The World of Leftover Energy

Question from Andrew:
Why do atheists like Stenger say that the universe can be eternal, when this does not hold?

Stenger argues that the universe can be eternal, non-created, extrapolating the law of conservation of energy-mass before the planck time, he says that because we do not see a violation to this law, the universe can perfectly be eternal.

But this is a fallacy as William Lane Craig exposed once. If the energy were eternal there would be no useful energy right now, it would have become useless, complete entropy an infinite time ago, and because we do not see this, the only conclusion is that the universe and the energy began a finite time ago. Where we Christians think, the best explanation is the creation by God.

Answer by SmartLX:
Even according to you, Stenger only said the universe can be eternal, not that it definitely is. If it isn’t, then God is only one possibility among who knows how many: spontaneous emergence (more on that in a sec), a previous universe, a deistic rather than theistic (let alone Christian) god and so on.

Anyway, there are at least three straightforward ways in which there can still be useful energy now after an eternity of existence. There might be others, but even one possible way is enough to keep someone like Craig from ruling out the possibility entirely.

1. There is infinite or potentially infinite energy as well as infinite time.
Our universe as we see it has existed for a finite amount of time since the Big Bang with a certain amount of matter and energy, but what if that only contained one portion of the available material of an endless universe or multiverse? Or can matter emerge regularly and spontaneously from the quantum foam as much as it likes, as long as the same amount of antimatter accompanies it and the total amount of “positive” energy stays constant? As Lawrence Krauss says, something can come from nothing if “nothing” is unstable.

2. The energy is periodically reclaimed.
Entropy doesn’t destroy energy (hence Stenger’s point), it only ends up radiating it towards the edges of the universe where it’s no use to anyone. If Big Bangs are regular rather than one-off occurrences, then there’s a long-standing hypothesis that the universe is first drawn together in a Big Crunch. The new singularity contains not only all the matter and energy of the crushed universe, but all the space as well. Whatever was lost to entropy is dragged back to a mathematical point, just like at the point of our own Big Bang, and the cycle can begin again.

3. The amount of available energy decreases exponentially.
The less energy there is, the slower it dissipates, the way a gush becomes a trickle when you tip out a bucket of water. Say that every billion years, the amount of available energy decreases by half. If so then a billion years ago there was twice as much, and two billion years from now there’ll be a quarter as much, but there will never, ever be none. It will approach zero (or, importantly, a non-zero constant) asymptotically, which is to say it will get closer and closer without ever reaching it. Perhaps the amount of energy we’re used to seeing in the world is practically nothing compared to the intense heat, light and motion that was everywhere in times gone by, with the universe in a state of near-saturation (perhaps asymptotically again). Without past reference points from before the Big Bang, which are probably impossible to attain, you can’t make a judgement that there can’t be this much energy now.

One final point: be very careful about expressions like “the best explanation” when discussing cosmology. If quantum mechanics have taught us anything, it’s that reality can be counter-intuitive, and the truth might well strike one as ridiculous. If there’s evidence for a claim then it’s a supportable claim, but if all it does is sound right then it’s worthless.

Eternity, and not by Calvin Klein

Question from Brenton:
Is the universe eternal?

Answer by SmartLX:
We don’t know, but whether it is or not, neither option makes a god very likely.

Cosmologists now almost universally accept the Big Bang as a factual event which occurred about fourteen billion years ago. A far greater point of contention is whether the matter and energy in the universe have always existed, and were simply in some other state before they coalesced into the singularity which “exploded”, or if the Big Bang was truly the beginning of time and causality.

If the universe is eternal, there is no need for a creator god. Most theistic gods are regarded by their believers as eternal and thus in no need of their own creators; this is a real possibility for the universe itself.

If the universe is not eternal, and nothing material preceded it, then either it was created or produced by something or it emerged directly from nothing. Neither of these can be judged as more or less likely than the other based on our experience so far because, while we have no direct evidence of anything emerging from nothing (though quantum mechanics may suggest this possibility), we have no evidence at all of anything being created from nothing as creator gods are meant to have done.

That leaves the idea that something material (or with direct material influence) and outside the universe pre-dated it, and somehow resulted in its emergence. Again a god is possible here, but it could also be another previous universe, or the “quantum foam”, or any number of hypothetical entities. A god as an explanation is the least useful entity in this scenario because a full-blown intelligent god is itself an inexplicable cause, and it’s no more likely than any of the others. It’s also the only one which requires that we posit anything supernatural.

I realise that I’ve read quite a lot into your very simple question, but delving into these issues is the usual purpose of asking questions like this on an atheist website.

Eternal inflation? No. Eternal universe? Maybe, nevertheless. And what’s it to ya?

“These three scientists in particular, by virtue of their joint paper, are name-checked more often than any others by apologists not just arguing for an absolute beginning to the universe but claiming that this has been established beyond doubt.”

Scientists Arvin Borde, Alan Guth and Alexander Vilenkin, in their 2003 paper “Inflationary Spacetimes Are Incomplete in Past Directions”, ruled out past-eternal inflationary models of the universe. Does this prove that
1. the universe had an absolute beginning,
2. that it must have had a cause and
3. that the cause was God?

No, no and no.

These three scientists in particular, by virtue of their joint paper, are name-checked more often than any others by apologists not just arguing for an absolute beginning to the universe but claiming that this has been established beyond doubt. Apologists up to and including William Lane Craig do this to support the cosmological argument for God, which requires such a beginning to be indisputable.

So what does the paper actually say? Feel free to read it via the link above (it’s dense but short), but the thrust is in the title: spacetime can’t have been inflating infinitely into the past.

That seems obvious since you’d think you’d eventually reach a singularity if you worked backwards, but models have been proposed wherein the farther back you go the slower the expansion is. Some reasoned that perhaps the universe has spent eternity inflating extremely slowly from a size barely larger than a singularity, speeding up as it went along.

Borde, Guth and Vilenkin examined this idea and found, essentially, that it wouldn’t work in the real world. In doing so they pretty much dismissed every model of an expanding universe (or multiverse) that doesn’t involve a proper singularity and Big Bang. Therefore, according to apologists, the universe definitely had an absolute beginning, which must have had a cause, and that cause was God.

That’s going way too far because, for a start, the paper doesn’t take a position on whether the now-confirmed Big Bang was an absolute beginning. There are many more universe/multiverse models wherein the Big Bang was merely an event in an ongoing sequence – where the matter in the singularity came from somewhere, not nowhere. Borde et al only intended to rule out a family of models that clearly don’t work.

Get that? Borde, Guth and Vilenkin did NOT rule out an eternal universe, even if the result of their paper is correct. They merely ruled out one kind of eternal universe, the kind where the Big Bang never happened. The fact that there was a Big Bang does not mean there was nothing before the Big Bang.

The Big Bang as absolute zero, or an absolute beginning in general, is a poor platform for apologetics in any case. The idea that whatever begins to exist has a cause is not based on anything which physically began to exist in the same way the universe supposedly did, completely ex nihilo (literally “from nothing”). We’ve never seen anything like that happen, so:
1. it’s curious that so many people assume the universe came about in this way,
2. there’s no basis for assigning a cause if it did and
3. even if it had a cause, it’s a huge leap to declare it any kind of god, let alone someone’s specific personal deity.