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Drax Spacex

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Drax Spacex last won the day on August 4

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About Drax Spacex

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  1. Some graphs I've seen of the variations of the Solar System Barycenter to Earth distance appear to contain min/max cycles not too unlike the 11 year solar cycle.
  2. From the Spaceweatherlive help section: "Delta groups are formed by the aggregation of sunspots with opposite polarity of various dipoles, which are linked to shared magnetic field lines rather than direct magnetic lines." One can visualize why delta sunspot groups would be more likely to give rise to large solar flares. One of the actions of sunspots is to hold tight to the ends of the hoop-like flux ropes. These flux ropes might be considered analogous to the patterns of iron filings near one or more magnets. In a bipolar sunspot group, North and South Poles create strong, tight magnetic fields that hold the flux ropes ends to the surface of the sun . But in a Delta sunspot group, the additional magnetic poles, unevenly distributed in spacing and polarity, complicate the magnetic field and may introduce field nulls (or local minima). With so much energy stored, when the magnetic fields morph in such a way that those cords binding the flux ropes become loosened, even for a short time, that can initiate a solar flare and/or CME.
  3. If p=probability of a single lottery ticket being a winner, then the probability of at least 1 in 5 lottery tickets being a winner=1-(1-p)^5. This falls in the "At least one" probability problem category which makes use of the probability complement rule P(A) = 100% − P(not A). https://www.stat.berkeley.edu/~stark/SticiGui/Text/probabilityAxioms.htm A team of researchers from Japan have tried to figure out how to predict solar flares automatically based on feature extraction and tracking of active sunspot regions. https://ui.adsabs.harvard.edu/abs/2018ApJ...858..113N/abstract In the introduction they note "It is empirically known that larger sunspots with a large number of umbra and a more complicated magnetic flux structure tend to produce larger flares." They've churned through 300,000 SDO images from the first half of solar cycle 24 in developing and training their neural net machine learning algorithms. Each active region of sunspots is tracked with 79 features extracted for each. If a flare occurs within 24 hours of being predicted by the algorithms it is tallyed as a "True Positive" (correct 63% for C-class or higher, 80% for M-class or higher.) However, there are many "False Positives." They indicate that their algorithm does a better job of solar flare prediction than human operators.
  4. If the Moon is a harsh mistress, the Sun is a tempestuous diva. With an attitude of roiling complexity, she does not yield her secrets easily. We can observe and record the activity of the Sun. We can marvel at its intricacies. But we cannot fathom the essence of it. Seers and prognosticators (aka scientists) will be constantly put to shame when they try to predict and understand the details of its ordinances. Those lucky enough to guess right in a given cycle will be lauded for their luck in rolling the dice. But the averaged opinion across all the experts will always be "The next solar cycle will be of average strength and last about 11 years."
  5. The usual depiction of the D layer is that the ionization level builds up incrementally in daylight. On the dawn side of the gray line, the D layer would not yet exist. The near-relativistic initial hit from a strong solar flare would be a glancing impact (90° incident angle) along the dawn gray line. I was pondering whether that is a region of particular vulnerability. It's off-topic but an interesting question (I think) which probably could be answered from scavenging data from strong solar flares in recent decades. Is "Solar Wind" in the right spot on this chart? It has a direct line to "Corona". But don't coronal holes (the localized thinning of the corona) give rise to strong solar winds, the particle source of the solar wind from a layer below the Sun's corona (chromosphere). Maybe add an extra solid or dotted line(s) somewhere to depict the phenomenon of coronal holes and effect on solar wind, and the particle source of solar wind.
  6. Ah OK thanks for elaborating - if I understand, in such case, it's not the satellite signal affected by space weather, but the Earth receiver being affected by thermal noise when pointed near the Sun. i.e. while the satellite signal S is unaffected, the (S+N)/N ratio at the Earth receiver is dominated by solar thermal noise N.
