Is the universe expanding? what is actually expanding? will the expansion slowly come to a halt and bring the universe falling back in on itself or continue to float apart but at a slower rate?
- The first piece of evidence that our universe is expanding came from distant galaxies, as light travels through the expanding space the photons themselves become stretched.
- In 2016 astronomers discovered GN-z11 a galaxy with the furthest distance ever seen – 400 million light years away, fast forward to today the galaxy is 32 billion light years away.
- we know the universe is 13.75 light-years old so how could there be a galaxy exceeding far beyond the 13.75 billion light-year distance – how is that possible?
- The mystery of the ever-expanding universe from a single point of singularity to everything that now exists is attributed to the big bang.
- The accelerating expansion is a phenomenon that has never been observed before, scientists assumed the big bang would slow down and gravity would pull things back together, but that is not what they were seeing in the cosmos – the universe seems to be expanding at an accelerating rate – we have no idea of what is causing it – dark energy.
- The mysterious Dark energy makes up 70% of what is out there in the cosmos, it’s stronger than gravity and may be stronger than the forces that hold the atoms together.
- we can’t see it directly since light can’t travel through such a dense and perversive field, unlike normal matter, it doesn’t behave as anything physicists know about – in reality there is no physical evidence for this.
- There is no way how dark energy can interact with matter or radiation, it just operates in a different manner.
- At the moment of the big bang, this dark energy was created as soon as expansion began, its expansion has been constant but not mainly uniform in nature – there are regions where expansion happens much faster.
- The constellation named Hydra has a relatively faster expansion rate and due to this all galaxies there will be outside our cosmic horizon – all the information they contain about their existence will be lost forever.
- imagine if this was to happen today on objects near us, say a planet and solar system – our future generations would not know that there was something called Jupiter or Saturn.
- We don’t know yet why this expansion occurs in the first place but one popular speculation is that expansion happens due to the mechanism called vacuum metastability – expansion might be due to the idea the universe is in a quantum fluctuation from nothing.
- The rate grows exponentially due to a feedback loop that feeds on dark energy tension.
- Imagine the expansion of the universe continues to infinity – maybe it will become weaker at some point but it will never stop, so what happens when the expansion wouldn’t pull everything back together
- The expansion will halt at some point – the expansion becomes weaker and gravity grows stronger and everything falls into a black hole.
- Expansion is slowed down until gravity overcomes expansion power – leading to a cycle of gravity and expansion power taking over from each other the cycles repeat themselves and there will never be an end to the universe.
- Expands forever until all matters are ripped apart into nothingness.