4 ms·
Meaning of G4: http://www.swpc.noaa.gov/noaa-scales-explanation http://www.swpc.noaa.gov/noaa-scales-explanation "Power systems: Possible widespread voltage co
by colanderman 9y ago
Meaning of G4: http://www.swpc.noaa.gov/noaa-scales-explanation http://www.swpc.noaa.gov/noaa-scales-explanation
"Power systems: Possible widespread voltage control problems and some protective systems will mistakenly trip out key assets from the grid.
Spacecraft operations: May experience surface charging and tracking problems, corrections may be needed for orientation problems.
Other systems: Induced pipeline currents affect preventive measures, HF radio propagation sporadic, satellite navigation degraded for hours, low-frequency radio navigation disrupted, and aurora has been seen as low as Alabama and northern California (typically 45° geomagnetic lat.)."
Apparently there are 100 of these per 11-year solar cycle.
- dbcurtis 9y agowhat "these" do we have 100 of? X class flares, or X class flares facing the Earth? Because just by chance we are usually out of harm's way.
- lgats 9y agoHaving subscribed to NOAA's alerts a couple years ago, I would say we might get an event like this once a year or two
- jsjohnst 9y agoPer the link above, this is the 8th most powerful CME hitting earth in recorded history. An X9.3 is not a yearly thing.
- Rebelgecko 9y agoHow far back does "recorded history" go for these sorts of detailed space weather measurements? The linked #8 ranking seems to be based on 20 years of data
- SolarNet 9y agoI think they go back to the early telegraph based off of observations of static on the wire and other related problems (a telegraph was basically a giant inductor).
- Rebelgecko 9y agoAre those classifications listed somewhere? I suspect that they'd be much less accurate than the measurements from modern equipment (e.g. satellites)
- PoachedSausage 9y agoAs far back as the Carrington Event at least. https://en.wikipedia.org/wiki/Solar_storm_of_1859 https://en.wikipedia.org/wiki/Solar_storm_of_1859
- colanderman 9y agoG4 geomagnetic storms. (I'm just parroting the chart I linked.)
- meseznik 9y agoApparently there are 100 of these per 11-year solar cycle. Seems that there are much more than 100 flares each cycle: https://hesperia.gsfc.nasa.gov/hessidata/dbase/hessi_flare_list.txt https://hesperia.gsfc.nasa.gov/hessidata/dbase/hessi_flare_l... It also seems that flares above X2.2 are quite rare. There have been only 10 of those since 2008: https://en.wikipedia.org/wiki/Solar_cycle_24#Events https://en.wikipedia.org/wiki/Solar_cycle_24#Events The latest flare, measured at X9.3 is VERY rare: https://www.spaceweatherlive.com/en/solar-activity/top-50-solar-flares https://www.spaceweatherlive.com/en/solar-activity/top-50-so... I wouldn't downplay this
- colanderman 9y agoG4 geomagnetic storms, not flares.
- ruleabidinguser 9y agoCaused by a x2.2 flare
- RandVal30142 9y agoThat last link is extremely interesting. Just spent some minutes watching the videos of previous record setting flares. The flares oriented towards Earth are very obvious due to the amount of static after flare ejection. We all exist in a narrow band of of environmental conditions, spooky thinking about how much energy is occasionally hurled towards us. Just a slight lick from Sol and we could be done for.
- nomel 9y ago> Spacecraft operations: May experience surface charging and tracking problems, corrections may be needed for orientation problems. What causes the tracking and orientation problems? Are they being pushed, or do satellites control their orbit?
- cjhanks 9y agoI would suspect they are using magnetometers for determining orientation. Those might be affected.
- brandmeyer 9y agoFor the most part, orientation is measured optically or thermally - with sun sensors, earth sensors, and star trackers.
- brandmeyer 9y agoIt takes huge amounts of deliberately applied energy to change their orbit. This is about the influence of the radiation on the sensors and systems which help to control the orientation of the satellites. In particular, magnetorquers use the magnetic field of the earth to (very slowly) dump excess angular momentum from the reaction wheels and control moment gyros. Solar storms can also add a weak torque onto the satellite, depending on the orientation and shape of its body and solar panels. Again, the satellite has an attitude control system to handle such things, but it will still suffer the impulse response from the transient.
- koyao 9y ago"Yup, that's why I was late to work this morning." :)