This weekend marks an important astronomical date, it is time for the southward equinox. This means that as for this day, every place on the planet receives 12 hours of daylight and 12 hours of darkness. For the coming months, nights will become longer in the northern hemisphere, while the southern hemisphere will receive more and more daylight. This is reason enough for me to dedicate this week’s piece to one of my passions, astronomy. But it will not really be about the equinox, it is rather about some common misconceptions about astronomy that I have encountered in all these years.
Throughout the history of our species, people have been looking up into the night sky. They have studied the movement of all these tiny dots of light they could see, and as is it our nature, they have seen pattern, and have connected dots to form constellations, which were often attributed to gods and other mythical figures. It is not surprising that to this day, there is a lot of wisdom, but also a lot of bullshit. And it isn’t always easy for people to draw the line between what to believe faithfully, or what to question skeptically and maybe even dismiss as untrue. Especially in this age of the internet, where all kind of information is accessible to everybody, the tendency is for people to rather believe things that they are told without taking the time to question them. In this article, I want to address some of these stories, that could be easily dismissed as untrue by anyone, with just a little research and thinking.
“Tonight Mars will appear as bright and big as the moon in the sky.”
This story is one of those unsinkable rubber ducks, it gets recycled all the time. And on social media I can see many homo sapiens – and not so sapiens – sharing it without even the slightest doubt. But they should doubt it. This is an easy problem of proportion. Every middle school student can do the math in their sleep. The moon is, on average and rounded, 400,000 kilometers away from us. And it has a diameter of roughly 3,500 kilometers. On the other hand Mars is, at its closest point, about 58,000,000 kilometers away, with a diameter of 6,800 kilometers. Let us simplify this. The diameter of Mars is about twice as big the the moon’s. This means that it would appear the same size in the night sky if it came as close as two lunar distances to us.
Well and this is it, no more research or math to be done. How could Mars ever get that close to us? Its closest point is at over 140 lunar distances! And it is on a stable orbit around the sun, and so is Earth, while the moon is on a stable orbit around Earth. There is no way, that Mars suddenly would “jump” into a position that close to us. So the next time you read this claim, just point your friends at the solar system’s distances and orbital mechanics.
“During the next solar eclipse, we will weigh 1 kilogram less for a few minutes.”
Okay, okay, I get it, I would also like to drop another kilogram. But there are more efficient ways. So, what happens during a solar eclipse? The moon gets exactly between the Earth and the sun, casting a shadow on the planet. So, yes, both the moon and the sun are lined up on the same side of our planets. And yes, their gravitational pull on us adds up. Here is the thing, although the sun is huge, so is its distance from us. And the gravitational force decreases with the square of the distance. Furthermore, haven’t we all learned that the moon’s gravitational pull is responsible for the tides on our planet? Right, because is pulls much stronger than the sun over all the distance.
Still both gravitational forces combine at this moment during an eclipse. But the difference is nowhere near a kilogram, it is rather at the order of magnitude of micrograms. And technically, this is still wrong, because the amount of kilograms in you won’t change because of an eclipse. This is your mass. Your weight is the force of gravity on you, and it is measured in Newtons. There is even more, every month, even though there might not be an eclipse, we still have a new moon. This is when the moon and the sun are on the same side of our planet, but do not exactly line up for an eclipse to happen. But the gravitational pulls are still nearly in the same direction, and we don’t see people making this weight loss claim during a regular new moon.
“The World is going to end on (insert date here) and it was predicted by (insert name here).”
This one also comes back all the time, possibly more frequently than the other two combined. Very often these claims are made by some religious leaders, being used as an argument to repent and follow Jesus right now. Anyway, this article focused on astronomy, not religion, that one is on my list for another occasion. The details for all the apocalypses vary, but the degree of baloney is always the same.
Often this is attributed to a mysterious planet Niburu that will suddenly come out of its hiding place, and collide with the planet. Or we will be swallowed by a black hole. Or all the planets will line up, messing with gravity on our planet, which might fling us into space. Sometimes it is because the calendar of an ancient civilization suddenly ended, which means they knew something thousands of years ago. Or it is just that computers cannot handle the jump from the year 1999 to 2000, and they would reset to 1900, leaving us in utter chaos
Well you guess it, just like Mars cannot jump into a closer position, the not even existing Niburu can’t either. And the gravity claim was just explained in the section about eclipses. And of course the ancient calendars ended somewhere. So does our calendar. It ends, on December 31st, every year! And then a new cycle begins. Civilizations like the Mayans didn’t write down all the cycles for the history of the planet, just as we don’t. When December 31st comes your buy a new calendar and you throw the old one in the trash. Last but not least, even twenty years ago computers were powerful enough to handle years with four digits.
