Zürcher Nachrichten - First audio recorded on Mars reveals two speeds of sound

EUR -
AED 3.831072
AFN 72.927229
ALL 98.419269
AMD 410.271893
ANG 1.872215
AOA 957.496706
ARS 1061.692588
AUD 1.668305
AWG 1.877444
AZN 1.777282
BAM 1.955189
BBD 2.097545
BDT 124.141237
BGN 1.955855
BHD 0.391978
BIF 3071.340978
BMD 1.043024
BND 1.410859
BOB 7.178758
BRL 6.347889
BSD 1.038876
BTN 88.318423
BWP 14.358517
BYN 3.399738
BYR 20443.276614
BZD 2.088248
CAD 1.495916
CDF 2993.480167
CHF 0.932343
CLF 0.037343
CLP 1030.408256
CNY 7.610327
CNH 7.606363
COP 4547.280118
CRC 524.136339
CUC 1.043024
CUP 27.640144
CVE 110.230581
CZK 25.128859
DJF 184.992236
DKK 7.459297
DOP 63.260247
DZD 140.605096
EGP 53.072428
ERN 15.645365
ETB 129.499464
FJD 2.41674
FKP 0.826056
GBP 0.830004
GEL 2.931306
GGP 0.826056
GHS 15.271232
GIP 0.826056
GMD 75.098122
GNF 8975.197506
GTQ 8.004501
GYD 217.342135
HKD 8.109462
HNL 26.370766
HRK 7.481515
HTG 135.907563
HUF 414.018477
IDR 16867.059138
ILS 3.811566
IMP 0.826056
INR 88.607528
IQD 1360.875069
IRR 43898.289923
ISK 145.105945
JEP 0.826056
JMD 162.539247
JOD 0.739613
JPY 163.175981
KES 134.118122
KGS 90.743481
KHR 4174.696457
KMF 486.179751
KPW 938.721302
KRW 1508.651632
KWD 0.3212
KYD 0.86573
KZT 545.579643
LAK 22737.90012
LBP 93027.952144
LKR 305.004763
LRD 188.551125
LSL 19.125728
LTL 3.07978
LVL 0.630915
LYD 5.104406
MAD 10.455435
MDL 19.135025
MGA 4901.469523
MKD 61.515792
MMK 3387.702296
MNT 3544.196494
MOP 8.316603
MRU 41.315099
MUR 49.23465
MVR 16.066474
MWK 1801.337535
MXN 20.945288
MYR 4.701994
MZN 66.653144
NAD 19.125728
NGN 1616.208293
NIO 38.228063
NOK 11.807144
NPR 141.309876
NZD 1.844266
OMR 0.401355
PAB 1.038876
PEN 3.868392
PGK 4.212685
PHP 61.403232
PKR 289.16061
PLN 4.263169
PYG 8100.470639
QAR 3.787117
RON 4.976899
RSD 116.931488
RUB 107.374772
RWF 1448.147818
SAR 3.91792
SBD 8.744252
SCR 14.545014
SDG 627.382961
SEK 11.507274
SGD 1.414241
SHP 0.826056
SLE 23.784779
SLL 21871.701575
SOS 593.714613
SRD 36.642527
STD 21588.497505
SVC 9.090162
SYP 2620.630141
SZL 19.121029
THB 35.692677
TJS 11.364851
TMT 3.661015
TND 3.310266
TOP 2.442871
TRY 36.580744
TTD 7.050798
TWD 34.034966
TZS 2467.229611
UAH 43.568696
UGX 3810.81008
USD 1.043024
UYU 46.335532
UZS 13393.817798
VES 53.689938
VND 26550.18399
VUV 123.829936
WST 2.881655
XAF 655.752242
XAG 0.03535
XAU 0.000398
XCD 2.818826
XDR 0.792453
XOF 655.752242
XPF 119.331742
YER 261.147252
ZAR 19.097296
ZMK 9388.474223
ZMW 28.750023
ZWL 335.853405
  • CMSD

