If you’re ever near the North or South Pole, you may be in for a very special treat. Frequently there are beautiful light shows in the sky. These lights are called auroras. If you’re near the North Pole, it is called an aurora borealis or northern lights. If you’re near the South Pole, it is called an aurora australis or the southern lights.This beautiful view of the aurora was taken from the International Space Station as it crossed over the southern Indian Ocean on September 17, 2011.
What makes this happen?Even though auroras are best seen at night, they are actually caused by the Sun.The Sun sends us more than heat and light; it sends lots of other energy and small particles our way. The protective magnetic field around Earth shields us from most of the energy and particles, and we don’t even notice them.But the Sun doesn't send the same amount of energy all the time. There is a constant streaming solar wind and there are also solar storms. During one kind of solar storm called a coronal mass ejection, the Sun burps out a huge bubble of electrified gas that can travel through space at high speeds.When a solar storm comes toward us, some of the energy and small particles can travel down the magnetic field lines at the north and south poles into Earth’s atmosphere.There, the particles interact with gases in our atmosphere resulting in beautiful displays of light in the sky. Oxygen gives off green and red light. Nitrogen glows blue and purple.The green bands of light in the sky are an aurora australis, an aurora at the south pole. Credit: Keith Vanderlinde, National Science Foundation

Do other planets get auroras?They sure do! Auroras are not just something that happen on Earth. If a planet has an atmosphere and magnetic field, they probably have auroras. We’ve seen amazing auroras on Jupiter and Saturn.These swirls of red light are an aurora on the south pole of Saturn. Image courtesy of NASA/ESA/STScI/A. Schaller.The NASA Hubble Space Telescope took this picture of an aurora on Jupiter using ultraviolet (UV) light.  (Tan Jit Hong ,3A1)

Aurora is a natural light phenomenon that usually forms at northern or southern which looks like greenish and purplish light in the sky. There are 2 types of aurora, aurora borealis which is formed at northern hemisphere while aurora australis is formed at southern hemisphere. They are formed when charged particles from solar flares or coronal mass ejections from the sun which cause solar wind collides with Earth’s atmosphere which cause electrons in atoms to move to a high-energy state. After electrons become a lower-energy state, they release light which is known as photon. When many of this reaction occurs, an aurora is formed as the electrons releases a lot of photon. If a solar wind is too strong, it may cause aurora to form around the world and it may blow out electric devices as the magnetic field is too strong.  (Mak Wei Han 3A1)

The resulting ionization and excitation of atmospheric constituents emit light of varying color, which includes green, red, blue and many more. The form of the aurora, occurring within bands around both polar regions, is also dependent on the amount of acceleration imparted to the precipitating particles. Precipitating protons generally produce optical emissions as incident hydrogen atoms after gaining electrons from the atmosphere. Proton auroras are usually observed at lower latitudes. Eunice, 3A1

Auroras are one of the effects caused by the Sun’s activities towards the Earth. The Sun, which is made up of hot gases and full of charged particles, will constantly release ions( charged particles) from it’s surface. These charged particles will then travel together at a high speed to the outer space (also known  as solar wind). When solar wind reaches the Earth, it will be blocked by the Earth’s magnetic fields. Interactions between magnetic fields brought by Solar Winds and Earth’s magnetic fields form Earth’s Magnetosphere(a natural’shield’ to protect earth from erosion of atmosphere by solar winds). Although most of the solar winds are blocked by the Earth’s Magnetosphere, some of the ions bought by solar winds will still enter through the poles of the Earth. The ions will then collide with particles in the Earth’s atmosphere and result in lots of bursts of lights. Different types of particles will also result in different colours of lights formed, for example, oxygen for aurora’s green and red colour while hydrogen results in the colour deep red or blue. These colours will eventually be seen across the night sky of places around the Earth’s poles.  

Most auroras happens because of solar wind, but other Sun’s activities such as coronal mass ejections and solar flares will also react with the Earth’s atoms and molecules in the atmoshere to produce auroras. Furthermore ,brighter auroras are also more visible during the height of Sun’s activity.

Although auroras are only seen during the night, it happens during the day too. Auroras in the day are less visible because of sunlight. Besides that, if the sky is cloudy and the moon is out(specifically during full moon) it will also make it hard to view these beautiful lights at night! 

