Today’s New Reason To Believe

by Jeff Zweerink

Twinkle, twinkle little star,
My, oh my, how large you are.
How’d you get to be so big? When gas pressure and magnetic fields should have prevented you from forming?

Okay, so my poem doesn’t rhyme, but it does communicate two important issues regarding stars. First, astronomers have detected many stars with masses ranging from 20 times the mass of the Sun to around 150 times. Second, astronomers struggled to understand how such massive stars form.

Gravity, radiation pressure, gas pressure, and magnetic fields constitute the dominant processes in star formation. The basic process starts when a gas cloud becomes sufficiently dense that it begins to collapse under its own gravity. As the cloud collapses, the radiation pressure and rotational energy of the gas and the magnetic fields permeating the cloud grow larger. In relatively simple formation models, these three effects halt the collapse of clouds larger than roughly 20 solar masses. The existence of stars more massive than this limit means that some process must overcome this difficulty, or that the model is oversimplified.

It turns out that these older models assumed that star formation occurred in a spherically symmetrical manner. In other words, the only direction in which things changed was the distance from the center of the gas cloud. These models were one-dimensional in that the radius represented the only variable. More sophisticated, two-dimensional models accounted for the fact that the gas would begin rotating about an axis. They revealed that energy from the cloud’s collapse could dissipate though jets emitted along the rotation axis. Nonetheless, rotational and magnetic effects still stunted growth of stars beyond 40 solar masses.

A team of U.S. scientists recently generated a fully three-dimensional model of stellar formation. Their model showed that gravitational instabilities form in the cloud and in the disk that surrounds the cloud. These instabilities serve to channel gas onto the star while the radiation escapes through optically thin parts of the cloud. Furthermore, the instabilities cause the disk to fragment and form companion stars. Not only does this model demonstrate how stars up to 100 solar masses can form, it also explains why massive stars tend to form in binary systems.

Why is this important? First, it is these massive stars that produce the bulk of elements heavier than helium. At the end of their “lives,” the stars undergo catastrophic explosions that distribute the heavy elements through space for future stars to use. They also live very short lives—a few million years for the most massive stars—so they inject these heavy elements into other stars that are forming from the same gas cloud. A growing body of evidence indicates that our solar system formed in such a chaotic environment. It’s good to know that the laws of physics permit these life-essential processes to occur in the universe. Seems like they might even be designed for that purpose.

Kenneth Richard Samples

How can a Christian think about eschatology (the study of “last things”) in a careful and intellectually responsible manner?

Let me offer three suggestions for believers to carefully consider when approaching the controversial theological topic of the “end times.”

1. Understanding the Bible’s Apocalyptic Literature

Evangelical theologian and eschatology specialist George Eldon Ladd notes the following:

Revelation is the most difficult of all New Testament books to interpret, primarily because of the elaborate and extensive use of symbolism.

Both apocalyptic books of the Bible (Daniel and Revelation) are very challenging to understand and properly interpret. Throughout church history biblical scholars and theologians have come to a variety of different positions on how these books are to be understood.

Acknowledging this diversity of thought should cause Christians to be measured and cautious in what they assert about the Bible’s teaching on eschatological issues. Far too many believers think that their specific interpretation of end times passages is synonymous with what the Bible actually reveals about the topic. Remember, the Bible must be responsibly studied through a careful analysis of literary genre, grammar, and context.

2. Mere Christian Eschatology

While significant differences over the final events of human history exist, nevertheless all historic Christian theological traditions affirm essential core orthodoxy when it comes to eschatology. Parts two and three of this series elaborate on five significant events on which believers agree. Here’s that list enumerated once again:

Five Point Mere Christian Eschatology

Second Coming of Jesus Christ

General Resurrection of the Dead

Final Judgment of Humankind

Eternal State

New Creation

3. Learning the Major Views on Eschatology

Because the study of future things is a hotly contested topic in Christian theology, believers should take the time and effort to study the field. If you have only been exposed to a form of premillennialism (which is very popular today among evangelicals), then consider looking into one of the best books on the amillennial and postmillennial positions. Or if you have only been exposed to amillennialism (probably the overall Christian consensus position over the centuries), then try reading the best books that defend a form of premillennialism.