    0.0000

    23.56

    0%

  • BCC

    -0.2600

    122.75

    -0.21%

  • RBGPF

    59.9600

    59.96

    +100%

  • SCS

    -0.5800

    11.74

    -4.94%

  • NGG

    0.8200

    58.5

    +1.4%

  • RELX

    -0.3100

    45.47

    -0.68%

  • RIO

    -0.0900

    58.64

    -0.15%

  • GSK

    0.1700

    33.6

    +0.51%

  • CMSC

    0.0200

    23.86

    +0.08%

  • JRI

    0.1100

    12.06

    +0.91%

  • BCE

    0.0500

    23.16

    +0.22%

  • BTI

    0.1131

    36.24

    +0.31%

  • VOD

    0.0100

    8.39

    +0.12%

  • RYCEF

    -0.0100

    7.27

    -0.14%

  • AZN

    0.9100

    65.35

    +1.39%

  • BP

    0.1900

    28.6

    +0.66%

First audio recorded on Mars reveals two speeds of sound
First audio recorded on Mars reveals two speeds of sound

First audio recorded on Mars reveals two speeds of sound

The first audio recordings on Mars reveal a quiet planet with occasional gusts of wind where two different speeds of sound would have a strange delayed effect on hearing, scientists said Friday.

Text size:

After NASA's Perseverance rover landed on Mars in February last year, its two microphones started recording, allowing scientists to hear what it is like on the Red Planet for the first time.

In a study published in the Nature journal on Friday, the scientists gave their first analysis of the five hours of sound picked up by Perseverance's microphones.

The audio revealed previously unknown turbulence on Mars, said Sylvestre Maurice, the study's main author and scientific co-director of the shoebox-sized SuperCam mounted on the rover's mast which has the main microphone.

The international team listened to flights by the tiny Ingenuity helicopter, a sister craft to Perseverance, and heard the rover's laser zap rocks to study their chemical composition -- which made a "clack clack" sound, Maurice told AFP.

"We had a very localised sound source, between two and five metres (six to 16 metres) from its target, and we knew exactly when it was going to fire," he said.

The study confirmed for the first time that the speed of sound is slower on Mars, travelling at 240 metres per second, compared to Earth's 340 metres per second.

This had been expected because Mars' atmosphere is 95 percent carbon dioxide -- compared to Earth's 0.04 percent -- and is about 100 times thinner, making sound 20 decibels weaker, the study said.

- 'I panicked' -

But the scientists were surprised when the sound made by the laser took 250 metres a second -- 10 metres faster than expected.

"I panicked a little," Maurice said. "I told myself that one of the two measurements was wrong because on Earth you only have one speed of sound."

They had discovered there are two speeds of sound on the surface of Mars -- one for high-pitched sounds like the zap of the laser, and another for lower frequencies like the whir of the helicopter rotor.

This means that human ears would hear high-pitched sounds slightly earlier.

"On Earth, the sounds from an orchestra reach you at the same speed, whether they are low or high. But imagine on Mars, if you are a little far from the stage, there will be a big delay," Maurice said.

"All of these factors would make it difficult for two people to have a conversation only five metres (16 feet) apart", the French CNRS research institute said in a statement.

- 'Scientific gamble' pays off -

It was otherwise so quiet on Mars that the scientists repeatedly feared something was wrong, the CNRS said, possibly provoking memories of two failed previous attempts in 1999 and 2008 to record sound there.

"There are few natural sound sources with the exception of the wind," the scientists said in a statement linked to the study.

The microphones did pick up numerous "screech" and "clank" sounds as the rover's metal wheels interacted with rocks, the study said.

The recording could also warn about problems with the rover -- like how drivers sense something's wrong when their car starts making strange noises.

Maurice said he felt the "scientific gamble" of taking microphones to Mars was a success.

Thierry Fouchet of the Paris Observatory, who was also involved in the research, said that listening to turbulence, such as vertical winds known as convection plumes, will "allow us to refine our numerical models for predicting climate and weather".

Future missions to Venus or Saturn's moon Titan could also now come equipped with microphones.

And Perseverance is far from done eavesdropping. While its core mission lasts just over two years, it could remain operational well beyond that -- the Curiosity rover is still kicking nine years into a planned two-year stint.

L.Zimmermann--NZN