What is a light echo?

In Hubble pictures taken just months apart of V838 Monocerotis, the dust ring around this star grows by several light-years during that time, called a “light echo.” How can something grow by 5 light-years in five months? Ronald VanAttaAnn Arbor, Michigan Congratulations on noticing an effect called superluminal expansion, a phenomenon we see in aContinue reading “What is a light echo?”

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