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A research team has discovered an oxygen isotope in space that could help in the search for aliens. The isotope Oxygen-18 (O-18) is also known as "heavy oxygen" and is actually produced by photosynthesis. So it is produced on Earth by plants and bacteria and released into space. If other planets also have such a biosignature, this could indicate extraterrestrial life.
O-18 is typically detectable at altitudes up to 60 kilometers from the Earth's surface. At this height one speaks of the lower part of the mesosphere. Now, however, high concentrations of heavy oxygen have also been detected at altitudes of 200 kilometers, i.e. in the thermosphere.
Life on habitable exoplanets
The team at the Max Planck Institute for Radio Astronomy, led by Helmut Wiesenmeyer, discovered the isotope using data from the already decommissioned NASA Stratopheric Observatory for Infrared Astronomy (SOFIA) telescope. The team had measured the infrared light coming from the moon. The researchers observed that this light is also absorbed by the oxygen isotopes in the thermosphere.
This means that there is also a high concentration of O-18 there. In the future, this finding could help to develop new methods to find evidence of life on habitable exoplanets by looking for such a biosignature.
