Compare the peak wavelength of the radiation in the universe at the end of the era of nucleosynthesis with the peak wavelength of the radiation in the universe currently. Assume the temperature at the end of the era of nucleosynthesis was 10^9 K. The current temperature in space is 2.73 K. By what factor have the wavelengths of the photons in the universe been stretched since that time? Hint: Use Wien's law to get the peak wavelengths then and now. Then, take the ratio of the peak wavelengths.

Your starship, the aimless wanderer, lands on the mysterious planet mongo. as chief scientist-engineer, you make the following measurements: a 2.50-kg stone thrown upward from the ground at 14.0 m/s returns to the ground in 5.70 s ; the circumference of mongo at the equator is 2.20×10^5 km ; and there is no appreciable atmosphere on mongo. (a) the starship commander, captain confusion, asks for the following information: what is the mass of mongo? (b) if the aimless wanderer goes into a circular orbit 2.20×10^4 km above the surface of mongo, how many hours will it take the ship to complete one orbit? (c) an unmanned spacecraft is in a circular orbit around the moon, observing the lunar surface from an altitude of 44.0 km . to the dismay of scientists on earth, an electrical fault causes an on-board thruster to fire, decreasing the speed of the spacecraft by 23.0 m/s . if nothing is done to correct its orbit, with what speed (in km/h) will the spacecraft crash into the lunar surface?