Journal

In effect, the expansion of our universe causes all points in space to be surrounded by an impenetrable horizon, beyond which nothing can be observed and no communications can reach. In the current epoch, our cosmic horizon is the surface of a sphere with a radius of about 46.5 billion light years, with us at the center. This sphere is, for all practical purposes, our universe. Its volume contains all of the space that we can see, study, witness, experience, communicate with, influence, or be influenced by. The boundary of this sphere is entirely impenetrable and forever will be—at least as long as the expansion rate of our universe doesn’t begin to slow down. Things beyond this distance are not merely obscured from our vision, but are utterly disconnected from us. All of space beyond this distance is forever lost from our world.

This book is about the first moments of our universe and how they’ve affected the state of our universe today.

This book covers a lot of the same concepts that other pop-sci cosmology books cover, but does so from the primary interesting lens of our universe’s beginnings and inflation.

There was a section in the first half of the book where the author clearly outlined what some of the largest challenges in cosmology are at the time of the book’s publishing. I really enjoyed this section—it was inspirational and valuable to see where the biggest open questions remain.

This is the best well-written cosmology book that I have read so far. I highly recommend it because it straddles the line of teaching unknown concepts and understandability / flow.

It’s very easy to forget that we rely on indirect information. The universe is full of matter: dust grains, gas clouds, moons, planets, stars, and galaxies. We don’t see this matter directly; we infer its properties by the way it interacts with electromagnetic radiation. Chemical elements are diagnosed by the particular spectral lines they emit or absorb. Dust grains reveal themselves by absorbing light and emitting infrared radiation. Moons and planets are seen in the reflected light of nearby stars. Stars are seen by the radiation they leak out as a byproduct of nuclear fusion. Galaxies are mapped using Doppler shifts of spectral lines from their gas and stars. All of this is indirect, and it only relates to the 5% of the universe that’s normal matter. The 95% that’s dark matter and dark energy is still invisible to us because it doesn’t interact with radiation. The astronomical objects are the actors, but the “stage” for this cosmic drama is also unseen.

Einstein’s Monsters is a good introductory book to the history and progression of humanity’s understanding of black holes.

One of the things this book does surprisingly well is to not overemphasize the creative possibilities that black holes and infinity produce. Even the most fundamental facts about black hole are insanely impressive and often overshadowed by talk of multiverses and other such things in other books I’ve read. While those what ifs are cool to consider, I’ve found other books focus on those at the expense of the fundamentals. To be fair, that probably sells better. The fact this book doesn’t do that is appreciated.

The book is well-written and easy to breeze through. Complexity wise, the book is not too simple to be boring for fans of space, but also not too complex to be a significant challenge. I suspect this is a good sweet spot for a book like this.

I highly recommend this book.

The world that emerges from these considerations is a rarefied one. A world in which, rather than independent entities with definite properties, there are entities that have properties and characteristics only with regard to others, and only when they interact. A stone does not have a position in itself: it only has a position in relation to another stone with which it collides. The sky does not in itself have any color: it has color with respect to my eyes when they look at it. A star does not shine in the sky as an autonomous entity: it is a node in the network of interactions that forms the galaxy in which it resides.

What a strange book! I thought it started strong, giving a broad historical overview of quantum mechanics and the state of quanta in present times. This part—the first half—was fine. It was light on detail, but this was expected of a popular science book meant to sell.

The second half got a little too philosophical for me. Perhaps this was mostly an expectations-setting problem—I just wasn’t ready for the transition and wanted to learn more about the theory!

Like an ostrich with its head in the sand, we humans have repeatedly assumed that all we could see was all that existed, hubristically imagining ourselves at the center of everything.

This book was a good broad intro to various modern cosmological ideas mixed with the author’s personal experiences and philosophical takes. For a broad overview, the book was excellent.

The middle section was most compelling. In this section, the author described four types of parallel universes which could possibly exist based upon what we currently know. These are thought-provoking possibilities and fun to imagine. These four types are described below:

• Type 1 — In an infinite space, there are many very similar copies of us somewhere, very far away. Small variations in state lead to a wide variety of different results in these other spaces.
• Type 2 — Our inflation bubble is just one of many. In other inflation bubbles some fundamental constants might be slightly or vastly different than in ours. Some are habitable. Some are not.
• Type 3 — This one is related to quantum mechanics and waveform collapse. Every time a quantum decision is determined, the universe splits. What appears to us as quantum randomness is one branch on that path.
• Type 4 — Our reality is a mathematical structure, one of many. Some are habitable, some are not. I truly like the Mathematical Universe Hypothesis (MUH) that Tegmark presents and defends as a possibility as part of this.

As an aside, one of my favorite out-of-context quotes from the book is below—

To the bird, reality is the geometry of the pasta.

Am I Japanese? Or am I American? This became the defining question I ruminated over daily. From my earliest memories, I had been both. I grew up playing hopscotch and jacks, learning kendo and ikebana. I studied U.S. history at school and Japanese on Saturday. For breakfast I ate scrambled eggs and mochi. Dinner could include fried chicken and sushi. I always felt that I was Japanese-American and I belonged in America, that I was part of the group. Before December 7, 1941, it never occurred to me that I was not.

Looking Like the Enemy is a meaningful historical memoir outlining the author’s experience during the interment of Japanese Americans during WWII.

It’s a poignant story—and a valuable read. It’s important to remember the injustices that this group faced and the impact it had on the rest of their lives. I was amazed at how strong and stoic Mary’s family was during these years, I can only imagine how tough it was.

To be honest, I am not a memoir person and that is what holds me back from rating this higher. But for anyone who has a preference for first-person storytelling and wishes to learn more about how the US treated its Japanese population during WWII, I highly recommend this book.