Life in a fine-tuned universe - Part 1

Let's make a new universe. Let's make it slightly different from the one that we are familiar with. We could change the laws of nature, just a little bit. We could change how the universe begins, or make it four-dimensional. In the last 30 years, scientists have discovered something astounding: the vast majority of these changes are disastrous. We end up with a universe containing no galaxies, no stars, no planets, no atoms, no molecules, and most importantly, no intelligent life-forms wondering what went wrong. This fact is called the fine-tuning of the universe for life. After explaining the science of what happens when you change the way our universe works, we will ask: what does all this mean?

This is a talk given at the Institute of Astronomy, University of Cambridge by Luke Barnes, in March 2009. It was part of the institute's open nights - every Wednesday throughout winter, all welcome.

Please feel free to leave questions and comments!

My website: http://www.phys.ethz.ch/~barnesl/
My Blog: http://letterstonature.wordpress.com

Category:

Science & Technology

Tags:

• fine
• tuning
• universe
• life
• anthropic
• principle
• multiverse
• laws
• nature
• astronomy
• cosmology
• science
• public
• lecture

[theBartone9119]

@Lone432345 If there is an all powerful God and he wanted the entire universe to be as dense as the air in this room without the universe collapsing, are you saying he couldn't do it? If there is a God, he could have made any universe he wanted without any restrictions. The fact that you admit limitations and restrictions actually hurts your case for God, funny actually lol

[theBartone9119]

@Lone432345 "The point is if you move any of OUR universal constants a little bit. There would be no stars"

How do you know the constants can be moved? 

[Lone432345]

@theBartone9119

1) we know enough of the most important laws in this universe.

2/3) Sure its possible. But were talking about our universe. 4) The point is if you move any of OUR universal constants a little bit. There would be no stars. no mass, no light, no heat. Tell me how life can come from that. This raise questions. And avoid asking these question because of your bias against a concept is Stupid.And no im not religious.Im Agnostic. Unlike you i like to ask questions.

[LukeABarnes]

@theBartone9119 3. No such assumption is made. If anything, the assumption is made that life-permitting universes require explanation. The best evidence for this is the existence of tidy explanations for life, e.g. the multiverse.

4. Yes, and we know why. If the entire universe were as dense as the air in this room, it would recollapse under its own gravity in a day. A universe that contains life needs to be very diffuse, and thus mostly hostile.

[LukeABarnes]

@theBartone9119 1. I don't need to know all possible laws. If the life-permitting subset is small amongst the set we are able to study, then we can reasonably infer that the trend is not miraculously reversed just over the horizon of our knowledge. Further, these other laws are provably mathematically consistent, and thus we have the strongest possible proof (i.e. mathematical proof) that the universes they describe are possible.

2. Nope. The assumption is only that life requires complexity.

[theBartone9119]

@LukeABarnes "Fine-tuning asks why the laws, constants and initial conditions of our universe are life-permitting when most possible laws are not."

1) You don't know all possible laws, you don't even know if the ones you think are possible, are

2) You are assuming carbon based life is the only type of life that can exist

3) You are assuming life is the most special thing conceivable, in a different universe something greater than life may be possible

4) 99.99% of the universe is hostile to life

[LukeABarnes]

@theBartone9119 Fine-tuning asks why the laws, constants and initial conditions of our universe are life-permitting when most possible laws are not. We cannot appeal to the laws, constants and initial conditions to explain fine-tuning - they are the very things to be explained. They cannot be taken as given, as they are in the case of the puddle. That's why the puddle analogy is not apt.

[LukeABarnes]

@theBartone9119 Nope. Why does the puddle fit into the hole? Because given the law of gravity, the shape of the hole, the properties of the water, the properties of the material that makes up the sides of the hole and the properties of the earth which creates the gravitational field, the puddles could have no other shape. In short, the puddle fits the hole because of the laws, constants and initial conditions of the universe.

[theBartone9119]

@LukeABarnes If I said I was so hungry I could a horse, would you counteract with "your stomach isn't big enough"? The puddle was an analogy to prove a point, you are taking the puddle fitting in the pot hole literally..

[theBartone9119]

If you fine tune something to make coffee and the coffee has bacteria in it that kills the coffee, then whoever fine tuned it should get kicked to the curb. If the earth was fine tuned for life with all these extinction level events that have happened in the past and with all the diseases and sicknesses we see, then it's logical to conclude the fine tuner was a dumbass. If I had the power I would fine tune the universe way better for life. I mean life can't even form on most planets lol