7 unnecessary assumptions about life in the Universe | by Ethan Siegel | Starts With A Bang! | Sep, 2024

MarylandDigitalNews.comSCIENCE

posted on Sep. 02, 2024 at 2:22 pm

That the Universe exists and that we are here to observe it tells us a lot. It enables us to place constraints on various parameters, and to the infer the existence of states and reactions that present themselves as gaps in our present-day knowledge. But there are severe limits to what we can learn from this type of reasoning as well, including about the probabilities of finding life elsewhere. (Credit: NASA/NEXSS collaboration)

So far, Earth is the only planet that we’re certain possesses active life processes. Here’s what we shouldn’t assume about life elsewhere.

Here in 2024, thousands of planets are known beyond Earth.

What do planets outside our solar system, or exoplanets, look like? A variety of possibilities are shown in this illustration. Scientists discovered the first exoplanets in the 1990s. As of 2024, the tally stands at over 5,000 confirmed exoplanets. None are known to be inhabited, but a few raise tantalizing possibilities: largely among the Earth-sized planets, but not so much among the larger ones. (Credit: NASA/JPL-Caltech)

Although many have biologically-friendly ingredients, only Earth is known to harbor life.

Although NASA’s Perseverance rover landed on Mars in early 2021, it took over 400 Martian sols for Perseverance to encounter and photograph the parachute that allowed it to gently set down on the red planet’s surface. In this region, photographed in April of 2022, the numerous organic compounds have been found in the Martian soils where liquid water must once have been abundant. Organics, however, do not necessarily mean life, and the instrument suite aboard Perseverance is insufficient to draw such a conclusion. Either a follow-on, or sample return, mission will be needed to learn more. (Credit: NASA/JPL-Caltech/ASU/MSSS)

However, many properties that Earth possesses may be unnecessary for life’s emergence.

Our notion of a habitable zone is defined by the propensity of an Earth-sized planet with an Earth-like atmosphere at that particular distance from its parent star to have the capacity for liquid water, without a cover of ice, on its surface. Although this describes the conditions that Earth possesses, it is unknown whether this is a requirement, or even a preference, of life. Many worlds assumed to be good candidates for life will likely be uninhabited; others not presently considered will likely surprise us down the line. (Credit: Chester Harman; NASA/JPL, PHL at UPR Arecibo)

Here are seven common assumptions that we should be eager to challenge.

The Moon and clouds over the Pacific Ocean, as photographed by Frank Borman and James A. Lovell during the Gemini 7 mission. Earth, around our Sun, has the right conditions for life. We frequently assume that a large Moon, which stabilizes Earth’s axial tilt, is helpful or even necessary for life. But this assumption may be unfounded. (Credit: NASA)

MarylandDigitalNews.comSeptember 2, 2024

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