-Faith Hii 3A1-

An aurora or aurorae are sometimes referred to polar lights, northern lights or southern lights, is a stream of colorful light resulting from reaction between charged particles, Earth’s magnetic field and atmospheric gases which occurs in the thermosphere. It is normally seen in high latitude regions because it is blown by the solar wind, the charged particles are largely deflected by the Earth's magnetic field. They are known as 'Aurora Borealis' in the North and 'Aurora Australis' in the South. Auroral displays appear in many colours but the most common colours are pale green and pink. Actually, shades of red, yellow, green, blue, and violet have been seen too. The lights appear in many forms from patches or scattered clouds of light to streamers, arcs, rippling curtains or shooting rays that light up the sky with an eerie glow. Most auroras occur in a band known as the ‘auroral zone’, most clearly seen at night against a dark sky. A region that currently displays an aurora is called the "auroral oval", a band displaced by the solar wind towards the night side of the Earth. Researchers have also discovered that auroral activity is cyclic, peaking roughly every 11 years. The next peak period is 2024. Generally winter in the north is a good season to view these lights. The long periods of darkness and the frequency of clear nights provide many good opportunities to watch the auroral displays. Usually the best time of night (on clear nights) to watch for auroral displays is local midnight. 

Jaclyn 3A1

Green, the predominant colour seen, is emitted by solar electrons interacting with molecular oxygen lower in the atmosphere. Blue light however is emitted by molecular nitrogen in the lower or mid atmosphere. Purple is emitted when electron interact with atomic nitrogen in the upper atmosphere while red, rarely seen, is emitted when electron interact with atomic oxygen also in the upper atmosphere.

The particular pattern of the aurora is a product of Earth’s magnetic field, which guides the electrons along with the North or South magnetic field lines towards the Earth’s North and South magnetic poles. Although the shapes and patterns are constantly changing, the particular shapes and patterns seen any one time are almost identical in the North and South hemisphere. This phenomena are known as conjoint auroras. 

-Tanyuzhen 3A1-

-Khoo Jia Yi 3A1

A lot of times, we tend to wonder how these lights are actually formed. Well, it all begins from the Sun. The Sun, though we may not notice it, is constantly sending things our way, not just heat and light, but a lot of other energies and small particles as well. Normally, our Earth's magnetosphere protects the Earth from these particles from the Sun and other bodies in the vast emptiness of space. However, there are times when occurrences known as coronal mass ejections (CMEs) happen on the Sun which dishes out a huge amount of particles at once. These particles travel at significantly high speeds and Earth's magnetosphere can't fend off all of them. Therefore, some of these particles travel down magnetic field lines at the North and South Pole into Earth's atmosphere where they interact with natural gases to form these wonderful displays of light, aurorae. 

*Interaction of these particles with oxygen results in red and green coloured lights; whereas interaction with nitrogen results in red and purple lights.

As if things weren't amazing enough yet, Earth isn't alone when it comes to these spectacular displays of light. Other planets in our solar system such as Saturn and Jupiter have been reported to experience beautiful sights of aurorae as well!

- Matthew Poh 3A1 -

Auroras are seen in latitudes of around 70 degrees. They generally occur in a band known as ‘auroral zone’ which is 3 to 6 degrees wide in latitude and it lies between 10 and 20 degrees from the geomagnetic poles. This is visible quite clearly during the night. Auroras can sometimes be seen at latitudes below the actual auroral zone. Auroras can appear in various forms like streamers, patches, arcs, scattered light and diffused light. 

An aurora is caused by the streams of electrified particles which are emitted by the Sun trapped in the magnetic field of the earth. It is produced when this magnetosphere is disturbed by the solar wind. These disturbances are sometimes strong enough to alter the trajectories of charged particles in both solar wind and magnetospheric plasma. These particles are mainly electrons and protons which precipitate into the upper atmosphere such as the thermosphere or the exosphere.

The resulting ionization and excitation of atmospheric constituents emit light of varying color and complexity. The form of the aurora, occurring within bands around both polar regions, is also dependent on the amount of acceleration imparted to the precipitating particles. Precipitating protons generally produce optical emissions as incident hydrogen atoms after gaining electrons from the atmosphere. Proton auroras are usually observed at lower latitudes. 

- Ng Zhi Yee 3A1

An aurora, also known as the northern lights, is a beautiful and natural light display in the Earth’s sky. It is often seen in the North Pole and South Pole, which are high-latitude regions. The regions that currently displays an aurora is called the “aurora oval”.

Although auroras are most clearly seen at night against the dark sky, they are actually caused by the Sun. The large amount of charged gas particles erupting from the sun, also known as a solar flare, often collides with atoms and molecules in Earth’s atmosphere. This collision produces auroras. 

A coronal mass ejection is a huge cloud of plasma that erupts from the Sun. It spouts magnetic gas particles at high speed into outer space that also reacts with atoms and molecules in Earth’s atmosphere to produce auroras.

Earth’s magnetosphere acts as a biological shield to block of charged gas particles erupted from the Sun. However, some of the energy and small charged gas particles can travel down the magnetic field lines at the north and south poles into Earth’s atmosphere, thus colliding with the atoms and molecules of the atmosphere. 

The auroras often appear as curtains of lights, they can also be arcs or spirals depending on the lines of force in Earth’s magnetic field. Different colours of an aurora are produced when the charged particles collide with different gases in the atmosphere. For example, oxygen gives off green colour while nitrogen causes blue or red colours of the aurora.

