{{tag>sun solar_cycle}}
====== Solar Activity Cycle ======
Assigned to Nick (on 01/22/2024)
===== General Description of the Simulation =====
A simplified, straightforward version of the simulation was done already (see [[https://svs.gsfc.nasa.gov/3505]]). This GSFC animation is showing a time-lapse video where spots are shifted in position due to solar rotation. We can create an animation of the non-rotating Sun, by shifting images anti-rotation direction such that the equatorial region appears to be non-moving. In such an animation, polar regions will appear to be rotating backward because of ''differential rotation''. The image shown right is a sequence of solar images taken by [[https://svs.gsfc.nasa.gov/search/?missions=SOHO|SOHO]] during Solar Cycle 23 (11.6 yrs long: May 1996 - Jan 2008).
We can improve the above trial by showing sunspots over one solar activity cycle using the solar disk, rather than a Mercator projection shown above. I.e., in Blender, we can create a rotating sphere with textured images taken from several Sun-observing satellites. By choosing a different time-interval (days or months), we can focus on the changing nature of Sun-spots over time to demonstrate (1) solar (differential) rotation, (2) solar activity (i.e., changing number of sunspots), and (3) migration of active region from polar to equatorial (i.e., latitude dependency of solar activity).
{{https://svs.gsfc.nasa.gov/vis/a000000/a003500/a003505/SynopticSequence_900x450.webmhd.webm?500|A sequence of synoptic solar images}}
For this project, we should be able to download a set of synoptic (i.e., rotation-corrected) images of the Sun. https://proba2.sidc.be/Synoptic-observations can be a good place to obtain relevant images. Then, use these images (one at a time) to lay down a texture on a Blender-created Sun. Periodically changing the texture images, we can simulate the rotation and activity cycle of the Sun.
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~~ Important/key tasks to be completed for this simulation ~~
Important pending tasks (or notes/ideas) to complete the simulation.
* Create a rotating Sun in Blender with a sequence of solar synoptic images applied as textured images.
* There should be two different sets of images: (1) one covers 2-3 solar rotations (~60 days long) and (2) another covers 11-year solar activity cycles. In each set, the number of suitable images can be determined from trial and error to ensure a smooth rendering while not increasing the model size unnecessarily.
* Develop a method of de-rotating images => i.e., camera co-rotating above the equator at the rotation speed of the equator. This will highlight the differential rotation at higher latitudes.
* Add a real sky background image
* Add a corotating camera above the Sun's equator at a certain height so that the equatorial region appears to be non-rotating.
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~~ Technical Aspects of the simulation: prerequisites, products, etc. ~~
=== Prerequisites ===
These are technical prerequisites (3D model components) to create this simulation.
* Rotating Sun model in Blender
* A method (preferably a Python script) to derotate images and choose a timescale (i.e., days or years)
=== Newly created components from this simulation ===
These are newly created components (functions, materials, cameras, etc.) from this topic simulation.
* A rotating solar model with a real textured surface image
* The textured images can be updated easily
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~~ Astronomical/Astrophysical Concepts ~~
These are underlying astronomical concepts to teach with this simulated topic.
* Sun spots
* Solar rotation
* Differential rotation
* Solar activity cycle
* Latitude dependency of sunspots
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~~ Scenes created in the simulation ~~
These are some key scenes or animations from the simulation.
{{ topics:rotatingsun.mp4 }}
A screen recording from a Blender session of creating //Solar Rotation & Activity// simulation.
[[:astro-3d|Go back to the list of topics.]]