Humanity may not be extraordinary but rather the natural evolutionary outcome for our planet and likely others, according to a new model for how intelligent life developed on Earth. The model, which ...
For decades, many scientists have relied on the "hard steps" model to suggest that intelligent life is rare — the improbable result of a series of unlikely evolutionary leaps. But new research by ...
How do terrestrial planets like Earth form and evolve to enable life to exist? This is what a recent study published in Nature hopes to address as a pair of scientists from the Southwest Research ...
The universe is a slow-changing place. While it's mostly true that the heavens and the deep-sky objects in it will look largely the same across an average human lifetime, there are dramatic examples ...
Unfortunately, this book can't be printed from the OpenBook. If you need to print pages from this book, we recommend downloading it as a PDF. Visit NAP.edu/10766 to get more information about this ...
When a star is young, it is often still surrounded by a primordial rotating disk of gas and dust, from which planets can form. Astronomers like to find such disks because they might be able to catch ...
Image: A Hubble Space Telescope image of circumstellar disc surrounding a young star. Just as anthropologists sought “the missing link” between apes and humans, astronomers are embarking on a quest ...
Planetary nebulae represent a brief but crucial phase in the life cycle of low- to intermediate-mass stars (1–8 M⊙). After exhausting hydrogen and helium in their cores, such stars ascend the ...
New theory proposes that humans — and analogous life beyond Earth — may represent the probable outcome of biological and planetary evolution UNIVERSITY PARK, Pa. — Humanity may not be extraordinary ...
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