NASA's Perseverance rover on Mars is the first probe to be outfitted with dedicated microphones. Now, a global science team has completed the first analysis of recordings captured by Perseverance's two onboard mics, from wind gusts to the buzzing of the Ingenuity autonomous helicopter's blades, to a laser that vaporizes rock to reveal its composition. Listen above. From the Jet Propulsion Laboratory:
The result of the recordings: a new understanding of strange characteristics of the Martian atmosphere, where the speed of sound is slower than on Earth – and varies with pitch (or frequency). On Earth, sounds typically travel at 767 mph (343 meters per second). But on Mars, low-pitched sounds travel at about 537 mph (240 meters per second), while higher-pitched sounds move at 559 mph (250 meters per second).
The variable sound speeds on the Red Planet are an effect of the thin, cold, carbon dioxide atmosphere. Prior to the mission, scientists expected Mars' atmosphere would influence sound speed, but the phenomenon had never been observed until these recordings were made. Another effect of this thin atmosphere: Sounds carry only a short distance, and higher-pitched tones carry hardly at all. On Earth, sound might drop off after about 213 feet (65 meters); on Mars, it falters at just 26 feet (8 meters), with high-pitched sounds being lost completely at that distance.
