Science Education Pedagogy Seminar

Venus is many things. I don’t know much about it besides the fact that it is hot, orange, it’s the second planet in the solar system, and is the goddess of love in Roman mythology.

On June 5th, 2012, a couple of days after I graduated from high school, my dad and I woke up at 5 am and drove to a large parking lot in downtown Beirut. There were local news station vans and minor celebrity figures. The transit of Venus across the face of the sun was the biggest headline that day. My physics teacher was there, too, and he introduced me to Majdi Saadi, an astrophysics professor at the American University of Beirut and scientific personality who I have now grown to liken to a sort of Lebanese Neil deGrasse Tyson – charismatic, cynical, and very passionate about science literacy.

I took off my glasses and pressed my eye into the telescope. The goddess of love looked largely unglamorous, a black dot on the face of the massive sun. But really it represented something – this was a couple of months before I was scheduled to fly out to America for the first time. I was in awe of its insignificance, really. This massive, massive celestial body, a speck in an eyepiece. It was quite lovely, rather akin to Tyson’s cosmic perspective. Bigness and smallness conflating.

“You are the future of science for this country,” Saadi told me as he vigorously shook my hand. “Make us proud.”

I have wanted to be a scientist ever since.

Here are some of my favorite sites for learning about eclipses (including the upcoming Great American Eclipse!):

• Mr. Eclipse (the guy NASA uses)
• NASA Eclipse Web Site
• eclipse2017.org (make sure to check out the AMAZING interactive Google map!)
• timeanddate.com (and their eclipse list)
• Of course, one can certainly use the Wikipedia article on Eclipses (you can also go specifically to lunar and solar)
• One of my favorite astronomer-bloggers, Phil Plait (the “Bad Astronomer”) has a nice article with some good diagrams and pictures

“Moon Slide (slim)” from Astronomy Picture of the Day. This “Moon-trail” by Stefan Siep was created by just opening the shutter and keeping it open for about 3 hours. Note the brightness difference between full and eclipsed 🙂

“Any sufficiently advanced technology is indistinguishable from magic.” – Arthur C Clarke’s third law.

I stumbled on a little thing I had posted some time ago, early in September when friendships were still tentative and the air was still crisp. -We spent the weekend in a cabin four dirt trails off the everyday. At night we cracked open beers and harmonized to loud electronic dance music and jazz. At one point my gaze drifted a little upward and I realized we were completely outside the belly of Nashville light pollution. The sky danced with playful glitter. In a moment of personal triumph I was reminded why I loved the night sky so much I had pledged to study the science that governs it. Amidst the thumping music in a moment of serenity I found a sliver of purpose again. The night sky in Nashville is purple smeared, bruised, unglamorous. I forget there is magic out there still-

I love looking up at the sky. Back home in Beirut, the sky was full of possibilities. But mostly smog, dark clouds, light pollution. One month, in 2006, drones. Then the sky became a place of fear, and anguish, and loss, and grief. It stopped giving sunlight, rain, wispy cloud, but only bombs. Where was the human endeavor? Where was the space race, national pride, stretching onto the rubber band of impossibility? Space travel, exploration, discovery?

Then it stopped. I was on a plane that shot up into the sky. Opportunity. The atmosphere was still my ceiling. I was still under all this evil. But now I was in the land of opportunity, and the sky opened up for me once more.

Earth’s Elliptical Orbit and Seasons

Though a common misconception about the cause of seasons is that they are caused by the Earth’s distance to the Sun, in actuality, seasons are caused by Earth’s 23 degree axial tilt. But why do changes in Earth’s distance from the Sun have virtually no effect on temperatures on Earth? It seems like a logical explanation for the changing of seasons and many brilliant people still hold this misconception to be true.

Earth orbits the Sun in an ellipse. At its closest point to the Sun, Earth is 147 million kilometers away from the Sun, while at its furthest point from the Sun, Earth is 152 million kilometers away from the Sun. This represents a difference of 5 million kilometers, which certainly seems substantial enough to change temperatures here on Earth. This, however, is not the case.

(Earth’s elliptical orbit)

Since the Earth is so far away from the Sun to begin with, this relatively small change of 5 million kilometers as virtually no effect. Imagine you are holding up a piece of paper and standing at a football field’s length away from a powerful flashlight. You first observe the amount of light hitting the paper and take note. Next, you step a yard closer to the light and observe how much light is hitting the piece of paper. You will not be able to tell the difference in light hitting the piece of paper since the flashlight is so far away to begin with and you only walked 1% closer to the flash light. If you had some very accurate machinery to measure the change you definitely would be able to pick up a tiny change, but there simply would not be any noticeable change.

