How big are those sunspots? Attached is an image (courtesy of our friends on the SDO project) showing Region 1476 at it's largest and finest. Some... ... <看更多>

To understand how much a sunspot can change during its life I think that the only solution is to see it. So I decided to produce short ... ... <看更多>

Sep 18, 2017 - synoptic-map.jpg (JPEG Image, 3380 × 2542 pixels), 091817. NOAA. [ - FILED BY MR. TRONA - ] ... <看更多>