... NGC 2346: A Butterfly-Shaped Planetary Nebula . ... These dramatic stellar explosions that destroy stars and disperse elements that compose people and planets are not so well understood that astronomers can accurately predict when a star will explode - yet. ... Situated over 2,000,000,000 (two billion) light-years from Earth, galaxies in cluster Abell 2390 (top) and MS2137.3-2353 (bottom) are seen in the right hand panels above, false-color images from the Hubble Space Telescope. ...