Earth’s elliptical orbit, though, does have a small effect on seasons. When Earth is closer to the Sun, it travels faster in its orbit than when it is further away from the Sun. During winter in the northern hemisphere, the Sun actually travels one kilometer per second faster than it does during summer in the northern hemisphere. This causes winter in the northern hemisphere to be a full five days shorter than it is in the southern hemisphere!  (See here for more)

When we think we can’t see the moon, it can definitely see us. This doesn’t just hold true when we’re sleeping. As the children’s book, “Goodnight Moon,” goes, we may say “Goodnight” to the moon – but it’s still there outside our window and outside our atmosphere. Different parts of the moon disappear at different points during the month, and we can observe this even as children.

In elementary school, though, our teachers enlighten us on the process that causes these weird shapes. Sometimes they give us proper explanations. Other times, they don’t. In my personal experience, my teacher didn’t quite get it right. She used a nice display of the Sun, the moon, and the earth. The Sun was actually a round ball that contained a light bulb, with a little hole in the side to allow “sunlight” to escape. The overhead lights went off, and she lit up the earth and moon with our little “Sun”; however, she positioned the earth directly between the Sun and the moon -meticulously casting Earth’s shadow on the moon figure in shapes imitating waxing crescents and quarter moons.

Every night, my seven-year-old self would look at the moon from my bed. I looked at it like I felt bad for it, as if to say, “Goodnight, Moon. Sorry for covering you up.”

But this isn’t how the moons phases work at all. In fact, the earth is positioned so far away from the moon (a distance of thirty Earth diameters) that it rarely gets the chance to cast a shadow on the moon’s surface. When we see phases, we are actually just seeing the moon illuminated from a different perspective or angle. This is because the moon revolves around Earth, yet it always has a side facing the Sun (an illuminated side).

So, as the moon spins and revolves around Earth, we see it from different angles. Sometimes we get to see more of its (currently) illuminated half. Other times, we see less or none.

Honestly, the moon is just doing its thing.

Unless the earth is exactly positioned between the Sun and the moon, which may only happen every six months, we never cast a shadow on it.

I don’t feel bad anymore – we don’t steal the moon’s spotlight. Even in the rare event that we do (during a lunar eclipse), everyone’s more excited about staying up late to see the moon anyway. Now, going to bed as an enlightened college student, I might say something like, “Goodnight, Moon. Looking especially waxing tonight.”

Feature image from “Acculturated – Pop Culture Matters” (http://acculturated.com/goodnight-stars/)

We’ve read it in our beloved science fiction books. Superheroes and intelligent beings from other worlds harness massive amounts of energy and cross through different dimensions – traveling faster than the speed of light. It’s the kind of thing space-obsessed kids (and adults, alike) dream about. We dedicate movies, like “2001: A Space Odyssey,” directed by Stanley Kubrick, to the very thought of such developed technology.

Stanley Kubrick’s take on Arthur C. Clark’s “The Sentinel”

Yet, is traveling at hyper speeds really the dream? Many of us come into college-level astronomy courses excited to learn about game-changing developments that scientists at NASA or researchers at Caltech somehow, miraculously discover. The reality, however, is that we should really be dreaming about traveling at light speed first.

How boring, right?

Actually, it’s pretty exciting. The speed of light is often referred to as the “speed limit” of the universe. Perhaps our dreaming about hyperspace is attributed to the notion that we see speed limits as suggestions. Light speed? We can go faster than that.

Oh, 300,005 km/s won’t get me pulled over. 

Wrong. This speed limit isn’t a suggestion at all – there’s no exceeding it with our current technology. Light travels through space at 300,000 km/s. That doesn’t necessarily look like an impossible number. Something like 1 million km/s might seem like a stretch to the ordinary citizen. So, let me put it into perspective. The fastest known aircraft on Earth, the SR 71, travels at a measly 1 km/s. A speedy space probe only zooms through space at 50 km/s.

We haven’t come close to breaching even 1/3 of the speed of light. Our “limit,” as far as we know, is currently 6,000 times slower than the universe’s.

If this basic knowledge changes our perspective at all, it may be valuable to look at our other attitudes towards space with new eyes. Why limit ourselves to dwelling on Pluto’s classification as a planet, when there are other objects (Planet 9, for example) to observe excitedly?

