Explanation:
For reasons
unknown, star V838 Mon's
outer surface suddenly greatly expanded with the
result that it became the brightest star in the entire
Milky Way Galaxy in January 2002.
Then, just as suddenly, it faded.
A stellar flash
like this has never been seen before.
It's true that
supernovae
and
novae
expel matter out into space.
But while the
V838 Mon
flash appears to expel material into space, what is
seen here is actually an outwardly moving
light echo of the bright flash.
In a light
echo, light from the flash is
reflected by successively
more distant
rings in the ambient
interstellar dust that already surrounded
the star.
V838 Mon lies about 20,000
light years away toward the constellation of
Monoceros
the unicorn.
In this Hubble Space Telescope image from
February 2004, the light echo is about six
light years in diameter.
