Nuovo articolo di Luca Frigerio pubblicato su AstronautiNEWS.it.
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Ci sarà una conferenza per discutere delle novità sui risultati scientifici dai dati della missione. 2025-01-29T16:00:00Z.
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Sui campioni recuperati su Bennu trovate molecole organiche, inclusi aminoacidi e basi azotate, oltre a tracce di acqua salata.
Detailed in the Nature Astronomy paper, among the most compelling detections were amino acids – 14 of the 20 that life on Earth uses to make proteins – and all five nucleobases that life on Earth uses to store and transmit genetic instructions in more complex terrestrial biomolecules, such as DNA and RNA, including how to arrange amino acids into proteins. Scientists also described exceptionally high abundances of ammonia in the Bennu samples.
Reporting in the journal Nature, scientists further describe evidence of an ancient environment well-suited to kickstart the chemistry of life.
Ranging from calcite to halite and sylvite, scientists identified traces of 11 minerals in the Bennu sample that form as water containing dissolved salts evaporates over long periods of time, leaving behind the salts as solid crystals.
Similar brines have been detected or suggested across the solar system, including at the dwarf planet Ceres and Saturn’s moon Enceladus.
Questione non da poco:
For all the answers the Bennu sample has provided, several questions remain. Many amino acids can be created in two mirror-image versions, like a pair of left and right hands. Life on Earth almost exclusively produces the left-handed variety, but the Bennu samples contain an equal mixture of both. This means that on early Earth, amino acids may have started out in an equal mixture, as well. The reason life “turned left” instead of right remains a mystery.
Il comunicato di NASA.
L’articolo su Nature (qui su Archive).
Asteroid fragments upend theory of how life on Earth bloomed
Glavin is most perplexed by the discovery of an equal mixture of left-handed and right-handed amino acids on Bennu. He, like many scientists, had thought that organic molecules from primordial asteroids would have had the same left-handed dominance as those from life on Earth. Now, researchers have to go back to the drawing board to understand how life might have been seeded on Earth.
“I felt a little bit disappointed at first, like it invalidated 20 years of my research,” Glavin says. “But this is why we explore — to learn new things.”
Paper:
Abundant ammonia and nitrogen-rich soluble organic matter in samples from asteroid (101955) Bennu
An evaporite sequence from ancient brine recorded in Bennu samples
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Pero’ io non sarei tanto ossessionato dalle molecole biologiche, quanto dal capire se ci sono tutti gli elementi per un futuro sfruttamento degli asteroidi.
Non ci sono molecole biologiche, assolutamente.
Solo molecole organiche.
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A livello di studi esobiologici, credo che sia una conferma del fatto che questo tipo di molecole organiche siano più diffuse, almeno ne nostro sistema solare, di quello che magari si pensava fino a qualche anno fa.
Adesso aspettiamo quali teorie scientifiche deriveranno da questa scoperta.
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