Blue Stars

The more we learn about the universe, the more we marvel at the extraordinary number and diversity of stars. They come in a wide range of sizes, colors, and temperatures; and each star has its own story to tell.

The origin and continued existence of such endless variety defies easy explanation. Some burn so brightly that they should soon run out of fuel, while others are relatively cold and would seem to last forever. One type of star in particular—the blue star—is a big problem if you assume the universe came into being 13.7 billion years ago.

Problem: Blue Stars Burn Up Their Fuel Quickly

Based on our current understanding of the nuclear “furnace” that fires each star, all stars must eventually burn out, some faster than others. (Indeed, only red dwarfs have enough fuel to burn 13 billion years, while the others should have burned out long ago.)

Astronomers have direct evidence that stars (including the sun) generally get their energy from the fusion of hydrogen deep in their cores. Based on these observations and a few basic physical assumptions, we can estimate how long a star’s energy can last (and thus the maximum age of the star).

Perhaps the most interesting are the brilliant blue stars, which have lots of fuel but are so hot that they consume their fuel quickly. In fact, the hottest blue stars could last only a few million years at best. Both creationists and evolutionists acknowledge this fact.

Astronomers agree that blue stars could only last a few million years at best. So why do we see blue stars throughout our universe if it is nearly 14 billion years old?

Yet blue stars are found throughout the universe in spiral galaxies, both nearby and far away. This is not a problem for biblical creationists, who date all stars at around 6,000 years. But it creates a big conundrum for astronomers who reject the Bible’s history.

To explain the prevalence of blue stars, these astronomers must assume they have been forming spontaneously throughout most of history, even in recent times. Despite their diligent search, however, they have never observed one of these blue stars forming—or any other star, for that matter. Nevertheless, they must believe that stars form continually because their theory demands it.

Proposed Solution: Condensing Gas Clouds

Where and how do stars form, then, according to evolutionary theories?

Astronomers have found huge amounts of gas within the arms of spiral galaxies (called the interstellar medium, or ISM). This gas has the same main ingredient as stars—hydrogen. The gas (and dust) clouds are very clumpy, with a wide range in density. Given the similar chemical composition of gas clouds and stars, astronomers assume that the more dense clumps of gas contract under their own gravity to form new stars.

How likely is this? After all, gas particles don’t naturally collapse into small, burning balls.

Think about how different these two things are. Gas clouds are millions of times larger than stars, and they have much lower temperatures and densities. The densest clouds in space may contain a few thousand particles per cubic inch (10³ atoms per cubic cm).

By contrast, even the air we breathe contains a quadrillion times more particles than interstellar gas clouds (10¹⁸ particles per cubic cm). The sun’s average density is a million quadrillion times denser than gas clouds (about 10²⁴ atoms per cubic cm).

Obviously, the contraction of a gas cloud to form a star would require a tremendous decrease in size and volume. Gas in the ISM is very cold (typically -250ºF, or 100K), while stars are very hot (up to 70,000ºF [40,000K] on the surface of some blue stars, with interior temperatures reaching tens of millions K). These vast differences must disappear before a cloud could condense to form a star.

This process may sound simple, but it is fraught with problems. The largest problem is that a gas cloud is so spread out that its gravity is miniscule. As thin as the gas is, it does have some pressure, and the pressure pushing particles apart tends to exceed the gravity that pulls them together. If the cloud were to shrink, the pressure would increase to cause the cloud to re-expand.

Theoretical Limits to a Collapsible Gas Cloud

If a cloud were small enough, gravity could take over and cause the cloud to contract. How small must the cloud be to collapse under its own gravity? The astronomer Sir James Jeans asked and answered this question in 1902. He found that the cloud must be somewhat larger than a star, but many orders of magnitude smaller than any observed cloud for this to happen. That is, no observed gas cloud is even close to the Jeans length.

Astronomers have long understood this fundamental problem, so they suggest that some outside mechanism may compress a gas cloud down to the Jeans length so that gravity can finish the process. Astronomers have suggested a number of mechanisms, such as the shock wave from a nearby supernova explosion.

The problem is that all of these mechanisms require preexisting stars that can explode and generate new stars. While this mechanism might possibly work in the universe today, it likely cannot produce new stars at the rapid rate required by modern evolutionary theories. Nor can it explain the origin of the first stars.

Appeal to Unknown Mechanisms

To solve this problem, astronomers suggest that the first stars formed in a burst of activity in the early universe triggered by some unknown mechanism.

Do astronomers have any evidence for such a mechanism early in the universe? They claim that they do. For example, since the collapse of gas clouds should produce stars of all masses, astronomers expect to detect light from the most massive, hot, bright stars—blue stars—wherever much star formation has occurred.

As predicted, very distant galaxies (and hence galaxies from the early universe) are systematically brighter than nearby galaxies. Astronomers call these “starburst” galaxies and say the blue color is evidence for explosive star formation early in the universe.

Furthermore, though astronomers have not observed the actual contraction of a gas cloud into a star, they have identified a number of different kinds of odd star-like entities that they view as snapshots of stars in various stages of formation.

Despite these claims, we should note that astronomers think that in the universe today, condensed clouds overwhelmingly produce low-mass red stars, but in the early universe they formed massive blue stars.

So evolutionary astronomers must ultimately rely upon some unknown mechanism to form the first stars in a manner that is very different from the inferred mechanism for present-day star formation. But when did unknown mechanisms and unobserved processes become scientific concepts?

Rather than appealing to unknown natural forces at work in the past, creation astronomers depend on the Book written by the infallible Creator who was there and made the stars. As we would expect, modern observations about the star-filled universe confirm the Lord’s creativity; and blue stars in particular are consistent with the Bible’s account of a young universe.

Time is not a Blue Star’s Friend

All stars eventually “burn out” if given enough time. Blue stars burn very hot and quickly compared to other types of stars. As a result, astronomers agree that blue stars can last a period of only several million years before they “burn out.” The proposed age of the universe is nearly 14 billion years old . . . so why are brilliant blue stars still shining across our universe?