A solar G2 geomagnetic storm is expected to strike Earth today (Saturday, March 23) leading to increased intensity and range of Aurora Borealis, the Northern lights, which may be visible from states as far South as New York and Iowa.
On Wednesday, March 20 at 0718 EDT, a C4 flare occurred at the Sun, leading to a Coronal Mass Ejection, whose orientation is such that the storm front of electrons and protons will arrive at Earth around 7:18 a.m. EDT. It is not clear whether we will get a direct hit or a glancing blow, hence the extent of the Northern lights may not reach as far south as is widely anticipated. But our neighbors to the North are definitely in for a treat. Also, a G1 (minor) geomagnetic storm forecast will be in effect on Sunday March 24.
The space storm may affect satellites and GPS, but is not expected to cause any major disruption or damage.
The following video shows the Coronal Mass Ejection at the Sun on March 20.
The Space Weather Forecast
The Space Weather forecast from NOAA indicates that the storm and aurora will be strongest from Saturday 10 a.m. EDT to Sunday 1:00 a.m. EDT.
The table below shows the NOAA Kp index (0-9) for geomagnetic activity. Geomagnetic storms are labelled G1 to G5, starting at Kp 5.
Mar 23 Mar 24 Mar 25
00-03UT 1 5 (G1) 2
03-06UT 1 5 (G1) 1
06-09UT 2 4 1
09-12UT 2 3 2
12-15UT 3 3 1
15-18UT 5 (G1) 3 1
18-21UT 6 (G2) 3 1
21-00UT 5 (G1) 3 2
Here is a graphic showing the extent and intensity of the Aurora at Saturday 7:00 a.m. EDT. Check back at the NOAA site for updates that cover the later hours in the evening.
Solar Wind, Flares, CMEs and Auroras
The following information is from ww.swpc.noaa.gov/… and www.nasa.gov/…, with some minor editorial changes.
Solar wind: The solar wind is a continuous stream of particles emanating from the Sun; it consists mainly of protons and electrons in a state known as a plasma.
Solar flare: Solar flares and CMEs are created when the motion of the sun’s interior contorts its own magnetic fields. Like the sudden release of a twisted rubber band, the magnetic fields explosively realign, driving vast amounts of energy into space. A solar flare releases large amounts of radiation, in addition to some high-energy particles; the energy released is spread in all directions.
Coronal Mass Ejections: A Coronal Mass Ejection (CME) is a large expulsion of particles and magnetic field from the Sun’s corona. CMEs can eject billions of tons of coronal material and carry a strong embedded magnetic field. CMEs travel outward from the Sun at speeds ranging from slower than 250 kilometers per second (km/s) to as fast as near 3000 km/s. The fastest Earth-directed CMEs can reach our planet in as little as 15-18 hours. Slower CMEs can take several days to arrive. They expand in size as they propagate away from the Sun and larger CMEs can reach a size comprising nearly a quarter of the space between Earth and the Sun by the time it reaches our planet.
CMEs can play havoc with satellites, GPS and electrical grids if Earth is directly in their path. This CME is not expected to have any damaging impact, but it is only a matter of time before a big one directly hits Earth.
The following video made using data from NASA’s Solar Dynamics Observatory, shows the dance of flares and CMEs on the surface of our Sun.
Aurora: The Aurora Borealis (Northern Lights) and Aurora Australis (Southern Lights) are the result of electrons colliding with the upper reaches of Earth’s atmosphere. (Protons cause faint and diffuse aurora, usually not easily visible to the human eye.) The electrons are energized through acceleration processes in the downwind tail (night side) of the magnetosphere and at lower altitudes along auroral field lines. The accelerated electrons follow the magnetic field of Earth down to the Polar Regions where they collide with oxygen and nitrogen atoms and molecules in Earth’s upper atmosphere. In these collisions, the electrons transfer their energy to the atmosphere thus exciting the atoms and molecules to higher energy states. When they relax back down to lower energy states, they release their energy in the form of light. This is similar to how a neon light works. The aurora typically forms 80 to 500 km above Earth’s surface.
Here is a video from NASA explaining the science behind Auroras -
Earth's Magnetic Field and Magnetosphere
The Earth's magnetic field serves to deflect most of the solar and cosmic high energy radiation, which would otherwise harm all living beings. Without the magnetosphere, charged particles would strip away the ozone layer that protects the Earth from harmful ultraviolet radiation and even strip away the atmosphere. Calculations show that Mars lost most of its atmosphere as its magnetic field dissipated over time, exposing the atmosphere to the ravages of the solar wind.
Some Images and Videos of Auroras Past
Since most of us will not get a chance to witness nature’s display tonight (or ever), we can enjoy them vicariously with the following images and videos captured by adventurous professionals across the globe.
Here is a beautiful video of Aurora Australis shot by Robert Schwarz, CMB-Observatory (Cosmic Microwave Backgroud) operator and technician at the Amundsen–Scott South Pole Station.
This is a video of the Northern lights seen from latitude 58.3 degrees north caused by a G2 geomagnetic storm on February 27, 2014.
Another outstanding video shot in the fjords of Northern Norway by Adrien Mauduit -
This video from NatGeo shows the multicolored curtains of light over northern Norway on March 21, 2012.
This video, based on time-lapse shots taken from the International Space Station, shows both the Aurora Borealis and Aurora Australis phenomena as seen from space.
Auroras are also present on other planets that sport planetary magnetic fields.
Epilogue
Of course we need more science, scientists and funding for Science and Heliophysics. The proposed FY 2020 trump budget, as expected, cuts NASA funding in science areas, to pay for military buildup, walls and tax cuts for the super-wealthy. Let’s make sure our congressional Reps make responsible use of our tax-dollars and provide adequate funding for science.
I hope some of you living in the northern latitudes get a chance to observe this phenomenon this weekend. How many of you have had a chance to observe watch these beautiful works of nature? Do share your experiences and observations.
Further Reading
- A Solar Storm Will Send the Northern Lights Surging South Tonight — www.extremetech.com/…
- Aurora — en.wikipedia.org/…
- NOAA Space Weather Prediction Center — www.swpc.noaa.gov
- Space Weather dashboard — www.swpc.noaa.gov/…
- Coronal mass ejection — en.wikipedia.org/…
- Solar Dynamics Observatory — en.wikipedia.org/…
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The Difference Between Flares and CMEs — www.nasa.gov/...