What you’re seeing in the 50-second video below is not a star exploding, but the movement of light from a star as it bounces off dust and reaches us on Earth. That star emitted a burst of light in 2002, which, as it moved outward, illuminated parts of the dust cloud surrounding the star. (No, the cloud isn’t moving.) As the light reaches parts of the dust cloud farther from the star, it gets reflected back to Earth in sequence. (By the way, if you want to spend an instructive 15 minutes, read the Wikipedia article on the speed of light, which is pretty good. Did you know that light moves through a diamond at one-third of the speed it moves in a vacuum?)
The video gives four years of time-lapse photos from the Hubble Space Telescope. Since light travels 186,000 miles per second (nearly 300,000 km/sec), you can see how vast space is compared to the speed of light. The YouTube description is below.
The unusual variable star V838 Monocerotis (V838 Mon) continues to puzzle astronomers. This previously inconspicuous star underwent an outburst early in 2002, during which it temporarily increased in brightness to become 600,000 times more luminous than our Sun. Light from this sudden eruption is illuminating the interstellar dust surrounding the star, producing the most spectacular “light echo” in the history of astronomy.
As light from the eruption propagates outward into the dust, it is scattered by the dust and travels to the Earth. The scattered light has travelled an extra distance in comparison to light that reaches Earth directly from the stellar outburst. Such a light echo is the optical analogue of the sound echo produced when an Alpine yodel is reflected from the surrounding mountainsides.
The NASA/ESA Hubble Space Telescope has been observing the V838 Mon light echo since 2002. Each new observation of the light echo reveals a new and unique “thin-section” through the interstellar dust around the star. This video morphs images of the light echo from the Hubble taken at multiple times between 2002 and 2006. The numerous whorls and eddies in the interstellar dust are particularly noticeable. Possibly they have been produced by the effects of magnetic fields in the space between the stars.