Virtually every definition of the word "life" includes the capability to undergo Darwinian evolution as a necessary characteristic. This is true of life on Earth and of thinking about what would constitute life beyond Earth. If it can't change, the thinking goes, then it cannot be truly alive. In addition, evolutionary selection and change occurs …
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https://www.youtube.com/watch?v=-3hO58HFa1M The Hayabusa2 touchdown movie, taken on February 22, 2019 (JST) when Hayabusa2 first touched down on asteroid Ryugu to collect a sample from the surface. It was captured using the onboard small monitor camera (CAM-H). The video playback speed is five times faster than actual time (JAXA). On March 5 the Japan Aerospace Exploration …
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If there was a simple meaning of the often-used scientific term “emergence,” then 100-plus scientists wouldn’t have spent four days presenting, debating and not infrequently disagreeing about what it was. But as last month’s organizers of the Earth-Life Science Institute’s “Comparative Emergence” symposium in Tokyo frequently reminded the participants, those debates and disputes are …
The question of how life-essential elements such as carbon, nitrogen and sulfur came to our planet has been long debated and is a clearly important and slippery scientific subject. Did these volatile elements accrete onto the proto-Earth from the sun's planetary disk as the planet was being formed? Did they arrive substantially later …
This story was written by Nicholas Siegler, Chief Technologist for NASA’s Exoplanet Exploration Program at the Jet Propulsion Laboratory with the help of doctoral student Markus Gogouvitis, at the University of New South Wales, Australia and Georg-August-University in Gottingen, Germany. This past July I joined a group of geologists, geochemists, microbiologists, and fellow …
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An essential characteristic of life is that it evolves. Whether on Earth or potentially Mars, Europa or distant exoplanets, we can assume that whatever life might be present has the capacity and the need to change. Evolution is intimately tied to the origin-of-life question, which this column often explores. Having more answers regarding how life …
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We all know that cut diamonds sparkle and shine, one of the great aesthetic creations from nature. Less well known is that diamonds and the bits of minerals, gases and water encased in them offer a unique opportunity to probe the deepest regions of our planet. Thought to be some of the oldest available materials …
What observations, or groups of observations, would tell exoplanet scientists that life might be present on a particular distant planet? The most often discussed biosignature is oxygen, the product of life on Earth. But while oxygen remains central to the search for biosignatures afar, there are some serious problems with relying on that molecule. It …
Along the edge of an inlet on a tiny Japanese island can be found– side by side – striking examples of conditions on Earth some 2.4 billion years ago, then 1.4 billion years ago and then the Philippine Sea of today. First is a small channel with iron red, steaming and largely oxygen-free water – …
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A version of this article first appeared in Astrobiology Magazine, http://www.astrobio.net. Life on early Earth seems to have begun with a paradox: while life needs water as a solvent, the essential chemical backbones of early life-forming molecules fall apart in water. Our universal solvent, it turns out, can be extremely corrosive. Some have pointed to …
Many Worlds 