The Search for Life in Solar Systems Beyond Our Own

  • Among the countless stars beyond the sun, some have planets (called exoplanets), and some of the planets have moons (called exomoons).
  • With the light years of distance between our Solar System and even the nearest neighboring stars, detection and gathering of information on exoplanets proves challenging, and on moons, even more so.  Yet, the possibility intrigues.  Could life thrive on, or in, the planets and moons of other solar systems, their own sun (or suns) shining above?
  • Our stellar neighbors are abundant in all directions, but they “live” extremely far away; The first image below gives a good sense of this.  Specifically, the 3D star atlas shows the 100+ known stars within a 20 light year radius from the Sun.  Our nearest neighbors are 4+ light years away, and shown toward the center: Proxima Centauri and the nearby binary star system of Alpha Centauri…which system is suspected to host a planet (which would be the nearest exoplanet).  The second image below is a Hubble Space Telescope photo of Proxima Centauri, our nearest stellar neighbor.
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Image by Richard Powell, available at, work licensed under Creative Commons Attribution-Share 2.5 License
Image by Richard Powell, available at, work licensed under Creative Commons Attribution-Share 2.5 License.
Shining brightly in this Hubble image is our closest stellar neighbour: Proxima Centauri. Proxima Centauri lies in the constellation of Centaurus (The Centaur), just over four light-years from Earth. Although it looks bright through the eye of Hubble, as you might expect from the nearest star to the Solar System, Proxima Centauri is not visible to the naked eye. Its average luminosity is very low, and it is quite small compared to other stars, at only about an eighth of the mass of the Sun. However, on occasion, its brightness increases. Proxima is what is known as a “flare star”, meaning that convection processes within the star’s body make it prone to random and dramatic changes in brightness. The convection processes not only trigger brilliant bursts of starlight but, combined with other factors, mean that Proxima Centauri is in for a very long life. Astronomers predict that this star will remain middle-aged — or a “main sequence” star in astronomical terms — for another four trillion years, some 300 times the age of the current Universe. These observations were taken using Hubble’s Wide Field and Planetary Camera 2 (WFPC2). Proxima Centauri is actually part of a triple star system — its two companions, Alpha Centauri A and B, lie out of frame. Although by cosmic standards it is a close neighbour, Proxima Centauri remains a point-like object even using Hubble’s eagle-eyed vision, hinting at the vast scale of the Universe around us.
Promima Centauri – the Sun’s nearest stellar neighbor.  Image Cedit: ESA/Hubble and NASA.

© 2015 Fosdick EDS  ☾><(((°>

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