The Universe comprises everything that physically exists, the entirety of space and time, all forms of matter and energy, and the physical laws and constants that govern them. However, the term Universe may be used in slightly different contextual senses, denoting such concepts as the cosmos, the world, or Nature.
Current interpretations of astronomical observations indicate that the age of the Universe is 13.73 (± 0.12) billion years, and that t...
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The Universe comprises everything that physically exists, the entirety of space and time, all forms of matter and energy, and the physical laws and constants that govern them. However, the term Universe may be used in slightly different contextual senses, denoting such concepts as the cosmos, the world, or Nature.
Current interpretations of astronomical observations indicate that the age of the Universe is 13.73 (± 0.12) billion years, and that the diameter of the observable universe is at least 93 billion light years, or 8.80 × 10 metres.
It may seem impossible that two galaxies on opposite sides can be separated by 93 billion light years after only 13 billion years, since special relativity states that matter cannot be accelerated to exceed the speed of light in a localized region of space-time. However, according to general relativity, space can expand with no intrinsic limit on its rate; thus, two galaxies can separate more quickly than the speed of light if the space between...
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