Why does the Bible seem to say that the earth is only about 6,000 years old?
First, it is important to note that the Bible does not provide a date for the creation of the earth. Some Bibles provide dates at the top of each page which are intended to indicate when the events mentioned on the page are thought to have occurred. These dates are typically taken from Archbishop James Usher (1581-1656). The Archbishop attempted to determine the date of creation and concluded that the creation of the earth started on the evening prior to Sunday, October 23, 4004. B.C. However, his conclusion must be rejected as authoritative, since the Bible does not provide enough information to come to that conclusion.
For example, the genealogies are the major source of information that one can use in an attempt to date the beginning of the creation. The first book in the Bible is called Genesis. In it one can find a list of genealogies and how long key individuals lived. By carefully adding these dates together (accounting for when each person was born and died), one is led to believe that they have a chronological record from the earliest times on the earth. One might assume that by carefully adding certain genealogical information, one can determine the date of creation. But there are two major problems with this approach. First, the genealogies throughout the Bible do not include all of the descendants; so much of the needed information is missing. Second, there are major gaps in the genealogical record. This means that one does not know how many people might actually be missing in the genealogical record. Therefore, one does not know how long these individuals lived nor how many are missing, and, consequently, one cannot accurately estimate the date of the creation.
It Looks Old
Yet, we believe that the earth is not 4.5 billion years old as claimed by the evolutionists. The first biblical clue that the earth is not 4.5 billion years old is found in Genesis 1-2 when it reveals that the first human parents were created by God as adults who were capable of having babies. They could have been teenagers, but they did not start as some sea creature emerging onto land. God also tells us in 1 Corinthians that the genetic material of human beings is different from that of other life on the earth.
But God gives it a body just as He wished, and to each of the seeds a body of its own. All flesh is not the same flesh, but there is one flesh of men, and another flesh of beasts, and another flesh of birds, and another of fish. (NASB) 1 Cor. 15:38-39
This reveals that humans are not the product of the traditional Darwinian evolutionary model. It also reveals that since the first human couple, Adam and Eve, were created as adults and since they could eat fruit from mature, fruit bearing trees, we conclude that the entire planet was created in an aged condition. That is, it appeared old. Otherwise, plants, animals, and the first couple would not have been able to grow. This is the correct conclusion for another reason. God made the stars, sun, and moon on the fourth twenty-four hour day, and yet instantly the celestial bodies provided light on the earth. Since the stars are millions of light-years away, God had to design the universe in an “aged condition.” That is, the universe already looked old. If one believes in God, this is a totally plausible scenario.
Now we will examine some very interesting “age barometers” that are not commonly discussed. According to evolutionists, the earth was a molten mass of material that was flung by the big-bang out into space. The second law of thermodynamics says that all hot objects will cool down over time and eventually become cold. That is, the molten mass will become hard like a rock. Now for the interesting question, “How long would it take the earth to cool down?” The answer will reveal the age of the earth.
According to the second law, if the earth was once a molten mass (i.e., the hottest such a solid body could be -perhaps because it was flung off from the whirling young sun), then it could not be infinitely old or it would have cooled down to be an entirely solid body. Volcanoes, and temperature measurements made in deep mine shafts, showed that the interior of the earth was very hot. By using such measurements, and a mathematical model of heat flow from the earth’s surface, Kelvin calculated that [he earth could not be more than 100 million years old. Further refinements of his calculations brought the maximum age down to only 24 million years.” 
It is common knowledge that rivers are called “fresh water” because they do not contain salt or sodium like our oceans and seas. The oceans and seas are salty because salt from the mainland is washed into the rivers which flow into the oceans. If we assume that the oceans and seas contained no salt immediately after the big-bang, then we can calculate a maximum age for the world.
He calculated that all the sodium in the sea (in the form of common salt, sodium chloride) could be accounted for in 99 million years. Salt is carried into the sea by the world’s rivers, but when the water evaporates from the ocean, it leaves the salt behind. Therefore, if we assume that the starting condition is zero salt, that the annual input is what we observe today, and that there has been no loss or gain in the accumulating salt, then the salt clock should be a fairly reliable chronometer and give us an approximate age for the earth. When he corrected for the presence of some original sodium, he came to an age of 89 million years. 
