enantiomers Archives

The Murchison meteorite fell in Australia in 1969, breaking into numerous fragments. It belongs to the carbonaceous chondrite group of meteorites. These meteorites are considered to be particularly pristine. © MPS / T. Klawunn

Biosignatures & Paleobiology, Fossils & Paleontology, Habitable Zones, Mars, Origin & Evolution of Life, Press Release, Tricorders & Sensors

Mars Mission: A Stress Test For The Search For Life

by Keith CowingJune 20, 2026June 20, 2026

Billions of years ago, environmental conditions on Mars were significantly more hospitable than they are today. Our neighbouring planet was likely warm, humid, and surrounded by a dense atmosphere.

This is how chirality-induced spin selectivity (CISS effect) manifests itself: Electrons (e– or red and green spheres with arrows indicating electron spin, either up or down) with the "wrong" direction of rotation (spin) are held back or filtered out when tunneling through spiral molecules, depending on the handedness of the spirals (left- or right-handed), so that one type of electron spin predominates (electrons with the arrow pointing downwards on the left side). The electric field of a metallic surface (E, pointing upwards, right side) shifts the electrons in the bound heptahelical molecules; these accumulate slightly in the lower part of the molecule near the surface. In the case of chiral molecules, electrons with different spins are also shifted differently depending on the handedness of the molecule. The molecule becomes "spin-polarized", i.e. also magnetic. Depending on the direction of magnetization of the metallic surface, chiral molecules therefore interact with it to different degrees. In this example, the purple spiral therefore binds more strongly to the surface than the yellow one, as opposite spins "attract" each other (the red and green electrons with different spins sitting on top of each other). Graphic: Empa

Astrochemistry, Biophysics, Biosignatures & Paleobiology, Magnetic Fields, Electromagnetism, bioelectricity,, Nanotechnology & SynBio, Press Release

Homochirality Of Life: Magnetic Effects At The Origin Of Life?

by Keith CowingFebruary 21, 2024February 21, 2024

The so-called homochirality of life – the fact that all biomolecules in living organisms only ever occur in one of two mirror-image forms – has puzzled a number of scientific […]