Many physicists assume we must live in a multiverse – but their basic maths may be wrong

 

One of the most startling scientific discoveries of recent decades is that physics appears to be fine-tuned for life. This means that for life to be possible, certain numbers in physics had to fall within a certain, very narrow range.

One of the examples of fine-tuning which has most baffled physicists is the strength of dark energy, the force that powers the accelerating expansion of the universe. If that force had been just a little stronger, matter couldn’t clump together. No two particles would have ever combined, meaning no stars, planets, or any kind of structural complexity, and therefore no life.

This is not how we expected science to turn out. It’s a bit like in the 16th century when we first started to get evidence that we weren’t in the centre of the universe. Many found it hard to accept that the picture of reality they’d got used to no longer explained the data.

I believe we’re in the same situation now with fine-tuning. We may one day be surprised that we ignored for so long what was lying in plain sight – that the universe favours the existence of life.

If that force had been significantly weaker, it would not have counteracted gravity. This means the universe would have collapsed back on itself within the first split-second – again meaning no stars or planets or life. To allow for the possibility of life, the strength of dark energy had to be, like Goldilocks’s porridge, “just right”.

This is just one example, and there are many others.

The most popular explanation for the fine-tuning of physics is that we live in one universe among a multiverse. If enough people buy lottery tickets, it becomes probable that somebody is going to have the right numbers to win. Likewise, if there are enough universes, with different numbers in their physics, it becomes likely that some universe is going to have the right numbers for life.

For a long time, this seemed to me the most plausible explanation of fine-tuning. However, experts in the mathematics of probability have identified the inference from fine-tuning to a multiverse as an instance of fallacious reasoning – something I explore in my new book, Why? The Purpose of the Universe. Specifically, the charge is that multiverse theorists commit what’s called the inverse gambler’s fallacy.

Suppose Betty is the only person playing in her local bingo hall one night, and in an incredible run of luck, all of her numbers come up in the first minute. Betty thinks to herself: “Wow, there must be lots of people playing bingo in other bingo halls tonight!” Her reasoning is: if there are lots of people playing throughout the country, then it’s not so improbable that somebody would get all their numbers called out in the first minute.

But this is an instance of the inverse gambler’s fallacy. No matter how many people are or are not playing in other bingo halls throughout the land, probability theory says it is no more likely that Betty herself would have such a run of luck.

It’s like playing dice. If we get several sixes in a row, we wrongly assume that we are less likely to get sixes in the next few throws. And if we don’t get any sixes for a while, we wrongly assume that there must have been loads of sixes in the past. But in reality, each throw has an exact and equal probability of one in six of getting a specific number.

Multiverse theorists commit the same fallacy. They think: “Wow, how improbable that our universe has the right numbers for life; there must be many other universes out there with the wrong numbers!” But this is just like Betty thinking she can explain her run of luck in terms of other people playing bingo. When this particular universe was created, as in a die throw, it still had a specific, low chance of getting the right numbers.

Either it’s an incredible fluke that our universe happened to have the right numbers. Or the numbers are as they are because nature is somehow driven or directed to develop complexity and life by some invisible, inbuilt principle.

At this point, multiverse theorists bring in the “anthropic principle” – that because we exist, we could not have observed a universe incompatible with life. But that doesn’t mean such other universes don’t exist.

Suppose there is a deranged sniper hiding in the back of the bingo hall, waiting to shoot Betty the moment a number comes up that’s not on her bingo card. Now the situation is analogous to real world fine-tuning: Betty could not have observed anything other than the right numbers to win, just as we couldn’t have observed a universe with the wrong numbers for life.

Even so, Betty would be wrong to infer that many people are playing bingo. Likewise, multiverse theorists are wrong to infer from fine-tuning to many universes.

What about the multiverse?

Isn’t there scientific evidence for a multiverse though? Yes and no. In my book, I explore the connections between the inverse gambler’s fallacy and the scientific case for the multiverse, something which surprisingly hasn’t been done before.

The scientific theory of inflation – the idea that the early universe blew up hugely in size – supports the multiverse. If inflation can happen once, it is likely to be happening in different areas of space – creating universes in their own right. While this may give us tentative evidence for some kind of multiverse, there is no evidence that the different universes have different numbers in their local physics.

There is a deeper reason why the multiverse explanation fails. Probabilistic reasoning is governed by a principle known as the requirement of total evidence, which obliges us to work with the most specific evidence we have available.

In terms of fine-tuning, the most specific evidence that people who believe in the multiverse have is not merely that a universe is fine-tuned, but that this universe is fine-tuned. If we hold that the constants of our universe were shaped by probabilistic processes – as multiverse explanations suggest – then it is incredibly unlikely that this specific universe, as opposed to some other among millions, would be fine-tuned. Once we correctly formulate the evidence, the theory fails to account for it.

