Reasons to Believe

Earth-like Planet Discovered

The news media is abuzz with the recent discovery of a new exoplanet (planet orbiting a star other than our Sun). It is the most Earth-like of any of the more than 200 planets detected so far (see here for a catalogue). The European team of astronomers responsible for this work (press release) has reported:

  • on two new planets orbiting the M-type dwarf star Gl 581 in Libra
  • a third body, a larger Neptune-sized planet (at least 16 times the mass of the Earth) had been discovered earlier very close to the star
  • the larger of the two new planets is at least 8 times the mass of the Earth
  • the larger planet orbits its star at a distance 4 times closer than Earth orbits the Sun
  • the smaller of the two planets has at least 5 times the mass of the Earth
  • the smaller planet's estimated size is as small as 1.5 times the Earth's (in radius)
  • the red dwarf star the planets orbit is much smaller and less luminous than our Sun
  • the smaller planet orbits 14 times closer to its star than Earth does to the Sun

These results have allowed the astronomers, as well as other researchers who have commented on these results, to speculate that:

  • the smaller planet's surface temperature could lie between 0 and 40 degrees C if the planet has an atmosphere as thin as Earth's
  • this temperature range is such that, if any water were present, it could be liquid
  • if liquid water is present, the conditions are such that life could arise
  • these larger-than-Earth planets may have the long-lasting plate tectonics necessary for life, assuming they are rocky planets
  • many M-type dwarf stars may be the parents of Earth-like planets

    Some scientists have even suggested, since the parent star is "only" 20 light-years away, there is the possibility we could visit this site. However, such a journey would take between 200 and 2000 years at limiting speeds falling somewhere between 0.1 and 0.01 the speed of light.

    While these characteristics make this planet the closest Earth twin to date, it seems premature to speculate that any of the other key characteristics necessary for life (see here for a discussion and list), are present in this planet. In fact, some scientists caution that the radiation from M-type dwarf stars precludes them as sites for a life-sustaining planet. (See next week's TNRTB blog entry by Jeff Zweerink on this subject.) Also, for a planet that minimum size, it would take a remarkable collision event, like Earth experienced, to result in an atmosphere so exceptionally thin. Then there is a possible orbital stability problem from the gravity of the other two planets.

    How do we view this research from a creation-model perspective? RTB encourages ongoing research as the way to determine scientific truth. "Test everything," the Scripture says (1 Thess. 5:21), so we adopt this position in our study of the cosmos. RTB expects, however, that as more information becomes available, the truth of God's word and the creation model derived from it will gain further support. We expect that scientific advance will further establish âthe uniqueness of the Earth as the place where advanced life exists, and for the purpose God has revealed in the Bible.

Subjects: Extrasolar Planets

Dr. David Rogstad

Dr. Dave Rogstad received his PhD in physics from Caltech and worked over 30 years for NASA’s Jet Propulsion Laboratory. Though now retired, Dave continues to serve as an RTB board member and participates regularly in several RTB podcasts.