Colors: Ring Nebula versus Stars

What if you could see, separately, all the colors of the Ring? And of the surrounding stars? There’s technology for that. The featured image shows the Ring Nebula (M57) and nearby stars through such technology: in this case, a prism-like diffraction grating. The Ring Nebula is seen only a few times because it emits light, primarily, in only a few colors. The two brightest emitted colors are hydrogen (red) and oxygen (blue), appearing as nearly overlapping images to the left of the image center. The image just to the right of center is the color-combined icon normally seen. Stars, on the other hand, emit most of their light in colors all across the visible spectrum. These colors, combined, make a nearly continuous streak — which is why stars appear accompanied by multicolored bars. Breaking object light up into colors is scientifically useful because it can reveal the elements that compose that object, how fast that object is moving, and how distant that object is. via NASA

Wikipedia article of the day for July 21, 2021

Wikipedia article of the day is Dementia with Lewy bodies. Check it out: Article-Link Summary: Dementia with Lewy bodies is a common dementia characterized by changes in sleep, behavior, cognition, movement, and automatic bodily functions. Symptoms worsen over time until cognitive decline interferes with normal daily functioning. The core features are REM sleep behavior disorder (in which people act out their dreams), visual hallucinations, marked fluctuations in attention or alertness, and parkinsonism. The exact cause is unknown, but involves deposits of abnormal clumps of protein in the brain, known as Lewy bodies. Gastrointestinal and heart function can be affected. Definitive diagnosis usually requires an autopsy, and a probable diagnosis—based on symptoms and tests—is often missed. Management of the many symptoms is challenging and involves multiple specialties. There is no cure or medication to stop the disease progression. After the suicide of Robin Williams (pictured) in 2014, his autopsy found that diffuse Lewy bodies explained his symptoms.