The universe, already impressively big compared to say, a planet, is expanding. According to the cosmic microwave background (CMB), this expansion is happening at the rate of about 67.5 kilometers (41.9 miles) per second per megaparsec (3,260,000 light-years). Meanwhile, measuring the distance of Cepheids stars – by observing how their light has redshifted as it loses energy on its long journey across the universe – leaves us with an estimated expansion rate of 73 kilometers (45.3 miles) per second per megaparsec.
While the astronomical community attempts to refine the expansion of the universe and attempt to explain the “Hubble tension”, very few scientists are of the opinion that it isn’t expanding at all. The distance between us and other stars is increasing, and one day this will result in our observable universe becoming smaller. There are puzzles to be figured out about the expansion rate. Observations suggest the expansion is accelerating, suggesting dark energy and exotic dark energy – or another explanation far beyond us – may be needed to explain it.
While interesting, people of the Internet have more basic concerns about the whole deal; namely, if the universe is expanding, are we expanding along with it?
While it may be fun to mock such questions (like why the magnet car won’t work) it’s a reasonable thing to ask for people first coming across such concepts as the expansion of the universe.
The short answer is no. The matter that you know and love, from olives to Danny DeVito, is not expanding along with the universe.
The expansion of the universe only affects regions of the universe not bound together by other forces. So the expansion does not affect the distance between the objects in the Solar System (e.g. between the Earth and the Sun) as they are held together by the force of gravity. Meanwhile gravitationally unbound objects – e.g. two galaxies far enough away from each other to not be held together by gravity – move away from each other as the space between them expands. The galaxies themselves, bound together by the gravity of matter and (far more prevalent) dark matter, do not expand, just the space between them.
The atoms that make up you, Danny DeVito, and olives, meanwhile, are held together in their pleasing clumps by the strong nuclear force, the electromagnetic force, and the weak nuclear force. The expansion of the universe does not overcome these forces (much stronger than gravity, the weakest fundamental force, that nonetheless binds the planet together) and so you do not have to worry about yourself inflating along with the universe.
All “explainer” articles are confirmed by fact checkers to be correct at time of publishing. Text, images, and links may be edited, removed, or added to at a later date to keep information current.
Source Link: People Are Asking If The Expansion Of The Universe Includes Them
