"The Seasons, Explained," Clarified

Well, this is embarrassing. Last week I made a video to help explain why we have seasons. My primary goal was to show that seasons have nothing to do with earth's distance from the sun. With the revolutionary filmmaking techniques I was using, I made a few errors in my representation of this whole earth-and-sun-and-seasons situation. I hereby issue not only the corrections for my errors but also a formal apology.

Part 1. Explanation of errors in "The Seasons, Explained"

There are two main mistakes I made in the video, and one area in which I was vague.

         Mistake numero uno:

40 seconds into the video, I show a stop motion sequence of the earth rotating and revolving around the sun.



The rotation is incorrect here. The earth should be spinning counter clockwise, not clockwise as shown. At all other points where I show the earth's rotation, I made sure to rotate it counter clockwise, but here I was so focused on the logistics of taking a bazillion pictures of this tennis ball and grapefruit that I simply neglected to verify I was moving the tennis ball 0.00001 inches in the correct spinning direction before taking the next picture. Super oopsie moment. At least I don't work for NASA.

         Mistake numero dos:

When I labeled summer and winter on the earth, I drew this wrong.

I should have drawn the earth's equator and labeled the seasons from there.

Here's a helpful summary.

         Explaining what may have been too vague:

I said that when the sun hits more "directly," that means it is summer. I also may have summarized this as "boom." As in, "Boom, it's summer."

Rhett Allain, from WIRED Science Blogs, pointed out that saying "directly" doesn't effectively explain why this equals summer.

My goal was to explain the seasons in 90 seconds or less, so I did leave out a more thorough explanation of how the angle of the sun's rays makes a difference. So I will do that now. Although, if you want to see an expert explain this (and after being subjected to my mistakes, you're probably begging for it), check out Rhett's blog on the reason for seasons in his post entitled Seasons, short and simple.

Indeed, just like a soccer ball to the face, the sun's energy is more noticeable when it strikes the surface at near perpendicular angles. THAT is why we have seasons.

Part 2. Apology

To whomever has seen the youtube video formerly known as "The Seasons, Explained":

While spending embarrassing amounts of time making this 105-second video, I allowed my creative fervor to overshadow my fact-checking skills, and I made errors. While it is my goal to make science fun and interesting, this should never be at the expense of accuracy. I sincerely apologize for any confusion I have caused about earth's rotation or the occurrence of earth's seasons.

While it would have been far easier to just take the video off youtube and wallow in self-loathing despair, I decided instead to take this opportunity to correct my mistakes and seize this learning opportunity for myself and my readers. I strive to provide funny and informative science comics and stories and will continue to do so with more care (and fart jokes).

The Seasons, Explained

Today is the solstice. If you're in the northern hemisphere, it's the first day of summer, and if you're in the southern hemi, it's the first day of winter.

I'm a big fan of solstices and equinoxes, so I made a video about why we have seasons. Enjoy. Or don't. It's cool.



Edit: Since posting this yesterday, I have gotten some feedback about issues with the way I explained/represented the seasons. I will explain in next week's post. Thank you for the feedback!

Corals, baby

I totally understand your dilemma. You'd think that corals were plants since they don't move around much, and they need sunlight to thrive.

But it just isn't so. They are most definitely animals. Sure, they don't seem to move much when you look at them, but neither does the average office employee.

Corals are moving around, but on a scale that we can't see very well unless we're all up in their space.

Not all corals need sunlight to live, but the tropical coral reefs we usually think about do. But even then, it's not technically the corals themselves that need sunlight, it's the photosynthetic algae (teeny tiny plants) that live inside the corals that need it.

It'd be like if you had a corn plant growing in your stomach. You'd need to expose it to sunlight for it to grow and make food for you to eat.

Corals also get food from filtering seawater and eating plankton, but the algae give them a constant supply of food and oxygen (the products of photosynthesis) so it's in the corals' best interest to grow where the algae will be happy.

This is technically a mutualistic relationship (see my post on symbiosis): the coral gets food and oxygen, and the algae get carbon dioxide and a safe place to hang out. But sometimes I wonder if the algae is being held against its will.

Or are the algae taking advantage of corals?

