How We Measure the Universe, Animated. Donating = loving Brain Pickings remains ad-free and takes hundreds of hours a month to research and write, and thousands of dollars to sustain.
If you find any joy and value in it, please consider becoming a Member and supporting with a recurring monthly donation of your choosing, between a cup of tea and a good dinner: Cosmology. Chapter index in this window — — Chapter index in separate window This material (including images) is copyrighted!.
See my copyright notice for fair use practices. At first you might think that in order to understand the structure of something as large as the universe, which by definition contains everything there is, you would need some very powerful telescope to see to the farthest reaches of space and a complex theoretical model. Actually, there are some powerful conclusions you can draw from observations with the naked eye. You will explore that first and then move on to conclusions you can draw from extending your eyesight. Supernovas & Supernova Remnants. Supernovas & Supernova Remnants Every 50 years or so, a massive star in our galaxy blows itself apart in a supernova explosion.
Supernovas are one of the most violent events in the universe, and the force of the explosion generates a blinding flash of radiation, as well as shock waves analogous to sonic booms. Supernovas were originally classified on the basis of their optical properties. Type II supernovas show conspicuous evidence for hydrogen in the expanding debris ejected in the explosion; Type Ia explosions do not. Recent research has led to a refinement of these types, and a classification in terms of the types of stars that give rise to supernovas. YouTube. YouTube. YouTube. Teach Astronomy - Cosmological Principle. Parsec Definition. Astronomical distance units -parsecs, light years and AU.