The conventional scientific wisdom is that these numbers have remained fixed from the Big Bang onwards. If this is correct, then we face a choice. Either it’s an incredible fluke that our universe happened to have the right numbers. Or the numbers are as they are because nature is somehow driven or directed to develop complexity and life by some invisible, inbuilt principle. In my opinion, the first option is too improbable to take seriously. My book presents a theory of the second option – cosmic purpose – and discusses its implications for human meaning and purpose.

This is not how we expected science to turn out. It’s a bit like in the 16th century when we first started to get evidence that we weren’t in the centre of the universe. Many found it hard to accept that the picture of reality they’d got used to no longer explained the data.

I believe we’re in the same situation now with fine-tuning. We may one day be surprised that we ignored for so long what was lying in plain sight – that the universe favours the existence of life.

Ancient 'Large-Scale Structure' Discovered In Deep Space: Bio-cosmos

The "Cosmic Vine" is a massive structure in the cosmic web that links 20 galaxies in the early universe.

The universe is more connected than you might think: In recent years, scientists have used new tools and techniques to map the “cosmic web,” which is made up of intertwined strands of gas structures known as filaments that link galaxies. Now, a team of researchers have identified a new “large-scale structure” in the universe that they call the “Cosmic Vine.”

The researchers hail from numerous universities and institutions across Denmark, Chile, the U.K., and the Netherlands. They published a preprint of their work to the arXiv server on November 8. According to the study, the Cosmic Vine was spotted after poring over data collected by the James Webb Space Telescope (JWST), humanity’s most powerful tool for peering into the far reaches of space and time. 

According to the researchers, it is a massive “vine-like structure” that encompasses 20 galaxies and stretches for over 13 million light years. It’s also very ancient: The researchers pegged it at redshift 3.44, meaning it’s situated in the early universe. Redshift refers to the way light stretches as it travels longer distances through time, with higher redshifts indicating an object is older. A redshift of 3.44 would mean light from the Cosmic Vine has been traveling for between 11 and 12 billion years before reaching JWST. The universe is roughly 13 billion years old. 

The discovery is notable because it can teach us more about how galaxies form. Indeed, recent work on the cosmic web has revealed that filament structures are crucial for delivering the materials galaxies need to grow—a previously-discovered filament was referred to as a “pipeline” for fueling this type of growth by researchers. The researchers who identified the Cosmic Vine wrote that galaxy clusters are the “most massive gravitationally-bound structures in the universe” and that studying their progenitors “in the early Universe is fundamental for our understanding of galaxy formation and evolution.” So, characterizing the dynamics of the Cosmic Vine and the galaxies embedded within it could teach us a lot. 

However, the Cosmic Vine raises more questions than it answers. The researchers note that our snapshot of the Vine indicates it’s still in its growing phase, and yet it contains two massive galaxies that are quiescent, meaning they’ve stopped forming stars. These quiescent galaxies are not in the core of the developing cluster, which some theories have held is a requirement for star formation to be halted. “This discrepancy potentially poses a challenge to the models of massive cluster galaxy formation,” the authors wrote. “Future studies comparing a large sample with dedicated cluster simulations are required to solve the problem.”

“What is the culprit quenching their star-formations at so early cosmic time?” the authors ask. Observed features of the galaxies indicate that the culprit could be a starburst triggered by merging galaxies—this is when star formation occurs at a rapid rate that quickly depletes available resources. Another explanation may be due to feedback from a supermassive black hole embedded in one of the galaxies, known as an Active Galactic Nucleus, or AGN. 

Until more work is done, though, we simply don’t know the answer. As our knowledge grows, so do the universe’s many mysteries.

NASA's James Webb telescope confirms planet formation theory: Evolutionary transubstantiation

"... the Creator waters His incipient sentience via cosmic life processes, and He seeds the universe with the raw materials needed to beget Life."

 

Scientists using NASA’s James Webb Space Telescope just made a breakthrough discovery in revealing how planets are made. By observing water vapor in protoplanetary disks, Webb confirmed a physical process involving the drifting of ice-coated solids from the outer regions of the disk into the rocky-planet zone.

Theories have long proposed that icy pebbles forming in the cold, outer regions of protoplanetary disks — the same area where comets originate in our solar system — should be the fundamental seeds of planet formation. The main requirement of these theories is that pebbles should drift inward toward the star due to friction in the gaseous disk, delivering both solids and water to planets.

