Observable boundary: The observable universe is about 93 billion light-years across.

Expanding universe: The universe has been expanding since the Big Bang.

Limit of observation: We can't see beyond this due to the speed of light and cosmic expansion.

Flat or curved: A flat universe might be infinite; a curved one could be finite but unbounded.

No physical edge: There's no known physical "edge" to the universe.

Shape unknown: The true shape and extent of the universe remain uncertain.

Infinite possibility: The universe could be infinite, but we can't confirm it.

may be no one is sure fully