Briefly summarize current knowledge about the term NHP in the equation
Number of Civilizations = NHP × flife × fcivilization × fnow.
What will be an ideal response?
NHP is the number of planets in the Milky Way that lie within the habitability zones of their parent stars. Currently, we have evidence for more than one thousand planets around other stars, and evidence for protoplanetary disks around many more stars. Although we cannot yet give a precise value to NHP, it now seems likely that it is quite large—perhaps as large as the number of stars in the Milky Way Galaxy.
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A ball is thrown vertically upwards at 19.0 m/s. For its complete trip (up and back down to the starting position), its average velocity is:
a. 19.0 m/s. b. 9.5 m/s. c. 4.8 m/s. d. 14.3 m/s e. not given.
What is the wavelength of the photon emitted when an electron in a hydrogen atom which is in the initial state n = 4 jumps to the final state n = 2? (c = 3.00 × 108 m/s, h = 6.626 × 10-34 J ? s, 1 eV = 1.60 × 10-19 J)
A) 243 nm B) 486 nm C) 556 nm D) 312 nm E) 609 nm
An electron slowing from 0.998c to 0.500c loses how much momentum? (express the answer in MeV/c as well as N-s)
What will be an ideal response?
The de Broglie wavelength of which of the following objects would be smallest if the objects had the same velocity?