Neil Degrasse Tyson Famous Quotes

A mere sixty-five million years ago (less than two percent of Earth’s past), a ten-trillion-ton asteroid hit what is now the Yucatan Peninsula and obliterated more than seventy percent of Earth’s flora and fauna–including all the famous outsized dinosaurs.

Along with osmium and platinum, iridium is one of the three heaviest (densest) elements on the Table—two cubic feet of it weighs as much as a Buick, which makes iridium one of the world’s best paperweights, able to defy all known office fans. Iridium is also the world’s most famous smoking gun. A thin layer of it can be found worldwide at the famous Cretaceous-Paleogene (K-Pg) boundary† in geological strata, dating from sixty-five million years ago. Not so coincidentally, that’s when every land species larger than a carry-on suitcase went extinct, including the legendary dinosaurs. Iridium is rare on Earth’s surface but relatively common in six-mile metallic asteroids, which, upon colliding with Earth, vaporize on impact, scattering their atoms across Earth’s surface. So, whatever might have been your favorite theory for offing the dinosaurs, a killer asteroid the size of Mount Everest from outer space should be at the top of your list.

The successful ideas survive scrutiny. The bad ideas get discarded. Conformity is also laughable to scientists attempting to advance their careers. The best way to get famous in your own lifetime is to pose an idea that counters prevailing research and that earns a consistency of observations and experiment. Healthy disagreement is a natural state on the bleeding edge of discovery.

But life is fragile. Earth’s occasional encounters with large, wayward comets and asteroids, a formerly common event, wreaks intermittent havoc upon our ecosystem. A mere sixty-five million years ago (less than two percent of Earth’s past), a ten-trillion-ton asteroid hit what is now the Yucatan Peninsula and obliterated more than seventy percent of Earth’s flora and fauna—including all the famous outsized dinosaurs. Extinction. This ecological catastrophe enabled our mammal ancestors to fill freshly vacant niches, rather than continue to serve as hors d’oeuvres for T. rex. One big-brained branch of these mammals, that which we call primates, evolved a genus and species (Homo sapiens) with sufficient intelligence to invent methods and tools of science—and to deduce the origin and evolution of the universe.

The sphere to end all spheres—the largest and most perfect of them all—is the entire observable universe. In every direction we look, galaxies recede from us at speeds proportional to their distance. As we saw in the first few chapters, this is the famous signature of an expanding universe, discovered by Edwin Hubble in 1929. When you combine Einstein’s relativity and the velocity of light and the expanding universe and the spatial dilution of mass and energy as a consequence of that expansion, there is a distance in every direction from us where the recession velocity for a galaxy equals the speed of light. At this distance and beyond, light from all luminous objects loses all its energy before reaching us. The universe beyond this spherical “edge” is thus rendered invisible and, as far as we know, unknowable. There’s a variation of the ever-popular multiverse idea in which the multiple universes that comprise it are not separate universes entirely, but isolated, non-interacting pockets of space within one continuous fabric of space-time—like multiple ships at sea, far enough away from one another so that their circular horizons do not intersect. As far as any one ship is concerned (without further data), it’s the only ship on the ocean, yet they all share the same body of water.

The name typically translates into an anatomical part of the constellation being described. Famous ones on the list (along with their loose translations) include: Rigel (Al Rijl, “foot”) and Betelgeuse (Yad al Jauza, “hand of the great one”—in modern times drawn as the armpit), the two brightest stars in the constellation Orion; Altair (At-Ta’ir, “the flying one”), the brightest star in the constellation Aquila, the eagle; and the variable star Algol (Al-Ghul, “the ghoul”), the second brightest star in the constellation Perseus, referring to the blinking eye of the bloody severed head of Medusa held aloft by Perseus.