by CRYSTAL ROSENE

This month’s subject is a bit closer to Earth than those of the previous articles, but I felt it was relevant. As you may have heard, this fall has been spectacular for displaying some breathtaking shows courtesy of the Aurora Borealis, or Northern Lights. So I thought this would be a good opportunity to illuminate (excuse the pun!) the inner workings of the Aurora Borealis.

A crucial part of learning how the Northern Lights work is to understand Earth’s magnetic field. A magnetic field is generated by moving electric charges; the liquid layer of the Earth’s core consists of flowing molten iron, which creates electric currents. This is the source of the moving charges that generate the Earth’s magnetic field.

Next is the interaction of the Earth’s magnetic field with protons and electrons ejected from the Sun. This stream of charged particles is known as a solar wind that moves radially outwards from the source.

The Earth’s magnetic field protects us from this stream of particles, the velocity of which is extremely high – almost a million miles per hour! The moment the particles hit the Earth’s magnetic field, they experience a shock wave, where they are drastically slowed down. Next, these particles reach the Earth’s magnetopause (essentially a boundary at which the outwards pressure of the magnetic field is exactly balanced by the inward pressure of the incoming particles). This encounter with the magnetopause is what deflects most of the charged particles that are streaming towards Earth.

However, not all of the particles from the solar wind are deflected which is essentially what creates the lights. Occasionally, some of the particles may sneak through the magnetopause and enter the Earth’s atmosphere.

The atmosphere consists of several elements, including oxygen and nitrogen which are found in the greatest abundance. When the charged particles that have snuck through the magnetic field reach the atmosphere, they may collide with the oxygen or nitrogen which is responsible for the brilliant lights that we see.

The collisions give energy to atoms that they encounter, thus ‘exciting’ them to higher energy levels. As they lose energy in returning to their ground state, the atoms give off a photon  as visible light. These are the Northern Lights that we see.

The colour of the lights depends on the type of collision. In general, when the charged particles collide with oxygen, we see green or yellow lights, while a collision with nitrogen is usually responsible for the reds and purples. It also depends on whether the collision occurs with an atom or a molecule: atomic nitrogen gives the rarer blue colours, whereas the purples and reds tend to come from molecular nitrogen.

So if you find yourself outside on a clear night in the upcoming weeks, be sure to look north, for a chance to experience the splendour for yourself!

An Inside Look Into the Costa Rica Field Course 

by YU FEI HUANG & SAMMY LOWE

Interested in learning all about tropical ecology? What if I told you Augustana offers a chance for you to do research in Costa Rica? We interviewed fourth-year biology student, Evan Whitfield, about his experience of the program. It consists of two courses, AUBIO 350 (Conservation Theory and Biodiversity in Tropical Systems) and AUBIO 459 (Field Studies in Tropical Ecology and Conservation). Students are required to take these courses in consecutive semesters.

The program allows students to research about bats, bugs or plants, depending on individual interests. The first class, AUBIO 350, teaches the process of making experimental design, including research relevant background information and writing a research proposal. The second class, AUBIO 459, allows you the chance to turn your learning into actions by conducting research over a period of 13 days in Costa Rica. The fun part of the course is “cross-pollination”, which means everyone has to help out with each other’s projects for a greater breadth of experience.

Evan’s project was done on how vegetation affected bats distribution. He sampled his experiment subject from 6 pm to 10 pm approximately. Every student had different daily schedules for observation; students with plants as subject sample throughout the day while the ones studying bugs had to sample both day and night! They spent a total of 9 days sampling in Costa Rica, using their research station as a home base.

The research station situated in Osa Peninsula, was around 30-35 °C when they went during February. For those of you who rely heavily on technologies, there is wifi available in the research station. The station is equipped with a main kitchen, research shed and sleeping area with bug nets.

While you are in Costa Rica, you get to tour a little bit, too! Evan and his group members spent their first night in San Jose, touring Osa peninsula, waterfall gardens and volcanoes. Evan particularly enjoyed seeing the cultural difference in Costa Rica. The richness of the culture even fueled his desire to learn new languages.

As Augustana is progressing towards the new academic schedule, Evan said it would be challenging, yet interesting to see how the program will pan out. He estimates that the traveling part of the program will take place in the 3-week semester. If so, there will be more time to plan for the trip without distractions from other courses. However, he also argues that the shortened period of time could hinders students’ ability to evaluate and reflect on the experience.

This program is about teaching you how to design, undertake and present a research project. You get the chance to present at SAC, the student academic conference, and show off your wonderful findings. More importantly, the different learning experience allows the exploration of a new city and cultural diversity. And hey, you can even enjoy the tropical warmth for two weeks while your friends are complaining about the cold winter in Canada.  