What is interesting though is one thing when you look at all the recent apocalypse claims. They do coincide with either and equinox or a solstice. These are the turning points of the seasons, on March 21st, June 21st, September 23rd and December 21st. And just as interesting, though not surprising, nobody comes forward after a non-apocalypse to let the world know that they were wrong about it. They either make cheap excuses, or just change the date, or remain in complete silence, counting on the world to forget about it. Usually it is a combination of all three, if we just wait long enough.
“There is no gravity on the moon.”
This is a common statement that I hear from my students in eighth grade, year after year, before they had classes with me. I don’t want to rant to much here. Of course by the end of the year, my students know better. Gravity is a force of attraction between two objects, and it is proportional to their masses. Every object has a gravitational field around it. Gravity is a weak force, it only becomes significant if at least one of the two objects has a significant mass, such as a planet for example. And the moon has a great mass, therefore it has a strong gravitational field around it. It is about one sixth the strength of the gravitational field on Earth’s surface, but it is there. Just look at the astronauts on the footage from the moon landings. In fact, you can kind of experience it for yourself, just jump around in a swimming pool. Buoyancy gives you a lift, making you fall more slowly, but you still fall.
What would really be interesting is sports on the moon, if it were possible. Just think about a homerun in baseball, a basketball slam dunk, a field goal in American Football, or a service on a tennis court, all in a lower gravity environment. If you need some help imagining, there is a great episode of Star Talk with the great Neil deGrasse Tyson, all about this topic.
“The position of the planets determines our personality and our fate.”
I saved the big one for last. Astrology! I don’t really believe in it, since we Virgos tend to be skeptical. But to be sincere, when I was younger I would take this more serious, and even read books about it. But sooner or later I would notice that there is nothing to it. First of all, there are 12 zodiacs, which means there would be only twelve kinds of personalities? And whatever the horoscope predicts, will happen to all people from that zodiac, which would be over half a billion people each?
Of course horoscopes are only vague, never specific. And people only focus on the hits, not the misses. I do not want to get into too much detail here, the characteristics of psychics might as well become an article on its own. But I do want to mention that technically there should be 13 zodiacs, Ophiuchus being the one left out, and some of them would only last for about 10 days, while others up to 45 days. But 13 in not the number of months, and attributed with bad luck, so why not arbitrarily throw one of them out? It’s not rocket science, right? It’s not science, period! So go ahead and read your horoscope, and enjoy it for entertainment purposes, but don’t think there is anything true about it. Whatever happens to you that was predicted by the horoscope is a mere coincidence. For every person like that there are thousands of people where the horoscope did not come true. And the same goes for the typical personality traits that go with each zodiac. I know, if you read the description of your zodiac, it sounds a lot like you. But so do all the others!
To conclude, don’t feel bad if you have believed one of these stories or a similar one, or might have even shared it. I think the main problem is that space is huge, far bigger than we possibly can picture. And so are the distances between the objects in the solar system. So we tend to underestimate them. For example, we all picture the asteroid belt of a solid region where the asteroids constantly bump into each other, and it is hard to penetrate for any vehicle. But space is so big that these asteroids are far away from each other, so far that you could stand on one and not even be able to see the others.
The misunderstandings about gravity are probably because it is a force that is everywhere, and we do not really see what causes it. Additionally, we live in an environment where the gravitational field has a strength of 9.8 N/kg, no matter where you go. We have never experienced any other gravitational force (unless you are one of the lucky people who went to the moon or the ISS, but I doubt that these guys are reading my blog). You cannot blame anyone for misunderstanding something they have never experienced.
I have kept it to some myths about the bodies in the solar system, and decided not to open the box of the moon landing conspiracy – yet. The same goes for the common (wrong) hypothesis of my students that heavier objects will fall faster. I will describe that and the quick lab experiment in another article as well.
All I hope to achieve with you, dear reader, is that whenever you read a claim like the ones made in this article, you just take a short moment and question the information and the source. It might only take you a few minutes and not even involve complex math. And believe me, it feels good when you actually notice what is wrong about a claim and do not fall for it.
On a final note, remember that the universe is an amazing place. There is all kind of fascinating stuff going on. There is no need to invent stories to make it more interesting. Just go with reality and try to understand what is really going on.
Here are some podcasts you should consider if you want to learn more:
And here are some great astronomy blogs to follow:
And finally, the sources of the images used:
Gravity on the moon: http://www.virneth.co.uk/topGravity/gravity0.php
Solar eclipse: https://www.youtube.com/watch?v=TQ-UHxPHh9A
The end of the world: https://smashmeme.wordpress.com/2012/12/21/the-world-is-ending/
The zodiac: https://twitter.com/13_ophiuchus/status/668487135922663424