Nothing was surround before the big Big Bang.

According to Einstein's general theory of relativity, space and time together form a space-time continuum,

or manifold which has not flat but curved by the matter and energy in it.

I adopt a Euclidian approach to quantum gravity

to describe the beginning of the universe.

In this, ordinary real time is replaced by imaginary time,

which behaves like a fourth direction of space.

In the Euclidean approach, the history of the universe in imaginary time

is a four-dimensional, curved surface

like the surface of the Earth, but with two more dimensions.

Jim Hartle and I proposed a "no-boundary" condition.

The boundary condition of the universe is that it has no boundary.

In order terms, the Euclidean space time is a closed surface without end,

like the surface of the Earth.

One can regard imaginary in real time as beginning at the South Pole,

which is thesmooth point of space-time where the normal laws of physics hold.

There is nothing south of the South Pole, so there was nothing around before the Big Bang