... one of the biggest stars known, and almost 1000 times larger than our Sun. It is also one of the most luminous stars known, emitting more light than 100,000 Suns.Marvelous Betelgeuse artist-impression graphic here. Alas, poor Pluto, we hardly knew ye!
If Betelgeuse were at the centre of our Solar System it would extend out almost to the orbit of Jupiter, engulfing Mercury, Venus, Earth, Mars and the main asteroid belt.
Speculation that Betelgeuse could go supernova any time now (or may have already) here at EarthSky.org.