Zürcher Nachrichten - Strongest 'hints' yet of life detected on distant planet

EUR -
AED 4.331468
AFN 82.441959
ALL 97.863803
AMD 452.240306
ANG 2.110453
AOA 1081.392608
ARS 1449.387625
AUD 1.792671
AWG 2.122691
AZN 2.004211
BAM 1.954678
BBD 2.374636
BDT 143.837403
BGN 1.954061
BHD 0.444554
BIF 3503.458467
BMD 1.179273
BND 1.498127
BOB 8.126334
BRL 6.408881
BSD 1.176125
BTN 100.757141
BWP 15.608037
BYN 3.84879
BYR 23113.747175
BZD 2.362343
CAD 1.602614
CDF 3402.202123
CHF 0.934061
CLF 0.028465
CLP 1092.313036
CNY 8.449962
CNH 8.442462
COP 4710.628845
CRC 594.158811
CUC 1.179273
CUP 31.25073
CVE 110.201718
CZK 24.67511
DJF 209.429737
DKK 7.4612
DOP 69.889866
DZD 152.506192
EGP 58.190981
ERN 17.689092
ETB 162.240635
FJD 2.635321
FKP 0.865709
GBP 0.862998
GEL 3.207334
GGP 0.865709
GHS 12.17201
GIP 0.865709
GMD 84.318804
GNF 10195.059143
GTQ 9.042807
GYD 246.048709
HKD 9.257156
HNL 30.737349
HRK 7.53119
HTG 154.360051
HUF 399.80057
IDR 19104.750277
ILS 3.964208
IMP 0.865709
INR 100.642085
IQD 1540.615318
IRR 49676.867331
ISK 142.774681
JEP 0.865709
JMD 188.012036
JOD 0.83616
JPY 169.634266
KES 152.420923
KGS 103.127795
KHR 4720.24942
KMF 492.935986
KPW 1061.376887
KRW 1604.683568
KWD 0.359797
KYD 0.980137
KZT 609.899772
LAK 25346.445072
LBP 105376.288782
LKR 352.737444
LRD 235.804592
LSL 20.776269
LTL 3.482086
LVL 0.71333
LYD 6.333363
MAD 10.572029
MDL 19.763651
MGA 5177.027147
MKD 61.456877
MMK 2475.536953
MNT 4228.025905
MOP 9.509439
MRU 46.719172
MUR 52.913559
MVR 18.200696
MWK 2039.42888
MXN 22.13988
MYR 4.978304
MZN 75.426587
NAD 20.776269
NGN 1802.588928
NIO 43.274783
NOK 11.886132
NPR 161.211426
NZD 1.940564
OMR 0.453429
PAB 1.176025
PEN 4.188595
PGK 4.854171
PHP 66.39069
PKR 335.475257
PLN 4.264047
PYG 9380.613282
QAR 4.287838
RON 5.060736
RSD 117.171396
RUB 93.190072
RWF 1689.429863
SAR 4.422716
SBD 9.831508
SCR 17.02886
SDG 708.178858
SEK 11.257362
SGD 1.501286
SHP 0.926723
SLE 26.474744
SLL 24728.765617
SOS 672.114046
SRD 44.039941
STD 24408.56633
SVC 10.29109
SYP 15332.645848
SZL 20.772072
THB 38.150663
TJS 11.501995
TMT 4.139248
TND 3.423834
TOP 2.761972
TRY 47.049096
TTD 7.97542
TWD 34.080749
TZS 3109.198802
UAH 49.107001
UGX 4218.577527
USD 1.179273
UYU 46.533279
UZS 14908.438987
VES 129.09912
VND 30891.051391
VUV 140.273445
WST 3.067915
XAF 655.58054
XAG 0.031839
XAU 0.000352
XCD 3.187044
XDR 0.815332
XOF 655.58054
XPF 119.331742
YER 285.560466
ZAR 20.647486
ZMK 10614.870995
ZMW 28.257773
ZWL 379.725365
  • 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%

Strongest 'hints' yet of life detected on distant planet
Strongest 'hints' yet of life detected on distant planet / Photo: Handout - University of Cambridge/AFP

Strongest 'hints' yet of life detected on distant planet

Astronomers announced Thursday that they had detected the most promising "hints" of potential life on a planet beyond our solar system, though other scientists expressed scepticism.

