Astrophysics for People in a Hurry (Astrophysics for People in a Hurry Series)

by Neil deGrasse Tyson

The German physicist Max Planck, after whom these unimaginably small quantities are named, introduced the idea of quantized energy in 1900 and is generally credited as the father of quantum mechanics.

with the weak force controlling radioactive decay, the strong force binding the atomic nucleus, the electromagnetic force binding molecules, and gravity binding bulk matter.

But high-mass stars fortuitously explode, scattering their chemically enriched guts throughout the galaxy. After nine billion years of such enrichment, in an undistinguished part of the universe (the outskirts of the Virgo Supercluster) in an undistinguished galaxy (the Milky Way) in an undistinguished region (the Orion Arm), an undistinguished star (the Sun) was born.

Within the chemically rich liquid oceans, by a mechanism yet to be discovered, organic molecules transitioned to self-replicating life.

People who believe they are ignorant of nothing have neither looked for, nor stumbled upon, the boundary between what is known and unknown in the universe.

We are stardust brought to life, then empowered by the universe to figure itself out—and we have only just begun.

Nebulium was simply the signature of ordinary oxygen doing extraordinary things.

In other words, after the laws of physics, everything else is opinion.

The universe was opaque until 380,000 years after the big bang, so you could not have witnessed matter taking shape even if you’d been sitting front-row center.

You couldn’t have seen where the galaxy clusters and voids were starting to form. Before anybody could have seen anything worth seeing, photons had to travel, unimpeded, across the universe, as carriers of this information.

The spot where each photon began its cross-cosmos journey is where it had smacked into the last electron that would ever stand in its way—the “point of last scatter.” As more and more photons escape unsmacked, they create an expanding “surface” of last scatter, some 120,000 years deep. That surface is where all the atoms in the universe were born: an electron joins an atomic...

By then, some regions of the universe had already begun to coalesce by the gravitational attraction of their parts. Photons that last scattered off electrons in these regions developed a different, slightly cooler profile than those scattering ...

Where matter accumulated, the strength of gravity grew, enabling more and...

These regions seeded the formation of galaxy superclusters while other regions we...

Ordinary matter is what we are all made of. It has gravity and interacts with light. Dark matter is a mysterious substance that has gravity but does not interact with light in any known way. Dark energy is a mysterious pressure in the vacuum of space that acts in the opposite direction of gravity, forcing the universe to expand faster than it otherwise would.

Einstein had, in effect, built what looks on the outside like a house of cards, with only two or three simple postulates holding up the entire structure. Indeed, upon learning of a 1931 book entitled One Hundred Authors Against Einstein,†† he responded that if he were wrong, then only one would have been enough.

The twentieth-century American theoretical physicist John Archibald Wheeler said it best, summing up Einstein’s concept as, “Matter tells space how to curve; space tells matter how to move.”††††

in 1929, the American astrophysicist Edwin P. Hubble discovered that the universe is not static. He had found and assembled convincing evidence that the more distant a galaxy, the faster the galaxy recedes from the Milky Way. In other words, the universe is expanding.

Lambda suddenly acquired a physical reality that needed a name, and so “dark energy” took center stage in the cosmic drama, suitably capturing both the mystery and our associated ignorance of its cause. Perlmutter, Schmidt, and Reiss justifiably shared the 2011 Nobel Prize in physics for this discovery.

The most accurate measurements to date reveal dark energy as the most prominent thing in town, currently responsible for 68 percent of all the mass-energy in the universe; dark matter comprises 27 percent, with regular matter comprising a mere 5 percent.