Exoplanet

February 06, 2024

Inside the front section of today’s local newspaper was a USA Today article on NASA’s January 31st release about detection of a “super-Earth” that has the potential temperature and conditions to sustain life.  This new planet was said to be “fairly close to us” at only 137 light-years away (a short hop) and orbits within a zone capable of having liquid water.  The planet (TOI-715 b) is about one and a half times the width of Earth and orbits a small, reddish star.  The same system might harbor a second Earth-sized planet, which if confirmed, “would become the smallest habitable-zone planet discovered by the Transiting Exoplanet Survey Satellite (TESS) so far.  NASA said the red dwarf is smaller and cooler than our Earth’s sun, and because of the short distance of the super-Earth orbit a “year” for the planet is equal to 19 Earth days.  When detected these worlds are called an exoplanet.

When I went online, I found an exoplanet or extrasolar planet is a planet outside our Solar System. The first possible evidence of an exoplanet was noted in 1917 but it was not identified as one until confirmation in 1992.  Another planet was initially detected in 1988 but was not confirmed until 2003.  As of February 1, 2024, there are 5,606 confirmed exoplanets in 4,136 planetary systems, with 889 systems having more than one planet.  The James Webb Space Telescope (JWST) is expected to discover more exoplanets, and determine more about them, including composition, environmental conditions, and potential for life.  While there are various methods for detecting exoplanets, transit photometry and Doppler spectroscopy have found the most.  These methods suffer from observation bias favoring the detection of planets near the star.  Of the exoplanets detected 85% are where one of the objects reaches a state where there is no longer any net change in its rotation rate over the course of a complete orbit (tidal locking).  About 1 in 5 Sun-like stars have an “Earth-sized” planet in the range that may support liquid water (habitable zone).  Assuming there are 200 billion stars in the Milky Way (our galaxy), it can be hypothesized that there are 11 billion potentially habitable Earth-sized planets.  The number rises to 40 billion if planets orbiting numerous red dwarfs are included.

Since its launch on April 18, 2018, TESS has been adding to the stockpile of habitable-zone exoplanets that could then be more closely scrutinized by NASA’s JWST telescope.  The first light image from TESS was taken on August 7, 2018, and released publicly September 17, 2018.  NASA says the Webb telescope is designed to not only detect exoplanets but “explore the composition of their atmospheres, which could offer clues to the possible presence of life.”  The super-Earth research and discovery was led by Georgina Dransfield at the University of Birmingham in the UK and published in the Monthly Notices of the Royal Astronomical Society journal in January.  These findings mark another step toward understanding the atmospheric conditions needed to sustain life and further explore the characteristics of exoplanets beyond our solar system.

THOUGHTS:  For a short while in grad school, I dreamed of exploring the billions of exoplanets in search of life.  I was already studying the origin of (human) civilization and thought combining that with a degree in astrophysics could boost my chances of catching an exploratory ship.  Added to this was a degree in theology as any discovery would raise immediate questions about the human role in the universe.  Not only did I not obtain these degrees, but humans have also not been able to set foot on the closest planet in our own solar system, Mars.  It was still a good dream.  Dreams to explore took humanity around the world, beneath the ocean, and to the moon.  None of those explorations were possible without cooperation.  We are stronger when we work together.  Act for all.  Change is coming and it starts with you.