Image courtesy of Evan Whitfield. 

 

by CRYSTAL ROSENE

It is a massive undertaking to explain black holes correctly, especially in five hundred words! There is no denying that this is one aspect of the cosmos that nearly everyone is somewhat familiar with, even if it’s only due to science fiction. Because black holes are so complex, they become an easy subject from which urban myths spawn. So, consider this article a myth de-bunker for black holes!

 

• Myth: Black holes are wormholes.

 

The gravitational effects of black holes sharply curve the fabric of spacetime around them, much like a bowling ball depresses a foam mattress. However, the ‘well’ created by a black hole is infinitely deep, which causes many to think that a black hole could curve around spacetime and lead you to another part of our universe. This is the idea of a wormhole, but sadly, it is just a myth. The intense gravity of black holes wouldn’t allow for wormholes to exist, as they would collapse the instant they form. The only way to travel through a wormhole successfully would be to travel faster than the speed of light, which is not possible.

 

• Myth: Black holes roam around space sucking up everything in their paths.

 

When most people think of black holes, this is what they picture: some massive vacuum cleaner of doom that sucks up everything around it, and someday Earth will ultimately succumb to this unfortunate end. Wrong. While black holes have immense gravity, they operate in much the same way as regular stars, at least from a distance. Across the event horizon, however, the gravity is so strong that you would need to travel faster than the speed of light to escape, which is impossible. But if a body is far enough away, it would simply orbit the black hole, much as it would another star.

 

• Myth: You can see a black hole.

 

Black holes are aptly named, as they are objects in space from which light cannot escape. As an extremely massive dying star compresses, Einstein’s general relativity predicts that the space surrounding the star will curve so much, it will just fold back in on itself. This means that if a photon is travelling outwards from the black hole, it cannot leave; instead, it will end up in orbit. Therefore, nothing can escape as nothing travels faster than light.

 

• Myth: Our sun will turn into a black hole.

 

It’s true that black holes are formed from dying stars. But, only select stars have the necessary characteristics for this to happen. Most massive stars end up as white dwarfs, and some that are even more massive may become neutron stars. But occasionally, stars that are larger could be too massive to remain stable as neutron stars, and may then become black holes. But this only occurs in stars about 2 to 3 times the mass of our sun, so we have nothing to worry about.

by CRYSTAL ROSENE

The universe is expanding. In fact, this was first determined 87 years ago by the famous astronomer, Edwin Hubble. Hubble proposed that the speed at which an object is receding is proportional to its distance from Earth with the formula v = Hod. Astronomers began to piece together the evolution of our universe from the time of the Big Bang and thought they were close to understanding where the universe is ultimately going as well.

Since the Big Bang was essentially a giant explosion, it made sense to assume it followed a standard model of any explosion: that at some point, the total energy of the pieces would dissipate, and thus, come to a stop.

However, astronomers began to note some really weird things happening the farther away they observed. Hubble’s Law predicted that extremely distant objects would recede faster than closer objects, and the evidence concluded that this is the case –albeit much faster than expected. In other words, the universe isn’t just expanding, it’s accelerating!

Now of course, the natural question is why? Why is the universe not slowing down, as predicted? And what could possibly account for this strange result?

It appears that there is some unknown force at work here, some anti-gravity that pushes everything perpetually outwards instead of pulling it in. In order to have such immense effects on something as large as our entire universe…well there must be an awful lot of this strange entity.

Everything that exists in our universe from radiation to matter (also including dark matter!) is only responsible for 20 – 40% of the density of the universe! The rest must therefore be this unknown force that is so plentiful. To make it even more interesting, it is also something that cannot be detected (yet). This mysterious entity that accounts for the remaining density of the universe is what astronomers have labelled ‘dark energy’.

The elusiveness of dark energy stems from its apparent nature. If it were a form of radiation, astronomers could use detectors aboard orbiting satellites to pick up traces of its existence, but so far this has not been the case. Similarly, dark energy seemingly has no identifiable gravitational effects that can be detected. (This is a method used to detect dark matter.)

Whether we can detect it or not, the data shows that dark energy definitely exists. If anything, it could be said that dark energy is more prominent now than it was in the past. As the universe expands, the density of matter and radiation both decrease, but the density of dark matter has stayed the same. This means that we live in what is called a ‘dark energy dominated universe’.

It’s interesting to think that despite all we know, the majority of the universe remains a mystery to us. But I imagine it won’t be long before new evidence emerges for understanding dark energy and its role in the universe.