Is the Concept of a Habitable Zone Too Wide?

Planetary system comparison
This size and scale of the Kepler-452 system compared alongside our own solar system, plus another planetary system with a habitable-zone planet known as Kepler-186f. The Kepler-186 system has a faint red dwarf star and a planet whose orbit would fit inside the orbit of Mercury.

In our search for exoplanets, we have found more than three dozen potentially habitable worlds. It’s estimated that there are 8 to 20 billion potentially habitable, Earth-like worlds in our galaxy alone. But there is a big difference between potentially habitable and actually habitable, and scientists are starting to narrow their definitions.

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German Impact Crater Could Have Hosted Early Life On Earth

Aerial view of Nördlinger Ries crater in Germany, a formation so subtle it was not even known as an impact crater until the 1960s. Credit: Credit: Jesse Allen/NASA/GSFC/METI/ERSDAC/JAROS/ASTER

Could life thrive in the devastated rock left behind after a meteorite impact? A new study hints that possibly, that could be the case. Researchers discovered what they think are geological records of biological activity inside of Nördlinger Ries, a crater in Germany that is about 15 miles (24 kilometers) wide.

What the researchers say could be microbial trace fossils — specifically, tiny “tubular features” — were spotted inside the impact glass created after the meteorite impact melted the surrounding rock. These features are tiny — one-millionth to three-millionths of a meter in diameter — and were examined with spectroscopy and scanning electron microscopy to confirm the findings, the team stated.

“The simplest and most consistent explanation of the data is that biological activity played a role in the formation of the tubular textures in the Ries glasses, likely during post-impact hydrothermal activity,” stated post-doctoral fellow Haley Sapers, a post-doctoral scholar at the University of Western Ontario who led the research.

The researchers suggest that on other planets, looking in impact glass might be a good spot to search for tubular features such as the ones they found. The findings are peer-reviewed, but we’ll be interested to see what independent research teams make of the data collected.

You can read more about the research in the journal Geology.

Source: University of Western Ontario