In 1920, Edwin Hubble, a leading astronomer of the twentieth century, discovered that the Universe is expanding by proving that there is a direct relationship between the speeds of distant galaxies and their distances from Earth. His work showed that most galaxies were receding from the Milky Way and that the further away they were, the faster they were receding. It was later found out that the constant ratio between speed and distance was 500 units of kilometres per second, per megaparsec (Meaning a whopping 73.8 km per second!).
It started with the Big Bang, around 13.7 billion years ago, when a massive expansion blew space up like a gigantic balloon. After the expansion, intense energy radiating from the heat of the relative singularity happened and caused the universe to expand rapidly so that everything became less dense and cooled down. This brings us to today—everything we can touch, feel, sense, measure, or detect comes from our universe. The home of living things, planets, stars, galaxies, dust clouds, light, and time.
When the term “expanding universe” is used, we often think that it grows like us, bit by bit every now and then. In reality, it’s growing constantly. Every 60 seconds, every 24 hours. Cosmologists have based their answers on the expansion rate of the measurements of radiation emitted by the Big Bang, revealing the exact ingredients of early existence. With this, they are then able to see how quickly space should be expanding that day.
The way the universe expands is no different than our mind. Our mind does not expand into anything else, we just get less dense. In the Universe’s case, it isn’t perfectly even: it has overdense realms, such as planets, stars, galaxies, clusters of galaxies, and underdense realms (like great cosmic voids where there are virtually no massive objects present in any respect). The reason for this is that there are other physical occurrences besides the Universe’s enlargement. On miniature scales, like animal-sized and below, electromagnetism and nuclear forces take charge. On larger scales, like that of planets, solar systems and galaxies, gravitational forces dominate. The big game is on the largest scales of all: on the system of the complete Universe.
The reason that this expansion feels small is that the expansion itself isn’t a force, but rather a rate.
Space expands on all scales, all directions, at all times, but its expansion only affects things in an accummutalive way. There’s a speed that space will expand between two destinations, but if that speed is lesser than the releasing momentum from those two points, there’s no increase in the distance within them. If there isn’t an increase, the expansion has no impact whatsoever on its surrounding objects. This means that the stars, our planet, solar system, sun and moon will remain untouched.
Even though we live in a universe that is constantly expanding, it has no impact on our lives because the speed of this expansion in space is incredibly small. The chances of this becoming a risk are close to nothing.
Originally Published on www.bandersnatch.ca Vol.50 Issue 02 on Wednesday, September 23rd, 2020