Text size:

There has been vigorous debate in scientific circles about whether the planet K2-18b, which is 124 light years away in the Leo constellation, could be an ocean world capable of hosting microbial life, at least.

Using the James Webb Space Telescope, a British-US team of researchers detected signs of two chemicals in the planet's atmosphere long considered to be "biosignatures" indicating extraterrestrial life.

On Earth, the chemicals dimethyl sulfide (DMS) and dimethyl disulfide are produced only by life, mostly microscopic marine algae called phytoplankton.

The researchers emphasised caution, saying that more observations were needed to confirm these findings, and that they were not announcing a definitive discovery.

But the implications could be huge, according to Nikku Madhusudhan, a Cambridge University astrophysicist and lead author of the study, published in The Astrophysical Journal Letters.

"What we are finding at this point are hints of possible biological activity outside the solar system," he told journalists.

"Frankly, I think this is the closest we have come to seeing a feature that we can attribute to life."

But outside experts pointed to disputes over previous discoveries about the exoplanet, adding that these chemicals could have been created by unknown means having nothing to do with life.

- Chemical clues -

More than eight times the mass of Earth and 2.5 times as big, K2-18b is rare among the roughly 6,000 exoplanets discovered so far in that it orbits its star in a habitable or "goldilocks" zone.

This means it is neither too hot nor too cold to have liquid water, considered the most important ingredient for life.

Telescopes observe such far-off exoplanets when they cross in front of their star, allowing astronomers to analyse how molecules block the light streaming through their atmosphere.

In 2023, the Webb telescope detected methane and carbon dioxide in K2-18b's atmosphere, the first time such carbon-based molecules were detected on an exoplanet in a habitable zone.

It also detected weak signals of the chemical DMS, leading astronomers to turn Webb towards the planet again a year ago, this time using its mid-infrared instrument to detect different wavelengths of light.

They found much stronger signs of the chemicals, though still well below the "five sigma" threshold of statistical significance scientists seek for such discoveries.

Even if the results are confirmed, it would not necessarily mean that the planet is home to life.

Last year, scientists found traces of DMS on a comet, which suggested it can be produced in non-organic ways and is perhaps not a "biosignature".

However the concentration of the chemical observed on K2-18b appears to be thousands of times stronger than levels on Earth, likely suggesting a biological origin, Madhusudhan said.

- Are we alone in the universe? -

K2-18b has long been considered the premier candidate for a "hycean planet" -- an ocean world bigger than Earth with a hydrogen-rich atmosphere.

These planets would not be expected to be home to intelligent alien life, but rather tiny microbes similar to those in Earth's oceans billions of years ago.

Some research has questioned whether the currently proposed hycean planets are too close to their stars to support liquid water -- including K2-18b, which orbits its star every 33 days.

Raymond Pierrehumbert, a planetary physics professor at Oxford University, has conducted separate research indicating K2-18b is too hot for life.

If the planet did have water, it would be "hellishly hot" and uninhabitable, he told AFP, adding that oceans of lava were more plausible.

Sara Seager, a professor of planetary science at MIT, called for patience, pointing to previous claims of water vapour in K2-18b's atmosphere that turned out to be a different gas.

Madhusudhan estimated that it would take just 16 to 24 more hours of Webb's time to reach the five-sigma threshold, which could happen in the next few years.

The current three-sigma is comparable to the odds of flipping a coin 10 times and getting the same result each time, Cambridge University statistician Stephen Burgess explained.

Five sigma would be getting that result after 20 flips, and would mean "we can be very confident that this observation isn't just a chance finding," he said.

Even beyond K2-18b, Madhusudhan said Webb and future telescopes could allow humanity to discover life outside our home planet sooner than one might think.

"This could be the tipping point, where suddenly the fundamental question of whether we're alone in the universe is one we're capable of answering," he said.

Ch.Siegenthaler--NZN