Reasons to Believe

Measuring the Taurus Star Association Helps Astronomers Understand the Milky Way

Opponents of the big bang creation model attempt to blow past the overwhelming physical evidence in favor of this biblically predicted model1 by picking apart the least understood components of the model. They use this same tactic to evade the mountain of evidence establishing that the structure and history of the Milky Way Galaxy (MWG) has been exquisitely designed over the past ten billion years to make possible a suitable home for humanity.

Astronomers' limited ability to measure accurate distances to stars, galaxies, and gas clouds poses an obstacle to determining the details of the structure and history of the universe and of the MWG. These measurements rely on the distance ladder method. The distance ladder method uses direct measurements on nearby objects to calibrate indirect methods for more remote objects.

Direct distance measurements rely on plane geometry theorems. For example, if one knows the length of the base of an isosceles triangle, then measurements of the angles at either end of the base will deliver the distance to the vertex of the triangle. Traditionally, the base of the triangle for such theorems has been the diameter of Earth's orbit. But, because that base is only 299 million kilometers (186 million miles), direct measurements deliver distances for stars located only a few thousand light-years out and to a precision of only 3-10 percent.

A new instrument and new measuring method are rescuing astronomers from their collective frustration. A team of Mexican and American radio astronomers has demonstrated how the (Very Long Baseline Array (VLBA) can generate distance measures to stars of unprecedented accuracy.2 Moreover, they achieved this accuracy on stars where accuracy has been most lacking, namely (pre-main sequence stars) (that is, stars so young they have yet to initiate stable nuclear burning).

Magnetically active pre-main sequence stars are visible at radio wavelengths. The great advantage of using radio telescopes is that the Earth's atmosphere disturbs neither the phase nor the amplitude information of the incoming radio waves. This combination of phase and amplitude information means that radio astronomers can link together ten large radio telescopes located throughout the United States (ranging from Hawaii to the Virgin Islands) to create an instrument with the equivalent resolving power of an 8,611-kilometer- (5,351-mile-) diameter telescope! By using the VLBA, the team achieved the ability to measure angles more than twenty times smaller than anything previously possible. The resolution capability of the VLBA is so good that it would be equivalent to reading the want-ad section of the Los Angeles Times from the top of the Empire State Building in New York.

Previously, the group had used the VLBA and this method to determine distances to three pre-main sequence stars in the Taurus Star Association. The precision achieved was 0.39, 0.37, and 0.45 percent respectively, all the more remarkable given that that the three stars ranged from 420-480 light-years away.3 The accuracy exceeded the previously best distance determinations by about a factor of ten.

Now, the team has published their measurement to a fourth star in the Taurus Association, HP Tau. This star's distance is 525.2 ± 2.9 light-years. The accuracy is 0.55 percent. The location of HP Tau corresponds to the far side of the Taurus Star Association while two of the previously measured stars, Hubble 4 and HDE 283572, correspond to the near side. Thus, for the first time astronomers have determined the extent or size of a star cluster in three dimensions.

Additional observations are underway on other stars in the association. The goal is for researchers to determine not just the size but the detailed structure of the Taurus Star Association in three dimensions.

By now, however, the team has sufficient distance measurements to determine the mean distance to the Taurus Star Association. They were able to reassure the astronomical community that the distance ladder method rests on a reliable foundation. Therefore, current models for the creation and development of the universe are quite sound. The big bang creation model is more secure than ever before.

In addition to determining a precise distance to the Taurus Star Association, for the first time the team accurately measured both the position and the movement of the association relative to the midplane of the MWG. They found that the association was located about 130 light-years below the galactic midplane and moving at 10.6 kilometers per second (23,700 miles per hour) oriented almost entirely along the direction of the galactic plane. The team concludes that the Taurus Star Association has "reached its farthest distance from the midplane and is about to fall back toward it."4

All this new information will enable astronomers to determine the structure and dynamics of the MWG in greater detail than what they had previously achieved. This will allow for increasingly definitive tests of the theory that the MWG was supernaturally designed for the specific benefit of human beings.

The researchers have already used their data to test competing models for star formation and stellar evolution. They established that the star formation and evolution models developed by Francesco Palla and Steven Stahler5 are the best. This particular model yielded an age for the Taurus Star Association of three million years.

With superior star formation and stellar evolution models, astronomers have the ability to produce a more accurate and detailed history of the universe as well as of the MWG. RTB's scholars predict that such detailed histories will reveal even more evidence for the supernatural, super-intelligent design of the universe and the MWG.

Endnotes:

  1. Hugh Ross, The Creator and the Cosmos, 3rd ed. (Colorado Springs: NavPress, 2001), 23-29.

  2. Rosa M. Torres et al., "VLBA Determination of the Distance to Nearby Star-Forming Regions. III. HP Tau/G2 and the Three-Dimensional Structure of Taurus," Astrophysical Journal 698 (June 10, 2009): 242-49; Laurent Loinard et al., "VLBA Determination of the Distance to Nearby Star-Forming Regions. I. The Distance to T Tauri with 0.4% Accuracy," Astrophysical Journal 671 (2007): 546-54; Rosa M. Torres et al., "VLBA Determination of the Distance to Nearby Star-Forming Regions. II. Hubble 4 and HDE 283572 in Taurus," Astrophysical Journal 671 (2007): 1813-19.

  3. Torres et al., "VLBA Determination of the Distance to Nearby Star-Forming Regions. II. Hubble 4 and HDE 283572 in Taurus," 1813-19.

  4. Torres et al., "VLBA Determination of the Distance to Nearby Star-Forming Regions. III. HP Tau/G2 and the Three-Dimensional Structure of Taurus," 248.

  5. Francesco Palla and Steven W. Stahler, "Star Formation in the Orion Nebula Cluster," Astrophysical Journal 525 (November 10, 1999): 772-83.

Subjects: Big Bang, Galaxy Design, Universe Design

Dr. Hugh Ross

Reasons to Believe emerged from my passion to research, develop, and proclaim the most powerful new reasons to believe in Christ as Creator, Lord, and Savior and to use those new reasons to reach people for Christ. Read more about Dr. Hugh Ross.