The Tunguska event. On June 30, 1908, a meteor burned up and exploded in the atmosphere above the Tunguska River valley in Siberia. It knocked down trees over thousands of square kilometers and started a forest fire, but produced no crater and apparently caused no human casualties. A witness sitting on his doorstep outside the zone of falling trees recalled events in the following sequence. He saw a moving light in the sky, brighter than the Sun and descending at a low angle to the horizon. He felt his face become warm. He felt the ground shake. An invisible agent picked him up and immediately dropped him about a meter from where he had been seated. He heard a very loud protracted rumbling. Suggest an explanation for these observations and for the order in which they happened.
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EBK PHYSICS FOR SCIENTISTS AND ENGINEER
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- A distant galaxy emits light that has a wavelength of 617.7 nm. On earth, the wavelength of this light is measured to be 623.6 nm. (a) Decide whether this galaxy is approaching or receding from the earth. (b) Find the speed of the galaxy relative to the earth. (Give your answer to 4 significant digits. Use 2.998 × 108 m/s as the speed of light.) (a) The galaxy is (b) Number ◆ from the earth Units ✪arrow_forwardA distant galaxy emits light that has a wavelength of 655.6 nm. On earth, the wavelength of this light is measured to be 661.9 nm. (a) Decide whether this galaxy is approaching or receding from the earth. (b) Find the speed of the galaxy relative to the earth. (Give your answer to 4 significant digits. Use 2.998 × 108 m/s as the speed of light.)arrow_forwardA distant galaxy emits light that has a wavelength of 655.7 nm. On earth, the wavelength of this light is measured to be 660.7 nm. (a)Decide whether this galaxy is approaching or receding from the earth. (b) Find the speed of the galaxy relative to the earth. (Give youranswer to 4 significant digits. Use 2.998 × 108 m/s as the speed of light.)arrow_forward
- A distant galaxy emits light that has a wavelength of 638.3 nm. On earth, the wavelength of this light is measured to be 639.7 nm. (a) Decide whether this galaxy is approaching or receding from the earth. (b) Find the speed of the galaxy relative to the earth. (Give your answer to 4 significant digits. Use 2.998 × 108 m/s as the speed of light.) (a) The galaxy is (b) Number i from the earth. Units SUPPORTarrow_forwardYou have been hired as an expert witness for an attorney who is representing a speeding driver. The driver of the car was given a ticket for running a red light at an intersection. According to the driver, who has taken some courses in physics, when he was looking at the red light as he approached the intersection, the Doppler shift made the light of wavelength 650 nm appear to be green light of wavelength 520 nm. Therefore, according to the driver, he should not be charged with running a red light because it appeared green to him. What advice do you give the attorney?arrow_forwardA) Suppose a star is 4.15 ✕ 1018 m from Earth. Imagine a pulse of radio waves is emitted toward Earth from the surface of this star. How long (in years) would it take to reach Earth? B) The Sun is 1.50 ✕ 1011 m from Earth. How long (in minutes) does it take sunlight to reach Earth? C) The Moon is 3.84 ✕ 108 m from Earth. How long (in s) does it take for a radio transmission to travel from Earth to the Moon and back?arrow_forward
- In the "red shift" of radiation from a distant galaxy, the light H, known to have a wavelength of 434 nm when observed in the laboratory, appears to have a wavelength of 462 nm. What is the speed of the galaxy in the line of sight relative to the Earth?arrow_forwardA person on earth communicating via radio transmission with an astronaut on the moon asks a question. At the time of transmission the moon is 4.00 x 10^5 km from the earth, and the speed of radio waves is 3.00 x 10^8 m/s. How long must the person on earth wait for a response if the astronaut answers 2.50 seconds after the message is received?arrow_forwardWhen high-energy charged particles move through a transparent medium with a speed greater than the speed of light in that medium, a shock wave, or bow wave, of light is produced. This phenomenon is called the Cerenkov effect. When a nuclear reactor is shielded by a large pool of water, Cerenkov radiation can be seen as a blue glow in the vicinity of the reactor core due to high-speed electrons moving through the water as shown. In a particular case, the Cerenkov radiation produces a wave front with an apex half-angle of 53.0°. Calculate the speed of the electrons in the water. The speed of light in water is 2.25 × 108 m/s.arrow_forward
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