As far as anyone knows, we have always been alone. It’s just us on this pale blue dot, “home to everyone you love, everyone you know, everyone you ever heard of,” as Carl Sagan so memorably put it. No one has called or dropped by. And yet the universe is filled with stars, nearly all those stars have planets, and some of those planets are surely livable. So where is everybody?
The Italian physicist Enrico Fermi was purportedly the first to pose this question, in 1950, and scientists have offered a bounty of solutions for his eponymous paradox since. One of the most famous came from Sagan himself, with William Newman, who postulated in a 1981 paper that we just need patience. Nobody has visited because … Read the rest
In August 2016, a research team claimed to have unearthed evidence of life in a remote outcrop of 3.7-billion-year-old rocks in Greenland. This bold claim not only pushed back the origin of life by at least 220 million years, it also added to a growing body of evidence that challenged the standard story of Earth’s violent beginning, as Quanta Magazine reported this year in “Fossil Discoveries Challenge Ideas About Earth’s Start.” Joining a series of ancient fossil finds — as well as geological evidence from Earth and the moon — the Greenland discovery added weight to the idea that Earth was warm and watery from the outset, and that in such conditions, life emerged quickly.
But a follow-up study published in Nature last week … Read the rest
At a meeting of the American Society of Naturalists in 1960, the noted British ecologist G. Evelyn Hutchinson posed what he called “the paradox of the plankton.” Look at a flask of seawater; it will be filled with diverse species of plankton, all competing for the same vital elements and nutrients. Yet natural selection implies that over time, only one species should occupy an ecological niche, a concept known as competitive exclusion. And what is true of plankton seems to be true of many protozoa, plants, birds, fish and other organisms, too. How can ecosystems routinely have so many competing species that stably coexist?
Ecologists have mulled over this vexing paradox ever since, but they have generally taken comfort in a solution known as … Read the rest
Physics contains equations that describe everything from the stretching of space-time to the flitter of photons. Yet only one set of equations is considered so mathematically challenging that it’s been chosen as one of seven “Millennium Prize Problems” endowed by the Clay Mathematics Institute with a $1 million reward: the Navier-Stokes equations, which describe how fluids flow.
Last month I wrote a story about an important new result related to those equations. If anything, the new work suggests that progress on the Millennium Prize will be even harder than expected. Why are these equations, which describe familiar phenomena such as water flowing through a hose, so much harder to understand mathematically than, say, Einstein’s field equations, which involve stupefying objects like black holes?
The … Read the rest