Heaven and Hell are examples of spiritual realms that may go to when they die.Heaven is described as the higher place,where spirits go when they are good and Hell described as a place of eternal torture and when spirits go when they are bad.It is unknown if they,and other astral realms are within The Omniverse,as they haven't proven to exist. At least a religious person can do is to believe. Also their size are . But it's size can be also light-years. However, we are atheists.