3 ms·
Radiation damage to Hubble has been 4.3 years out of phase with the Solar cycle
- superkuh 1mo agoIt's well known that higher solar wind/CMEs density/speed/etc that comes with the peak of the 11 year intensity cycles scatters cosmic rays before they enter the inner heliosphere. Combine this with the 1~3 years it takes for the solar wind to travel out through the heliosphere and you get the phase difference. Really cool unintended sensor empirical data on it though. Don't try to correlate with the sun spots, correlate with the solar wind/cmes from the spots getting out far enough to effectively scatter the incoming cosmic rays away.
- terminalbraid 1mo agoThe paper claims directly "the rate of degradation over time remains unsatisfactorily unpredictable" but you are claiming the authors do not understand or are unaware of the point you are making?
- superkuh 1mo agoI think what I explained is known by anyone in solar physics. I cannot believe they would not have discussed it. It's absence in the paper is weird. But I think unpredictable refers more to LEO in the context of the paper where things are indeed more dynamic that just the 11 year periodicity of cosmic rays from solar activity causing scattering in the heliosphere.
- DANmode 1mo agoIdentifying a mechanism is not predicting its rate. There may be another variable they’re trying to pin down.
- 3lambda 1mo agoI thought it only takes a few days for solar wind to travel from the sun to the Earth? Can you clarify?
- aaron_m04 1mo agoIf you carefully re-read what GP wrote, you'll see there's no reference to Earth's orbit or 1 AU in there. GP wrote about the solar wind scattering cosmic rays when it reached some point in its outward travel.
- m3047 1mo agoCoronal mass traveling at a higher speed "sweeps" what's before it. You can see the spiral shape, and you can probably figure out that the stuff is slowing down as it moves outward. Watch this occasionally for a few months and you'll get the idea, although solar activity is slowing down somewhat (as expected). https://www.spaceweather.gov/products/wsa-enlil-solar-wind-prediction https://www.spaceweather.gov/products/wsa-enlil-solar-wind-p...
- ck2 1mo agoyou should see what cosmic rays do to space telescopes public almost never sees what raw images look like RAW https://blog.galaxyzoo.org/wp-content/uploads/2010/04/spiraliraw.jpg https://blog.galaxyzoo.org/wp-content/uploads/2010/04/spiral... FINAL https://blog.galaxyzoo.org/wp-content/uploads/2010/04/spiralifix.jpg https://blog.galaxyzoo.org/wp-content/uploads/2010/04/spiral... * https://blog.galaxyzoo.org/2010/04/12/how-to-handle-hubble-images/ https://blog.galaxyzoo.org/2010/04/12/how-to-handle-hubble-i... they also slowly destroy the sensors since they are physical particles moving at almost the speed of light
- r_lee 1mo agothanks for the links, that's really interesting to look at do you happen to know how exactly those artifacts are cleaned up?
- shrubble 1mo agoOne way is to take a “blank” picture which will then show just the noise; then use that as a reference for what can be removed from the image.
- rbanffy 1mo agoThe blank should only show long term damage. Hits while the sensor is collecting light can be averaged out from multiple readings of the sensor.
- lofaszvanitt 1mo agophotoshop ;D, or using multiple pictures
- javier2 1mo agoits actually quite doable. any cosmic rays will not be present in two pictures in a row. any permanent damage will be exactly the same in all pictures.
- icegreentea2 1mo ago
- two_handfuls 1mo agoThis sounds like the "hmm this is strange" first step of discovery.
- metalman 1mo agocue:ominous creapy alien sound track .play
- jimrandomh 1mo agoIs the relevant radiation solar radiation, or is there damage from radiation coming from the direction the optics are pointed? If it's the latter, then maybe the sun's emissions interact with inbound particles from sources outside the solar system? (I don't have sufficient background or time to check whether the paper already rules this out.)
- gramie 1mo agoAnd the nearest star to our solar system is 4.3 light years away. Coincidence? :-)
- insane_dreamer 1mo agocareful, the Alpha Centaurians might be on HN ...
- hn7jmxa7oc 1mo ago[dead]
- AgentLemon 1mo agoThere is a known reason for this (among radiation belt enthusiasts) that the authors either don't mention or don't know. Hubble's orbit is in the inner Van Allen belt, where the radiation intensity is out of phase with the solar cycle (because the atmosphere is thinner at solar minimum, and expands at solar maximum, affecting the inner radiation belt). See Figure 6 (https://agupubs.onlinelibrary.wiley.com/cms/asset/718954d6-34e2-4c8a-9f35-134cac5000fa/jgra55906-fig-0006-m.jpg https://agupubs.onlinelibrary.wiley.com/cms/asset/718954d6-3...) of this paper (https://agupubs.onlinelibrary.wiley.com/doi/10.1029/2020JA028198 https://agupubs.onlinelibrary.wiley.com/doi/10.1029/2020JA02...). Hubble is in a low altitude, near equatorial orbit, so the red curve (small L) is the most relevant one.