The Prague Post - First audio recorded on Mars reveals two speeds of sound

EUR -
AED 4.302888
AFN 81.916613
ALL 97.902049
AMD 450.136794
ANG 2.096812
AOA 1074.403591
ARS 1469.848083
AUD 1.794588
AWG 2.108971
AZN 1.994112
BAM 1.952659
BBD 2.367324
BDT 142.853889
BGN 1.957396
BHD 0.441704
BIF 3493.202692
BMD 1.17165
BND 1.498972
BOB 8.090986
BRL 6.384309
BSD 1.172565
BTN 100.422329
BWP 15.653531
BYN 3.837005
BYR 22964.349685
BZD 2.355128
CAD 1.602332
CDF 3381.383512
CHF 0.933815
CLF 0.028754
CLP 1103.414015
CNY 8.405479
CNH 8.416862
COP 4747.094292
CRC 592.730776
CUC 1.17165
CUP 31.048738
CVE 110.834423
CZK 24.648246
DJF 208.79039
DKK 7.461246
DOP 70.349915
DZD 151.915361
EGP 58.229393
ERN 17.574757
ETB 162.720143
FJD 2.632991
FKP 0.863233
GBP 0.862387
GEL 3.175781
GGP 0.863233
GHS 12.18599
GIP 0.863233
GMD 83.777767
GNF 10169.096726
GTQ 8.999755
GYD 244.988501
HKD 9.197398
HNL 30.659247
HRK 7.534062
HTG 153.886066
HUF 400.216482
IDR 19047.814996
ILS 3.924766
IMP 0.863233
INR 100.576119
IQD 1535.961483
IRR 49355.777276
ISK 142.999707
JEP 0.863233
JMD 187.136573
JOD 0.830733
JPY 172.250216
KES 151.693066
KGS 102.461195
KHR 4707.655966
KMF 492.670214
KPW 1054.459685
KRW 1610.246333
KWD 0.357904
KYD 0.977121
KZT 609.236063
LAK 25258.788623
LBP 105052.907426
LKR 352.46937
LRD 235.082884
LSL 20.853146
LTL 3.45958
LVL 0.70872
LYD 6.333192
MAD 10.550712
MDL 19.844334
MGA 5178.521534
MKD 61.525551
MMK 2459.888866
MNT 4204.537111
MOP 9.480393
MRU 46.564706
MUR 53.063981
MVR 18.037076
MWK 2033.019574
MXN 21.798902
MYR 4.980101
MZN 74.93866
NAD 20.853146
NGN 1794.547027
NIO 43.147681
NOK 11.838346
NPR 160.676127
NZD 1.953546
OMR 0.450484
PAB 1.170927
PEN 4.152912
PGK 4.916596
PHP 66.252143
PKR 333.331834
PLN 4.245312
PYG 9344.332196
QAR 4.265507
RON 5.075471
RSD 117.180281
RUB 91.977776
RWF 1694.216302
SAR 4.394421
SBD 9.767962
SCR 17.192081
SDG 703.572951
SEK 11.172057
SGD 1.501066
SHP 0.920733
SLE 26.370592
SLL 24568.92933
SOS 670.108684
SRD 43.730096
STD 24250.799675
SVC 10.259071
SYP 15233.951871
SZL 20.845049
THB 38.247947
TJS 11.261485
TMT 4.112493
TND 3.394536
TOP 2.744124
TRY 46.922963
TTD 7.954729
TWD 34.124668
TZS 3087.299325
UAH 48.973918
UGX 4209.229791
USD 1.17165
UYU 47.015583
UZS 14862.756687
VES 131.56206
VND 30626.943917
VUV 139.782501
WST 3.225978
XAF 655.769778
XAG 0.03195
XAU 0.000356
XCD 3.166444
XDR 0.815567
XOF 655.769778
XPF 119.331742
YER 283.363731
ZAR 20.835285
ZMK 10546.260708
ZMW 28.402891
ZWL 377.270981
  • CMSC

    0.0900

    22.314

    +0.4%

  • CMSD

    0.0250

    22.285

    +0.11%

  • RBGPF

    0.0000

    69.04

    0%

  • SCS

    0.0400

    10.74

    +0.37%

  • RELX

    0.0300

    53

    +0.06%

  • RIO

    -0.1400

    59.33

    -0.24%

  • GSK

    0.1300

    41.45

    +0.31%

  • NGG

    0.2700

    71.48

    +0.38%

  • BP

    0.1750

    30.4

    +0.58%

  • BTI

    0.7150

    48.215

    +1.48%

  • BCC

    0.7900

    91.02

    +0.87%

  • JRI

    0.0200

    13.13

    +0.15%

  • VOD

    0.0100

    9.85

    +0.1%

  • BCE

    -0.0600

    22.445

    -0.27%

  • RYCEF

    0.1000

    12

    +0.83%

  • AZN

    -0.1200

    73.71

    -0.16%

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.

J.Marek--TPP