what is univarsal set? Does it contain all the numbers from {-infinite ,......, infinite}?

Depending on the context, the Universal set is a set that is the superset of all the sets being considered.

Universal set refers to a particular context.

It is the basic set that is relevant to that context. The universal set is usually denoted by U, and all its subsets by the letters A, B, C, etc.

Universal set contains every thing that is relevant to the problem you have.

While speaking about the set of divisors of a number or the numbers, the universal set can be set of natural numbers, as we will not go beyond the natural numbers while considering the divisor of a number.

When we discuss the numbers that represent the sides of a triangle, we take the universal set as the set of positive real numbers because the sides of a triangle cannot be given by negative numbers.

For our solar system universal set  can be milky way   galaxy.