It’s my understanding that in astronomical distances, things can be moving further apart by the space between them expanding, *not* simply by motion.
For example, say you have star A, 1 million light years from star B, both completely motionless for argument. These stars have a relative motion because the space between them expands, correct? So 1 million light years becomes 1,000,007 light years after 1 year of time.
If all that is true, does this affect smaller scale measurements? Does a mile of road technically become 1.000007 miles? Please let me know what I’m not understanding.
In: 6
Matter itself doesn’t expand. Matter held together by gravity or molecular bonds isn’t ripped apart because those forces are way, way stronger than the expansion of space itself. If this expansion keeps accelerating without end, eventually the space between the Sun and Earth will expand faster than gravity can keep them together, and eventually eventually the space between molecules, atoms and particles will expand faster than their forces can keep them together. Fortunately for our descendants 100 billion years in the future, what little evidence we have tells is that the [Big Rip](https://en.m.wikipedia.org/wiki/Big_Rip) isn’t the fate of the universe.
Latest Answers