A time lapse video showing the spectacular lights in Norway;)

Aurora Borealis

Everyone has heard about the stunning Northern Lights, otherwise known as the Aurora Borealis. But what are they? and what causes this incredible display? There was a time this spectacular light show was believed to be some sort of sign from God or even a vast fire surrounding the ocean.  As other worldly as the lights may seem they are simply caused by charged particles smashing into the Earth's atmosphere.

The Earth acts as a giant magnet, and as such it produces magnetic field lines that encompass the whole planet. They help deflect any
charged particles caused by solar flares. Every so often the Sun's magnetic field lines get tangled up to such an extent that they suddenly "snap" and huge amounts of energy and charged particles are released. Of course, this wouldn't be a problem, except for the fact that they pose a great threat to Earth. Luckily, we may rest at ease because our planet provides a shield that prevents them from reaching Earth's surface.



The Earth's magnetic field lines are nonuniform so any charged particles heading our way get trapped, and spiral about the field, oscillating between the end points. These particles spiral from pole to pole in a matter of seconds. Most particles originate from the sun, but some come from other celestial objects. When they get close enough to the poles they collide with atoms in the atmosphere causing them to emit visible light. This causes the Aurora Borealis, visible in the north pole, and the Aurora Australis, visible in the south pole.

They vary in color depending on the excitation, and ionization of the atoms of Earth's upper atmosphere brought on by collisions with solar winds. The atmosphere is made up of oxygen, and nitrogen that when excited emit a photon of light. For instance, when an oxygen atom collides with a rapidly accelerating charged particle it absorbs energy, and then releases it by emission of a photon. Usually, oxygen emits green light because it takes three quarters of a second to emit. It can also emit red light, but this is uncommon as it takes about two minutes for oxygen to return to its ground state, and by that time the energy gained might be lost to  collisions with other molecules. Nitrogen, on the other hand, is known to emit blue or red light depending on whether it regains an electron after being ionized or whether it returns to ground state after being excited. There is also a color difference with altitude. In higher regions of the atmosphere there exists a greater amount of oxygen where red emission prevails, followed by oxygen green and nitrogen blue.


Usually the Auroras are confined to polar regions because that's where the charged particles get closer to the Earth's surface. Once in a while, Earth's magnetic field lines are distorted considerably due to a large number of charged particles entering the Van Allen Belts (belts of charged particles). As a result, the Auroras are visible in lower latitudes. Although they put on a good show for people in these low latitudes, they can cause power blackouts like the one in Canada in 1989.




So next time you find yourself visiting any of the poles keep a look out for these lights, and you might just be amazed!



*As a good side note: Auroras can also occur on other planets as long as it has a dense atmosphere.*

black hole

I have always been fascinated by black holes, and the fact that little is known about them only heightens my interest. These enigmatic celestial objects rest among the stars, and at the center of galaxies. They can only be detected by the effects they have on their neighbors. No one really knows what goes on inside them although there are many speculations suggesting they serve as a type of portal into another point in space. It's all in the theoretical stage, but it doesn't make it any less intriguing!




While thinking of topics to discuss I came across what I consider to be a great question: what would it be like to "fall" into a black hole?  It can't be tested out, as of yet, but with the help of physics, and logic the effects it would have on a human body can be deduced.  

AN AWESOME EXPLANATION

Lets say, for instance, that a couple of twins decide to take a suicidal trip to a black hole. One of them, the boy (obviously), is crazy enough to venture outside the space craft, and across the event horizon where the escape velocity is equal to the speed of light. After this point he can pretty much kiss his sister good bye. 

The female twin, whom I will call Deborah, had enough sense to watch from some distance far enough away that the black hole's gravity field is approximately zero. As her brother, Eric, nears the black hole they will encounter a relativistic  phenomenon called time dilation. This simply means that, as he is pulled by the black hole's strong gravitational field, a time interval that Eric  measures as one second will appear longer to Deborah. Also, the light bouncing off her brother's body will be redshifted. That is to say, the light will drop in frequency due to the black hole's strong gravitational field. Now, if you combine these two effects, the time interval Eric measured as being one second will seem longer and longer to Deborah. In short, Deborah will see Eric approach the event horizon ever more slowly until he appears to freeze just outside of it. After this point, not even light can escape so technically speaking Deborah won't get to see Eric cross the event horizon. By this time the light from Eric's body will be red shifted out of the visible light spectrum before reaching the event horizon. So to Deborah it would have seemed that Eric just "faded out" of existence. 

It is important to note that since time dilation, and gravitational redshift are RELATIVE, what Eric experiences in his reference frame greatly differs from what Deborah experiences in hers. From his perspective it appear's his sister's clock has sped up. In addition from Eric's point of view he doesn't "freeze" at the event  horizon, he goes in at a great speed until enormous tidal forces, due to the curvature of spacetime, tear him apart.

*A note to all: this is meant to be a simplified explanation of what could happen in such an event. There is a lot of rigorous mathematics and a whole lot of physics that go into this:)* 

Just something I thought would be interesting...

   Astronomers Today

I always had the romantic idea that astronomers still sat outside in the dark, sometimes in the comfort of their own home, and pointed their telescope up at the night time sky while meticulously taking note of any changes. However, I soon found out that this is still true to an extent, but now they use much larger telescopes located in the middle of nowhere, and instead of looking through the eyepiece of the telescope they sit in front of a computer screen collecting data. In short, the advances in technology has made it so astronomers can gather information more accurately, and more efficiently. Even though I would have liked to experience the romantic side of astronomy, now called amateur astronomy, I think that the new improvements have opened up a whole new world to scientists. More discoveries have been made now than ever before, and we now possess quantitative knowledge about the cosmos.

           Furthermore, astronomers today can now retell the the history of the universe with the help of telescopes both on land and on orbit something that was unimaginable during the time of great minds like Galileo, and Copernicus. With these instruments they have taken magnificent images of distant stars and galaxies whose light has taken millions of years to reach Earth. Thus, astronomers are in a way space explorers that work hard to unveil the secrets of the universe. These modern day adventurers pave the way to far away worlds, and celestial objects that reveal a little bit more about our beginning and what could be our demise.