Science Education Pedagogy Seminar

There’s a spectacular light show every year at the Opryland Hotel in Nashville, Tennessee. The grand venue boasts thousands and thousands of lights each year around Christmas. Yet, you don’t have to find a $30 parking spot at a debatably overrated hotel to see a grand, sparkling event.

In fact, there’s a place giving light shows as often as several times a day (or in slow periods, a couple times a week).To see it, you can be anywhere in the world – all you have to do is look up.

The Sun is essentially a collection of boiling, rolling matter. Its surface can reach temperatures anywhere around 6000 degrees, though its core is much hotter. Additionally, just like Earth, it also has a magnetic field. We see phenomena, called “solar flares” occur in what look like patterns along these magnetic lines.

In the photo above, you can see the Sun’s matter flowing in an arc-like shape outward from its surface, or corona. The shape seems to follow the lines of a magnetic arc. The sheer mass of energy is spectacular, and it sends these “flares,” or brief shoots of matter, out above the corona until it falls back to the surface. The seemingly tiny outbursts – that can occur several times per day – each require 160 billion megatons of TNT. That amount of fuel seems unreal and attests to the star’s sheer size. I can’t imagine what 160 billion tons of TNT looks like, much less 160 billion megatons.

We get it.

The Sun has power it sometimes decides to spare. But all that energy has to go somewhere, and solar particles are often thrust into space during these spectacular shows. Particles like protons and x-rays are often swung off these flailing arms of the Sun; however, Earth’s atmosphere is much too thick for x-rays to pass through and harm our bodies. Even still, these bursts of energy can interact with and disrupt our communication devices (including orbiting satellites) here on/around Earth.

The Sun likes to show off, and with all that energy and its beautifully boiling rivers, it certainly has merit in doing so. Yet, as with life on Earth, too much arrogance can cause damage. The Sun hasn’t let us down yet.

Feature image credit:http://www.cprigging.com/portfolio/gaylord-opryland/

The size of the Sun is difficult to comprehend. With a diameter of 865,000 miles, The Sun has the volume of 1.3 million Earths. If we were to place the Earth next to the Sun, we would simply see a tiny spec next to the Sun. However, the Sun is not even close to the biggest star in the universe.

About 3 kilo parsecs away from Earth sits UY Scuti, a red supergiant that has a diameter of roughly 1.5 billion miles. If this star were placed at the same location as our Sun, it would fully encompass Saturn’s orbit and almost encompass Uranus’s orbit. Furthermore, UY Scuti has the volume of over 5 billion Suns. To put the size of the Earth, the Sun, and UY Scuti in perspective, if the Earth were the size of a beachball, the Sun’s diameter would be about the height of a seven story building and UY Scuti’s diameter would be over four times the height of Mount Everest (Rebern).

(Size of UY Scuti compared to Sun)

UY Scuti, however, is simply the biggest star that we know about. It is very possible that another star exists that dwarfs even UY Scuti. Wrapping our head around the size of this hypothetical star would be even harder.

What’s going on under the surface of pluto? The New Horizons probe passed Pluto just last year, after a nine year journey to the Kuiper Belt. Over the last few months, images from the probe have been being received back here on Earth. These images are the most high quality photos of Pluto we have ever seen. In this article, Nasa explores why it appears that part of Pluto is “disappearing” in front of our own eyes. What’s going on?

Scientists think it is a process called sublimation, which means that parts of the surface is converting into gas. The surface of Pluto is rich in Methane, and scientists believe it is this Methane that is evaporating into the atmosphere of the dwarf planet. In the attached, image, one can see the cliffs and valleys that have been created as a result of sublimation.

Scientists have also detected a later of ice-like material under the rock bed of the planet. The surface is so cold, however, that it is immobile. More inferences will be made as more images are received from the New Horizons probe.

You can read the article here

The Guardian published an intriguing article today regarding climate change and the huge impact it is having on our planet. More specifically, the impact it is having near the North Pole. It describes the rising temperatures and rising sea levels and the impact that this has on people residing in this area. The scariest part? Those impacted aren’t foreigners: they’re Americans. “This winter, both January and February brought record low coverage of arctic sea ice” the article states.

