibrations in the surface of the Sun itself, its magnetic fields, etc.) pretty well how it works internally. Just as an example, a recent discovery of a hitherto-unmeasured type of neutrino emission confirmed the current understanding of how the Sun works.

We know that the Sun "burns" hydrogen (loosely speaking) to make energy, and that helium is a by-product of this; and we know (from simply measuring the energy output) how fast this is happening. We know that the Sun started out as a ball of mainly hydrogen, and we know that it is now 25% helium; this helium was all produced by "burning" hydrogen.

From this we can calculate how long the Sun must have been burning to make that much hydrogen turn into helium; and the answer is 4.5 billion years or so. This figure is, of course, approximate, but the true answer is certainly billions of years -- rather than, say, 6000 years.

There are thousands of unrelated pieces of evidence that back this up. For example, the presence of radioisotopes of different kinds in the Earth, the solar system, and in the Sun itself, matches what would be predicted, based on the age of the solar system, and the known (ie. can be easily measured in a lab) rates of radioactive decay.

All of this astronomical and physical evidence ties in with the geological evidence. We know how fast rock sediments are being laid down; we know how deep they are; so we know how old any given rock layer must be. And, when we actually dig up some of those rocks, we find radio-isotopes in relative quantities that give the same age. So what we find is that these different theories -- radioactive decay, sediment deposition, etc. -- all make statements individually about the age of the Earth; but when they are brought together, they actually fit together exactly as they should, and they all contribute to a single, harmonised view of the history of the world.

The large-scale geological evidence also backs this up. Look at a map which shows the Pacific Ocean, and which shows the bottom shape. You will see a line of sea-mounts stretching northwest from Hawaii, then bending sharply north towards Kamchatka. This was formed by the Pacific plate moving over a large magma bubble; the heat pushed up volcanoes, forming sea-mounts. The largest of these broke the surface and became Hawaii. The bend was made when the Pacific plate started moving in a different direction. We know how fast the plate is moving, and so we can tell how old that line of sea-mounts is (hundreds of millions of years); and when we dig up the rocks and date them, that's what we find.

Similarly, the structure and composition of the universe (composition both in terms of stars and galaxies, and in terms of sub-atomic particles) all tie up with the universe being about 14 billion years old. For example, the galaxies are all where they would be, and moving in the directions in which they would be moving, and at the speeds with which they would be moving, if they had all exploded outwards from a central point around 14 billion years ago.

Again, this is backed up by myriad separate pieces of evidence. One example is the cosmic microwave background radiation; this is actually the remnant of the Big Bang, and its structure, intensity and dispersal are all consistent with it being about 14 billion years old. Of course, there are many unknowns (and always will be), so this figure is approximate, but in the 10 to 20 billion years range -- certainly not 6000 years.

Closer to home, analysis of ice cores from the Arctic and Antarctic shows climactic variations over millions of years; these cores also contain remnants from geological and astronomical events (dust from volcanoes and asteroid impacts), illustrating once again how each piece of evidence stands not alone, but is supported and supports many other strands.

All of these pieces of evidence mesh together, and tie in with the fossil record, both in terms of our (incomplete) understanding of evolution, and in terms of carbon-dating of fossils, and other techniques. Explored meteor impact craters match the extinction events visible in the fossil record, and with changes in rock strata, and dust deposits in ice cores, and with our understanding of how asteroids form and move around in the Solar system, and with observed climate changes, etc., etc. It's a huge, phenomenally complex, multi-dimensional jigsaw; we don't have all the pieces, but every piece we have locks into dozens of other pieces, and the overall shape is clear.

So, given that there are literally millions of scraps of evidence, and that they've been scrutinised for centuries by many thousands of scientists, and that they all fundamentally agree, I think that the chances of the evidence simply having been misinterpreted are zero. The evidence is there, and it is clear and unambiguous -- given the degrees of approximation stated above.

Conclusion

So, it seems to me that there exists in nature a very solid evidential structure that clearly indicates an ancient Earth (and universe). As far as I can see, this leaves two possibilities:

A.

The universe is about 14 billion years old; the Earth, about 4.5 billion years.

B.

God created the universe about 6000 years ago (or whenever you like), but he deliberately created "fake" evidence to give the impression of an "aged" universe, by putting all the galaxies in places consistent with 14 billion years of expansion, by creating the microwave background radiation, by creating all kinds of radio-isotopes in quantities consistent with billions of years of decay, etc. He gave us a Sun which had already burned off half its fuel, and was already half-way through its useful life. And He made lots of dinosaur bones, and buried them under deep rock strata to make us think they were millions of years old.

Either of these options is possible; however, in the case of B, I would have to say that I can't see the point. It is interesting that B would absolutely prove the existence of an omnipotent God, since only He could arrange things like this on a universal scale. But it still seems like a strange thing to do.

Some people defend B, calling it the "Omphalos Hypothesis", arguing that the appearance of age is necessary for function; for example, the world would not work without mountains and canyons, so God put them there, thus creating the impression of an aged Earth. Under this theory, Adam must have had a navel (Greek "omphalos"), despite having been created as an adult. This theory is not widely popular, as it has many problems; for example, as far as I can see, the world would work perfectly well without all those old dinosaur bones in the ground.

Personally, I'm betting on A.

Note that this absolutely does not mean that there is no God. I certainly think that Archbishop Ussher's calendar is wrong; but that doesn't mean that the universe wasn't deliberately created, or, indeed, that humans weren't deliberately created -- only that the method was more subtle than direct creation. God could have created the universe by setting up the laws of physics, assembling all of the mass and energy matter in one place, and letting it fly -- with the appropriate initial arrangement of physical laws, mass, and energy, an omnipotent God could certainly arrange things so that humans would eventually emerge from the mix. What does God care if it takes 14 billion years?

Further Reading

So that's my view; as for the scientific aspects, there are millions of resources you can use to confirm the individual details for yourself. Rather than try to provide a huge list, I'll point you to the excellent Talk.Origins website, which has an excellent library of information on this topic, including much more detail than I have presented here. There are also links to more information and other resources.

I also highly recommend Bill Bryson's beautifully written and highly accessable book, A Short History of Nearly Everything, which provides an excellent account of the development of the modern scientific view.