Bang Crunch Bounce Rip

I still think it’s funny that they say the universe was conceived in a “big bang”.... I know it’s just as childish as laughing at “Uranus” but come on! “Big Bang”! Really!? This is the start of the universe, sound wouldn’t exist and the physicists that coined the term had to know that! I think ‘bang’ never meant sound... It was an inside joke that went too far and now no one wants to fess up to correct it, it just doesn't make sense any other way. Part of why it’s too late to change this inside joke is this terminology has been exported to some of the theories of the end of the universe as well such as; the “big crunch” "big bounce" and the “big rip”.

rtist's conception of the observable universe with the Solar System at the center,with a logarithmic scale showing the universe further out: Kuiper belt, Oort cloud, Alpha Centauri, Perseus Arm, Milky Way galaxy, Andromeda galaxy, nearby galaxies, Cosmic Web of galaxies, Cosmic microwave radiation and the Big Bang's invisible plasma on the edge.

Let's start just like everything else with the big bang. When looking at distant galaxies we have noticed that the vast majority of them are traveling away from us. And the ones that are further from us are going away from us faster than ones that are nearby. We make sense of this observation by saying the universe is expanding.

As the universe expands things that are farther away move farther away faster. In this picture The raisins represent galaxies. One raisin is 5cm the other 10cm when baked the bread becomes twice as big moving the near raisin 5cm (to 10cm away) while moving the far raisin 10 cm (to 20cm away) over the same amount of time.

Like baking a raisin bread when you put dough in an oven and take it out later and it has doubled in size as bread. If you saw this in the perspective of a raisin you might start in the dough with raisins spaced uniformly 1cm apart meaning a raisin's closest neighbor raisin would be 1 cm away next is 2 cm next 3cm and so on. Once the bread doubled in size the closest one would now be 2cm away next 4cm, 6cm and so on. This doubling effect would appear to the raisin that everything was moving away from it with things further away from it moving faster away.

Using this observation we can infer that if we rewind the clock we would find that earlier in the universe these galaxies were much closer to us. And rewinding all the way back it’s thought that there was once a time that everything in the universe was tightly packed in one place and started t=expanding from there we call this “the big Bang” *snickers*

Timeline of the universe. Starting with the big bang at the far left and ending 13.77 billion years later with the present day at far right.

Now let’s turn the clock forward and see what this could predict for the future. As the universe currently expands there’s 3 ways this could end:

1. The universe stops expanding and starts contracting

2. The universe stops expanding at some point and stays static

3. The universe expands forever

The first scenario seems to be favored by most people I talk to, I think it's human nature to favor cyclical or symmetric cycles of the universe forming at one point, expanding and then boomerang back to contracting to one point. This is possible as the force of gravity pulls mass together so it would be conceivable at some point this force will slow the expansion to a stop and revise to pull everything back together. This is called “the big bounce” or “the big crunch”. If the universe contracts back to one point and ends there it would be a big crunch. If once the universe is back to one point it starts to recycle and gives rise to a new universe, in a new big bang, then it would be a big bounce.

Galaxies merging in a “big crunch” this might result in a new universe but life in this universe wouldn’t be able to survive

The second scenario where the universe just stops expanding and stays still seems to be the least likely and most boring. This is often called a “flat universe” where the universe will find some equilibrium and remain static until heat death (see previous blog) or some other fate ends the universe.

The last scenario of the universe continually expanding seems to currently have the most evidence to support it. There is no indication that the expansion is slowing at all, actually it appears to be speeding up if anything. There seems to be an unknown force that is pushing to expand faster and faster. We call this force Dark energy, If you think back to the raisin bread analogy, dark energy is like the yeast that makes the bubbles that ultimately makes the bread expand. This is called “the big rip” as there will be a point where all galaxies that are not tied to our gravity will be traveling so fast so far away from us that not even their light will reach us. Future astronomers might not believe or have the records we keep of other galaxies and become convinced that the universe is only our galaxy or our local group of galaxies. It’s kind of ironic that the scenario of an ever expanding universe ends with life having access to a smaller and smaller portion of the universe.

a graph showing the size of the universe over time omega is basically a ratio between the force of dark energy over the force of gravity if the forces equal out ohm=1 and it is a flat universe if gravity is bigger ohm>1 and we have a big crunch/bounce if dark energy is greater than gravity then ohm<1 and universe will expand forever.

