In a prior post for Crush The Street, I discusses the vitriol surrounding certain conspiracy theories; namely, that Americans have an “unwritten law” regarding which conspiracy theories are acceptable and which are not. Believing in Bigfoot is tolerated, if not intriguing. Believing that 9/11 was an “inside job” may jeopardize your career and social standing.
An extremely popular, albeit marginalized theory is the flat earth. Most people regard it as junk science, a concept that was initially considered a harmless trolling of the mainstream community but has since picked up considerable steam. Due to the flat earth theory’s incredible momentum, we see a concerted effort to label the movement as “fake news.”
Indeed, flat earth sounds absolutely ludicrous because we have thousands upon thousands of satellite photos demonstrably proving that the earth is spherical. However, just for the simple purpose of playing devil’s advocate, let’s assume that there were no such thing as satellites. Would the flat earth theory sound like fake news then?
At that point, most people would engage one of two options: accept the opinions and analyses of “experts,” or perform their own research to ascertain whether flat earth is junk science or not. The sad thing is, the vast majority of people would rely on expert knowledge and “group think” rather than investigate on their own.
A clear example is Paul A. Heckert, Ph.D., and his answer as to why we don’t feel the earth’s motion and acceleration. Since he is a “professor of physics and astronomy at Western Carolina University with over 30 years experience teaching college level physics and astronomy,” this should be an easy, breezy explanation, something that he surely has given over his many decades of teaching astronomy.
Indeed, Heckert easily tackled the first segment of the question – we don’t feel the earth move because it’s moving at a constant speed (approximately 1,000 mph at the equator). Unless we have a frame of reference (ie. whizzing trees or other objects), we don’t perceive constant speed at any magnitude.
However, the second component of Heckert’s answer leads into fake news and junk science. He concedes that earth doesn’t just move at constant speed; it’s rotating on its axis, and therefore, this is necessarily centripetal acceleration. We feel acceleration. How is it that we don’t feel the earth’s acceleration?
Heckert surprisingly doesn’t answer the question. Instead, he deflects the matter entirely by discussing gravitational-force variance between same objects standing on different parts of the earth. Heckert states the following:
A person standing on Earth’s equator will experience an additional acceleration of about 0.03 meters per second squared, caused by Earth rotating on its axis. The acceleration caused by Earth revolving around the Sun is considerably less; 0.006 meters per second squared. Both of these accelerations are so much smaller than 9.8 meters per second squared that we do not notice the additional effect. For a 150 pound person, these accelerations due to Earth’s motions have the combined effect of about 1/2 of a pound on the person’s apparent weight. Most people wear more than 1/2 pound of clothing, so the effect of getting dressed or undressed is greater than the effect on our apparent weight from Earth’s motion.
Were it not for my calling out this physics professor, most of you probably would have taken the above statement as fact. But, it’s either junk science or a typo. Unfortunately for our education system, I believe it’s junk science due to the fact that he doubled-down on his error.
Contrary to what Heckert asserts, a person standing on the equator will not experience “additional acceleration,” but less. The professor doubles-down on this error when he states that the earth’s motions “have the combined effect of about 1/2 of a pound on the person’s apparent weight (emphasis mine).” That a person will weigh slightly less at the equator has been firmly established, scientific knowledge!
More importantly, we can shed light on this junk science by doing the equations ourselves. According to Wikipedia, “Newton’s Law of Universal Gravitation states that a particle attracts every other particle in the universe with a force which is directly proportional to the product of their masses and inversely proportional to the square of the distance between their centers.”
In other words, the force generated by earth’s gravity can be defined as the product of the gravitational constant, G, the masses of the two bodies in question, divided by the square of the distance between these two masses.
To prove that a person standing on the equator weighs less, not more as the professor asserts, we do three things: find the distance between the earth’s non-equator surface and its core, find the distance between the equator’s surface and the core, and the weight of the earth (the person’s weight, or 150 lbs, is a given, and G is a constant).
For our purposes, I took the average distance of the earth’s surface to the core, and calculated the force generated by the earth, which is 667.5 Newtons (N). Then, I calculated the force at the equator, which is 666 N.
Finally, to calculate the variance in acceleration, we rearrange Newton’s Second Law of Motion, which states that force is the produce of an object’s mass and acceleration. Since we know the force generated by the earth, we simply divide this figure by the person’s weight (150 lbs, or 68 kg).
When we do this for the average distance between the earth’s surface and the core, voila!…we get 9.816 meters per second squared, or the acceleration of freefall. But for this same person standing at the equator, the acceleration is 9.79 meters per second squared, which is definitely less than 9.81.
This is to debunk the junk science aspect of Heckert’s claim. That aside, Heckert further states that the small difference between these two accelerations is the reason why we don’t feel the earth’s acceleration – it’s simply too small of a magnitude.
Unfortunately, this is fake news. The gravitational attraction between two bodies has nothing to do with their motions, or lack thereof. In simpler language, the earth would exert the same force on me whether it was completely stationary and motionless, or if it was moving at Mach 10. This is the reason why a bullet shot from a gun or dropped by hand from the same height and time will hit the ground at the same time (assuming no external interference).
However, the bullet chambered in the gun is certainly experiencing the acceleration from being at rest to rifling through the barrel! This motion is independent of the earth’s gravitational pull to its center. The bullet will experience two motions – falling to the ground at 9.81 meters per second squared, and the initial acceleration of being fired out of the gun.
Heckert conveniently explains an irrelevant motion, that of the earth’s gravitational pull. But the question was not about gravitational pull, but about the earth’s multiple accelerations – its rotational axis (orientation vector), its elliptical orbit around the Sun (orientation and magnitude vectors), and its orbit around the Sun as the Sun elliptically orbits the center of the Milky Way galaxy (orientation and magnitude vectors).
Surely, we should at least feel one component (magnitude or orientation) of these accelerated motions, but we do not! And frankly, Heckert and the scientific community’s supposed explanations are the worst kind of fake news.
It answers a question by not answering it at all! Again, in this case, gravitational attraction is a completely separate concept from the earth’s motion. Just look at Newton’s Law of Universal Gravitation – it only factors in mass, distance, and the gravitational constant, not the objects’ motions! Since the initial inquiry is about motion, gravity cannot answer it!
Perhaps you may believe that this issue is of no consequence. You may be right. However, fake news is not. You should never be too quick to accept knowledge, especially from the government or the scientific establishment.
As President Reagan once said, trust but verify.