Auroras or the Northern Lights
How do auroras come to be in our night skies? And do auroras even happen on the other planets in our universe?
First, if a planet or moon has an atmosphere and is bombarded by energetic particles, it will have an aurora. Jupiter and Saturn have auroras much like ours in the shape of oval shaped crowns of light on both poles. The magnetic field around the planet or moon shapes the auroras and where they show up. On the planet Neptune, the magnetic field of a planet is not aligned with the rotational axis so the lights show up near the equator.
Aurora on the planet Saturn
Now for that other question -How do auroras appear in the night skies? I am going to explain this moving first from our skies to the space around our sun..
The colorful, rapidly varying glow is cause by the collision of charged particles in the magnetosphere with the atoms in the Earth's upper atmosphere. There's always some aurora at some place on Earth, most often seen at high latitudes and enhanced during the geomagnetic storms created by the CME. The "enhancement" can cause the big light show events of the auroras. A light show so big that in 1958, Mexico saw the lights in the Northern sky. This big event happens when a CME (coronal mass ejection) hits the Earth's magnetic field and much like a light dimmer switch, turns the glow to the high setting.
A coronal mass ejection (CME) is a massive burst of solar wind and magnetic fields rising above the solar corona or being released into space by a solar flare.
A solar flare is an explosion on the Sun that happens when energy stored in twisted magnetic fields (usually above sunspots) is suddenly released. Flares produce a burst of radiation across the electromagnetic spectrum, from radio waves to x-rays and gamma-rays.
Scientists classify solar flares according to their x-ray brightness in the wavelength range 1 to 8 Angstroms. There are 3 categories: X-class flares are big; they are major events that can trigger planet-wide radio blackouts and long-lasting radiation storms. M-class flares are medium-sized; they can cause brief radio blackouts that affect Earth's polar regions. Minor radiation storms sometimes follow an M-class flare. Compared to X- and M-class events, C-class flares are small with few noticeable consequences here on Earth.
When a coronal mass ejection (CME) from X- and M- class flare is expected to crash into Earth's magnetic field, the auroras will grow in the night skies at both ends of our earth. The below maps show the CURRENT locations where the ring of the action or the extent and position of the auroral oval at each pole
If one is standing in under the light blue shade around the yellow/red rings, you would see some of the "Northern Lights" along the edge of the night sky over you. So if you are under the ring of the yellow and red, you will be in the best place to view the action.
Our sun runs in something like eleven year cycles of solar activity of when we will see flares ejected from the Sun. The activity can happen at any time but the solar flares are more common at the peak and for about three years after this peak. Currently this year, 2012, we are just now heading into the peak time. Therefore the action or radiation storm of July 14 and 15 might just be a start of some fun time watching the night skies.
Will I be able to see this? Do I live too far south in the USA?
During very large auroral events, the aurora may be seen throughout the US and Europe, but these events are rare. During an extreme event in 1958, aurora was reported to be seen from Mexico City. During average activity levels, auroral displays will be overhead at high northern or southern latitudes. Places like Fairbanks, Alaska, Dawson City, Yukon, Yellowknife, NWT, Gillam, Manitoba, the southern tip of Greenland, Reykjavik, Iceland, Tromso, Norway, and the northern coast of Siberia have a good chance to have the aurora overhead. In North Dakota, Michigan, Quebec, and central Scandinavia, you might be able to see aurora on the northern horizon when activity picks up a little. On the southern hemisphere the aurora has to be fairly active before it can be seen from places other than Antarctica.
HOWEVER, the event of July 14 and 15 was a good one with folks in Ozark, AR, USA catching some of the show. This gives me hope that I might see one from Mississippi.
Brian Emfinger shared this information and his photos:
There was a very faint red glow off and on most of the night but around 2am CDT it began increasing. Around 3am and 330am there were pretty good outburst. The red was naked eye visible at times after 2am but the outburst that included some tall columns was much more visible with the naked eye. Canon T2i
Pretty cool Brian Emfinger and thank you for sharing your photos online. I believe the white light to the far left was from a nearby town. Too bad most of us live where we have little truly dark skies.
The Earth's magnetic field is still reverberating from the CME strike of July 14th. The web site, spaceweather.com reported," This morning, July 17th, at 1:00 am CDT, Shawn Malone witnessed one of the aftershocks over Lake Superior:
"My dog hates lightning and awoke me at 1am," says Malone. "I caught a double light show: an isolated thunderstorm moving across Lake Superior plus the bright glow of the Northern Lights above the clouds, awesome!"
Now finally from Chris Ratzlaff, shared on Flickr - Aurora, planetary alignment and noctilucent clouds in one shot!
Truly a special time and what a wonderful catch! I will be on the lookout for more special photos.
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UpDate! INCOMING CME, WEAK IMPACT EXPECTED: A coronal mass ejection (CME) produced by Saturday's M6-class flare is heading toward Earth. According to analysts at the Goddard Space Weather Lab, the cloud could deliver a glancing blow to our planet's magnetic field on July 31st around 1500 UT (+/- 7 hours).
This is a slow-moving CME. The cloud's low speed (382 km/s estimated) combined with its glancing trajectory suggests a weak impact is in the offing. Nevertheless, polar geomagnetic storms are possible when the cloud arrives.
The CME will also hit Mercury, probably with greater force. Mercury's planetary magnetic field is only ~10% as strong as Earth's, so Mercury is not well protected from CMEs. When the clouds hit, they can actually scour atoms off Mercury's surface, adding material to Mercury's super-thin atmosphere and comet-like tail.