So it all comes down to a fight between the known Gravity and the unknown Dark Energy. If Gravity is stronger than Dark Energy then we will have a big crunch or big bounce. If gravity is exactly equal in strength to dark energy we will have a flat universe. And finally if dark energy is stronger than gravity our universe will end in the big rip.

So could life survive any of these ends?... probably not but maybe. Famously in the hard SciFi novel “Tau Zero” author Poul Anderson describes how a crew on a spaceship with a damaged engine is propelled outside the condensing universe and watches as a big bounce happens the universe condenses until they watch another big bang create a new universe.

Tau Zero a hard science fiction novel by American writer Poul Anderson. The name comes from time dilation tau being proper time and as the ship gets closer to the speed of light tau approaches zero. A small tau means big time dilation towards the end tau is so small the crew experiences "billion-year cycles which pass as moments"

Outside of Tau Zero, if the universe is cyclic like this it’s probable that this might not have been the first cycle of the universe and our very presence shows that life can survive a big crunch or at least sometimes develops/redevelopes between bangs and crunches.

Surviving a flat universe is simple as there is no cataclysmic end that is brought on by that scenario, life could explore the static universe until some other fate puts an end to it.

The big rip on the other hand might be the hardest one to survive as so little is known about dark energy. The big rip wouldn't necessarily harm life directly. Dark energy dose not seem to have a measurable effect on much immediately around up (our solar system, galaxy, or local group of galaxies). However, because so little is known about dark energy this could change and cause us much more immediate problems problems

But even a big rip effecting only the outer galaxies would limit resources available to life. Making it harder to survive something else like heat death. We would need some serious SciFi equipment to continue exploring the universe in a big rip like, worm holes, or have life immediately expand to the outer reaches of our universe so that once it is expanded to be too far to get it would be already seeded with life. Optimistically maybe once more is discovered about dark energy it could be used or harness somehow to create the solutions we would need like faster than light travel to combat a big rip.

Heat Death

Photo of Jökulsárlón, Iceland. swimming here would be considered hot when compaired to the tempature of the inevidable heat death of our universe.

With our current understanding of thermodynamics heat death seems to be an unavoidable outcome of our universe given enough time. That is because it is built into our understanding of time. We all experience time giving us a fairly good understanding of how sequential events take place in our day to day lives. Time always goes forward, today came after yesterday, and tomorrow will come next. There’s no way to go back to yesterday (without some scifi time travel Magic) it will always be in the past but tomorrow and the future we just have to wait and we will be there.

[Boulder's Court House then and now the old one burned down in 1932]

Physicists call this the “arrow of time” time. Time always marches forward and therefore the arrow of time always points that direction. This makes sense to our day to day life and plans but, scientifically this arrow of time is only quantified in one equation. Looking at all of our physics equations there is only one that gives us this forward direction of time and that is the second law of thermodynamics. There are 4 laws of thermodynamics and this is how I best remembered them before my thermo test:

0 - There is a game (The ‘zeroth’ law of thermodynamics basically defines equilibrium as everything being at the same temperature. It was added later because it was seen as an oversight to assume everyone knew what ‘equilibrium’ means)

1 - You can't win. (The first law of thermodynamics says energy is always conserved “you can’t win” meaning you always get out what you put in. You cannot have a system, like a perpetual motion machine, that makes more energy than you put in)

2 - You can't break even. (The second law of thermodynamics being what we are interested in most for the purposes of this essay says that ‘entropy’ always increases. There is no large scale processes that you truly get the same amount of energy that you put in you always lose a little to friction/heat/other forms of energy)

3- Everyone must play the game (The third law of thermodynamics basically is defining the coldest something can be ‘absolute zero’ is the absence of usable energy. Luke the 0th this law was added later because it was seen as needed to define absolute zero)

So let's look at an ideal example to explore the 2nd law; if you analyze the motion of a pendulum going back and forth you start with it raised to one side. This position holds energy as a raised object will fall (if there is gravity), this is called potential energy. As it falls that potential energy is converted to speed, this speed is called kinetic energy, once the pendulum is at the bottom of its swing it is traveling the fastest speed, having the maximum kinetic energy of this swing. Then the pendulum starts trading out this kinetic energy back to potential energy as it climbs the other side of its swing, until it loses all of its kinetic energy to potential energy and begins to swing back in the opposite direction starting the process over again.