A fundamental prediction of this theory is that as icy pebbles enter into the warmer region within the “snowline” — where ice transitions to vapor — they should release large amounts of cold-water vapor. This is exactly what Webb observed.

“Webb finally revealed the connection between water vapor in the inner disk and the drift of icy pebbles from the outer disk,” said principal investigator Andrea Banzatti of Texas State University, San Marcos, Texas. “This finding opens up exciting prospects for studying rocky planet formation with Webb!”

“In the past, we had this very static picture of planet formation, almost like there were these isolated zones that planets formed out of,” explained team member Colette Salyk of Vassar College in Poughkeepsie, New York. “Now we actually have evidence that these zones can interact with each other. It’s also something that is proposed to have happened in our solar system.”

Planet-forming Disks

Artist’s Concept: This artist’s concept compares two types of typical, planet-forming disks around newborn, Sun-like stars. On the left is a compact disk, and on the right is an extended disk with gaps. Scientists using Webb recently studied four protoplanetary disks—two compact and two extended. The researchers designed their observations to test whether compact planet-forming disks have more water in their inner regions than extended planet-forming disks with gaps. This would happen if ice-covered pebbles in the compact disks drift more efficiently into the close-in regions nearer to the star and deliver large amounts of solids and water to the just-forming, rocky, inner planets. Current research proposes that large planets may cause rings of increased pressure, where pebbles tend to collect. As the pebbles drift, any time they encounter an increase in pressure, they tend to collect there. These pressure traps don’t necessarily shut down pebble drift, but they do impede it. This is what appears to be happening in the large disks with rings and gaps. This also could have been a role of Jupiter in our solar system — inhibiting pebbles and water delivery to our small, inner, and relatively water-poor rocky planets. [NASA, ESA, CSA, Joseph Olmsted (STScI)]

Harnessing the Power of Webb

The researchers used Webb’s MIRI (the Mid-Infrared Instrument) to study four disks — two compact and two extended — around Sun-like stars. All four of these stars are estimated to be between 2 and 3 million years old, just newborns in cosmic time.

The two compact disks are expected to experience efficient pebble drift, delivering pebbles to well within a distance equivalent to Neptune’s orbit. In contrast, the extended disks are expected to have their pebbles retained in multiple rings as far out as six times the orbit of Neptune.

The Webb observations were designed to determine whether compact disks have a higher water abundance in their inner, rocky planet region, as expected if pebble drift is more efficient and is delivering lots of solid mass and water to inner planets. The team chose to use MIRI’s MRS (the Medium-Resolution Spectrometer) because it is sensitive to water vapor in disks.

The results confirmed expectations by revealing excess cool water in the compact disks, compared with the large disks.

Water Abundance

As the pebbles drift, any time they encounter a pressure bump — an increase in pressure — they tend to collect there. These pressure traps don’t necessarily shut down pebble drift, but they do impede it. This is what appears to be happening in the large disks with rings and gaps.

Current research proposes that large planets may cause rings of increased pressure, where pebbles tend to collect. This also could have been a role of Jupiter in our solar system — inhibiting pebbles and water delivery to our small, inner, and relatively water-poor rocky planets.

Solving the Riddle

When the data first came in, the results were puzzling to the research team. “For two months, we were stuck on these preliminary results that were telling us that the compact disks had colder water, and the large disks had hotter water overall,” remembered Banzatti. “This made no sense, because we had selected a sample of stars with very similar temperatures.”

Only when Banzatti overlaid the data from the compact disks onto the data from the large disks did the answer clearly emerge: the compact disks have extra cool water just inside the snowline, at about ten times closer than the orbit of Neptune.

“Now we finally see unambiguously that it is the colder water that has an excess,” said Banzatti. “This is unprecedented and entirely due to Webb’s higher resolving power!”

Icy Pebble Drift

This graphic is an interpretation of data from Webb’s MIRI, the Mid-Infrared Instrument, which is sensitive to water vapor in disks. It shows the difference between pebble drift and water content in a compact disk versus an extended disk with rings and gaps. In the compact disk on the left, as the ice-covered pebbles drift inward toward the warmer region closer to the star, they are unimpeded. As they cross the snow line, their ice turns to vapor and provides a large amount of water to enrich the just-forming, rocky, inner planets. On the right is an extended disk with rings and gaps. As the ice-covered pebbles begin their journey inward, many become stopped by the gaps and trapped in the rings. Fewer icy pebbles are able to make it across the snow line to deliver water to the inner region of the disk. [(NASA, ESA, CSA, Joseph Olmsted (STScI)

The team’s results appear in the Nov. 8 edition of the Astrophysical Journal Letters.

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