Are you a Boltzmann Brain? Why nothing in the Universe may be real

A mind-bending paradox questions the nature of reality.

Are you a Boltzmann Brain? Why nothing in the Universe may be real
Pixabay
  • Boltzmann Brains are hypothetical disembodied entities with self-awareness.
  • It may be more likely for a Boltzmann Brain to come into existence than the whole Universe.
  • The idea highlights a paradox in thermodynamics.

The paradox of the Boltzmann Brain can really pull the rug from under you if you follow it to all of its logical and illogical extents. This mind-churning idea proposes that the world is quite possibly just an effect of your disembodied consciousness and doesn't really exist. And your sense of self is just a statistical fluctuation. It's something that is more likely to come into existence by chance than the Universe that would have had to produce it.

So are you really a Boltzmann Brain? Let's look at the underlying thinking.

Our Universe is extremely vast and complex, still filled with as much of the unimaginable as what we have already figured out. It has laws like an arrow of time that seems to be flowing only in one direction. It's got planetary bodies of various shapes and sizes. It also has us, humans, nature's supreme creations (at least according to us). But all this amazing amount of varied matter is also very hard to pull off, requiring a tremendous amount of energy. We know that generally things tend to fall apart and decay.

What the influential Austrian physicist Ludwig Boltzmann (1844-1906), one of the founders of the field of thermodynamics, hypothesized is that while the entropy of a system (its measure of disorder) always increases (moving towards disorder), there is some tiny possibility that a fluctuation can bring a system from disorder to order. Thus it would decrease its entropy, moving it further away from equilibrium.


Ludwig Boltzmann. 1901

From the physicist's work it follows that it would be more likely for random quantum fluctuations in nature to create something simpler than our astounding Universe – for example, a self-aware entity that believes it is a person in a world full of people, history, and particular physics. But such a person - let's say you - is only full of all the knowledge and experiences because you are made that way by the fluctuation that created you. There is nothing really there but your self-awareness.

These types of entities have been dubbed "Boltzmann Brains" by modern physicists Andreas Albrecht and Lorenzo Sorbo. They did not claim to such brains really being in existence but rather used the idea to point out the absurdities and limitations of taking the idea of thermodynamic fluctuations to their extent.

Boltzmann Brains have also been criticized as philosophical paradoxes that are experientially unprovable. The Caltech theoretical physicist Sean Caroll called them "cognitively unstable: they cannot simultaneously be true and justifiably believed" in his 2017 paper "Why Boltzmann Brains Are Bad."

Debates of the idea persist, however, especially as it is hard to disprove. After all, if you were a Boltzmann Brain, everything that you could come up with to prove or disprove it would likely be because of the hallucinations your consciousness is having.

Other types of solipsistic thinking have also entered our culture. Case in point - the notion that we may be living in a simulated reality, propagated by luminaries like Elon Musk and Neil deGrasse Tyson.

This is what aliens would 'hear' if they flew by Earth

A Mercury-bound spacecraft's noisy flyby of our home planet.

Image source: sdecoret on Shutterstock/ESA/Big Think
Surprising Science
  • There is no sound in space, but if there was, this is what it might sound like passing by Earth.
  • A spacecraft bound for Mercury recorded data while swinging around our planet, and that data was converted into sound.
  • Yes, in space no one can hear you scream, but this is still some chill stuff.

First off, let's be clear what we mean by "hear" here. (Here, here!)

Sound, as we know it, requires air. What our ears capture is actually oscillating waves of fluctuating air pressure. Cilia, fibers in our ears, respond to these fluctuations by firing off corresponding clusters of tones at different pitches to our brains. This is what we perceive as sound.

All of which is to say, sound requires air, and space is notoriously void of that. So, in terms of human-perceivable sound, it's silent out there. Nonetheless, there can be cyclical events in space — such as oscillating values in streams of captured data — that can be mapped to pitches, and thus made audible.

BepiColombo

Image source: European Space Agency

The European Space Agency's BepiColombo spacecraft took off from Kourou, French Guyana on October 20, 2019, on its way to Mercury. To reduce its speed for the proper trajectory to Mercury, BepiColombo executed a "gravity-assist flyby," slinging itself around the Earth before leaving home. Over the course of its 34-minute flyby, its two data recorders captured five data sets that Italy's National Institute for Astrophysics (INAF) enhanced and converted into sound waves.

Into and out of Earth's shadow

In April, BepiColombo began its closest approach to Earth, ranging from 256,393 kilometers (159,315 miles) to 129,488 kilometers (80,460 miles) away. The audio above starts as BepiColombo begins to sneak into the Earth's shadow facing away from the sun.

The data was captured by BepiColombo's Italian Spring Accelerometer (ISA) instrument. Says Carmelo Magnafico of the ISA team, "When the spacecraft enters the shadow and the force of the Sun disappears, we can hear a slight vibration. The solar panels, previously flexed by the Sun, then find a new balance. Upon exiting the shadow, we can hear the effect again."

In addition to making for some cool sounds, the phenomenon allowed the ISA team to confirm just how sensitive their instrument is. "This is an extraordinary situation," says Carmelo. "Since we started the cruise, we have only been in direct sunshine, so we did not have the possibility to check effectively whether our instrument is measuring the variations of the force of the sunlight."

When the craft arrives at Mercury, the ISA will be tasked with studying the planets gravity.

Magentosphere melody

The second clip is derived from data captured by BepiColombo's MPO-MAG magnetometer, AKA MERMAG, as the craft traveled through Earth's magnetosphere, the area surrounding the planet that's determined by the its magnetic field.

BepiColombo eventually entered the hellish mangentosheath, the region battered by cosmic plasma from the sun before the craft passed into the relatively peaceful magentopause that marks the transition between the magnetosphere and Earth's own magnetic field.

MERMAG will map Mercury's magnetosphere, as well as the magnetic state of the planet's interior. As a secondary objective, it will assess the interaction of the solar wind, Mercury's magnetic field, and the planet, analyzing the dynamics of the magnetosphere and its interaction with Mercury.

Recording session over, BepiColombo is now slipping through space silently with its arrival at Mercury planned for 2025.

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