Instead of regarding the speed of light as a boring limit to pass up, what if ordinary citizens regarded its sheer speed with wonder? At least this way, in the miraculous event that the human race ever discovers a way to reach light speed, we’d all understand the true weight of such a discovery. Let’s not set ourselves up for disappointment.

A total solar eclipse. Source: SoftPedia

There are two types of eclipses, lunar and solar, but I’d like to talk about the latter. Solar eclipses can be broken down into four subtypes: total, partial, annular and hybrid. In order for any of these to happen, the Sun, Moon and Earth must form a straight–or almost straight– line. A total eclipse is pictured above, and is when the Moon blocks the entire sun, though one could argue that this is actually an annular eclipse, where the Moon blocks most of the Sun but a ring, or annulus, of the Sun is still visible. Partial eclipses are when the Moon, partially, blocks the Sun and hybrid eclipses are combinations of 2 of these types, where the Moon partially and then either totally or annular-ly blocks the Sub.

These eclipses happen due to chance. The first is the huge coincidence that the Sun is about 400 times the size of the Moon, and is also about 400 times further than it, relative to Earth. Because of this, the Sun and Moon appear to be roughly the same size in the sky. The Moon also has to be at one of its nodes for this phenomenon to occur. The Moon’s nodes are where it crosses the ecliptic as it orbits the Earth, which makes sense, because the Moon has to be between the Sun and Earth to block the Sun’s light from reaching us here. Now, in order to have a total solar eclipse, the Moon must be at or very near the perigee of its orbit, which is where it is closest to Earth. If the Moon is not at or near the perigee, it appears slightly smaller in the sky and we would be left with an annular eclipse, as opposed to the total eclipse.

The effects of aberration and the Doppler Effect. Source: Comic Vine

During one of the first class sessions, we were given a minute or so to write down what would happen if the speed of light was only 100 mph. I’d never really thought about this before, so I struggled to get anything more than “The light from the Sun would take forever to reach us” and “it would be cold”, so I figured this would be a good time to tweak the question and ask “What would happen if we traveled at the speed of light?”

There are a couple of really strange consequences that would occur if you were to travel at the universal speed limit. The first is called time dilation, where time moves slower for someone moving at higher speeds. Let’s say you moved at 90% the speed of light, your watch would show 10 minutes have passed but to an outside observer, 20 minutes have actually gone by. The next two consequences will distort your vision, and you’ll see something like the image above. The first cause behind this vision change is due to aberration, which is where you would essentially get tunnel vision. This view occurs because the photons around you all appear to be coming from in front of you, even any behind you. I believe this makes sense because these massless photons move at the speed of light and if you traveled faster than them, in the split second you saw them, they would appear as a streak in your view. I imagine this as someone moving during a series of photos, where they’re blurred in each. The other vision-changer is the Doppler Effect, which causes the light from everything in front of you to bunch together and appear blue, as show in the picture. All the light behind you would actually spread out and appear red. If your speed were to continue increasing, the light would appear to shift out of your view and fade into the darkness.

Now, this is actually impossible because of Einstein’s equation E=MC^2, where energy and mass are the same thing. Since E and M are the same, you can conclude that the faster an object goes, the more mass it will have (and this of course only happens at realllllly high speeds). So if an object were to travel at the speed of light, it would have infinite mass and you would need an infinite amount of energy to actually move that object, which is sadly why this is impossible, for now.

I got this information from a good piece at How Science Works, that explained this topic very well.

Many sci-fi books, shows and movies incorporate the idea of faster-than-light (FTL) travel. The first appearance of the term “warp-drive” was in John W. Campbell’s novel Islands of Space (all the way back in 1931), but the accepted value of the Speed of Light (c) had only been discovered 51 years earlier (in 1879). That is not to say that people had not thought about or attempted to measure this limit. Aristotle argued with Empedocles about the speed of light in the first known discourse on the subject (and as with many of his ideas about physics, Aristotle was wrong-he thought light traveled instantaneously).

Even as early as Galileo, people were attempting experiments to measure the speed of light- usually these experiments failed because they were carried out at distances that were too small to be able to detect any differences.

Finally, Albert Michelson (a former Navy Officer) came up with the accepted speed of light after his experiment with Edward W. Morley proved that there was no aether to cause drag.

Further Reading:

History of the Speed of Light

Warp Drive

Michelson’s Bio

Michelson-Morley Experiment