Recently there have been several news items related to astronomy. Some people have asked Answers in Genesis about them, so perhaps I ought to comment on them.
The Dust Disk around TW Hydrae
One story from September 14, 2016, was about the possible discovery of a planet orbiting the star TW Hydrae (often abbreviated TW Hya). TW Hya is a T Tauri star, a class of stars that most astronomers think are very young. In fact, astronomers think that T Tauri stars are so young that they are still forming. T Tauri stars are found near molecular clouds, which most astronomers think are the places where stars are born. T Tauri stars are larger, and hence brighter, than stars of similar temperatures. This is attributed to these stars still collapsing to form stable stars. The contraction is thought to be unstable, which explains why T Tauri stars are marked by variability in brightness and have strong chromospheric emission. Of course, this contraction is so gradual that we can’t actually observe it going on, but astronomers merely assume that it is happening. This sort of thinking is typical with man’s ideas about star formation. Star formation supposedly takes a very long time, at least compared to human lifetimes. Therefore, we can’t really observe star formation. Instead, astronomers observe what amounts to snapshots of various astronomical bodies that they think are at various stages of star formation. Then astronomers arrange the snapshots into the order that they think stars follow as the form.
T Tauri stars often have disks of dust orbiting them. Astronomers think that as a star forms and eventually becomes stable, these disks dissipate, so the dust disks suggest stellar youth. Astronomers also think that the planets in the solar system formed out of such a disk, so astronomers view these disks around T Tauri stars as sites of planet formation. If planets form this way, then looking at dust disks around T Tauri stars might permit discovery of planets in the process of forming. Or at the very least, they may offer a glimpse of recently formed, and hence very young, planets.
At a distance of only 176 light years, TW Hya is the closest T Tauri star to the earth. Our line of sight to TW Hya is nearly perpendicular to the plane of its dust disk, so we have a very good view of the disk. A team of astronomers used the Atacama Large Millimeter Array (ALMA) to image the disk of TW Hya. ALMA is an array of 66 radio telescopes at an altitude of 16,000 feet in the Atacama Desert of Northern Chile. The telescopes observe at relatively short radio waves at millimeter and submillimeter wavelengths. This part of the spectrum is adversely affected by water vapor, which is why ALMO is located at such altitude in the driest desert in the world. The images revealed several gaps in the disk, the most pronounced at a distance of 22 astronomical units (AU) from the star. An AU is the average distance between the earth and sun. For comparison, Uranus is nearly 20 AU from the sun. The authors of the study suggested that the gap could be caused by the gravitational interaction of an unseen planet and dust in the disk. They estimated that the mass of the planet is close to 1.5 times the mass of Neptune.
Well, did the researchers find a new planet here? Notice that they didn’t actually see the planet, but rather inferred its existence from a gap in the dust disk surrounding the star. This doesn’t mean that the planet isn’t real, but that the detection is indirect. Furthermore, the researchers were cautious in their assessment. In the abstract of the paper, they wrote, “The most prominent gap at 22 au could be caused by the gravitational interaction between the disk and an unseen planet with a mass of .1.5 MNeptune although other origins may be possible” (emphasis added). So the planet may not exist.
The formation of planets by naturalistic means still is conjecture.
Does any of this matter in the discussion of creation or evolution? Though the interpretation of TW Hya and its disk is laden with evolutionary assumptions, it doesn’t really matter much to us. Keep in mind that the process of planet formation is supposedly far too slow for people to directly observe, so no one has ever seen a planet form. Therefore, the formation of planets by naturalistic means still is conjecture. We don’t know if a planet actually is present around TW Hya, but if there is, we now know that planets orbiting other stars are common, so why would TW Hya be any different in this regard? Extrasolar planets in no way threaten the creation model. The impetus for the search for extrasolar planets is to find earth-like planets in the hope of finding life elsewhere. But so far, no earth-like planets have been found. This is something that we might expect in the creationary worldview, but not from the evolutionary worldview.
How Did Earth Get its Carbon?
This story is related to the one above. Evolutionary theories of the origin of planets is that they amalgamate out of disks of dusk orbiting young stars. The earth and other planets supposedly did this nearly 4.6 billion years ago. A problem with this scenario is how to explain the presence of elements that have relatively low boiling points, such as carbon and sulfur, on the earth’s surface. Those elements would have easily boiled away from the intense heat of the magma oceans that supposedly covered the early earth. Or, since they have affinity for bonding to iron, they would have sunk into the earth’s core along with most of the earth’s iron. Either way, these elements ought to be sparse on the earth’s surface.