  7. Solar flares from the photosphere can also cause terrestrial HF radio blackouts (aka sudden ionospheric disturbance or "SID"). X-ray radiation from a flare strongly ionizes the D-layer of the ionosphere, the layer closest to the Earth (30-60 miles altitude). Skip propagation requires refraction of the radio signals from the higher layers of the ionosphere (E and/or F). The blackout period occurs because the abnormally high ionization of the D-layer absorbs these radio transmissions. The blackout period may last from seconds to hours before the D-layer settles to normal ionization. Since signals from geosynchronous satellites must pass through the D-layer to reach Earth, I presume this is the same mechanism for the blackout of communications between Earth and satellites (only sunlit Earth side). A highly disturbed geomagnetic field (high K or A index) can also disrupt HF communications, affecting the upper layers of the ionosphere; though conductive ionized gas from Auroras can enhance propagation for radio frequencies above 20MHz (including VHF). The D-layer disappears at night and quickly reconstitutes in daylight. I shudder to think what the terrestrial effect might be of a strong solar flare at dawn aimed at Earth before the D-layer has reconstituted (shields down).
  8. NASA could certainly use the help. The solar dynamo does not have a good model to describe in detail the mechanisms of the Sun's changing magnetic fields. https://solarscience.msfc.nasa.gov/dynamo.shtml I read your paper, and if I understand it, like the currently accepted methods, you cannot declare a solar minimum until many months after it has occurred, given the need to use ahead-looking data to provide smoothed fitted data for solar flux index and sunspot number. It would be a significant discovery to find specific precursor data or features that can detect earlier and definitively the start of a new solar cycle. Solar flux index and sunspot number convey generally the same information. Its like comparing apples to apples. Linear formula coefficients relating the two can be obtained using least-mean-squares fitting from empirical data. e.g. https://www.electronics-notes.com/articles/antennas-propagation/ionospheric/solar-indices-flux-a-ap-k-kp.php https://www.researchgate.net/publication/333533478_A_Study_of_the_correlation_between_Sunspot_Number_and_Solar_Flux_during_Solar_Cycle_24 Your derived statistic "Strength" uses solar flux index as the numerator and sunspot number as the denominator. It should come as no surprise that the maximum value for Strength occurs when sunspot number is lowest. (e.g. if sunspot number drops from 4 to 2 while SFI drops from 74 to 68, "Strength" almost doubles.) If you review your results, would you not find that the month of your predicted solar minimum simply occurs in the month with the lowest smoothed fitted sunspot number, irrespective of solar flux index? Please consider this a constructive criticism. We live in a world of too much data and too little thinking. As you have applied much thought to this, applaud your efforts. https://en.m.wikipedia.org/wiki/Solar_cycle_25
  9. I submit that determining/predicting the time and intensity of the *maximum* of a solar cycle is far more important than predicting the *start* of a solar cycle. The sun is at its most active during its maximum in the solar cycle when adverse solar effects impacting astronauts, power grid, communications, etc. are more likely to occur.
  10. For posterity, the "Honolulu event" occurred on 2020-06-29 22:47:00 UTC. The Honolulu DST has been negative-shifted since that time. The Honolulu DST Index was reported as invalid (99999) for a few minutes after the event, but soon resumed reporting DST Index. Though suspect due to the negative shift, the Honolulu reported DST Index could be presumed to be valid by consumers (e.g. Kyoto). The Honolulu geomagnetic data has been flagged as invalid (99999) since the event, but the Honolulu DST Index has not. https://geomag.usgs.gov/plots/dst https://geomag.usgs.gov/ws/edge/?elements=MDT&endtime=2020-06-29T23:15:00.000Z&format=iaga2002&id=HON&sampling_period=60&starttime=2020-06-29T22:45:00.000Z&type=variation 2020-06-29 22:45:00.000 181 -7.27 88888.00 88888.00 88888.00 2020-06-29 22:46:00.000 181 -7.36 88888.00 88888.00 88888.00 2020-06-29 22:47:00.000 181 99999.00 88888.00 88888.00 88888.00 2020-06-29 22:48:00.000 181 99999.00 88888.00 88888.00 88888.00 2020-06-29 22:49:00.000 181 99999.00 88888.00 88888.00 88888.00 2020-06-29 22:50:00.000 181 99999.00 88888.00 88888.00 88888.00 2020-06-29 22:51:00.000 181 99999.00 88888.00 88888.00 88888.00 2020-06-29 22:52:00.000 181 99999.00 88888.00 88888.00 88888.00 2020-06-29 22:53:00.000 181 1288.70 88888.00 88888.00 