Did the creator of the universe leave a hidden message in the cosmos for intelligent life? If so, scientists have yet to find it.
A search for a message on "the most cosmic of all billboards, the Cosmic Microwave Background (CMB)," has failed, a new study finds. The CMB is the oldest light in the universe, visible across all of space. Its microwaves have been traveling since the first atoms formed out of a haze of protons and electrons that filled the universe soon after the Big Bang. They form a background radiation pattern across the whole sky. Physicists have long studied the CMB looking for features that might offer clues about the structure of the universe. Michael Hippke, a self-described "gentleman scientist" affiliated with the Sonneberg Observatory in Germany, went looking for a sign from a creator in that background radiation. But, either way, he didn't find one.
A beacon across the universe
Leaving aside all the hidden assumptions in the question — that there is a cosmic creator, that a cosmic creator wants people to know about them, that the cosmic creator has an insight into the minds of future intelligent creatures and can therefore predict the future — the CMB would be a good place to hide a message if you were a creator trying to target civilizations at our current level of development, said Avi Loeb, a Harvard astrophysicist who wasn't involved in Hippke's work published to the arXiv database on Nov. 29. (The paper has not been peer reviewed.)
"There could be different media on which you'd encode the message," Loeb said. The CMB is a good option because we've been able to detect it since the first good microwave study of the sky in 1964, as opposed to, say, gravitational waves, which require more technical equipment and we only detected in February 2016. "It all depends on what level of intelligence you want to approach. It's almost like writing different sections of a newspaper for different audiences."
Another advantage to hiding a message in the CMB for a would-be cosmic creator is that right now, the CMB is visible from almost any vantage point in space, said Yoni Brande, a University of Kansas astrophysicist who also wasn't involved in this paper. (The exception might be at the center of a very dense cluster of stars or dust.)
"If I was a creator and I wanted to delay the slam-dunk evidence of, here is the message that says 'Hi guys, I created the universe. And you're welcome.' And I wanted to make people work for that a little bit, I'd make it this sort of subtle-yet-universally observable thing," Brande said.
In that case, humanity might have reached that level of subtlety fairly recently.
Hippke wasn't the first researcher to speculate about the presence of a message in the CMB. Steve Hsu of the University of Oregon and Anthony Zee of University of California, Santa Barbara wrote a paper proposing the idea in the journal Modern Physics Letters A in 2006. But they had much less CMB data to work with.
(They also wrote in that paper that: "Our work does not support the Intelligent Design movement in any way whatsoever, but asks, and attempts to answer, the entirely scientific question of what the medium and message might be IF there was actually a message.")
An imperfect messenger
If you were a creator looking for a "cosmic billboard" on which to announce yourself to your subjects, the CMB has disadvantages as well as advantages. Hippke wrote in the study. For instance, the CMB will fade beyond recognition at about 100 billion years after the Big Bang, Brande said. (We're at 13.8 billion right now.) That's well within the period when the universe will still make new stars and when intelligent civilizations might develop. It would be a bit odd, Brande said, to write a message to creation but erase it before the emergence of its later denizens.
Perhaps more importantly, the CMB probably doesn't actually look the same from every point in space. Mostly, the microwave radiation is a perfectly random "static" in the sky. But there are slightly cooler spots and warmer spots, which physicists believe are signatures of early irregularities in the universe that later led to the formation of galaxies. And that pattern of cool and warm would likely look different from different points in space.
Hippke got around that by not looking for a message in the image of CMB itself, but in its "power spectrum," a graph of the different energy levels underlying CMB radiation. It's at least possible, Hippke wrote, that the power spectrum would be consistent across the universe (though most researchers think this is unlikely). And even if it weren't, a creator might have set up the CMB to deliver one message to one part of space and a different message to a different part of space.
But there is a bigger issue with using the CMB to send us a message.
"The real problem I have with the microwave background is … what we see in the sky is a two-dimensional surface surrounding us," Loeb said.