Our churches stand to benefit when its members grow in their knowledge of the Bible and of historic Christian doctrine. I strongly recommend that pastors and teachers in churches and colleges encourage their people to read broadly on the topic of eschatology. It is certainly acceptable for churches and Christian colleges to affirm and defend a particular view concerning last things, but those affirmations mean a whole lot more when all the major views have been considered.

Here are a few good books explaining the different evangelical Christian positions on eschatology:

Historic Premillennialism:
George Eldon Ladd, The Blessed Hope.

Dispensational Premillennialism:
John F. Walvoord, The Blessed Hope and the Tribulation.

Postmillennialism:
John Jefferson Davis, Christ’s Victorious Kingdom.

Amillennialism:
Anthony Hoekema, The Bible and the Future

Future articles explore other issues relating to Christian eschatology.

For an introduction to the topic of general eschatology, see Donald G. Bloesch, The Last Things and Robert Clouse ed., The Meaning of the Millennium: Four Views.

by Hugh Ross

One of the most extraordinary features of the solar system is that it contains adequate abundances of all the elements essential for advanced life. What makes it so exceptional is that the elements must come from different sources: asymptotic giant branch stars, a Type I supernova (see here and here), Type II supernovae of at least two different types, white dwarf binary stars, and now, according to a new study also from a “faint supernova with mixing fallback.”¹

A team of six Japanese astronomers, plus an American astronomer, carefully recorded the amounts of decay products from the following short-lived radionuclides (SLRs): beryllium-10, aluminum-26, chlorine-36, calcium-41, manganese-53, iron-60, palladium-107, iodine-129, and hafnium-182. In their calculations the team demonstrated that ejection of heavy-element material into the primordial solar system’s protoplanetary disk came from all but the last source mentioned above. However, none of these astrophysical sources can account for the early solar system’s abundances of SLRs with half-lives less than five million years, namely aluminum-26, calcium-41, manganese-53, and iron-60.

The astronomers’ calculations revealed that a rare kind of supernova could explain the solar system’s abundances of these particular SLRs. This supernova type is a low-luminosity (that is, faint) supernova where, during the star’s explosion, the inner region of the star experiences mixing. A small fraction of the mixed material is ejected into the interstellar medium and the remainder falls back into the core. In the words of the research team, “The modeled SLR abundances agree well with their solar system abundances.”

They also calculated the time interval between the explosion of the faint supernova and the formation of solar system’s oldest solid materials. That interval is approximately equal to one million years. The faint supernova eruption would need to be quite near the solar system forming region but not so close as to disturb its formation. Likewise, the timing and the proximity for the other sources (asymptotic giant branch stars, Type I supernova, Type II supernovae of at least two different types, white dwarf binary stars) of the heavy elements would need to be similarly fine-tuned.

SLRs make two important contributions to the solar system. One, they are heat sources for primordial asteroidal metamorphism and/or differentiation. Primordial asteroids are the building blocks for the solar system’s rocky planets (Mars, Earth, Venus, and Mercury). Thus, Earth’s exceptional interior differentiation (a crucial factor for establishing its strong, long-lasting magnetic field) is due, in part, to the primordial solar nebula’s exceptional abundances of SLRs.

Two, they provide high-resolution chronometers for events that took place during the first few million years of the solar system’s formation. Continuing studies could potentially yield a detailed history for early solar system events with a timing precision of better than a hundred thousand years for the different occurrences. Such historical accuracy could deliver much more evidence for the supernatural design of the solar system for life’s, and humanity’s, benefit.

1. A. Takigawa et al., “Injection of Short-Lived Radionuclides into the Early Solar System from a Faint Supernova with Mixing Fallback,” Astrophysical Journal 688 (December 1, 2008): 1382-87.