New research has found that amino acids, the building blocks of life, may have travelled to Earth on interstellar dust grains, potentially helping kickstart biology as we know it.
In a recent study published in the Monthly Notices of the Royal Astronomical Society, Stephen Thompson, I11’s principal beamline scientist, and Sarah Day, I11 beamline scientist, explored how amino acids like glycine and alanine could survive the harsh conditions of space and make their way to Earth embedded in cosmic dust.
Amino acids are the molecular foundations of proteins and enzymes, which drive every biological process in living organisms. While scientists have long debated whether these molecules formed on Earth or arrived from space, this new study offers compelling evidence that cosmic dust may have played a crucial role in delivering them. The team synthesised tiny particles of amorphous magnesium silicate, a major component of cosmic dust, and deposited amino acids – glycine, alanine, glutamic acid, and aspartic acid – onto them. Using infrared spectroscopy and synchrotron X-ray powder diffraction, they then examined how these molecules behaved when the silicate particles were heated, simulating the warming that occurs as dust grains travelled through the early solar system.
They found that only glycine and alanine successfully adhered to the silicate particles. These amino acids formed crystalline structures and in the case of alanine remained stable at temperatures well above its melting point. The study also found that the two mirror-image forms of alanine (L- and D-alanine) behaved differently under heating, with L-alanine showing more reactivity than its D-form. Glycine, on the other hand, was lost from the silicate at temperatures lower than its pure decomposition point, indicating that it detached from the grain surface rather than breaking down.
The team prepared two batches of amorphous silicate and subjected one batch to heat treatment prior to depositing the amino acids. This was to remove hydrogen atoms from the silicate surface, producing two silicates with differing surface properties, which were also found to influence the temperatures at which the amino acids were lost.
These subtle differences may have had profound implications for the types of molecules that seeded life on Earth.
Read more on the Diamond website
Image: Stephen Thompson, I11’s principal beamline scientist, and Sarah Day, I11 beamline scientist, working on their cosmic dust research
Credit: Diamond Light Source