The Orionids radiate from a point near the upraised Club of the constellation Orion the Hunter. The bright star near the radiant point is ruddy, somber Betelgeuse. You might catch an Orionid meteor any time between about October 2 to November 7. In 2021, the peak morning is October 21, but, around then, the full or nearly full Hunter’s Moon will be shining brightly.
When a meteor enters the earth’s atmosphere, friction between the particle and the increasingly dense air causes meteor particle to boil off. The particle collides with the air molecules forming trails of positive ions and free electrons used to reflect the radio waves. The reflecting process is primarily due to the effect of the electrons, since the positive ions are too massive to vibrate under the influence of an electric field.
The electron density of the ionized trail is commonly assumed to be Gaussian in the radial direction and the ionization may or may not be uniform in the axial direction. The length of the ionization region of a trial is approximately 20-40 Km from start to finish. It was found that useful ionized trails occur in an altitude of about 80 to 120 Km above the earth’s surface.
Trails with useful electron densities for reflecting radio signals were found to be plentiful enough to provide communication in the lower portion of (VHF) bond ranging from 30 to 100 MHz over a range of roughly 2000 Km. The minimum range limitation was found to be 400 Km. Ionized trails were found to have a lifetime of only a few tenths of a second, creating the need for rapid exchange of communication. The transmission rate had to be very fast (a burst of data) to take advantage of ionized trail. Hence the term “meteor burst” was coined.
Mike Terry to WOR iog (2021-10-20)
A large southern hole in the sun’s atmosphere is spewing solar wind toward Earth. ETA: Oct. 19-20.
Solar wind speeds could top 500 km/s, sparking auroras around the Arctic Circle.
Mike Terry to WOR iog (2021-10-18)
Another CME [coronal mass ejection] is coming, but this one might miss. A magnetic filament connected to sunspot AR2882 erupted on Oct. 12th (~0200 UT). The debris is expected to pass in front of Earth on Oct. 15th. The near-miss could spark Arctic auroras, but probably no geomagnetic storm.
Ydun Ritz (2021-10-13)
Solar Cycle 25 continues to overperform. Sunspot counts for Sept. 2021 were the highest in more than 5 years. And, for the 11th month in a row, the sunspot number has significantly exceeded the official forecast.
Mike Terry to WOR iog (2021-10-05)
Minor Geomagnetic Storm Watch.
A CME is approaching Earth for a close encounter on Sept. 17th. It will either miss or deliver a glancing blow. Both outcomes are equally possible given uncertainties in the CME’s trajectory. A hit could spark minor G1-class geomagnetic storms and high-latitude auroras.
Mike Terry to WOR iog (2021-09-16)
A stream of solar wind is approaching Earth. ETA: Aug. 25th.
The gaseous material is flowing from a northern hole in the sun’s atmosphere and could cause polar geomagnetic unrest when it arrives.
Mike Terry to WOR iog (2021-08-23)
Waiting for the CME.
A CME expected to sideswipe Earth’s magnetic field on July 23rd did not arrive on time. It might have missed, or it may yet deliver a glancing blow later today. There is a slight chance of G1-class geomagnetic storms in response to a tardy arrival on July 24th.
Long duration solar flare.
Today began with an explosion on the sun. Minutes after UT midnight, sunspot AR2849 erupted, producing a long-duration C4-class flare. NASA’s Solar Dynamics Observatory recorded the ultraviolet flash:An hour-long pulse of X-rays and ultraviolet radiation ionized the top of Earth’s atmosphere, disrupting the usual propagation of radio waves over the Pacific Ocean. Mariners, aviators, and ham radio operators may have noticed sudden drops in signal strength at frequencies below 20 MHz.
Mike Terry to WOR iog (2021-07-24)
Yesterday, sunspot AR2838 burst through the surface of the sun and promptly unleashed the strongest solar flare in 4 years, an X1.5-class explosion. As quickly as it appeared, the sunspot is already gone. On July 4th it rotated over the sun’s northwestern limb and will spend the next two weeks transiting the far side of the sun. If AR2828 holds itself together, it will re-appear on the Earthside in late July.
Mike Terry to WOR iog (2021-07-04)
Is our sun going into hibernation?
Each sunspot cycle has been getting less intense. Is our star falling asleep? Solar activity refers to the state of the sun’s magnetic field and associated phenomena: sunspots, flares, solar wind and coronal ejections. During periods of minimal solar activity, such events are often uncommon and weak. During solar maximum, they’re at their strongest and most frequent. Magnetic field fluctuations on the sun can happen on drastically different timescales, ranging from seconds all the way to billions of years. When astronomers speak of a “slowdown” or a period of quiescence in the sun’s activity, it doesn’t mean the sun will stop shining, but that there’s a slowdown in activity. The sun has one particular rhythm, lasting approximately 11 years, in which its polar magnetic field flips polarity. Sunspots serve as an indicator of this change. Indeed, it’s often known as “the sunspot cycle.”
Mike Terry to WRTH FB group (2021-0-03)