It seems to be common knowledge that on or around the year 6,000 of the Jewish calendar "everything" (left intentionally vague) will come to an end and there will be a 1,000 year 'Shabbos'. I'm looking for an explanation as to why this is necessarily so. Meaning, why should things ever come to and end at all?
I wondered about this fact myself for a while, and so I looked up the sources.
It turns out that this idea is based on only two sources.
The Talmud has an aggadatot which says:
Talmud, Tractate Sanhedrin [97a]: “Rav Kattina said: ‘The world will exist for 6000 years and one (thousand) of destruction’ ... We have a teaching which is in agreement with Rav Kattina, as the seventh is the sabbatical year – one in seven years. Likewise the world will rest 1,000 in 7000 … ‘a thousand years in Your eyes are like yesterday which has passed …’ [Psalms 90:4].”
Talmud, Tractate Avodah Zarah [9a]: “The world will exist for six thousand years: two millennia of void (‘tohu’); Two millennia of Torah; and then two millennia of the age of Moshiach.”
However, the context of these statements are ones which in my mind, prove to be false certainties. (Not that they are false, but to state that they are certain is false) The midrashim can certainly be understood in different ways, and if understood literally, these midrashim have proven so far, to be false. Arguments against the general idea, being a "necessity" can be found here: Basically, we have "conflicting midrashim", as well as knowledge that the physical planet is not only 5772 years old.
I should add, that there is an opinion that there have been many 7,000 year cycles already. (mentioned in the link above, in some midrashim) So the fact that things rise and fall, and come in cycles is no chidush to the world we live in. The idea that once the 7,000 year cycle is over, that there will be no more cycles after that, is also unfounded. In some ways, since the invention of the steam engine, or the internet, (and a myriad of other historical events) the world has ended "as we know it."