Fireworks go off at the same time according to Earth clocks in two cities, Alum and Boron, that are 300 km apart. The people in a spaceship that is flying in a straight line from Alum to Boron at 0.80 c also observe the fireworks. Do they see the fireworks in the two cities simultaneously? If the people in the spaceship say the fireworks were not simultaneous in Alum and Boron, how long before or after the fireworks flashed at Alum did the fireworks flash at Boron according to their calculations? (The spaceship is directly over Alum when the fireworks flash.)
a. Yes; 0
b. Before; 1.0 10-3 s
c. After; 1.0 10-3 s
d. Before; 1.3 10-3 s
e. After; 1.3 10-3 s
Question 2
A spaceship from another galaxy passes over the solar system directly above a radial line from the sun to the Earth. (We measure that distance to be 1.5 1011 m.) On Earth, the spaceship is observed to be traveling at a speed of 0.80 c, for which g = 5/3 . As measured on Earth it takes the spaceship 625 seconds to travel from the sun to Earth. When a scientist in the spaceship measures the Earth-sun distance and the time it takes her to travel that distance, she finds the results are respectively
a. 9.0 1010 m; 375 s.
b. 9.0 1010 m; 625 s.
c. 1.5 1011 m; 625 s.
d. 2.5 1011 m; 625 s.
e. 2.5 1011 m; 1042 s.
The greenhouse effect: heat trapping by earth's atmosphere.
Views of Earth’s Surface
Hints of Earth’s Early Appearance
Distance from Earth to Sun schematic
Precession of Earth
Earth’s Early Atmosphere