Aurora possible Friday night across Canada
Meteorologist/Science Writer
Friday, October 14, 2016, 12:22 PM - There may still be a chance to see auroras, Friday night, due to the lasting effects of Thursday's geomagnetic storm, plus the pre-dawn planetary duo continues and Sunday morning kicks off a season of supermoons. It's the Night Sky this Week!
The article as been updated to reflect the latest conditions regarding the geomagnetic storm continuing to affect Earth on October 14. Read on for details.
Geomagnetic storm continues for Friday?
You know what that means! More potential for auroras across Canada!
As of Friday morning, Oct 14, NOAA's Space Weather Prediction Center has forecast more after effects, tonight, from Wednesday night's arrival of the coronal mass ejection that blasted out from the Sun on Sunday.
After the initial arrival sparked a G2 (moderate) geomagnetic storm on Thursday, accompanied by some displays of the Aurora Borealis that stretched down as far as Lake Ontario, the latest forecast is projecting an even stronger storm tonight, potentially reaching up to G3 (strong) levels from about 8 p.m. to midnight, Eastern Daylight Time. As conditions are still evolving, this may be downgraded to a G2 or G1 storm watch, however these levels can also produce some extensive auroral displays.
Geomagnetic storm warning graphic, issued by NOAA SWPC on Oct 13, 2016.
When the arrival of a CME, or a particular fast-paced ribbon of the solar wind, sets off a disturbance in Earth's magnetic field, it sends streams of charged particles down into the atmosphere near the planet's poles. When these high-energy particles strike the nitrogen and oxygen molecules in the air, they transfer some of their energy in the process, and the oxygen and nitrogen molecules dump that excess energy by emitting it as light. This shows up in our night skies as the aurora - Aurora Borealis around the north pole and Aurora Australis around the south pole.
The stronger the CME or faster the solar wind, the stronger the geomagnetic disturbance, and the farther the auroras stretch away from their respective pole.
The map above shows the typical extent of the auroras, based on the Planetary K-Index (Kp), which is a measure of the strength of the geomagnetic disturbance. A G1 (minor) geomagnetic storm corresponds to a Kp value of 5, a G2 (moderate) storm corresponds to a Kp value of 6, and a G3 (strong) storm corresponds to a Kp value of 7. For us to see a Kp value of 9, we would be in the middle of a G5 (extreme) geomagnetic storm, which would bring with it a high risk of satellite failures, power grid disruptions (and possible blackouts!), radio blackouts and GPS navigation outages.
This CME blasted out from the Sun on Sunday, October 9, and spread out into space in Earth's direction, as shown in images from the Solar and Heliospheric Observatory (SOHO).
SOHO LASCO C3 coronagraph images from 05:18 to 20:30, UTC, October 9. Credit: NASA via spaceweather.com
It is notoriously difficult to track coronal mass ejections in real-time. They quickly exit the view of satellites like SOHO and are difficult to pick out against the blackness of space on their journey towards Earth orbit. The animation above shows the faint CME expanding outward from the Sun (the small white circle at the centre of the coronagraph disk) on Oct 9.
While many of the CMEs that interact with Earth are just glancing blows - only the edge of the cloud of solar matter washes over Earth's magnetic field - this was more or less a direct hit, as shown in the computer model animation below:
Zoomed in view of NOAA SPWC's WSA-Enlil solar wind prediction model for Oct 9-14, 2016. The animation runs at normal speed when features and events are highlighted, and at 2x speed for the rest. Images courtesy: NOAA. Animation by S. Sutherland. For the full view, visit the NOAA SWPC website.
As expected, it was late Wednesday night when the CME reached the various satellites positioned to monitor these approaching clouds of solar material. Between Sunday and Wednesday, NOAA forecasters used imagery and data from SOHO and other satellites to map the shape of the CME and the direction it was heading, to produce the WSA-Enlil solar wind prediction model (above). This gave them an idea of how the CME was evolving as it expands outward, and provided an early warning for this interaction with Earth.
