CHANCE OF STORMS THIS WEEK: NOAA forecasters say there is a 40% chance of G1-class geomagnetic storms on May 16th when a solar wind stream is expected to hit Earth's magnetic field. The gaseous material is flowing from a hole in the sun's atmosphere, shown here in an image from NASA's Solar Dynamics Observatory:
This is a coronal hole (CH)--a place where the sun's magnetic field peels back and allows solar wind to escape. The stream of solar wind flowing from this CH is wide enough to envelop Earth for at least 2 days.
The action could begin as early as May 15th when a co-rotating interaction region (CIR) preceding the solar wind stream arrives. CIRs are transition zones between slow- and fast-moving solar wind streams. Plasma and magnetic fields pile up in these regions, and often do a good job of sparking geomagnetic activity when they reach Earth. High-latitude sky watchers should be alert for auroras, especially in the southern hemisphere where deepening autumn darkness favors visibility. Free: Aurora Alerts
SOLAR MINIMUM IS APPROACHING... Today marks the 5th day in a row and the 35th day in 2017 that the sun has been blank--no sunspots. This exceeds the total number of spotless days in all of 2016 (32). The accelerating pace of spotlessness is a sign that Solar Minimum is approaching. Forecasters expect the sunspot cycle, which swings like a pendulum between high and low sunspot number every ~11 years, to reach its nadir in 2019-2020. Stay tuned for more blank suns. Free: Aurora Alerts
... AND COSMIC RAYS ARE INTENSIFYING: Many people think Solar Minimum is boring. Wrong. During the nadir of the sunspot cycle, the entire heliosphere changes its personality with many consequences for the space around our planet. One of the most important changes involves cosmic rays--high-energy radiation reaching Earth from deep space. As sunspot numbers decline, cosmic rays intensify.
Is this actually happening? The answer is "yes." Spaceweather.com and the students of Earth to Sky Calculus have been monitoring radiation levels in the stratosphere with frequent high-altitude balloon flights over California. Here are the latest results, current as of May 6, 2017:
The data show cosmic ray levels intensifying with an approximately 13% increase since March 2015.
Cosmic rays are high-energy photons and subatomic particles accelerated in our direction by distant supernovas and other violent events in the Milky Way. Usually, cosmic rays are held at bay by the sun's magnetic field, which envelops and protects all the planets in the Solar System. But the sun's magnetic shield is weakening in 2017 as the solar cycle shifts from Solar Maximum to Solar Minimum. More and more cosmic rays are therefore reaching our planet.
How does this affect us? Cosmic rays penetrate commercial airlines, dosing passengers and flight crews enough that pilots are classified as occupational radiation workers. Some research shows that cosmic rays can seed clouds and trigger lightning, potentially altering weather and climate. Furthermore, there are studies ( #1, #2, #3, #4) linking cosmic rays with cardiac arrhythmias in the general population.
The sensors we send to the stratosphere measure X-rays and gamma-rays, which are produced by the crash of primary cosmic rays into Earth's atmosphere. The energy range of the sensors, 10 keV to 20 MeV, is similar to that of medical X-ray machines and airport security scanners.
NOTE: This increase is not happening ONLY over California. All parts of the world will be experiencing elevated levels of cosmic rays. The amount varies from place to place depending on the uneven protection afforded by our own planet's magnetic field. In the week ahead we will share new data from intercontinental balloon launches tracing the global response to this phenomenon.
Realtime Space Weather Photo Gallery
THIS PENDANT HAS TOUCHED SPACE: The radiation monitoring program of Earth to Sky Calculus receives no support from corporate sponsors or government grants. Instead, we are crowd-funded. Or, to be more precise, bling- funded:
To raise money for more cosmic ray balloon flights, on May 6th the students launched a payload of these Northern Lights pendants to the top of Earth's atmosphere. You can have one for $79.95. Each piece of space jewelry comes with a greeting card showing the item in flight and telling the story of its journey to the stratosphere and back. They make great birthday and Mother's Day gifts.
More far-out gifts may be found in the Earth to Sky Store. All proceeds support atmospheric radiation monitoring and hands-on STEM education.