Ask A Genius 1288: Calculating the Information Content of the Universe: Physics, Cosmology, and Information Theory
Author(s): Rick Rosner and Scott Douglas Jacobsen
Publication (Outlet/Website): Ask A Genius
Publication Date (yyyy/mm/dd): 2025/03/02
Scott Douglas Jacobsen: So, hey, Rick. How would you calculate the information content of the universe over time in an IC model?
Rick Rosner: Well, I’m sure that if we checked Wikipedia, we would find a roughly agreed-upon estimate of the universe’s information content, likely measured in bits, based on physical principles like the Bekenstein bound or the holographic principle.
Jacobsen: The next question is: how much of that information is accessible, and by whom or what?
Rosner: We’ve talked before about how, if you simply consider the raw number of interactions in the universe—such as the emission and absorption of photons, or electrons scattering off each other—most of these interactions do not leave a permanent record. For example, interactions occurring in the plasma at the core of the Sun—assuming it remains in a fully ionized plasma state—generally do not encode long-term retrievable information.
That’s the key issue: for an interaction to count as part of the universe’s information content in a meaningful way, it must leave a persistent imprint, such as being recorded in a stable structure. But then we must define what “persistent” means. Moreover, is there any entity that can access all this information?
I would guess no. Anything within the universe certainly cannot, because observers are local and have severely limited access to information beyond their causal horizon. Due to the expansion of the universe and the limits imposed by the speed of light, vast regions of the cosmos are permanently inaccessible to us. Even within our observable universe, we have only been collecting detailed empirical data for a few hundred years, despite the universe’s estimated age of 13.8 billion years.
We are incredibly limited in both space and time. So, the real question is: is there any way to “win” the game of having access to the most information in the universe? One speculative idea is to consider whether the universe itself functions as an observer.
Jacobsen: But does that mean every event that results in a permanent change in the universe counts as perceived information simply because it is physically encoded somewhere?
Rosner: Honestly, I don’t know. It seems questionable. If we reason by analogy, the universe registering its own changes might be loosely compared to consciousness—experiencing itself in some way. However, the amount of information processed in human consciousness from moment to moment is relatively small, typically estimated at around 16 to 60 bits per second. If there were an equivalent large-scale information-processing system in the universe, one with all the hallmarks of cognition—such as dynamic state representation, multimodal integration, and Bayesian updating—it would still be difficult to argue that this entity has access to all available information in the universe.
The observable universe may contain an immense amount of information, but accessibility remains a fundamental limitation, shaped by physics, causality, and the constraints of local observation.
Or you could argue the other way by saying that each individual neighborhood of the universe “knows” what it knows—what it specializes in—with more detail than the entire universe as a whole. So maybe we need to reexamine the definition of information. Perhaps, in an information-processing system, this is just how it works: the system functions as a whole, but the whole doesn’t “know” much, while the individual parts have more detailed knowledge about their respective regions than the whole does.
I mean, what we arrive at pretty quickly is that we don’t really know what information is in a way that fully connects it to physics and cosmology. We know how to use information locally. It’s a measure of the number of choices in an open question, and the information that is produced when that question is resolved depends on the number of choices available within that system.
The easiest way to understand this is through coins and dice. If you flip a coin, you get a binary outcome—one of two possibilities. If you roll a standard six-sided die, you get one of six outcomes, which means more information is being generated. And if you roll a 20-sided die, like in Dungeons & Dragons, you generate even more information. That’s a nice, localized definition of information.
But we have no comprehensive understanding of what information is within a self-contained, self-consistent structure that is itself composed of information.
And within that forthcoming understanding of information is a cosmology that doesn’t necessarily align with all aspects of Big Bang theory. In standard Big Bang cosmology, I believe the amount of information in the universe is considered constant. Even when all matter and energy are compressed into an extremely hot, dense singularity at or near t = 0, it supposedly contains the same total amount of information as our present universe, 13.8 billion years later. There’s an assumption of information conservation in standard cosmology, though this might break down in extreme conditions, such as near black holes, where some interpretations suggest that information could be lost or scrambled beyond retrieval.
But in informational cosmology, information isn’t necessarily conserved—it can be created or destroyed.
Last updated May 3, 2025. These terms govern all In Sight Publishing content—past, present, and future—and supersede any prior notices. In Sight Publishing by Scott Douglas Jacobsen is licensed under a Creative Commons BY‑NC‑ND 4.0; © In Sight Publishing by Scott Douglas Jacobsen 2012–Present. All trademarks, performances, databases & branding are owned by their rights holders; no use without permission. Unauthorized copying, modification, framing or public communication is prohibited. External links are not endorsed. Cookies & tracking require consent, and data processing complies with PIPEDA & GDPR; no data from children < 13 (COPPA). Content meets WCAG 2.1 AA under the Accessible Canada Act & is preserved in open archival formats with backups. Excerpts & links require full credit & hyperlink; limited quoting under fair-dealing & fair-use. All content is informational; no liability for errors or omissions: Feedback welcome, and verified errors corrected promptly. For permissions or DMCA notices, email: scott.jacobsen2025@gmail.com. Site use is governed by BC laws; content is “as‑is,” liability limited, users indemnify us; moral, performers’ & database sui generis rights reserved.
In-Sight Publishing 