Sugars in Meteorites

21 Nov 2019

This story is at https://phys.org/news/2019-11-sugars-meteorites-clues-life.html ... virtually anything organic in comets and meteors is deemed to be a clue to the origin of life - without many clues on how they convert from primitive building blocks into actual building blocks. Research continues and more information is popping up all the time. Here we have an international team that say that sugars found in a couple of meteorites support the hypothesis that chemical reactions in asteroids, their parent bodies, can make sense of life's ingredients. Not everything though. The idea is that an ancient bombardment of the Earth by meteorites may have assisted the origin of life - with a steady supply of buiilding blocks.

The t4eam discovered ribose and other bioessential sugars including arabinose and xylose in two different meteorites that were rich in carbon as well as NWA 801 and Murchsion ribose etc. The latter are crucial components of RNA (ribonucleic acids). In much of modern life RNA serves as a messenger molecule copying genetic instructions from the DNA molecules and delivering them to what are called molecular factories wihin the cell called ribosomes that read the RNA to build specific proteins needed to carry out life processes. Other building blocks have been found previously in meteorites - such as amino acids (or components that make up amino acids) which therefore are components of proteins, and nucleobases (components of RNA and DNA). Sugars, until now, have been a missing piece of the puzzle - so this discovery is important. Yoshihiro Furukawa, lead author, says the research provides the first evidence of ribose in space - and the delivery of sugars to Earth.

An enduring mystery regarding the origin of life, we are told, is how biology could have arisen from non-biological chemical processes. DNA is the template for life, carrying the instructions for how to build and operate a living organism. However, RNA also carries important information and researchers think it evolved first and was later replaced by DNA. This is because RNA molecules have capabilities that DNA lacks. RNA can make copies of itself without help from other molecules, and it can also initiate or speed up chemical reactions as a catalyst.

Over at https://phys.org/news/2019-11-subaru-telescope-mid-infrared-emission-ban... ... the Subaru telecope has detected organic molecules in Comet 21P/G-Z - in addition to thermal emissions from silicates and carbon grains. These include aliphatic and aromatic hydrocarbons (shades of Velikovsky). Comet 21P/G-Z has an orbital period of 6.6 years (after escaping from the Jupiter gateway) and is thought ot be the parent of the October Draconids meteor shower. Again, the Japanese are driving the research.