Today’s New Reason To Believe

by Jeff Zweerink

Every now and again, a cool scientific discovery comes along that doesn’t have an obvious apologetic connection. I have decided that these discoveries occasionally warrant mention simply because they are interesting. So, here are three.

1. Most Distant Gamma-ray Burst

One aspect of my research in gamma-ray astronomy involved looking for very high-energy gamma rays associated with gamma-ray bursts (GRBs). These events rank as the most energetic processes occurring in the universe. Scientists have detected thousands of GRBs since they were first discovered in the 1960s (for a description of their serendipitous discovery, see this site). The most distant GRB yet detected occured when the universe was a mere 800 million years old. This places it among the most distant objects in our universe ever observed.

2. Brightest Gamma-ray Burst

Another GRB discovered stands as the most distant object viewable with the naked eye. All the individual stars one observes when looking at the night sky inhabit our Milky Way Galaxy and therefore are no more than a hundred thousand light-years away (the diameter of the Milky Way). At 2.5 million light-years away, the Andromeda Galaxy is one of the few objects outside the Milky Way visible to the naked eye (at least for those in the northern hemisphere). The brightest GRB, designated GRB 080319B, was briefly visible to the naked eye, even though it occurred 7.5 billion years ago, more than halfway across the observable universe!

3. Earth’s Oldest Crust Material

Here on planet Earth scientists recently found the oldest known rocks. Dated at 4.28 billion years old, these rocks best the previous oldest known rocks by 300 million years. Although Earth formed 4.6 billion years ago, rocks more than three billion years old are rare because they have usually been eroded and/or recycled back into Earth’s interior via plate tectonics. These particular rocks escaped that fate and were found along the Hudson Bay in Northern Quebec.

Previously Posted on January 11th, 2008 by David H. Rogstad, Ph.D.

In the television series Cosmos: A Personal Voyage, originally broadcast in 1980, Carl Sagan, the highly successful popularizer of astronomy, coined the phrase “we are made of star-stuff.” While not a new idea, nevertheless, it called attention to a remarkable fact related to our growing understanding of how the universe began and developed over time.

Dr. Sagan outlined this process, beginning with the Big Bang, where the lightest elements, hydrogen and helium, were produced. He then proceeded to describe the various generations of stars that were formed, aged, and eventually “went supernova,” finally coming down to the formation of our solar system made from the ashes of these earlier stars. The end result is that humans, who are made from “the dust of the Earth,” originally came from material that was “cooked” from lighter elements in the very heart of stars and their subsequent supernova.

With NASA’s 1999 launch of the Chandra X-ray Observatory into orbit around the Earth astronomers have been able to use this new tool to detect many different objects in a band of light beyond what’s visible to human eyes, and at a much higher resolution than previously available. A recent press release revealed a spectacular new image of the supernova remnant G292.0+1.8. A supernova remnant is the expanding debris field blasted out from the parent star as it explodes. G292.0+1.8, which contains large amounts of oxygen, is one of only three remnants in our Milky Way Galaxy. The image shows an intricate structure in its debris field that contains element such as oxygen, neon, and silicon that forged before and during the explosion.

Understanding the details of G292.0+1.8 is especially important because astronomers have considered it to be a “textbook” case of a supernova created by the death of a massive star. Supernova events such as this have been determined to occur in the neighborhood of our solar system prior to its collapse, seeding the cloud out of which the Earth formed with elements critical for life (see the 23 January 2007 edition of Today’s New Reason To Believe ).

With instruments like the Chandra telescope, astronomers are developing a deeper understanding of the processes that clarify in detail Sagan’s observation that we are made from material that originated in stars. At the same time, the evidence supports the fine-tuning necessary for the “star-stuff” to have just the right amounts of the various elements to allow life to exist and survive. Not only do we have spectacular images of the “stuff,” which “declare the glory of God,” but we also have better understanding of the processes for making that stuff that reflects the hand of an elegant designer.

Previously Posted January 2nd, 2008 by Dr. Jeffrey Zweerink, Ph.D

In the sixteenth century, Nicolas Copernicus revived an idea originating with early Greek philosophers that the Sun, instead of the Earth, resided at the center of the solar system. Subsequent observations by Galileo and others validated the Copernican, or heliocentric, view (for a brief introduction to the conflict between Galileo and the Roman Catholic Church, look here.) In the early 1920s, Harlow Shapley correctly argued that the sun did not reside at the center of the Milky Way Galaxy (MWG). Shortly afterward, Edwin Hubble demonstrated that other galaxies similar to the Milky Way existed and that the MWG did not reside at the center of the universe.

Known as the Copernican Principle (or Cosmological Principle), it remains an uncontroversial statement that Earth occupies no special location in the universe—not the center, not near the edge, nor any other geometrically interesting point. However, many people extend this concept further, positing that there is nothing unique or special about Earth or the life inhabiting it. Scientists refer to this extension as the Principle of Mediocrity.

While the Copernican Principle is largely a philosophical statement, a large body of evidence supports its validity. Even so, scientists continue to put the principle to the test. An article posted to arXiv.org outlines a new test to see if the region of space to about 3 billion light-years exhibits any special or unique characteristics. One possible explanation for the current cosmological data (mainly the cosmic microwave background radiation, the large-scale structure of galaxies, and the Hubble diagram derived from Type Ia supernova measurements) is that the Sun resides at the center of a large void where the density inside is less than that outside the void.

Rather than focus on the details of the particular test outlined, I want to highlight how willingly and eagerly astronomers and cosmologists seek to test bedrock principles. While the tests explained in the paper rule out any voids with large density contrasts, the authors describe even more-detailed tests to discern any uniqueness of Earth’s location. A previous TNRTB further demonstrates this willingness to test foundational principles.

In contrast, as my colleague Fuz Rana points out, scientific disciplines related to the origin and development of life don’t seem as willing to test their fundamental assumptions and principles. Since testing is fundamental to scientific advance, RTB appreciates a willingness to test across all disciplines