Gazing over the countless fluctuations and transformations in Earth’s multibillion-year history, I am struck by the unique strangeness of the present moment. We suddenly find ourselves sort of running...
Cassie comes across as serious and studious, but once, after dinner in Washington with a group of NASA people, I asked her if her job title invited a lot of Men in Black questions. With little provoca...
Now, traveling about twice as far back again in Earth time, back to 542 million years ago, we encounter another sudden massive wave of extinction instigated by runaway biology: The Cambrian substrate...
Since, as I’ve indicated, we don’t fully understand the mechanism by which the orbital Milanković forcing causes large climate swings, there is a lot of uncertainty here. The last warm interglacial be...
Work, Jacob was not claiming to make a detailed and correct prediction of climate changes over the next several hundred thousand years, only to determine whether our influence could be strong enough t...
The Big Five extinctions are simply slightly more intense than the sixth- or seventh-largest declines, and you could just as easily discuss the Big Seven or Big Ten, depending on how you sliced up the...
Now nearly circular, compared to other epochs, where it is slightly more egg-shaped—we inhabit an interglacial of exceptionally long duration. Models incorporating this fact suggest that, even without...
I began to see this as a series of dilemmas nested like Russian dolls. Can today’s SETI community agree on a policy about active SETI? Even if collectively forged and broadly ratified, would such an a...
Cities will be smarter, greener places. Over the centuries, we’ve made a lot of progress in learning how to urbanize. We invented plumbing and sanitation systems, learned not to stain our cities brown...
The exact kill mechanisms are still being worked out, but the chronology has now convincingly implicated the volcanic culprit. At just the precise geological moment when most species suddenly dropped...
Celled. Then a catastrophe occurred (in the sense of sudden change), a dramatic increase in biodiversity, an anti-extinction, if you will. In a flash, there were not just some animal forms, but all of...
Most of the evidence uncovered by Galileo would have been discovered by a similar fly-by spacecraft as long ago as about 2 billion years. In contrast, modulated radio transmissions could not have been...
Konstantin Tsiolkovsky (1857–1935), a reclusive, near-deaf, self-taught rural schoolteacher who, working alone and having almost no contact with the wider scientific community, invented ingenious engi...
Wonderful, because life gained the ability to harvest sunlight for energy. What a fantastic breakthrough! Earth’s biosphere learned to plug into the best power source the universe has to offer, tappin...
The Anthropocene represents a braiding together of these into one inseparable narrative. This is the end of history, and of biology and geology—at least as separate stories. Have they become irreversi...
Less than eighty years later, we know all these ideas about origins (of Earth, the planets, the Moon, and mountain ranges) to be completely wrong. We’re certainly not any smarter today than they were...
This way, we’ve changed the geometry of the planet. Before we came along, the world was discontinuous. Oceans, deserts, and mountain ranges formed impenetrable barriers, breaking Earth into separate r...
Here, I find it useful to point out the distinction between cleverness and wisdom. Cleverness is the ability to solve problems through invention and innovation. We’ve got that in spades. Wisdom is the...
The TTAPS study and the wider debate it ignited helped drive home the absurdity of nuclear strategies dependent on massive deterrence. The United States and the USSR had created a situation where even...
Species. In this way, we’ve changed the geometry of the planet. Before we came along, the world was discontinuous. Oceans, deserts, and mountain ranges formed impenetrable barriers, breaking Earth int...
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