Exploring Astronomy Photography Of Outer Space Universe

• Definition as reality
More customarily, the universe is defined as everything that exists, (has existed, and will exist). According to our current understanding, the universe consists of three principles: spacetime, forms of energy, including momentum and matter, and the physical laws that relate them.
• Definition as connected space-time
It is possible to conceive of disconnected space-times, each existing but unable to interact with one another. An easily visualized metaphor is a group of separate soap bubbles, in which observers living on one soap bubble cannot interact with those on other soap bubbles, even in principle. According to one common terminology, each "soap bubble" of space-time is denoted as a universe, whereas our particular space-time is denoted as the universe, just as we call our moon the Moon. The entire collection of these separate space-times is denoted as the multiverse. In principle, the other unconnected universes may have different dimensionalities and topologies of space-time, different forms of matter and energy, and different physical laws and physical constants, although such possibilities are currently speculative.