Oscillating pendulum, showing vectors repesenting potential energy (a) and Kenetic energy (v)

This example is a nearly perfect example of the 1st law as the potential energy you put in when you raise the pendulum is the same you get back when it swings back. The pendulum will never swing higher than it started without an extra push from another source of energy. However the second law limits this even further as you will always lose some energy to friction at the pivot of the pendulum or resistance from the air it’s swinging through. This is why you have to wind up old grandfather clocks every so often, this is actually what old clocks (and everything else) use to measure the passing of time.

A Shortt-Synchronome free pendulum clock, the most accurate pendulum clock ever made. A pendulum is kept in a vacum in the cylender to the right to reduse loss due to friction with air.

Let's look at a more obvious example; a log burning in a fire pit. Burning the log you are releasing chemical energy trapped inside the molecules that make up the log turning that energy into heat energy. Looking at three frames of a film of a log burning: one with a log in a fire pit, one of a pile of ash and one with the log on fire, it’s simple for us to put these in order and say first the log was placed in the pit, then set on fire, then burned to a pile of ash (ore just the three pictures of the Boulder Court House at the start of this blog). That comes easy with human experience of seeing fires, but the only way to prove that was the order of things using physics is using the second law of thermodynamics. Entropy is like another word for chaos, disorder, or mess, seeing all of the energy piled neatly in the chemical bonds within the log is very ordered having some of that energy making light of the flame and some of it making heat of the flame is much more disordered.

It‘s impossible to reverse these processes to take the heat and light made by the flame and use it to make the ash back to a whole log again. It would be a miracle if you saw this go the opposite way. The only way the tree was able to make the log in the first place is by siphoning off a little bit of the energy released by the nuclear explosions taking place in the sun (which is of course releasing a lot more energy than what is captured as chemical energy in the log) . Every step there is a little loss that makes it non reversible. As time marches forward everything becomes more unorganized. You cannot clean/organize something without making something else dirty/unorganized, you may wipe down a surface with a cloth but then the cloth must be cleaned in water which is then cleaned by a sewage system, which needs power, usually from burning coal, which makes a mess and so on and so on....

Heat is a good way to see how unorganized a system is. In your kitchen you likely have a freezer and an oven. Both of these appliances use energy (let’s say they are both powered by electricity) to keep that space cold or hot. If you were to leave both of these appliances off for a few days eventually the temperature in the oven will be the same as in the fridge heat tends to balance out. The only thing stopping this is the electricity which is pumping energy into the system to make these two locations very different temperatures. Normally electricity is made at a power plant where they use coal/natural gas to heat water into steam that then powers a turbine. Making power this way only works because having something at higher temperature than its surroundings do work to lose that excess heat.

Coal Power Plant Diagram showing hot and cold reservoirs to spin a turbine to create electricity.

If we are to go along with the arrow of time indefinitely eventually energy will spread out so evenly there would be no way to do any meaningful work. Once the last sun burns out there won’t be anything to drive wind on any planet or photosynthesise to make swamps which eventually turn into coal. Everything will slowly come to a stand still and the temperature of the universe will even out like our kitchen when we cut the power.

It would be impossible for anything to live through this outcome of the universe. All life needs to use energy to survive and once all energy becomes unusable life becomes impossible. Further more time would stop. As entropy would have hit its maximum there would no longer be a way for entropy to increase meaning there would be no way of keeping time or seeing the direction of time.

National Institute of Standards and Technology (NIST) in Boulder Colorado. The coldest place in the universe is Boulder Colorado as in this labatory they conduct experiments getting things as cold as theoreticaly possible, even colder than a post-heatdeath universe.

Now there is a little outside chance of hope. The second law of thermodynamics is a statistical law, which makes it less of a hard ‘law’ as other laws of physics are. A more nuanced way of state the second law of thermodynamics is things TEND towards disorder. If you were to take a dump truck full of bricks and dump all of the bricks off of the truck at once you would expect those bricks to land in an unorganized pile not in a neet stack, but one could argue if you did this trillions of times you’re bound to every once and a while have all the bricks miraculously fall in an organized pile at least once. Or like the saying if you have enough monkeys bashing on typewriters for long enough one of them is bound to eventually reproduce the works of shakespeare. Simmerarly heat fluctuations will spontaneously pop up. Hotter (faster moving molecules) statistically are more likely to spread out and even out but there is a very slight probability as particles are bouncing randomly around the room they will randomly fall into an organized state of all the hotter particles on one side and all the cold ones on the other side. If you were to leave your kitchen with the oven and freezer unplugged for a limitless amount of time eventually the particles will randomly bump around to a place where all of the cold ones are in your freezer and all the hot ones are in your oven. The likeliness of this is very close to zero but not zero. One could conceive of future past-heat-death life having to track these random fluctuations of low entropy in the universe and harvest them for usable energy to continue.

