Our most amazing astronomical photos come from the Hubble Space Telescope. Hubble launched into space to bring us these detailed photos that have changed our understanding of the universe over 30 years ago. Hubble’s successor is the James Webb Space Telescope, now fully deployed. The JWST stands poised to change our perspective of the universe yet again. JWST has a much greater collecting area than Hubble and a more sensitive detector.
The JWST may change our understanding of our place in the cosmos by studying extrasolar planets, planets orbiting other stars. On Earth, plants cover much of our land surface. NASA launched the Galileo mission to Jupiter in 1989. On the way there, the spacecraft took a look back at Earth and detected our planet, vegetation red edge (VRE) biosignature, the mixture of red and infrared light reflected by plants, a signal JWST could observe from exoplanets.
Any exoplanet that bears life will likely have large areas covered with forest- and prairie-like plants just as on Earth. JWST possesses the capability to detect the VRE signal from such planets. While extensive plant cover won’t necessarily indicate the presence of intelligent life, it proves that life on those planets has evolved beyond the simple, single-celled forms that alone populated Earth for a billion years.
JWST’s detectors are sensitive enough to identify another tell-tale sign of life on alien planets. When a planet moves in front of its star, the starlight passing through the planet’s atmosphere, if it has one, allows the telescope to determine what gasses make up that atmosphere. Oxygen is a very reactive element. It is easily used up in chemical processes, such as combining with iron-bearing rock to turn it red, which is common on Earth. Our planet maintains a large supply of oxygen in our atmosphere because it is constantly replenished by photosynthesizing plants.
Methane is also a gas that can’t remain long in a planet’s atmosphere. On Earth, many forms of life give off methane. Think of cows burping. So, if a planet has a steady supply of methane in its atmosphere that likely indicates the presence of life.
JWST’s greatest contribution to our understanding of the universe will undoubtedly come from detailed images of astronomical objects and phenomena, just as with Hubble. But finding proof of extraterrestrial life may well be the most exciting discovery made by the James Webb Space Telescope.
Each month, I write an astronomy-related column piece for
the Oklahoman newspaper. On the
following day, I post that same column to my blog page.
