The Million Year is a time unit often used in astronomy and geology of one million years. It is also abbreviated as J. million or in the literature based on the SI units by Ma ( "Mega - years "). Accordingly, there are also Ga for billions of years, an indication of ka for a thousand years but not used in practice.
Since the human imagination fails in such long periods, the year a million is often made clear by comparison. One million years include:
- ( Was reckoned from the 3000 BC) 200 times longer than the period of our history
- About a thousand times longer than the longest-lived civilization
- About 35,000 generations
- Few percent of the duration of orogeny.
Geologically, interested persons can refer to the following consideration: all seemingly so solid rocks such as granite or slate behave plastically over very slow bending. Only when these accounts for more than about 1 mm per year, they break.
- In the high mountains large folds are sometimes seen in the rocks of a steep mountain slope. If these 1,000 m high, took their origin ie about 1 million years.
- The Alps stand for millions of years still - currently about 1 to 2 mm per year. This is about 10 times slower than a tree trunk in thickness increases.
- In Figure 1 million years to "grow" the Alps, then, assuming a constant growth rate to 1,000 to 2,000 m.
- At the same time they are removed at a similar rate of wind, water and ice - by crash of each summit, for example, for 1000 years, a one to two meters thick " layer " of rocks at depth.