GEOMAGNETIC UNREST: Earth is entering a stream of solar wind flowing from a hole in the sun's atmosphere. This is causing geomagnetic unrest around the poles. High-latitude sky watchers should be alert for auroras on July 21st, especially in the southern hemisphere where winter darkness favors visibility. Free: Aurora Alerts
CME SWEEPS ASIDE COSMIC RAYS: On July 16th, a CME hit Earth's magnetic field, sparking two days of geomagnetic storms and beautiful southern auroras. The solar storm cloud also swept aside some of the cosmic rays currently surrounding Earth. Spaceweather.com and the students of Earth to Sky Calculus launched a space weather balloon to the stratosphere hours after the CME arrived. We detected a 7% decrease in X-rays and gamma-rays (two tracers of secondary cosmic rays). Neutron monitors in the Arctic and Antarctic recorded similar decrements. For instance, these data from the Bartol Research Institute show a nearly 8% drop in cosmic ray neutrons reaching the South Pole:
This is called a "Forbush Decrease," named after physicist Scott E. Forbush who first described it in the 20th century. Wherever CMEs go, cosmic rays are deflected by magnetic fields inside the solar storm clouds. As a result, when solar activity is high, cosmic radiation around Earth is relatively low--a yin-yang relationship that holds throughout all phases of the solar cycle.
Lately, cosmic rays around Earth have been intensifying as the solar cycle plunges toward minimum. The CME of July 16th reversed that trend--but only for a few days. Solar activity has returned to low levels and cosmic rays are on the rise again.
Why do we care about cosmic rays? For one thing, they penetrate commercial airlines, dosing passengers and flight crews so much 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.
Realtime Space Weather Photo Gallery
SOLAR ECLIPSE SPACE PENDANTS: Would you like to support our Solar Eclipse Balloon Network? Here's one way: Buy a space pendant. This solar eclipse-themed necklace flew to the stratosphere on July 2, 2017, attached to the payload of an Earth to Sky Calculus space weather balloon:
The payload contained more just like it. If you buy one now for $79.95, we will fly it back to the stratosphere during the Great American Solar Eclipse on August 21, 2017, where it will be enveloped by the Moon's cool shadow above our launch site in Oregon. No additional charge! Just make a note in the COMMENTS BOX of the shopping cart: "Please fly my pendant into the eclipse!" Each pendant comes with a greeting card showing the jewelry in flight and telling the story of its journey to the stratosphere and back again.
More items from the edge of space may be found in the Earth to Sky Store. All proceeds support atmospheric radiation monitoring and hands-on STEM education.
Far Out Gifts: Earth to Sky Store
All proceeds support hands-on STEM education
MEANWHILE ON THE FAR SIDE OF THE SUN: Three days ago, big sunspot AR2665 rotated off the solar disk, beginning a two-week transit of the farside of the sun. AR2665 may no longer be visible, but we know it's still active. On July 20th, a coronal mass ejection (CME) billowed over the edge of the sun, signaling an explosion in the sunspot's magnetic canopy:
This means another slice of the Solar System is having its cosmic rays scooped up. A Forbush Decrease is underway in the wake of the CME. Earth will not be affected this time, however, because the CME is moving in a completely different direction. In the environment of our planet, cosmic rays from deep space are once again penetrating without the push-back of solar explosions.
Realtime Noctilucent Cloud Photo Gallery