What with timestamp 10000-01-01 00:00:00000000000?

Oracle defines the maximum of a date (or timestamp) to be 9999-12-31 23:59:59(.999999999). Nonetheless it is possible to get a date as told in the subject. It is sort of a rounding problem. If you insert 9999-12-31 23:59:59.999999999 into an attribute of type timestamp(x) with x < 9 Oracle rounds up to the date in the subject.