So far, we have two clocks that indicate the maximum age of our planet is 99 million years of age, if we assume that there was no salt in the oceans in the beginning. It should be noted that the oldest salt lakes on the earth reside in Australia. They yield only a few thousand years for the age of their origin. 
Another clock involves radioactivity.
Although it was not well understood to begin with, radioactivity was quickly perceived [in 1896] to be a source of energy, and if the earth’s rocks contained their own heat source then Lord Kelvin’s calculations must be wrong. In 1913, Arthur Holmes published the first book on the age of the earth using radioactivity (see isotope daring diagram below), and while much still remained to be clarified, he claimed that the most ancient rocks must be at least 1.6 billion years old, so the earth must be older than that. In 1956 Claire Patterson used isotope ratios in meteorites to obtain a figure of 4.55±0.07 billion years, and the age of the earth has not changed since then.
How old are the comets? Comets are composed of water, methane, and ammonia along with dust. That is, they are snowballs. The following statement concludes that the comets give us a maximum age of the universe of 10,000 to 100,000 years.
They orbit the sun in an elliptical pattern and every time they come near the sun, some of the ice is evaporated and blown away by the solar wind – thus creating the characteristic “tail” that always points away from the sun. Because of the evaporation problem, comets cannot survive too many close encounters with the sun and so have maximum lifetimes in the range of 10,000 to 100,000 years. Evolutionists therefore require a mechanism to replenish the supply of comets. They propose that a reservoir of long-period comets exists in the “Oort cloud,” way out beyond the orbit of Pluto, and a reservoir of short-period comets exists in the “Kulper belt,” just outside the orbit of Pluto. The Oort cloud has never been observed, and the objects so far located in the Kulper belt are too big to explain the observed comets. 
The earth’s own magnetic field is another clock that we can use to determine the age of the earth.
The earth’s magnetic field is supposed to be maintained by a “dynamo” in its interior, fueled by the rotation of the planet around a molten core. One of many problems with this theory is that the strength of the field is decaying at a rapid rate, while the mechanism (the rotation and the molten core) remains constant. A better explanation, as mentioned earlier, is that the magnetic field was created in place and is now freely decaying. Using this theory, Humphreys predicted the magnetic fields of all the planets, and the results upon subsequent measurement matched far better than the dynamo models. Freely decaying magnetic fields in all the planets thus point to a young solar system. 
What about the stars?
Closer to home in our own galaxy, supernova remnants provide a time scale that defies explanation in the big-bang time frame. When a star explodes as a supernova, its remnants are scattered into space in all directions. Many of these remnants provide spectacular viewing for astronomers. Models of the physical processes involved suggest that three separate stages occur. The first stage, up to the point where a blast wave forms, emits lots of energy and endures for about 300 years. The second stage strongly emits radio waves and lasts about 120,000 years. The third stage emits little energy and lasts for 1 to 6 million years, after which it becomes no longer visible. Since it is believed that supernovae occur in our galaxy about once every 25 years on average, there should be thousands of second-and third-stage remnants if the galaxy is really billions of years old. However, only about 200 stage two remnants have been found, with no stage three remnants found at all.” Since the Milky Way galaxy is also a spiral galaxy, the combined testimony of its evident spirals (not wound up yet) and its missing supernova remnants powerfully supports our young-earth scenario. 
This clock reveals that the earth cannot be much older than 120,000 years. This clock does not support the estimate of 4.55±0.07 billion years for the age of the earth.
All of these clocks assume that the earth was not created in an aged condition. Those clocks suggest that the earth is very young – probably less than 10,000 years.
Dismantling The Big Bang, by Alex Williams and John Hartnett
1. Alex Williams and John Hartnett. Dismantling The Big Bang. Master Books. 2005, p.187.
2. Ibid, p.187-188.
3. Ibid, p. 196.
4. Ibid, p. 188.
5. Ibid, p.198.
6. Ibid, p.199.
7. Ibid, p.202.
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Is it not laughable to think of dinosaurs in the ark?