The article tells the story of Mr. Wilson Andrew, a resident of Atmautluak Alaska, who’s house is close to being underwater as a result of rising sea levels. This winter has been particularly warm, in fact the warmest January and February on record.

As we learned in Chapter 10, climate change and global warming are a result of our human actions. We emit billions of tons of greenhouse gases into the atmosphere, and greenhouse gases hold hot air low in our atmosphere rather than letting it be released. Moreover, our actions have caused damage to the ozone layer, allowing more UV radiation to reach us here on earth. While the Ozone layer has been improving, global temperatures have still been rising at a significant rate.

The event horizon of a black hole is the point of no return. When an object gets close to this event horizon, extreme tidal forces from the black hole create a gravitational field that is so strong it begins to compress objects into long, thin shapes, like spaghetti. These are the same tidal forces we’ve discussed with the Moon, Earth and Sun. However, the difference in acceleration at the event horizon could be thousands of Earth gravities, so you would literally be pulled apart, or maybe you would just be infinitely stretched into a strand that never broke apart and could never be too thin? Who knows.

On August 5th, 2012, the Curiosity rover touched down on Mars. The most crucial part of its journey to Mars weren’t the 8 months travelling the space, but rather the final descent, called Entry Descent Landing  (EDL) which was dubbed ‘Seven Minutes of Terror‘. It’s called this because the rover had 7 minutes to get from the top of Mars’ atmosphere to the surface, and to go from 13,000 miles an hour to 0 miles an hour.

The first step in this descent begins about 45 minutes and 2,000 miles above Mars, with Curiosity being tucked inside the spacecraft’s aeroshell. As the rover enters the atmosphere at nearly 13,200 miles an hour, it is protected by the heat shield, which is facing the ground, and a backshell. Spanning 14.8 feet, this is the largest aeroshell used in a mission to Mars thus far. After a bit of hypersonic aero-maneuvering, whatever that is, a parachute measuring 51 feet across is deployed to help slow the shell down. The heat shield is then ejected to allow the computers and cameras on Curiosity to see the ground and guide the descent. Once closer to the surface, computers on the rover cut off the parachute and turn on rockets to slow the descent even more.If the whole unit got close to the ground with the rockets on, dust from the ground could hurt the rover, so Curiosity is lowered via a sky crane with a 21 foot tether. The rover is then gently placed on the ground, wheels down.

Source: Space.com

Though the power of the Sun is quite amazing, the Sun is simply a giant, burning ball of hydrogen. Due to the immense gravity of the Sun, hydrogen particles at the Sun’s core are under enough pressure that they collide with one another despite the force of the positive charges to repel one another. In this, hydrogen is converted to helium and energy is released, which powers the Sun.

Engineers are coming closer and closer to developing devices that can create sustained nuclear fusion reactions on Earth. The primary difficulty lies in making the hydrogen particles move fast enough in a confined enough space so that fusion can occur, since these conditions do not naturally exist anywhere on Earth. In the last month alone, we have taken huge strides toward making this a possibility. Scientists in China used their Experimental Advanced Superconducting Tokamak (EAST) to heat hydrogen plasma to nearly 50 million degrees celsius for 102 seconds.

(China’s EAST machine)

The benefits of using nuclear fusion as an energy source are profound. Nuclear fusion would provide nearly unlimited energy since it is fueled by hydrogen. Since hydrogen can easily be extracted from sea water, the earth’s oceans would essentially become Earth’s energy source. Furthermore, using nuclear fusion as our energy source would be great for the environment. The only by-product of nuclear fusion (besides energy) is helium, which is not harmful to the atmosphere and mostly escapes into space. Lastly, nuclear fusion is relatively safe and is fairly easy to control. On the other hand nuclear reactors can be radioactive for thousands of years after they are turned off. Nuclear fusion truly has the potential to be the energy source of the future.   

