All posts tagged Mars

Suspended dust mass over time. Vertical lines mark the start of constant-speed descent (solid), visually detected dust lifting under the helicopter (dotted), and touchdown (dashed). The curves for sols 58, 61, 76, and 193 were obtained with the right eye, sol 69 with the left eye, and sol 64 with each eye (right eye dashed). From sol 64, there were times with the helicopter out of the field of view that were not measured.
Friction velocity and helicopter altitude. The Rabinovitch et al. (2021) model, adapted for atmospheric density of 0.020 kg/m3, 2,800 rpm, and Thrust:Weight = 1, is shown as a red dashed line. Horizontal lines show representative thresholds for a conventional model (Shao & Lu, 2000) and a low-pressure model (Swann et al., 2020); the calculated thresholds are for mobilization of sand (200 diameter, 3,200) and aggregates (500 μm, 380 kg/m3). Vertical solid lines show representative altitudes at which dust lifting was seen during landing and traverse; dotted lines are extended upward to 2x the model prediction.
The roar of the Death Star exploding would have been impossible to hear at a distance since sound can’t travel in space.

Even though sound cannot propagate through the vacuum of space, that doesn’t mean we don’t know what space sounds like. Audio recordings have provided a wealth of information for space scientists almost since the beginning of the space era. Because of their simple and robust operation, microphones have been included on many past and recent space missions, on which they have recorded wind sounds and dust sounds. They will even accompany NASA’s return mission to Saturn’s moon Titan in the 2030s. Audio recordings allow us to reach far across space but also back and forth through time, and probably the last, soulful vestiges of human civilization will persist in the form of audio long after we’re gone.

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