Solar Cycle 25

Respond to this Friday Faithfuls challenge by writing anything about magnetic fields on the Sun, or if you are worried about an upcoming solar apocalypse, or write about whatever else that you think might fit.  In a complex process, the Sun’s polar magnetic field reverses or flips approximately every 11 years following the solar cycle progressions.  It happens at the peak of each solar cycle as the sun’s inner magnetic dynamo re-organizes itself.  Conductive fluids (plasmas) can support magnetic fields, as is the case in all gases, the atoms in plasma are highly mobile and move with high speeds.  When movement of the conducting fluid occurs in a magnetic field, this causes electromagnetic induction of electric currents in the fluid.  The presence of magnetic fields leads to forces that in turn act on the plasma, thereby potentially altering the magnetic fields themselves.  The solar cycle was discovered by the German amateur astronomer Heinrich Schwabe during his observations of the sun between 1826 and 1843.  He determined that the Sun rotates on its axis once in 27 days and he also established that activity on the Sun increases and decreases over approximately an 11-year cycle.  Scientists have been numbering solar cycles since 1755, where Solar Cycle 1 began in March 1755 and ended in June 1766.

The sun is now in Solar Cycle 25, which is driven by the sun’s magnetic field as sunspots create solar flares and emit radiation, mainly in the form of ultraviolet light and X-rays.  The radiation reaches the sunlit side of Earth within 8 minutes, traveling at the speed of light.  These energetic blasts can interfere with radio signals and some flares are accompanied by Coronal Mass Ejections CMEs, which are highly charged bubbles of the sun’s plasma emerging from the sun’s outer atmosphere, which can eject billions of tons of coronal material and carry an embedded magnetic field.  Energetic particles from these events, carried by the solar wind, affects our weather and can cause disruption to communication, navigation, and power systems.  If these storms reach our planet, large solar flares can lead to a radio blackout storm on Earth, whereby electromagnetic energy disrupts the Earth’s upper atmosphere.  This disruption occurs mainly in the ionosphere, where long-distance communications signals travel, and can lead to radio blackouts across the world.  The Sun’s activity cycle goes from minimum to maximum and back to minimum, as sunspots are absent, increase over time, and then decrease.  The period of rise from minimum phase (when sunspots may be absent for several weeks) to maximum phase (when 20 or more groups may be present at one time) takes an average of four years.  The decrease from maximum back to minimum occurs over the following seven years.

Like on Earth, the sun has a magnetic North and a magnetic South.  But unlike Earth, whose poles flip on the order of hundreds of thousands of years, the sun’s shuffle is a regular occurrence.  The sun’s poles last reversed in 2013, so we are just about due for another magnetic pole reversal, likely starting sometime this year.  Solar Cycle 24 was average in length, it had the 4th-smallest intensity since regular record keeping began and it was also the weakest cycle in 100 years.  The sun shrinks and grows a tiny bit over cycles lasting about 11 years and an active sun is a somewhat smaller sun, but since our sun has no solid surface, it is hard to calculate this seismic radius.  The magnetic flip is expected to take place any time between now and October of 2024 and the solar maximum is expected to arrive a few months later.  When this happens, chances are that you won’t even notice it, so there is no need to prepare for an impending apocalypse.  The Aurora Borealis, or Northern Lights should be more prominent during this time.

Solar Cycle 10 was dubbed “The Carrington Event” and this 1859 event was the most intense geomagnetic storm in recorded history, as people living in Florida were able to see the Northern Lights.  English astronomer Richard C. Carrington was studying a group of sunspots using dark filters to protect his eyes, and around 11:00 AM, he sees a sudden flash of intense white light from the area of the sunspots.  Seventeen hours later, the night sky in North America and as far south as Panama in Central America lights up like daytime.  It is another wave of even brighter Auroras.  People read newspapers by the light.  Gold miners in the Rocky Mountains wake up and make coffee, bacon and eggs at 1:00 AM, thinking the Sun has risen on a cloudy morning.  If such a storm happened today, it could severely damage satellites, disable communications by telephone, radio, and TV, and cause electrical blackouts over whole continents.  Solar storms like the one in 1859 happen only about every 500 years, but smaller storms happen frequently, and storms half as intense as the 1859 storm happen about every 50 years.