Knowledge is power. We want more and more of it. It’s no surprise, then, that we see the Solar System as a well full of knowledge we’ve never encountered before. So, we send spacecrafts out into the Solar System, looking for information. We want pictures, data, surprises, and (now) sound. We’re obsessed.

But we too often forget to give credit where credit is due. We wouldn’t be near as deep in our understanding of the Solar System if it were not for spacecrafts.

In the Solar System, spacecrafts face many challenges and have been tweaked so as to cross incredible distances, overcome the forces of gravity that try to suck them back down to Earth, and reap heaps of data about our spatial neighbors.

The “special forces” versions of spacecraft, so to speak, are landers and probes. These machines kick in the doors of obstacles on other planets and face excruciating conditions head-on. Perhaps the most famous examples of such machines are the Martian rovers, like Curiosity.

NASA’s Curiosity Mars Rover at Namib Dune (360 view)

According to our text (“The Cosmic Perspective”), Curiosity landed on Mars in August of 2012 and underwent an intense operation that allowed it to gently rest on the planet’s surface. The landing required a parachute, which served to slow the spacecraft down as it flew through the Martian atmosphere (about 350 km/hr). Rockets attached to the spacecraft then guided it toward the surface, where a “sky crane” placed the rover on the surface of Mars.

It is difficult to discern just how far the rover has trekked, since the Martian terrain is very loose in some areas and rovers could sometimes simply dig ruts in the ground as their “distance” travelled increases. However, this machine has overcome an atmosphere and climate that no human could penetrate without protection, and it has spent nearly three years on the red planet – time we humans would much rather spend interpreting data.

In essence, spacecrafts in the Solar System – whether they probe planets for organic compositions or take pictures of icy rings from a distance – are a major contributor to the information we have. Without them, our current knowledge of the Solar System (the knowledge we obsess over) might not be near as in depth as it is today. These mechanical heroes may not be what we’re looking for in the Solar System, but we certainly wouldn’t see much without them.

The above photo is a picture captured by NASA’s Hubble Space Telescope of what is now known as the “Pillars of Creation.” Located in the Eagle Nebula, which is around 6,500 – 7,000 light years away from Earth, the structures are named as such because of their pillar-like shape, as well as because the gas and dust in the picture are in the process of creating new stars. Looking at the photograph, it is easy to see why the pillars have become so iconic for its beauty.

For scientists, the pillars are useful because they provide new insights on the creation of a solar system. Astronomer  Jeff Hester says that the pillars “are actively being ablated away before our very eyes. The ghostly bluish haze around the dense edges of the pillars is material getting heated up and evaporating away into space. We have caught these pillars at a very unique and short-lived moment in their evolution.” The pillars were important because they were the first time that direct observational evidence of the erosionary process of a nebula was being seen.

Scientists have known how to use the process of nuclear fusion as a weapon for over 50 years at this point. However, we have yet to find a way to repurpose it as a safe, nearly unlimited energy source.

One of the main issues that researchers are facing with trying to tackle this issue is that that nuclear fusion requires an extremely high activation energy. As a weapon, this activation energy was provided by first detonating an ordinary fission bomb. It is easy to see how this process would not be ideal for creating clean fusion energy. Instead, scientists are now trying to heat nuclei using magnetic fields and lasers, neither of which has yet been able to provide the necessary temperature.

Another issue scientists face is creating a container out of materials that will be capable of withstanding assaults from the products of fusion reactions. First of all, the temperatures to kick off nuclear fusion are so hard that just finding a method of heating nuclei that could also survive high temperatures itself is already a challenge. Also, nuclear fusion releases some short-lived radioactive byproducts, and so the materials will need to be able to both extract heat effectively and survive battering from these particles at the same time.

There is much dispute over the use of nuclear energy today because of a public conception that nuclear power is a dangerous energy source. Although accidents are rare and nuclear power plants are pretty safe today, it is true that a serious accident could release massive amounts of radiation. However, rather than releasing radiation, the product of nuclear fusion is non-radioactive Helium and thus it does not share the same risk. It is for this reason that scientists are optimistic about using it as a power source in the future.