I remember reading in some of the talks of Venerable Hsuan Hua, (see for instance
http://cttbusa.org/shurangama5/shurangama5_10.asp), that in the the current era of decline, the average life-span of humans decrease by one year every century, and the average height of humans decrease by one inch every century. This will continue until the average life-span is 10 years, and the average height is 10 inches. At that time people will have sexual desire from the time of birth, and they will also be able to kill from the moment they are born. Then the average life-span and height will increase by one unit every century until the life-span is 84000 years, and the height of humans is 84000 inches. Then decrease again at the same rate, and when the life-span is 80000 years, and the height is 80000 inches, (at that time humans will have white blood) Maitreya will descend from Tushita to manifest Buddhahood. He will teach all those connected with him in a single day and night.
If this is correct, then the time until we reach bottom should be (66 (approx. current life-span)-10)x100 = 5600 years, then the period until the peak of 84000 would be (84000-10)x100 = 8399000 years, and then the period until Maitreya comes would be (84000-80000)x100 = 400000 years. So then it should be approximately 8804600 years until Maitreya appears.
Also if this way of calculating is correct, at the time when Shakyamuni lived, if this was 2400 years ago, the average life span should be 66 + 24 = 90 years, but I have read some places that the average life-span at the time of Shakaymuni was 100 years, but then once I read it was supposed to have been between 70 and 80. If the life-span at the time of Buddha was 100 years, and the current life span is 66 years, and it did indeed decrease by one year every century, then shouldn't Buddha have lived 3400 years ago? Do you know which of all this that is correct?
Is the time of the enlightenment of Shakyamuni Buddha known? Is the age and height of humans of that time known?
Do any of you know about text translated into English that describes such things in detail? Is it from the
"The Fortunate Eon" the best source for this?