Astrobiology and the life sciences: how life works at its limits, and what it would take to recognize it somewhere else.
2 stories. Section line: Magnesium b, 518.4 nm.
A rock in an ancient Martian river valley carries chemical patterns that, on Earth, are usually made by microbes. NASA calls it a potential biosignature. The sample that could settle it may never come home.
Half a millimeter long and found almost everywhere, tardigrades can survive drying, freezing, radiation and even the vacuum of space. They are not indestructible. Their tricks are more interesting than that.