Issac Asimov's favorite short story of his own authorship, "The Last Question" explorers how a civilization will survive heat death.

Furthermore there is an indication that the second law of thermodynamics can be broken. One of the most outstanding physicists to have ever lived, James Clerk Maxwell came up with a thought experiment which seems to obey every law of physics except the 2nd law of thermo and reverse the increase of entropy. This thought experiment is called “Maxwell’s demon” and many physicists have tried to make an argument as to why this cannot exist and many have also tried to prove it can exist by making one. Neither side has undeniably proven their case and it is still a hot topic of debate in physics.

Diagram of Maxwell’s demon who sorts a gas in to hot and cold thus decreasing energy. theoreticaly possible however it has never been made in practice.

In my opinion (I say this to denote that this is now leaving science's understanding and entering my own speculation) I think we could build a Maxwell’s demon. I would go even further and say that I believe time is not as linear as we experience it, if we can see the true form of time the whole ‘heat death’ might one day seem just as silly as the idea if you were to sail to the edge of the ocean you would fall off. I would like to back this idea up more eloquently with one of my favorite quotes “As long as we believe in sequential time, we see becoming instead of being. Beyond time, we are all one.”— Richard Bach

Disaster!

The word disaster comes from Greek meaning “Bad star” deriving from the astrology interpretation that catastrophes are caused by the position of the planets. Given the current pandemic making most of the world distance from each other let’s take a step back and look at how bad this ‘star’ really is.

I have thought up a scale to rank disasters and it starts at the Zeroth Degree and getting progressively worse till the Fifth Degree. In this system I would only rank COVID-19 as only maybe a ~0.7 there’s a lot that could be far worse.

Starting with Zeroth Degree, any disaster which causes minor to significant hassle would be in the 0th Degree. This is sort of a bottom end catch all for everything from this current pandemic to burning your dinner. Anything that might make a major impact on civilization but not enough to wipe it out. That’s why I give COVID a .7 it’s definitely worse than a day to day disaster, and being global it ranks higher and localized disasters like volcanoes. However all told COVID might make even a huge impact on civilization but not change our dominance on earth.

NOAA-19 satellite - The satellite fell while it was being worked on by Lockheed Martin Repairs to the satellite cost $135 million.

Making a First degree disaster of course something that threatens human civilization. Humans might continue to live in small pockets and maybe repopulate or be around to see what lifeforms take over earth next but either way we would no longer be the obvious dominant life form on earth. This would be something like an all out nuclear war, depletion of resources, or alien invasion.

passed extinction events - blue bars show the percentage of marine animals apearing to become extinct during given time interval, peaks are evidance of "mass extinction" events.

A Second degree disaster is something that wipes out all human life, but not all life. A scenario where only the hardiest of microbes or the deepest of sea creatures survive. Something like the loss of our atmosphere, meteor strike, or a chain of catastrophic tectonic activity.

The Third would obliterate all life on earth and therefore all known life maybe the sun flares up and boils the oceans off or the earth gets knocked off course and sent out of the solar system to freeze.

The Fourth Degree is where we really start to see some damage. This is where the entire solar system is destroyed there is no hope that any record of humanity or earth survives. This would be where the sun explodes, or we drift too close to a black hole.

The sun expanding to engulf the earth 1AU = the distance to the sun from the earth right now.

Lastly leaving the Fifth Degree one in which the entire universe is destroyed, something fundamental in the laws of physics that lead to a universe where life as we know it is impossible.

The "big crunch" one of the proposed fates of our universe.

Hopefully this helps make the outbreak seem mundane and unremarkable by comparison. For the next few weeks I plan on going down each degree of destruction and talk about how likely it is and what hope if any we have to prevent them. So I’ll see you next week with the maximum destruction, the 5th degree!