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41 " Other branes might be parallel to ours and might house parallel worlds. But many other types of braneworld might exist too. Branes could intersect and particles could be trapped at the intersections. Branes could have different dimensionality. They could curve. They could move. They could wrap around unseen invisible dimensions. Let your imagination run wild and draw any picture you like. It is not impossible that such a geometry exists in the cosmos. "
― Lisa Randall , Warped Passages: Unraveling the Mysteries of the Universe's Hidden Dimensions
42 " I was awestruck and enchanted not only by our current knowledge of our environment — local, solar, galactic, and universal — but also by how much we ultimately hope to understand from our random tiny perch here on Earth. I was also overwhelmed by the many connections among the pieces that ultimately allow us to exist. To be clear, mine is a deeply unreligious viewpoint. I don’t feel the need to assign a purpose or meaning, yet I can’t help but feel the emotions we tend to call religious as we come to understand the immensity of the universe, our past, and how it all fits together. It offers anyone some perspective when dealing with the foolishness of everyday life. "
― Lisa Randall , Dark Matter and the Dinosaurs: The Astounding Interconnectedness of the Universe
43 " All of the lightest stable quarks and leptons have heavier replicas. No one knows why they are there, or what they are good for. When physicists first realized that the muon, a particle first seen in cosmic rays, was nothing other than a heavier version of the electron (200 times heavier), the physicist I.I. Rabi asked, “Who ordered that? "
44 " However, you will need to know about flavors and generations because of the strong constraints on the particles’ properties, which give us vital clues and constraints on the physics that lies beyond the Standard Model. Chief among these constraints is that different flavors of quarks and leptons with the same charges rarely, if ever, turn into one another. "
45 " it was not scientists, but a reporter—Carlos Byars of the Houston Chronicle—who first made the connection. After listening to Hildebrand present the Arizona group’s research at a scientific meeting, Byars told him about Penfield’s earlier discovery of a potential impact crater—helping the scientists bring the mystery of the missing crater to its remarkably satisfying conclusion. "
46 " The Arizona team named the crater after an unfortunately hard-to-pronounce small nearby fishing harbor, Chicxulub Puerto, which is located above the center of the structure. The term, which is pronounced CHICK-shuh-lube, is sometimes translated as the devil’s tail—appropriately enough for the imposing feature that Walter Alvarez dubbed the “crater of doom. "
47 " My second concern about Occam’s Razor is just a matter of fact. The world is more complicated than any of us would have been likely to conceive. Some particles and properties don’t seem necessary to any physical processes that matter—at least according to what we’ve deduced so far. Yet they exist. Sometimes the simplest model just isn’t the correct one. "
48 " The uncertainty principle tells us that you need high-momentum particles to probe or influence physical processes at short distances, and special relativity relates that momentum to a mass. "
49 " Gravity in our world would be weak because extra dimensions are large, not because there is fundamentally a big mass responsible for the tiny gravitational force. "
50 " the young Sun’s energy output was probably about 70 percent of what it is today. With the Sun’s initially lower luminosity, even the water that did form wouldn’t have been in a liquid phase without some other explanation—a quandary known as “The Faint Sun Paradox. "
51 " The fermionic nature of most fundamental particles determines many properties of the matter around us. The Pauli exclusion principle, in particular, states that two fermions of the same type will never be found in the same place. The exclusion principle is what gives the atom the structure upon which chemistry is based. "
52 " the continuously habitable zone, which is the region that could have supported liquid water over the lifetime of the planet. According to current climate models, the continuous habitable zone is a more restricted region within fifteen percent of the Earth-Sun distance. "
53 " In fact, essentially most of the great movie disaster scenarios (with the exception of a zombie apocalypse) follow in the wake of a sufficiently big impact. "
54 " Although there are many possibilities, the branes that will be most interesting to us later on will be the three-dimensional ones. We don’t know why three dimensions should appear to be so special. But branes with three spatial dimensions could be relevant to our world because they could extend along the three spatial dimensions we know. Such branes could appear in a bulk space with any number of dimensions that is more than three—four, five, or more dimensions. Even if the universe does have many dimensions, if the particles and forces with which we are familiar are trapped on a brane that extends in three dimensions, they would still behave as if they lived in only three. "
55 " we currently live in a region—300 light-years across—called the Local Bubble, which is a vacuum-like domain with very low hydrogen density within the interstellar medium in the Orion Arm of the Milky Way. "
56 " When a field takes a nonzero value, the best way to think about it is to imagine space manifesting the charge that the field carries, but not containing any actual particles. "
57 " Even if we know the basic ingredients, in a multiverse populated by more than one brane, exotic new scenarios for the geometry of space are conceivable as well as myriad possibilities for how the particles we know and don’t know are distributed among them. "
58 " When it comes to the world around us, is there any choice but to explore? "
― Lisa Randall
59 " Perhaps a quarter of meteoroid impacts have led to potentially profitable deposits—at least half of which have already been exploited. "
60 " Nothing about our world is inconsistent with the existence of a multiverse. "