The first naked-eye supernova since the invention of the telescope lit up the global astronomy world on the morning of February 23, 1987, as news spread by phone and teletype. Supernova 1987A in the Large Magellanic Cloud eventually reached magnitude 2.9, before beginning a long fade and a cascade of unexpected developments that continues to this day. We published a full recap in the February Sky & Telescope, page 36.
Here's a video that, obviously, we couldn't print! On Friday (February 24th) NASA and the European Space Agency released this animation of the evolving supernova remnant, as seen in 23 years of Hubble Space Telescope images:
Starting in 1994, we see the exploded star's central debris cloud fade and expand into an irregular shape, inside a bright red ring of stationary hydrogen gas. The ring, a light-year across, took shape thousands of years earlier from material expelled from the aging star as it neared the end of its life. We see blobs in the ring light up as the outermost shock wave first strikes them starting in the mid- and late 1990s. The blobs remain lit as they shrink back and erode under the onslaught. Eventually the ring will be blown away completely.
The visual appearance, of course, just scratches the surface of the intricate events that astronomers have deduced by spectroscopy and imaging at wavelengths from radio to X-rays — not to mention the neutrinos and the initial ultraviolet flare from the explosion's early seconds and hours. The story is far from over!