The document provides an overview of Earth's atmosphere and how it protects the planet, as well as examples of meteor impacts on Earth and their effects. It then discusses observations of other planets like Mars, Venus, and the outer planets including Jupiter, Saturn, Uranus, and Neptune. The summary concludes with information about trans-Neptunian objects beyond Neptune's orbit.
28. Atmosphere lets the visible sunlight in, but traps infrared radiation and prevents rapid cooling of the surface at nights
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31. "It will be possible to see cities on Mars, to detect navies in [its] harbors, and the smoke of great manufacturing cities and towns... Is Mars inhabited? There can be little doubt of it ... conditions are all favorable for life, and life, too, of a high order. Is it possible to know this of a certainty? Certainly." Samuel Leland 1895 Seasons on Mars? Channels for irrigation ???
65. The Kuiper Belt – home for short-period comets?? Starting in 1992, astronomers have become aware of a vast population of small bodies orbiting the sun beyond Neptune. There are at least 70,000 "trans-Neptunians" with diameters larger than 100 km in the radial zone extending outwards from the orbit of Neptune (at 30 AU) to 50 AU.
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Editor's Notes
Huge rocky ball 8000 miles across. It is so nice and cozy!
Remove atmosphere – scorching heat during the day (300 F) and deadly cold at night (-200 F). Oceans evaporate into space. Earth will be a lifeless desert.
Figure 19.12: (b) Like all larger-impact features, the Barringer Meteorite Crater has a raised rim and scattered ejecta. (USGS)
Figure 17.3: The greenhouse effect. (a) Short-wavelength light can enter a greenhouse and heat its contents, but the longer-wavelength infrared radiated by the warm interior cannot get out.
Figure 17.3: The greenhouse effect. (b) The same process can heat a planet’s surface if its atmosphere contains CO 2 .
Figure 18.7: The Galilean moons of Jupiter from left to right are Io, Europa, Ganymede, and Callisto. The circle shows the size of Earth’s moon. (NASA)