Corals are very sensitive to changes in water temperature, salinity (how salty), and pH (how acidic). Changes in any of these areas can really stress corals out. And when they freak out, they eject their algal guests. This is called "coral bleaching."

If the stress subsides, corals recolonize themselves with algae, but if the stress continues, the coral may die.

It seems strange that corals would eject the algae when they're stressed. It's like a person who doesn't talk to anyone when they're going through a tough time. Let your friends be here for you, coral. They can help.

Want to know more about corals? Check out oceanservice.noaa.gov

Evolution of Teamwork

Supposedly humans are good at working together because long ago we survived a few very serious natural disasters by working together. People that couldn't work with the group perished, so the ability to engage in teamwork was a trait that natural selection preserved.

As any present day natural disaster or zombie movie has taught us, during times of intense danger and stress, 99% of people emerge as teamwork heroes, helping their neighbors and sticking together. The other 1% decide to be jackholes and exploit the situation to benefit themselves. Great example = the people who set up a fake Red Cross website to siphon some money from the Haiti Earthquake Relief donation stream. Super jackholes.

Evolutionarily, people have the urge to preserve their genes, especially in times of danger. This means foremost looking out for yourself and your family.

It usually takes tragedy to remind us that we share a universal humanity, and that helping each other is not only a fun thing to do, it's a human thing to do. Teamwork is one of the key qualities that has allowed our species to come so far. To shirk this responsibility is to deny our humanity.

If we could remember this between natural disasters, the world would be a far better place.

Dolphin Sexual Harassment

*This post is rated PG-13.*

Perhaps because of the last post's reference to dolphins' sleeping strategy, or perhaps for no reason at all, someone asked me for (actually, sort of demanded) a post about the dark side of dolphins.

This person heard that dolphins occasionally attack people, drown them, and sexually assault them (although not necessarily in that order). If you, like me, have never heard of this urban legend, I'm sorry to be the one to tell you. But before you freak out and vow to tear down all the dolphin posters in your room, burn them, and dance naked around their ashes, please listen up.

It's not really true.

There are a few instances of dolphins sort of sexually harassing humans (much like dogs occasionally do), but as far as a spreading scourge of murderous, raping dolphins--eh, not so much.

I'm not saying that dolphins are oceanic angels that are incapable of aggression.

Dolphins are fiercely intelligent wild animals with incredibly complex behaviors and social structures. We can't pretend to be able to predict their behavior. For instance, not long ago, a trainer at Sea World was drowned when an orca (which is a type of dolphin) held her underwater.

To make absolutely sure that the dolphin rumor wasn't true and to separate fact from google search result, believe it or not, I emailed a dolphin researcher and asked her straight up if dolphins ever sexually assault people. Please take a moment and think about how embarrassing that was for me. Thanks.

Maddelena Bearzi co-authored one of my favorite books, Beautiful Minds: The Parralel Lives of Great Apes and Dolphins. The book discusses both groups of animals and describes how even though they live in very different environments, because of their comparable intelligence, they have some behavioral and social similarities. This book gave me several mindgasms. Needless to say, I recommend it.


There is also a great anecdote about a pod of dolphins leading Maddalena's research vessel toward a girl who was nearly drowning. I've seriously considered pretending to drown so that I might be saved by dolphins, but luckily, I'm too lazy to actually do it.

Since I so loved her book, I subjected this poor person to the most random email ever, but luckily she was nice (and patient) enough to answer my rather bizarre questions about dolphin sexual aggression rumors. She has my eternal gratitude and apologies.

She debunked the sexual assault rumor (as I explained above), but she acknowledge that a dolphin might curiously "play" with the occasional human because in dolphin world, sexual play is just a normal part of growing up and participating in dolphin society.

She will talk more about dolphins' sex lives in her next book, which will be available March 2012. It's a ways away, but fret not; I'll remind you.

UPDATE 4/3/12: I kept my promise about her new book. 

See info here: Dolphins Can't Read (yet), But You Can

She also stressed that we always need to remember that these are wild animals and need to be considered as such.

Check out the Ocean Conservation Society, which Maddalena co-founded: www.oceanconservation.org

You can adopt a dolphin and volunteer for an ocean clean-up mission. So act like a dolphin, and go help someone (but please don't sexually harass them).