It's a view of that ancient moment in space-time when the universe became clear that is particular to our neighborhood of space. It's the inner surface of a sphere with a 13.8 billion light year radius and Earth at the center. That sphere is composed of all the points in space 13.8 billion light-years from Earth as they looked at the moment after the Big Bang when the universe became transparent. A viewer in another galaxy would see a different 13.8 billion light year radius sphere centered on themselves, composed of what all the points that far away looked like at the same moment in time. The further apart the two viewers are, the more different their views of the CMB would be.
"The problem is, if I move away from Earth, to the center of the Milky Way galaxy or the Coma Cluster [321 million light-years from Earth] or somewhere else a great distance away, then the two-dimensional surface around that point would be a different sphere," Loeb said. "The sphere is always centered around the observer."
That's important, Loeb said, because it means the CMB isn't really a billboard to the cosmos. It's a billboard to our particular location in the cosmos. Sending coherent messages to the whole universe would be like manufacturing untold trillions of billboards, not one big one. It might be possible to structure the universe such that there were one or many messages in the CMB power spectrums at different points in space. But that's a different project for the creator to have undertaken than the relatively simple one initially suggested by the paper. (Loeb also noted that there are many expert cosmologists studying the CMB all the time looking for patterns, and it would be surprising if Hippke had found a pattern on a lark where all those scientists had failed.)
It's also the case, Brande said, that there's no particular reason to locate a message in physics as opposed to some other science. Why wouldn't the universe's message be encoded in, say, the parts of the cell, or DNA, or the periodic table?
While he sees the CMB as the best example of a subtle, universal thing, Brande said, "my dad would probably say something different because he's a geologist. Like 'Why not do something with the physical chemistry of how planets are formed? Something you can pick up and look at?' But I do think there's enough variation in basically every other easily-observable thing [besides physics] around us [to rule it out]."
Where to really find a message, if one is out there
Loeb and Brande both said that despite their questions about the idea of the paper, there's nothing wrong with a scientist looking into questions like this. It's an interesting way of framing some basic physical questions, Brande said. And Loeb asked, "Who does it hurt to look?"
No one can speak for the full diversity of religious feeling on any topic, but Avigayil Halpern, a rabbinical student at New York's Hadar Institute, said that whatever the scientific merits of the project, it doesn't work as theology.
"The central problem … is that it fundamentally misunderstands who or what 'God' is," Halpern said. "The implicit goal … seems to be to attempt to prove God's existence, but it's a category error to think that scientific evidence has something to say about if God exists."
Related: Does your 'self' have a 'soul'?
In other words, a creator that wrote physical proof of itself on a cosmic billboard wouldn't be intelligible as the God she believes in.
"It makes no more sense to assert that God can be found in a code written into the cosmic microwave background than to say that morality can be derived from the study of chemistry," she said. "Those looking to find God in the universe would do better to seek out the image of the Divine as reflected in the faces of those around them."
Religion isn't the only framework for imagining a creator though. Some physicists, Loeb pointed out, imagine a sort of prosaic theology where our universe might be a laboratory experiment in some higher-order universe.
If Loeb were our creator, he said, the sign of his own existence that he would have left us would have been the capacity to create yet another universe within our own.
Right now, that's impossible, he said. But one day, perhaps when the ingredients that made our universe are better understood, researchers will develop another universe in a laboratory, Loeb speculated. If that happens, he said, it would make sense to understand it as a sort of message from a higher-order creator: Just like you have the ability to create universes, so too was your universe created.
Hippke, for his part, didn't find an intelligible message in the cosmos. But he was able to convert the CMB power spectrum into a binary code — which is basic enough that it would likely be recognizable to most intelligent civilizations, Brande said:
"We may conclude that there is no obvious message on the CMB sky," Hippke wrote. "Yet, it remains unclear whether there is (was) a Creator, whether we live in a simulation, or whether the message is printed correctly in the previous section, but we fail to understand it."
Originally published on Live Science.