Expired News - Blustery solar wind set to return auroras to Canada's skies - The Weather Network
Your weather when it really mattersTM

Country

Please choose your default site

Americas

Asia - Pacific

Europe

News
Auroras are set to spark in Canada's night skies early this week, and what is the Belt of Venus? It's the Night Sky this Week!
OUT OF THIS WORLD | Night Sky this Week - a weekly look at what there is to see in the night sky

Blustery solar wind set to return auroras to Canada's skies


Scott Sutherland
Meteorologist/Science Writer

Tuesday, October 25, 2016, 12:55 PM - Auroras are set to spark in Canada's night skies early this week, and what is the Belt of Venus? It's the Night Sky this Week!

Aurora Watch - Oct 24-26

An enormous hole in the Sun's corona has turned Earthward, and this is set to spark off potentially vibrant auroras across Canada for at least Monday and Tuesday night, and possibly beyond.

NOAA's Space Weather Prediction Center has issued a G2 (moderate) geomagnetic storm watch for Monday, October 24 through Wednesday, October 26, due to the effects of a Coronal Hole High Speed Stream.


Text from NOAA SWPC's 3-day Forecast, updated 8:30 a.m. EDT, Tuesday, Oct 25, 2016. Colour coding added by S. Sutherland.

Times in the text, above, are in UTC, so for reference subtract 4 hours to convert to Eastern Daylight Saving Time. Thus, the peak of activity on Tuesday is expected between 8 a.m. and 2 p.m. EDT, when there should be G3 (strong) geomagnetic storm activity, after which it will subside to a mixture of G2 (moderate) and G1 (minor) conditions for the rest of the night.


As of 11:15 a.m. EDT, Oct 25, NOAA recorded G3 (strong) geomagnetic storm levels occuring. Credit: NOAA SWPC

A G3 (moderate) geomagnetic storm watch remains in effect for Tuesday night and Wednesday.

The animation below - the Monday run of NOAA's WSA-Enlil solar wind model - shows this low-density, high-speed stream of particles extending away from the Sun in a wide ribbon of space, which sweeps past Earth from the night of Oct 24 through the morning of Oct 29.


The 14UTC 2016-10-24 WSA-Enlil solar wind model, showing solar wind conditions from 00UTC Oct 25 (8 p.m. EDT Oct 24) to 12UTC Oct 29 (8 a.m. EDT, Oct 29). Credit: NOAA SWPC

This region of low-density particles is expected to have a strong influence on Earth's magnetic field as it passes, due to the speed at which the particles are flowing. For a Coronal Mass Ejection - an eruption of solar material into space, typically associated with a solar flare - it's the large number of solar particles interacting with Earth's magnetic field, all at once, that sets off a geomagnetic storm and sparks auroras. Speed is just as important as numbers, however. So, as the fast-moving particles in this low-density stream interact with Earth's magnetic field, their energy is capable of sparking off the same level of reaction as a much denser, slower-moving cloud of particles.

The region this stream is originating from on the Sun is quite impressive.


The Sun's corona, as of roughly midnight, Sunday night into Monday morning, seen in the 193 Angrstrom view of NASA's Solar Dynamics Observatory. Credit: NASA SDO/S. Sutherland. H/T to spaceweather.com

In the image above, NASA has added in the magnetic field lines that are looping out from the Sun's surface (thin white lines) and those magnetic field lines that are stretching out into space from the coronal hole (thin grey lines). The white arrows have been added (by the author) to emphasize the coronal hole high speed stream flowing out into space.

According to NOAA, the auroras seen over the next two nights, at least, should be visible between the Kp=5 and Kp=7 limits, the green and yellow lines, as shown on the map below:

The farther north you are, and the farther you are from bright city lights, the easier it will be to see the aurora.

Check back for more updates as this story develops.


RELATED: What is Light Pollution and how does it affect Canadians?


What is the Belt of Venus?

Seeing a red sky at sunset or sunrise is quite common, when the part of the sky that's coloured coincides with where the Sun is - east in the morning and west in the evening... but what's going on if you look to the horizon opposite to where the Sun is, and you see this?

This panoramic image, taken just after sunset, on September 12, 2016, from Milton, Ontario, shows a stretch of the eastern horizon, which has a rather dramatic band of pink/red across it, overtop of a dark band right at the horizon.

This phenomenon is what's known as The Belt of Venus.

What you're seeing here is a combination of two things. 1) The band of pink is from the light of the setting Sun being scattered back towards your eyes by haze and clouds to the east, and 2) the shadow of Earth being cast on that same haze and cloud at the edge of the horizon.

This is only visible before sunrise or after sunset, with the Sun is still beyond the horizon, so that Earth's shadow is just creeping up above the horizon. It also helps to have a high pressure air mass in the area, which tends to trap more haze for the edge of Earth's shadow to fall on. Otherwise, the effect is typically too subtle to notice.

Source: NOAA

Default saved
Close

Search Location

Close

Sign In

Please sign in to use this feature.