Here’s Proof: The Sun’s Distance and Apparent Size Change Throughout the Year

This leaves out a very important fact: orbits are never perfectly circular. Rather, orbits are always elliptical, with the sun at one of the two focuses of the ellipses. Johannes Kepler discovered this four centuries ago, a fact we call Kepler’s first law of planetary motion. Consequently, earth is not a constant 93 million miles from the sun throughout the year. The 93 million miles is the average distance between the earth and the sun, a distance that we astronomers call the astronomical unit (AU). Throughout the year, the distance to the sun varies from a low of 91 ½ million miles at closest approach (perihelion) to a high of 94 ½ million miles at the greatest separation (aphelion). That is a difference of 3% in the distance to the sun throughout the year.

Now, I’m sure to blow some people’s minds by informing them that perihelion is in early January and that aphelion is in early July. That’s right—for people in the Northern Hemisphere, we are 3% closer to the sun in early January than we are in early July. So we in the Northern Hemisphere are closest to the sun when the temperatures are the coldest, and we are farthest from the sun when it is hottest. How can this be? Keep in mind that the situation is reversed in the Southern Hemisphere. People south of the equator experience their coolest weather near aphelion and their warmest weather near perihelion. I’m sure that many of you are confused at this point. If so, the problem is that you weren’t properly taught the cause of the seasons while growing up. Before I explain the true cause of the seasons, let me demonstrate that what I have told you about when perihelion and aphelion occur is true.

The Demonstration

Objects appear smaller when they are farther away, so if the sun’s distance changes throughout the year, then the apparent size of the sun ought to change throughout the year too. More specifically, the sun ought to appear 3% smaller at aphelion than it appears at perihelion. The sun was last at aphelion on July 6, 2023, and the sun recently was at perihelion on January 2, 2024. I took the first photograph of the sun on July 12, 2023, six days after aphelion, and I took the second photograph of the sun on January 4, 2023, two days after perihelion. I took both photographs with my Nikon D3200 camera attached to the 3.5-inch Questar telescope of the Johnson Observatory here at the Creation Museum. I didn’t crop or adjust the size of either photograph, so they are at the same scale. Looking at the images, you can’t see a difference in the size of the sun between the two photographs, but would you really expect to see a 3% difference so easily?

There is a way to directly measure and hence compare the changing apparent size of the sun. I printed the photographs and measured the diameter of the sun in either photograph. The diameter of the sun in the July photograph was 173 mm, and the diameter of the sun in the January photograph was 178 mm. This difference of 5 mm is 3%, just as expected, confirming that the sun’s distance changes by 3%, with the sun closest in early January and farthest in early July. Feel free to copy and print my two photographs and test this for yourself.

The True Cause of the Seasons

This is sure to bring up the question of how we in the Northern Hemisphere could have summer when we are farthest from the sun and winter when we are closest to the sun. Again, the situation is reversed south of the equator—people there experience summer when we are closest to the sun and winter when we are farthest from the sun. Obviously, many of us were not properly educated about the cause of the seasons, because distance from the sun doesn’t have much to do with it.

So, if changing distance from the sun doesn’t cause the seasons, then what does? During summer in either hemisphere, we are tilted toward the sun, which means the sun’s rays strike the ground more vertically than during the winter. Consider a shaft of sunlight. When the shaft of sunlight strikes the ground nearly vertically, that shaft will be spread out very little, so the energy contained in the shaft of sunlight can efficiently heat the ground. But when a shaft of sunlight strikes the ground at a much lower angle, the amount of area that the energy of the shaft of sunlight must heat is greatly increased. Hence, during winter months, when rays of sunlight strike the ground at a much lower angle, the energy in the sunlight cannot heat the ground as much as in summer, so temperatures are cooler. Since this is due to the changing amount of area that must be heated, I call this the area effect.

