(Source: Spaceweather via Troy Riedel)
This weekend, old sunspot AR2738 is returning from a two-week trip around the farside of the sun. After re-appearing late yesterday, the sunspot quickly produced two CMEs (coronal mass ejections), signalling that it may be even more active than before. Last month when it crossed the face of the sun, AR2738 crackled with low-level flares and strafed Earth with loud shortwave radio bursts.[…]
Many thanks to SWLing Post contributor, Eric (WD8RIF), who writes:
This came in the most recent ARRL Contest newsletter:
The Sun, The Earth, and Near-Earth Space: A Guide to the Sun-Earth System by J. A. Eddy is a readable and accessible textbook that explains the dynamics of the Sun and its interaction with the Earth’s ionosphere. It’s available as a free download, courtesy of NASA and the International Living with a Star Program. Anyone using the ionosphere as a medium for radio wave transmission and wants to better understand propagation should find this book of interest. (Ward, N0AX)
Thank you for the stellar tip, Eric!
As an avid amateur astronomer, solar observation has been quite boring during 2018. As a shortwave radio enthusiast, the lack of solar activity has impacted that hobby as well.
Well, the catchword of the day is “surprise”!
I was alerted yesterday evening by Spaceweather.com that a large sunspot had emerged and developed into a group – with the two main sunspots’ diameter about as large as the earth.
Credit: Spaceweather.com – Sunspot group AR2720, photographed by Thierry Legault on Aug. 25th from the Saint-Véran/Astroqueyras observatory in the French Alps. An image of Earth has been inserted for scale (Link).
Another overnight email notification from Spaceweather.com stated a “surprise” G-3 Class Geomagnetic storm is underway (now!) caused by a coronal mass ejection.
Credit: Spaceweather.com – According to a NOAA computer model, almost 80 billion watts of power surged through Earth’s auroral oval during today’s geomagnetic storm (This image/forecast is updated every 30-minutes at this link).
Has this “surprise” impacted your radio weekend? I know it has impacted my astronomy weekend … I’ll be out there, soon, setting up my solar telescope to view today’s show in hydrogen-alpha!
Go to spaceweather.com to follow the developments.
Edit: Yes indeed, even excluding the sunspots the solar disc yielded more surface detail today via my H-alpha solar telescope than I’ve seen all year – as well as several nice solar prominences along the limb. I encourage anyone who has the proper telescope AND proper filters to take a look at ‘Ole Sol today (and hopefully for the next several days). I’ll have to check the shortwaves later.
Guest Post by Troy Riedel
Not a sunspot to be found. (Credit: SDO/HMI via Spaceweather.com)
Unfortunately, this is not news to brighten your day. According to Spaceweather.com, sunspots are disappearing faster than expected:
Sunspots are becoming scarce. Very scarce. So far in 2018 the sun has been blank almost 60% of the time, with whole weeks going by without sunspots. Today’s sun, shown here in an image [above] from NASA’s Solar Dynamics Observatory, is typical of the featureless solar disk.
The fact that sunspots are vanishing comes as no surprise. Forecasters have been saying for years that this would happen as the current solar cycle (“solar cycle 24”) comes to an end. The surprise is how fast.
“Solar cycle 24 is declining more quickly than forecast,” stated NOAA’s Space Weather Prediction Center on April 26th. This plot shows observed sunspot numbers in blue vs. the official forecast in red:
“The smoothed, predicted sunspot number for April-May 2018 is about 15,” says NOAA. “However, the actual monthly values have been lower.”
Continue reading the full story at Spaceweather.com.
I will be very happy to see sunspot numbers rise again–they eventually will, of course. I’ve almost forgotten what a proper band opening feels like.
(Source: Southgate ARC)
The ESA just discovered a second magnetic field surrounding our planet
A trio of satellites studying our planet’s magnetic field have shown details of the steady swell of a magnetic field produced by the ocean’s tides.
Four years of data collected by the European Space Agency’s (ESA) Swarm mission have contributed to the mapping of this ‘other’ magnetic field, one that could help us build better models around global warming.
Physicist Nils Olsen from the Technical University of Denmark presented the surprising results at this year’s European Geosciences Union meeting in Vienna, explaining how his team of researchers managed to detail such a faint signature.
“It’s a really tiny magnetic field,” Olsen told BBC correspondent Jonathan Amos. “It’s about 2 – 2.5 nanotesla at satellite altitude, which is about 20,000 times weaker than Earth’s global magnetic field.”
On a fundamental level, both fields are the result of a dynamo effect produced by charged particles being sloshed around in a fluid.
The stronger magnetic field that tugs on our compass needle forms from the steady movement of molten rock deep under our feet.
This field also leaves its signature in the alignment of particles embedded in Earth’s crust, a pattern that has also been analysed in detail by Swarm
Read the full story at:
https://www.sciencealert.com/esa-swarm-satellite-map-ocean-tides-magnetic-field
Credit: NOAA SWPC
(Source: Southgate ARC)
Equinox ‘cracks’ forming in Earth’s magnetic field
The vernal equinox is less than 10 days away. That means one thing: Cracks are opening in Earth’s magnetic field.
The seasonal phenomenon is known as the “Russell-McPherron effect,” named after the researchers who first explained it more than 40 years ago.
These “equinox cracks” are causing geomagnetic activity and bright auroras around the Arctic Circle even without strong solar activity.
Visit today’s edition of Spaceweather.com for the full story.
Many thanks to SWLing Post contributor, TomL, who writes:
Regarding the last couple of posts recently about what affects Space Weather (and HF radio communications), this talk last week from Solar scientist Joan Burkepile of the High Altitude Observatory discusses what causes Radiation storms from Coronal Mass Ejections. She makes it interesting from a physics point of view. And as we understand the sun better, we also learn more about how the rest of the universe behaves.
Thanks for sharing this, Tom!
