Confidence in Astronomical Observations

Confidence in Astronomical Observations
Crab Nebula

Some people have asked how we can know that astronomers’ statements about the evolution and demise of stars are factual. This question is usually asked by those in religious denominations that demand a young Earth, which means a young cosmos. Even though the time factors are much longer than human existence, we can have confidence in astronomical observations.  

Although humanity has not been around long enough to observe the complete life of a star, we have seen intermediate steps in star evolution. Astronomers plot the luminosity (brightness) of stars against their surface temperature (or color/spectral type) with graphs called the Hertzsprung-Russell (H-R) diagram. It’s a powerful tool for classifying stars, studying their evolution, and understanding their properties. An example is the Crab Nebula.

In 1054, astronomers saw a star explode. The debris pattern of the explosion resembles a crab, so astronomers call it the Crab Nebula. Almost a millennium later, measurements show that the nebula is roughly 10 light years in diameter and is expanding at 1,500 kilometers per second. Observations of the Crab Nebula by the Hubble telescope in 2005 and the Webb telescope in 2023 show steps in the life of a star. Observations of other stars provide more information about a star’s lifetime, giving us confidence in astronomical observations.

Even though I didn’t see the launch, if I see a rocket climbing higher in the sky with every passing second, I know it was launched.  I can even compute the launch time. When a car comes to a stop, leaving tire tracks, I know the car was going fast when someone applied the brakes. Every day, we understand evidence of a process without seeing it from start to finish. Astronomers come to understand the life history of stars in the same way.

As we have pointed out before, the Bible does not tell us the age of the cosmos or Earth. We can have confidence in astronomical observations. Young-earth theology is not only in opposition to the evidence but is also inconsistent with the biblical account.

— John N. Clayton © 2025

References: apod.nasa.gov for May 8, 2025, and Wikipedia.

Supernova 1987A Celebrates 30th Birthday

Supernova 1987A
Supernova 1987A

On February 23, 1987, a historic explosion was witnessed by astronomers on Earth. A massive star known as Sanduleak -60 degrees 202 exploded. What was previously classified as a supergiant star became a supernova. For the first time since A.D.1054, there was a supernova close enough to the Earth for scientists to observe first-hand what was happening.

Hertzsprung-Russel Diagram
Hertzsprung-Russel Diagram

Students in high school physics and earth science classes study a diagram known as the Hertzsprung-Russell diagram. It is simply a scattergram of the temperature of stars plotted against their luminosity. Stars begin as very hot blue giant stars. As they cool, they turn white-hot, then red, then brown. Then they may become a cinder. In the case of larger stars, the internal processes change, and they become giant stars which in some cases explode. Because these processes require a very long time, we don’t live long enough to see a single star go through all of these phases. But we can see stars in all of these stages. Seeing a star explode is a very rare event (about once a century), and Sanduleak -60 degrees 202 was thus a fantastic opportunity to see in detail what happens when a star explodes.

There is much to learn from Supernova 1987A. Exploding stars seed space with the heavier elements. We are learning how the elements that make up our world were formed. For those of us who believe God is the engineer of all of this, we can see how God made iron, copper, gold and the materials of the Earth’s crust. The incredible energy and power of the process testify to God’s power and creative wisdom. As we compare this supernova with the one that happened in A.D. 1054, which produced what is now called the Crab Nebula, we see it is different in many ways. In 1 Corinthians 15:41 the Bible tells us that “one star differs from another” and we now know that is true even of exploding stars. This supernova also gives us another tool to measure the size and age of the universe. We have several methods of measuring how far away this supernova is, but they all give us the same answer. The explosion took place 160,000 light years away from us, or 160,000 years ago. We are safe from the incredible radiation because of the huge distance.

We now have 30 years of measurements of this historic explosion. This birthday will be celebrated by scientists, but it is also significant to those who enjoy looking into space and seeing the handiwork of God.
–John N. Clayton © 2017