K2-18b and MeerKAT: The Search for Life in the Cosmos

Source: Image by Kipargeter on Freekip.

<a href="https://br.freepik.com/fotos-gratis/cena-do-espaco-3d-com-planetas-ficticios-e-estrelas_1077125.htm">

The discovery of potential biomarkers in exoplanet atmospheres has been revolutionized by the James Webb Space Telescope (JWST) 2021 (https://jadc.swin.edu.au/#IAUS391), which provides unprecedented capabilities for spectroscopic data collection and analysis. Spectroscopic methodology enables scientists to identify molecular markers in planetary atmospheres by detecting specific wavelength absorptions, offering crucial insights into their chemical composition. The exoplanet K2-18b represents a compelling case study, where recent spectroscopic observations revealed the presence of carbon-containing molecules, including methane (CH₄) and carbon dioxide (CO₂), alongside potential dimethyl sulfide (DMS) signatures — a compound predominantly produced by biological processes on Earth. K2-18b exemplifies the “Hycean world” classification, a term designating exoplanets with water-rich interiors and hydrogen-dominated atmospheres (H₂), possessing intermediate density between super-Earths and mini-Neptunes. These Hycean planets have emerged as particularly promising habitability candidates due to their potential to maintain liquid water at their surfaces despite orbiting in regions previously considered outside traditional habitable zones, with their extensive hydrogen atmospheres potentially providing pressure and temperature conditions conducive to sustaining complex chemistry and possibly even biological processes (MADHUSUDHAN, CONSTANTINOU, 2021).

Scientists from the University of Cambridge, coordinated by Professor Nikku Madhusudhan, utilized the JWST to identify in the atmosphere of a distant exoplanet, located 124 light-years from Earth, specific molecular markers – detectable chemical compounds that function as "fingerprints" – of gases that, on our planet, are typically generated by biological activities. The study was published in the “Monthly Notices of the Royal Astronomical Society” (MITCHELL, MADHUSUDHAN, 2025).

Source: https://www.correiobraziliense.com.br/ciencia-e-saude/2025/04/7113368-james-webb-detecta-maior-sinal-de-vida-extraterrestre-ja-visto.html

The image above is a computer-generated illustration based on spectroscopic data collected by the JWST.

The Impact of New Astronomical Discoveries

Recent discoveries in astronomy, such as those related to exoplanet K2-18b, have had a profound impact on our understanding of the universe and our place in it. The detection of carbon-containing molecules, such as methane and carbon dioxide, in K2-18b's atmosphere, along with the possible detection of dimethyl sulfide (DMS), a compound that on Earth is almost exclusively produced by living organisms, opens the possibility that this exoplanet might harbor microbial life.

These discoveries not only expand our understanding of habitable zones to include planets with hydrogen-rich atmospheres but also demonstrate the capability of the JWST to characterize atmospheres of relatively small exoplanets, an unprecedented technical capability. Furthermore, they establish a precedent for the detection of multiple chemical compounds which, when analyzed together, provide a more complete context for assessing habitability potential.

But how does Africa fit into this cosmic narrative?

The continent has increasingly distinguished itself in the global astronomical scenario, with South Africa leading the way.

South Africa's Role at the Forefront of Astronomy

In the heart of South Africa's semi-arid Karoo, the MeerKAT radio telescope stands as a revolutionary milestone for global astronomical science. Operated by the South African Radio Astronomy Observatory, MeerKAT represents not only one of South Africa's largest scientific infrastructure projects in the last 30 years of democracy but also a symbol of Africa's growing prominence in global astronomy.

Source: https://360news.com.br/radiotelescopio-meerkat-vai-procurar-sinais-de-vida-alienigena-em-estrelas/

The MeerKAT radio telescope is an impressive array of 64 parabolic antennas and serves as a precursor to the ambitious Square Kilometre Array (SKA) project, which, when completed in 2028 or 2029, will be the most powerful radio telescope in the world. Distinguished by its exceptional sensitivity and resolution, MeerKAT has provided astronomers with an unprecedented view of the universe, revolutionizing particularly the field of transient astronomy – the study of celestial objects that exhibit changing characteristics over relatively short periods.

MeerKAT's extraordinary technical capabilities have already resulted in fundamental discoveries, such as the detailed observation of the collision between two neutron stars in 2017, contributing significantly to our understanding of the most energetic phenomena in the cosmos. More than a technological advancement, MeerKAT represents the flourishing of African scientific excellence, cultivating local talent and establishing the continent as a global center for astronomical innovation.

Perspectives for the Future of the African Continent in Astronomy

The future of astronomy in Africa is promising. With projects such as MeerKAT and SKA, South Africa is becoming a global center for astronomical research. Furthermore, educational and scientific outreach initiatives are helping to inspire the next generation of African scientists.

The inclusion of Africa in major global scientific debates is fundamental to ensuring that science is truly global and inclusive. Africa has a rich history of astronomical knowledge and a bright future in astronomical research. By investing in science and technology, the continent that is the cradle of humanity can play a leadership role in the search for life in the universe and in understanding the mysteries of the cosmos.

In an increasingly connected world, international collaboration is essential for the advancement of science. Africa has much to offer the global scientific community, and the world has much to gain from the inclusion of Africa in major scientific debates.

Image created by GPT Image (Adapt∆ One) – MeerKAT (SKA) in South Africa.

References:

Madhusudhan, N., Piette, A. A., & Constantinou, S. (2021). Habitability and biosignatures of Hycean worlds. The Astrophysical Journal, 918(1), 1.

Mitchell, E. G., & Madhusudhan, N. (2025). Prospects for biological evolution on Hycean worlds. Monthly Notices of the Royal Astronomical Society, staf094.

To know more:

Davidson, D. B. (2012, October). MeerKAT and SKA phase 1. In ISAPE2012 (pp. 1279-1282). IEEE.

Impey, C. (2025, April 25). Extraordinary claims require extraordinary evidence: An astronomer explains how much evidence scientists need to claim discoveries like extraterrestrial life. The Conversation, [S.l.], 25 abr. 2025. Disponível em: https://theconversation.com/extraordinary-claims-require-extraordinary-evidence-an-astronomer-explains-how-much-evidence-scientists-need-to-claim-discoveries-like-extraterrestrial-life-254914.