But that is not the entire story. During summer months in the Northern Hemisphere, the sun is north of the equator. This causes the sun to rise north of east, get very high in the sky, and then set in the north of west. This very long path causes the sun to be in the sky for a long time, producing long days and short nights. On the other hand, during winter months the sun rises in the southeast, and it doesn’t get very high in the sky before it sets south of west. This short path across the sky causes the days to be short and the nights to be long in winter. Nearly everyone knows about the seasonal difference in the amount of daylight and night, but few people think about why or its consequence. The consequence is that with the sun high in the sky for so long during the summer, the sun heats the earth quite a bit, but during the winter with the sun low in the sky for just a short while, there is little time for the sun to heat the earth. I call this the time effect.

Together, the area and time effects explain the difference in temperatures between the seasons. However, there is a bit more to the story. The greatest amount of winter cooling is in the Arctic and Antarctic, where the sun hardly heats at all. Meanwhile, the maximum heating of the tropics rhythmically moves north and south through 47 degrees of latitude each year. Thus, during the winter, one is far from where the major heat is being introduced on the earth. The global climate system tends to equalize these temperature differences by moving warm air from the tropics and cool air from the Arctic and Antarctic. Consequently, a great portion of our seasonal temperature differences are driven over great distances.

So how many of you feel a little cheated that you weren’t properly educated about the seasons while growing up? Yeah, me too. But let’s not judge our teachers too harshly—they merely repeated false ideas about seasons that they learned growing up too. Perhaps this blog post can help turn this problem around.

One More Thing

Some of you may realize that the Northern Hemisphere being closer to the sun during winter and being farther from the sun during summer would moderate seasonal temperature differences, making our seasons less extreme than they would be otherwise. Indeed, that is correct. But what about the Southern Hemisphere, where the situation is reversed? Wouldn’t that cause the seasonal temperature differences to be greater, leading to warmer summers and cooler winters than in the Northern Hemisphere?

Indeed, if that were all there was to it, that would be the case. But there is something else going on. If you have a globe, pick it up and look at the Northern Hemisphere by looking down onto the North Pole. Now flip the globe over and look down on the South Pole. You will notice that the Southern Hemisphere is about 90% water and only about 10% land, but the Northern Hemisphere is about evenly split between water and land. Now recall from science class growing up that water has a high specific heat, meaning it takes much addition of heat to increase the temperature of water, and much removal of heat to decrease the temperature of water. That is the source of the adage, “A watched pot never boils.” On the other hand, land has a low specific heat, meaning that land heats up and cools down quickly. Locations near large bodies of water tend to have more moderate temperatures than locations far from large bodies of water. Some of the most extreme seasonal temperature differences happen in the centers of continents, far from water. This is the case of the Dakotas and eastern Montana in the United States—it can get very warm in the summer and very cold in the winter. Meanwhile, coastal areas don’t have such huge extremes.

Happenstance or Design?

The much greater amount of water in the Southern Hemisphere moderates the seasonal temperature differences so that there isn’t any real difference between the two hemispheres. Isn’t that a nice coincidence? Perhaps, but how many coincidences is one allowed to have before one realizes that maybe they aren’t coincidences after all? There are many other “coincidences” about the earth, such as the earth’s mass, atmosphere, magnetic field, orbit, tilt, and mass and orbit of the moon, that work to our advantage, much as the distribution of land and water on the earth’s surface related to the dates of perihelion and aphelion.

An honest assessment of these “coincidences” ought to lead one to at least consider the possibility that they aren’t coincidences at all but rather are evidence of design. Alas, to those committed to philosophical naturalism, that the natural world is all there is, the possibility of design is anathema because it leads to the conclusion that there must be a Designer. Of course, this would lead one to realize that perhaps we are beholden to our Creator and that God can expect some things from us. But man in his natural state is in rebellion against God. Therefore, recognition of design in the world is not a matter of science (though it ought to be) or even a matter of intellect. Rather, recognition of design in the world is a spiritual matter. Unlike other conclusions one may reach, the conclusion that design exists in the world around us demands that one make a spiritual decision.