Important: It should be noted that solar storms are completely harmless to us on the ground, and only present a potential risk to satellites in orbit, which may be affected by the influx of solar particles, and to certain power lines here on the ground (especially long transmission lines, like those in northern Quebec), due to the fluctuations in Earth's magnetic field. Passengers and crew on trans-Arctic or trans-Atlantic flights can receive a dose of radiation from these events, roughly the equivalent of having an x-ray performed at the hospital.
If this was projected to be a strong event, it could, possibly, cause satellite outages or power disruptions. It is highly unlikely that a G2 geomagnetic storm would cause any significant problems, though. The only result from this should be displays of the Aurora Borealis, which may stretch down to cover all of Canada on Thursday night.
Here's a look at what this has produced so far, as Theresa and Darlene Tanner captured the aurora from Alberta on Wednesday night, and David Piano snapped pictures of his view from Belwood Lake, near Fergus, ON, on Thursday.
Just incredible earlier tonight at Belwood Lake, Ontario! @NorthLightAlert @TweetAurora @Aurora_Alerts @AuroraNotify @_SpaceWeather_ pic.twitter.com/k1IiYNyPAF
— David Piano (@ONwxchaser) October 14, 2016
Stay tuned for more updates!
Pre-dawn planetary duo
Two planets, Jupiter and Mercury, are together in the sky each morning this week, and are visible just before the Sun rises.
Easter, pre-dawn sky from Oct 10-16, 2016, showing the positions of Mercury and Jupiter at 7 a.m. local time. Credit: Stellarium/S. Sutherland
The best time to watch this is between 6:30 and 7 a.m., local time.
Mercury will be lost from sight first, each morning, as it's the dimmer of the two planets, and it will be closer and closer to the horizon each morning, since the planet is making its way around the other side of the Sun from Earth now, getting nearer to its Oct 27 "superior solar conjunction" - when Mercury and Earth are on exact opposite sides of the Sun from each other.
Jupiter, on the other hand, stays visible longer each morning, due to its size and brightness, and it gets farther away from the horizon each morning, since the giant planet passed through solar conjunction a little over two weeks ago (on Sept 26), and Earth is now coming aound to "catch up" to it again (although Jupiter opposition - when the planet is directly opposite the Sun from Earth's perspective - isn't until April 2017).
Sunday's Full Moon kicks off "season of supermoons"
This weekend, at 12:26 a.m. EDT, Sunday morning, the Moon's face will be fully illuminated by the Sun, and while this happens every month, there's something special about this Full Moon.
It is the first of three "Super Full Moons" that we will see this season.
Fall 2016's lineup of Super Full Moons. Credit: NASA Goddard Scientific Visualization Studio/S. Sutherland
It's not easy to tell that the Moon looks bigger on the night of a Super Moon. One factor that comes into play is the famous "Moon Illusion" - where our brains are tricked into thinking that the Moon is very large when it's near the horizon, as it tries to reconcile a very distant object against the closer buildings, trees, and other objects on the ground. Another is the fact that we don't have a direct reference - that is, there is not a "normal" sized Moon in the sky at the same time to compare with. Even so, the Full Moon on the morning of Oct 16 will be roughly 16 per cent larger than the one we saw back on July 19, and nearly 30 per cent larger than the Full Moon we saw back on April 22 (this year's "apogee Full Moon").
This moon isn't the closest of the year, though. Stand by for that to happen on November 14!
BONUS: Keep an eye out for Taurid fireballs!
Over the past few weeks, we've seen some fireball activity over or near parts of eastern Canada and the Great Lakes region, and this might just be the start.
The Northern Taurid and Southern Taurid meteor showers are going on right now, as Earth passes through two streams of debris left behind by Comet 2P/Encke. Since these are old streams of dust, ice and rocks, they've been spread out, and Earth spends about three months, total, inside them.
What the Taurids are known for, however, is fireballs. While the Perseids account for the greatest number of fireballs for an annual meteor shower, the Taurids produce a fair number, even for a relatively weak showing, otherwise.
Given the path of these three fireballs, linked above, and the direction they originated from, it's quite possible that all three were associated with one of these meteor showers.
Keep watching this week, and the weeks ahead, in case we see more!
Sources: NOAA SWPC | American Meteor Society
Teaser image courtesy Team Tanner, via Facebook
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