A chart of when, and to some extent how, the amount of oxygen in Earth’s atmosphere has risen. It took more than a half of the time that life has existed on Earth for oxygen levels to rise enough to become a discernible biosignature. xxx.
There are many worlds out there waiting to fire your imagination. This site is for everyone interested in the burgeoning fields of astrobiology and in particular exoplanet detection, research and habitability. It is for the general public as well as scientists, and it will present columns, news stories and in-depth features, as well as the work of guest writers.
The “Many Worlds” column is supported by the Lunar Planetary Institute/USRA and informed by NASA's NExSS initiative, a research coordination network dedicated to the study of planetary habitability. Any opinions expressed are the author’s alone.