88888.00 2020-06-29 22:54:00.000 181 -26028.94 88888.00 88888.00 88888.00 2020-06-29 22:55:00.000 181 -27095.66 88888.00 88888.00 88888.00 2020-06-29 22:56:00.000 181 -27038.09 88888.00 88888.00 88888.00 2020-06-29 22:57:00.000 181 -26783.00 88888.00 88888.00 88888.00 2020-06-29 22:58:00.000 181 -26759.66 88888.00 88888.00 88888.00 2020-06-29 22:59:00.000 181 -26759.66 88888.00 88888.00 88888.00 2020-06-29 23:00:00.000 181 -26759.66 88888.00 88888.00 88888.00 2020-06-29 23:01:00.000 181 -26759.67 88888.00 88888.00 88888.00 2020-06-29 23:02:00.000 181 99999.00 88888.00 88888.00 88888.00 2020-06-29 23:03:00.000 181 -101.28 88888.00 88888.00 88888.00 2020-06-29 23:04:00.000 181 -101.22 88888.00 88888.00 88888.00 2020-06-29 23:05:00.000 181 -509.73 88888.00 88888.00 88888.00 2020-06-29 23:06:00.000 181 -101.08 88888.00 88888.00 88888.00 2020-06-29 23:07:00.000 181 -101.01 88888.00 88888.00 88888.00 2020-06-29 23:08:00.000 181 -100.96 88888.00 88888.00 88888.00 2020-06-29 23:09:00.000 181 -100.94 88888.00 88888.00 88888.00 2020-06-29 23:10:00.000 181 -100.76 88888.00 88888.00 88888.00 2020-06-29 23:11:00.000 181 -100.62 88888.00 88888.00 88888.00 2020-06-29 23:12:00.000 181 -100.58 88888.00 88888.00 88888.00 2020-06-29 23:13:00.000 181 -100.57 88888.00 88888.00 88888.00 2020-06-29 23:14:00.000 181 -100.61 88888.00 88888.00 88888.00 2020-06-29 23:15:00.000 181 -100.61 88888.00 88888.00 88888.00 P.S. Whatever consulting fees may be due and payable by USGS etc. to those who have participated in this thread, in consideration for their time, effort, and expertise in the review and analysis of this issue, I suggest should go to the spaceweatherlive general fund.
  11. I've had an interest in astronomy since I was a child and first saw the rings of Saturn through my small refractor telescope. As for space weather, that interest is recent, coincident with an interest in amateur radio. As a licensed amateur radio operator, I look at KP index, sunspot number, and other space weather metrics and observable atmospheric phenomenon to see if I can to correlate them to empirical observations of band conditions, background noise levels, signal fading, and propagation characteristics that enhance or degrade radio communications between myself and other hams across the US and across the world.
  12. Here's a really good slideshow presentation about the observed DST index calculation. Delving into the details of how the DST Index is calculated, it is quite a complex procedure. It is not merely a matter of taking instantaneous magnetometer readings from several observation sites and averaging them. Far from it! It's a good read for anyone interested in understanding more detail. I learned a lot from it - particularly realizing how difficult it could be to identify the root cause of apparently anomalous DST Index data and to track down the component(s) that may be contributing to it. https://slideplayer.com/slide/4307987/
  13. Correct! Great observation - yes that could be the indeed be the reason. The Kyoto web site does show how data from 4 observation sites are combined. There are supposed to be multiple levels of quality checks, but something perhaps went awry in that process. If for example a data value of -99 from one site is intended to be a flag that the data is invalid or unavailable, but it is instead used AS-IS and averaged in with the data from the other 3 sites, then you would get a downward offset in the observed DST data of about -25nT. http://wdc.kugi.kyoto-u.ac.jp/figs/three_versions.jpg
  14. Was an interfering magnetic field introduced on 2020-Jun-29? Did someone at Kyoto take a magnet to work and leave it near the detector? Were some computers, monitors, or other EMI-generating electrical equipment introduced or moved? Were new power distribution lines or networks installed or activated? Does Comet Neowise have a strong magnetic core that was exposed as it passed the plane of the ecliptic around June 29? Or did someone accidentally insert a typo of "-25 nT" in the reported DST quicklook formula? That's a problem with Occam's Razor. It is a subjective matter of opinion which is the simplest explanation, and "all other factors being equal" is rarely the case. But if the observed DST reaches a nadir on July 23rd, I say it's Neowise.
  15. Yes, it does seem that "the bottom dropped out" on 2020-Jun-29. A notable aberration in the current data is the observed DST has been negative for over 2 weeks. There are examples in the data of such abrupt negative dips (often preceded by a positive bump), such as occurred on 2019-Aug-05. In that case the DST remained negative for 1 week before the next zero-crossing to positive values: 2019-Aug
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