Then, what causes the aurora to happen? Unsurprisingly it is the sun who creates the aurora.  The sun with superhot gases that made up of ions which are released from the sun’s surface are so called the solar wind. Our Earth has a special protection , which is the magnetosphere , who helps preventing the solar wind particles to enter the atmosphere. But unfortunately , there are still some stubborn ions partly trapped and successfully enter the Earth. This results in the collision of ions with Earth’s atmosphere atoms. Therefore , this interaction created beautiful lights display in the sky. 

The colours of the aurora depends on the types of atoms plus different altitude involved in the collision . Like : 

-          collide with oxygen = red , yellow , green

collide with nitrogen = blue , purple

-          the green lights typically in areas appear up to 150 miles (241 km) high, red above 150 miles; blue usually appears at up to 60 miles (96.5 km); and purple and violet above 60 miles.

Auroras occur when high energy particles from the sun collide with neutral atoms in our atmosphere. The energy emitted from this crash produces a spectacle of light .The protons and electrons creating the auroras depart from the Sun’s corona. The corona is the outermost layer of the Sun’s atmosphere and is one of the hottest regions. Its intense heat causes the Sun’s hydrogen and helium atoms to vibrate and shake off the protons and electrons. These free protons and electrons move too fast to be contained by the Sun’s gravity and group together as plasma. They travelled away from the Sun as a constant gale of plasma known as the Solar wind. 

However, the Earth prevents the solar wind from travelling straight into the planet by setting up a detour which is the magnetosphere. The magnetosphere is formed by the Earth’s magnectic currents and shield our planet from the solar winds by sending out the particles around the Earth This event is known as Corana Mass Ejection (CME). CME occurs when the Sun shoots out a massive ball of plasma into the solar wind. When one of these CME collides with Earth, it overpowers the magnetosphere and creates a magnectic storm. 

The Sun’s particles finally produce their dazzling light after travelling 93 million miles across the galaxy There, the particles interact with gases in our atmosphere resulting in beautiful displays of light in the sky. Oxygen gives off green and red light.while Nitrogen glows blue and purple.

-Tan Zhyi Phei 3A1-

Auroras are visible almost every night near the Arctic and Antarctic Circles, which are about 66.5 degrees north and south of the Equator. In the north, the display is called aurora borealis, or northern lights. In the south, it is called Aurora Australis, or Southern Lights (see figure).

Aurora displays are created when protons and electrons stream out from the solar surface and slam into the Earth's magnetic field. Since the particles are charged they move in spirals along the magnetic field lines, the protons in one direction and the electrons in the other. Those particles in turn hit the atmosphere. Since they follow the magnetic field lines, most of them enter the atmospheric gases in a ring around the magnetic poles, where the magnetic field lines come together.

The air is made up largely of nitrogen and oxygen atoms, with oxygen becoming a bigger component at the altitudes auroras happen – starting about 60 miles up and going all the way up to 600 miles. When the charged particles hit them, they gain energy. Eventually they relax, giving up the energy and releasing photons of specific wavelengths. Oxygen atoms emit green and sometimes red light, while nitrogen is more orange or red.

-  Khor Kin Soon 3A1 -

The Southern Lights or Aurora Australis

Aurora is sometimes referred to as ‘polar light’. It is predominantly seen in the regions of high altitudes like the Arctic and Antarctic. An aurora is caused by the streams of electrified particles which are emitted by the sun trapped in the magnetic field of the earth. It is produced when this magnetosphere is disturbed by the solar wind carrying the charged particles. Auroras are seen in latitudes of around 70 degrees. They generally occur in a band known as ‘auroral zone’. The auroral zone is 3 to 6 degrees wide in latitude. It lies between 10 and 20 degrees from the geomagnetic poles. This is visible quite clearly during the night. Auroras can sometimes be seen at latitudes below the actual auroral zone. Auroras can appear in various forms like streamers, patches, arcs, scattered light, diffused light etc. The brightest and the most distinctive of all forms of auroras are the ones which are curtain-like in the shape of an arc, extending in the east-west direction. This natural light effect is known as ‘aurora borealis’ in northern altitudes, while the effect in the southern latitudes is known as ‘aurora australis’. Auroras that occur in Northern hemisphere are known as aurora borealis and auroras that take place in Southern hemisphere are known as aurora australis. Aurora borealis is also known as ‘Northern lights. Similarly, aurora australis is also known as ‘Southern lights.

 

-Loo Chee Yang- 3A1

What causes the colour? The colours most often associated with the aurora borealis are pink, green, yellow, blue, violet, and occasionally orange and white. Typically, when the particles collide with oxygen, yellow and green are produced. Interactions with nitrogen produce red, violet, and occasionally blue colours.

 -Wong Jia Hui 3A1-