Aurora facts for kids
An aurora, also called polar light, northern light or southern light, is a natural light display in the sky. They are usually seen in the high latitudes (Arctic and Antarctic) regions. Auroras are produced when the Earth's magnetosphere is disturbed by the solar wind.
An aurora around the North Pole is called the Aurora borealis or 'northern lights'. Around the South Pole it is the Aurora australis or 'dawn of the south' or 'southern lights'. It can be seen from long distances, stretching in the sky many hundreds of miles far.
Auroras can happen at any time, however they can only be seen at night because their light is not as strong as the light of day. Faint stars can even be seen through the aurora.
Many legends are associated with the aurora in all countries where this phenomenon regularly occurs.
Contents
Etymology
The term aurora borealis was coined by Galileo in 1619, from the Roman Aurora, goddess of the dawn and the Greek name for the north wind (Boreas).
The word aurora is derived from the name of the Roman goddess of the dawn, Aurora, who travelled from east to west announcing the coming of the sun.
The words borealis and australis are derived from the names of the ancient gods of the north wind (Boreas) and the south wind (Auster) in Greek mythology.
What are auroras?
Imagine the sun as a giant, powerful lightbulb. It doesn't just give us light and warmth; it also sends out tiny particles called solar wind. This solar wind is made up of electrons and protons, which are tiny bits of matter that zoom through space.
When the solar wind reaches Earth, most of it is deflected away by Earth's magnetic field, which acts like an invisible shield protecting our planet. However, some of these particles get trapped by the magnetic field and are guided towards the Earth's poles – the North Pole and the South Pole.
As these particles zoom towards the poles, they collide with gases in Earth's atmosphere, like oxygen and nitrogen. These collisions are like tiny bumper cars crashing into each other! When these collisions happen, they release energy in the form of light. This light is what we see as the aurora!
Why are auroras different colors?
The colors of the aurora depend on which gas particles are being hit and how high up in the atmosphere the collisions occur.
- Green: This is the most common color of the aurora. It's produced when solar wind particles collide with oxygen at lower altitudes (around 60 miles high).
- Red: Red auroras are produced when solar wind particles collide with oxygen at higher altitudes (above 200 miles high).
- Blue and Purple: These colors are produced when solar wind particles collide with nitrogen.
When is the best time to see the aurora?
The best time to see the aurora is during the winter months (from September to April in the Northern Hemisphere and from March to September in the Southern Hemisphere). This is because the nights are longer and darker, making it easier to see the faint light of the aurora.
You also need a clear, dark sky away from city lights. Light pollution from cities can make it difficult to see the aurora.
Another important factor is solar activity. The more solar activity there is, the more likely you are to see a bright and active aurora. Scientists can predict solar activity, so you can check the aurora forecast before you go aurora hunting!
Occurrence
Most auroras occur in a band known as the "auroral zone", which is typically 3° to 6° (approximately 330–660 km) wide in latitude and between 10° and 20° from the geomagnetic poles at all local times (or longitudes), 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 Earth.
In northern latitudes, the effect is known as the aurora borealis or the northern lights. The southern counterpart, the aurora australis or the southern lights, has features almost identical to the aurora borealis and changes simultaneously with changes in the northern auroral zone. The aurora australis is visible from high southern latitudes in Antarctica, Chile, Argentina, South Africa, New Zealand and Australia. The aurora borealis is visible from areas around the Arctic such as Alaska, the Canadian Territories, Iceland, Greenland, Norway, Sweden, Finland, Scotland, and Siberia. On rare occasions the aurora borealis can be seen as far south as the Mediterranean and the southern states of the US.
Fun facts about the aurora
- Auroras can appear in many different shapes, including arcs, bands, curtains, and rays.
- Sometimes, auroras can even make sounds! People have reported hearing crackling, hissing, or popping noises during intense auroral displays. However, these sounds are still a mystery to scientists.
- The strongest aurora ever recorded was during the Carrington Event in 1859. This event was caused by a massive solar flare, and the aurora was seen as far south as Cuba and Hawaii!
- Other planets in our solar system, like Jupiter and Saturn, also have auroras!
- You can even see auroras from space! Astronauts on the International Space Station have captured stunning images of the aurora from above.
Images for kids
-
Aurora australis seen from the ISS, 2017.
-
Different forms
-
Construction of a keogram from one night's recording by an all-sky camera, 6/7 September 2021. Keograms are commonly used to visualize changes in aurorae over time.
-
The Aboriginal Australians associated auroras (which are mainly low on the horizon and predominantly red) with fire.
-
Church's 1865 painting Aurora Borealis
See also
In Spanish: Aurora polar para niños
