A spaceship approaches Earth with a speed 0.38c. A passenger in the spaceship measures his heartbeat as 72 beats per minute.
How many beats per minute are observed in the telemetry radio signals received on Earth? Note that, in addition to time dilation, one must take into account that the signals of successive heartbeats have to travel shorter distances because the spaceship is moving closer (Doppler Effect). A) 75
B) 107
C) 48
D) 100
E) 67
Question 2
Hydrogen emits light at certain discrete frequencies. One particular emission has a frequency of 4.57 1015 s-1, as measured in the frame of reference of the hydrogen atom.
Light from this emission is observed coming from a star that is moving away from Earth at 0.900c. What is the observed frequency? Note that, in addition to time dilation, one must take into account that successive wavefronts have to travel longer distances because the star is moving away (Doppler Effect). A) 1.99 1015 s-1
B) 7.62 1015 s-1
C) 1.99 1016 s-1
D) 1.05 1015 s-1
E) 0.90 1015 s-1
Animation of the apparent retrograde motion of Mars in 2003 as seen from Earth
The Sun is the nearest star to Earth.
Evaluative measures
The geomagnetic polarity time scale shows how Earth’s magnetic pole has changed through geologic tim
Views of Earth’s Layered Structure
Idealized Tidal Bulges on Earth