Viewed from a star in some other comer of the galaxy, Earth would be a speck, a faint blue dot hidden in the blazing light of our sun. While our neighbors Venus and Mars would reflect a fairly even glow, Earth would put on a little show. Earth's light would brighten and dim as it spins, because oceans, deserts, forests and clouds—which are all too small to be seen from such a distance-reflect varying amounts of sunlight. The variations, it turns out, are so strong and distinctive that surprising amount of information could be taken from a simple ebb and flow of light. Scientists at Princeton University and the Institute for Advanced Study conducted a detailed study of Earth's reflections as a way for human scientists to learn about distant planets that may be like our own.

(2) "If you looked at our solar system from far away, and you looked at the terrestrial planets--Mercury, Venus, Earth and Mars--one of the quickest ways to see that Earth is unique is by looking at the light curve," said Ed Turner, professor of astrophysics and a co-author of the study. "Earth has by far the most complicated light curve." The standard thinking in the field had been that most of the information about an Earth-like planet would come from spectral analysis, a static reading of the relative component of different colors within the light, rather than a reading of changes over time. Spectral analysis would reveal the presence of gases such as water vapor, carbon dioxide and oxygen, in the planet's atmosphere, looking at the change in light over time docs not replace spectral analysis, but it could greatly increase the amount of information scientists could learn, said Turner. It may indicate, for example, the presence of weather, oceans, ice or even plant life. "Earth would put on a little show" means: as it spins, ______. A.Earth is a more active planet than Venus and Mars B.Earth reflects a brighter light curve than Venus and Mars C.Earth shows oceans, deserts, forests and clouds, while Venus and Mars don't D.Earth reflects sunlight in an ebb-and-flow manner

时间:2023-09-26 09:05:27

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