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February 21, 2023 - August 11, 2025
The heaviest of the elements, such as gold and silver, can form only in a particularly violent environment, such as neutron star mergers. In these mergers, too, heavy nuclei are blown out and distributed throughout galaxies, where they catch electrons and become atoms.
And gravity continues its work. If the clouds get too dense, they will collapse again, give birth to new stars, solar systems, planets, and, potentially, life on these planets.
many people reflexively reject the possibility that human consciousness arises from interactions of the many particles in their brain.
And while the scientifically minded among them do not call it a soul, it is what they mean. They are looking for the mysterious, the unexplainable, the Extra that would make their existence special.
The conductivity of a metal, for example, is a property of materials that derives from the behavior of electrons. But it makes no sense to speak of the conductivity of an electron. Indeed, the whole concept of a metal makes no sense if you are working with a model of subatomic particles. A metal is a certain arrangement of many small particles.
properties and objects, which play a key role in the effective theory but do not appear in the fundamental theory, are emergent.[*]
Fundamental is the opposite of emergent. A fundamental property or object cannot be derived from or reduced to anything else.
The whole reason we use this math is that there isn’t anything else like it.
There are no exact metaphors, not for quantum mechanics and not for anything else, because if they were exact, they wouldn’t be metaphors.
But the future is still fixed except for occasional quantum events that we cannot influence.
I think the best way to deal with the impossibility of changing the future is to shift the way we think about our role in the history of the universe.
Instead of thinking of ourselves as selecting possible futures, I suggest we remain curious about what’s to come and strive to learn more about ourselves and the universe we inhabit.
We frequently associate free will with moral responsibility in this way, which is how it enters our discussions about politics, religion, crime, and punishment.
one claims a creator is necessary; the other claims it’s unnecessary. Nevertheless, they are similar in that they are both ascientific. They both postulate the existence of things that are unnecessary to describe what we observe.
I have found it futile to argue with fine-tuning believers. They just aren’t interested in separating the scientific from the ascientific part of their argument.
The clutter stayed throughout my school education. But much of it suddenly vanished in the first semester of university physics, when the principle of least action was introduced.
A particularly controversial attempt to explain the constants of nature is the strong anthropic principle, which says the constants are what they are because the universe gave rise to life.
The strong anthropic principle, however, makes a much bigger claim: that the existence of life today is the reason the universe is this way and not any other. Life doesn’t just constrain the constants; it explains them.
Our cosmological constant seems to be “the best” for making black holes.
To be more precise, the distribution of matter in the universe looks a little like the connectome, the network of nerve connections in the human brain.
Could it be, then, that the universe is a giant brain in which our galaxy is merely one neuron?
Unfortunately, this idea flies in the face of physics.
Electrons aren’t small balls that orbit around the nucleus; they have pronounced quantum properties and must be described by wave functions. An electron’s position is highly uncertain within the atom, and its probability distribution is a diffuse cloud that takes on symmetrical shapes, called orbitals. The electrons’ energy in the orbitals comes in discrete steps—it is quantized. This quantization gives rise to the regularities we find in the periodic table.
Even galaxies themselves are held together by their own gravitational pull and don’t expand together with the universe. It’s only somewhere between the distances of galaxy clusters and filaments that the expansion of the universe wins over and stretches the galactic web.
Einstein’s special and general relativity don’t forbid faster-than-light motion per se. Rather, they forbid accelerating something from below to above the speed of light, because that would take infinite energy. The speed of light is thus a barrier, not a limit.
the Koch snowflake. It’s generated by adding smaller equilateral triangles to equilateral triangles, as shown in figure 16a. The shape you get if you continue adding triangles indefinitely is a fractal; the area is finite, but the length of the perimeter is infinite.
This is how it works for the strong nuclear force, which holds quarks together inside protons.
An expanding universe can make its own energy.
Even more interesting, unpredictability might be an essential element of creativity, and thus something that artificial intelligence could draw on in the future.
Most hypotheses for the early universe, for example, are just complicated stories that are unnecessary to describe anything we observe. The same goes for attempts to find out why the constants of nature are what they are, or theories that introduce unobservable parallel universes. This isn’t science. It’s religion masquerading as science under the guise of mathematics.
Stephen Jay Gould got it right when he argued that religion and science are two “nonoverlapping magisteria.”
too many people perceive science as cold, technocratic, and unhumanly rational. It has the reputation of being a killjoy that constrains our hopes and dreams.
Far from taking away wonder, science gives us more to marvel at. It expands our minds.
many of us have the desire to understand the universe—for no other reason than understanding the universe. Our thirst for knowledge is ubiquitous, in both individuals and societies. We want to understand, partly because understanding is useful, but also, I think, out of a primary need to make sense of ourselves and our place in this world.