One way to solve this problem is to hypothesize that after the earth’s surface cooled and hardened, objects containing carbon and sulfur fell to the earth, again placing those elements on the earth’s surface. However, it is not at all clear where such bodies could have come from, and scientists have not identified any solar system bodies with the right composition to do this. A new study has proposed another solution. This new theory suggests that about 4.5 billion years ago a body about the size of Mercury collided with the earth. According to the new scenario, some of its carbon and sulfur from the interior of the impacting body remained on the earth’s surface.
This is sure to stir controversy. For one thing, for the past 3–4 decades, the standard explanation for the moon’s origin is that a Mars-sized object had a grazing incidence collision with the earth. Thus, this new proposal would double the number of catastrophic events early in earth’s history. The second collision might have eliminated the reseeding of carbon and sulfur on the earth’s surface. But this means that the earth endured not one, but two, “just right” collisions. This makes the earth incredibly improbable.
The biblical worldview on this matter is very different. Isaiah 45:18 tells us that God made the earth to be inhabited. Genesis 1:2 tells us that God initially created the earth unformed and unfilled, but over the six days of the Creation Week, God carefully shaped, formed, and filled the earth. It was not the result of random processes. Nor is there any suggestion in the creation account of collisions with other bodies.
The Reionization of the Early Big Bang Universe
A third article concerns the reionization of gas early in the universe (assuming a big bang origin). The big bang has been the dominant cosmology for a half century. According to the big bang model, the universe began 13.8 billion years ago in a very hot, dense state. Since then, the universe has expanded and cooled tremendously. For millions of years, there were no astronomical bodies. Instead, all that existed was gas, and most of that was hydrogen. However, in the early universe hydrogen atoms as we know them did not exist. Because it was too hot, the hydrogen was ionized, meaning that electrons and protons that normally make up hydrogen atoms were separated. But 380,000 years after the big bang, the universe supposedly cooled enough for the electrons and protons to form stable atoms of hydrogen for the first time. Astronomers call this event the age of recombination. Prior to the age of recombination, the universe was opaque, but now it became transparent. The cosmic microwave background (CMB) supposedly is radiation from that time period, albeit greatly cooled due to expansion since then. The existence of the CMB, discovered in 1964, is the one good evidence for the big bang, which accounts for it being the dominant cosmology since then.
Observations show that much of the intergalactic medium (the thin gas between galaxies) is ionized. Therefore, astronomers had long hypothesized that soon after galaxies formed, the gas between galaxies once again became ionized. Astronomers refer to that as the age of reionization. The amount of gas ionized this second time was far less than before. Also, because the density of the universe at the age of reionization was far less than prior to the age of recombination, the universe did not become totally opaque once again. However, the partial opacity does affect the radiation of distant objects, including the CMB. For years, astronomers had thought that the age of reionization was about 450 million years after the big bang. This presented a problem, because ultraviolet radiation from massive, hot stars had to be the source of reionization of the intergalactic hydrogen gas. But this was thought to be far too early for those hot stars to exist in sufficient number to cause the reionization (I might add that it is unknown how the first stars formed anyway).
A new study of the CMB solves this problem by suggesting that the age of reionization was much later, about 700 million years after the big bang. Being about 250 million years later than previous estimates, most astronomers think that by then a sufficient number of hot stars existed to have ionized the intergalactic medium. The opacity of ionized intergalactic gas slightly attenuates radiation in the CMB, a process that also imprints a slight polarization signature. Polarization is a preference in the direction that radiation, a wave phenomenon, vibrates. This study analyzed the polarization of the CMB precisely measured by the Planck spacecraft. Earlier studies had relied upon other data, such as polarization measurements of the WMAP spacecraft.
There are many different versions of the big bang, and the preferred model keeps morphing.
What does this mean to biblical creationists? Not much. First of all, the results of this new study are extremely model dependent. Actually, it depends upon several different models. The authors of the study acknowledged that their result depended upon a particular model of ionization. If one adopted a different ionization model, a different time for the age of reionization would result. But beyond that, the study also depended upon which particular version of the big bang that one adopts. There are many different versions of the big bang, and the preferred model keeps morphing.
However, as biblical creationists, we know that the big bang model does not square with Scripture. Therefore, the big bang is not the correct story of the origin of the universe. If there was no big bang, then what is the source of the CMB? I’ve previously published a suggested mechanism for the CMB, a mechanism that comes straight from the Genesis 1 account of creation on Day Two and what we know of physics.