Quark Soup In the first fraction of a second after the big bang, the universe was
a hot, dense ocean of perfectly free-flowing particles called a quarkgluon plasma. It didn’t last long—all the gluons and various flavors
of quarks and antiquarks were almost immediately sucked into
protons and neutrons and held in place by the powerful fundamental force called the strong force. And that’s where they all remained
for 13.7 billion years, until scientists figured out how to re-create a quark-gluon plasma in a particle accelerator. By studying this
fleeting primordial ooze, they hope to better understand the beginnings of the universe, as well as what’s really happening inside a
proton, which, as Scientific American senior space and physics editor Clara Moskowitz explains on page 34, is basically chaos.
Do you ever have the sense that you can perceive numbers? One of the oldest debates in philosophy is whether people have
an innate ability to process numbers or must be taught. Philosophers Jacob Beck and Sam Clarke on page 42 say they can finally
answer the question. According to recent research in infants, young children, adults and animals, it’s clear to the authors that
humans do have some natural perception of quantities that is inborn and unconscious. It’s fun to explore how we think about
numbers and how our numeracy may have evolved. The world population recently surpassed eight billion people,
up from seven billion in 2011, six billion in 1999 and five billion in 1987, and doubling the planet’s 1975 population of four billion. Such
growth presents challenges for us and other species on Earth, as historian of science and Scientific American columnist Naomi
Oreskes observes on page 76. Graphic journalist and Scientific American contributor Katie Peek on page 68 shows how birth rates
are beginning to decline, especially in poorer countries. The best way to make the world population healthy and sustainable, experts
agree, is to educate and empower girls and women. Researchers are coming to a consensus that long COVID
is in many cases a neurological disease. The virus that causes COVID, SARS-CoV-2, can persist in the nervous system for
months, and it may bring on ministrokes, inflammation, or immune system disruptions that affect the nervous system.
科学美国人 Scientific American-2023-03 英文版 PDF电子版 网盘下载：
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