May/June 2003 Table of Contents
of NASA, ESA, and Howard Bond (STScI).
bizarre star erupts in Monoceros, creating a beautiful bull's-eye
I first saw these spectacular Hubble Space Telescope images at an
astronomy conference this past January, my initial reaction was
"Oh my gosh!" My second reaction was that I was seeing
the expansion of a nebula, perhaps resulting from a stellar explosion
such as a nova or supernova.
In reality, there is nothing moving or expanding at all. Instead,
we're seeing light echoes. As light from the central star sweeps
outward through the surrounding cloud, it is reflected toward Earth
by successive shells of dust.