Strangulation Efficiency in Galaxy Clusters

Strangulation Efficiency in Galaxy Clusters

Astronomers Daisuke Kawata and John Mulchaey have uncovered features of star formation in galaxies that also provide one more design characteristic to add to a list of several hundred indicating the supernatural, super-intelligent design of our planet and galaxy for the support of life, human beings in particular.

Kawata and Mulchaey’s discovery arose from a detailed chemodynamical simulation of how neighboring galaxies and gas clouds impact the star formation history of a disk galaxy.1 (All spiral galaxies form out of rotating collapsed gas disks.) They found that the environment in which a disk galaxy finds itself determines the timing of the formation of most of its stars and the degree to which future star formationis quenched.

Kawata and Mulchaey’s simulation demonstrated that for any disk galaxy the bigger and denser the galaxy cluster in which it is found, the earlier its stars form, and the more aggressively future star formation is extinguished. The quenching or “strangulation,” to use Kawata and Mulchaey’s word, results from the stripping of hot gas from the disk galaxy. For a typical cluster of galaxies the strangulation will occur within the first billion years after the disk galaxy first forms. However, even for a small galaxy cluster, like the Milky Way Galaxy’s Local Group, the strangulation mechanism is not trivial.

Kawata and Mulchaey compared their theoretical results with observations of disk galaxies in a wide range of galaxy cluster sizes and disk galaxies “in the field.” By in the field, they meant a disk galaxy that exists external to any clustering or grouping of galaxies. They noted that, as their chemodynamical cosmic model predicts, field galaxies manifest a much higher present-day star formation rate than galaxies located inside clusters of galaxies. Furthermore, galaxies in small, well-dispersed galaxy groups show higher present-day star formation than galaxies in large, dense galaxy clusters.

Although Kawata and Mulchaey’s research paper concludes with this comparison, RTB scholars see more to the story. The design comes in from the fact that a highly specified star formation history within a disk galaxy is necessary for physical life to be possible in that galaxy. Some minimum level of ongoing star formation is essential to preserve the kind of spiral structure in a life-friendly galaxy. A slightly greater level of ongoing formation must occur for an adequate buildup of heavy elements, especially long-lived radiometric isotopes such as thorium-232 and uranium-238, at the just-right locations within the galaxy and the just-right times in the history of the galaxy for advanced life to be possible.2

However, too much ongoing star formation late in the history of the galaxy would be devastating for life. It would lead to the formation of too much substructure in the spiral arms.3 Spurs and feathers of such large sizes and numbers would form in the arms so as to gravitationally disturb the galactic orbit of potential life support planetary systems. Those systems would also be too heavily exposed to deadly radiation emanating from nearby bright stars. Equally bad, too much present-day star formation would expose advanced life to too many nearby supernova eruptions. Such eruptions had to be plentiful when Earth was forming but few, if any, occurred during the era of human occupation.

The bottom line: unless the degree and the timing of strangulation for the Milky Way Galaxy (MWG) were at just-right values, our galaxy would never be able to support advanced life. For efficient strangulation, the just-right amount of hot gas must be stripped out of the MWG during its youth. For this just-right stripping to occur, the MWG must reside in a grouping of galaxies where the number of galaxies in the group is fine-tuned, the kinds of galaxies in the group are fine-tuned, the average distance separating the galaxies is fine-tuned, and the location of the group relative to other groups and clusters of galaxies is fine-tuned. When added to all the other evidences of vital fine-tuned characteristics,4 the painstaking calibration of all the elements of efficient strangulation points unmistakably to a supernatural, super-intelligent Creator.

  1. Daisuke Kawata and John S. Mulchaey, “Strangulation in Galaxy Groups,” Astrophysical Journal Letters 672 (January 10, 2008): L103-L106.
  2. Hugh Ross, Creation As Science (Colorado Springs: NavPress, 2006), 102-6.
  3. Woong-Tae Kim and Eve C. Ostriker, “Formation of Spiral-Arm Spurs and Bound Clouds in Vertically Stratified Galactic Gas Disks,” Astrophysical Journal 646 (July 20, 2006): 213-31; Rahul Shetty and Eve C. Ostriker, “Global Modeling of Spur Formation in Spiral Galaxies,” Astrophysical Journal 647 (August 20, 2006): 997-1017.
  4. Hugh Ross, The Creator and the Cosmos, 3rd ed. (Colorado Springs: NavPress, 2001), 176-99.