A scientific lander on Mars transmits telemetry data back to a research station on Earth via a high-frequency radio link.
The table below shows the orbital distances from the Sun to Earth and from the Sun to Mars, when the two planets are at their closest approach (opposition).
| Location | Distance from the Sun (m) |
|---|---|
| Earth | 1.50×10111.50 \times 10^{11}1.50×1011 |
| Mars | 2.28×10112.28 \times 10^{11}2.28×1011 |
The radio signal travels at a speed of 3.00×108 m/s3.00 \times 10^8\text{ m/s}3.00×108 m/s.
Calculate the minimum time, in seconds, for the telemetry signal to travel from Mars to Earth. Use the data in the table and the equation: distance=speed×time\text{distance} = \text{speed} \times \text{time}distance=speed×time
Time=\text{Time} =Time= ......................... s\text{s}s
The average surface temperature on Earth is 15∘C15^\circ\text{C}15∘C.
Suggest whether the average surface temperature on Mars is higher or lower than 15∘C15^\circ\text{C}15∘C. Use the data in the table to explain your answer.