SDSS J1038+4849 is a galaxy cluster 4.5 billion light-years away in the constellation Ursa Major, famous for its appearance as a smiley face. The yellow eyes and white nose are distant galaxies, while the Einstein ring-forming smile and border are caused by gravitational lensing.Wiesner, M. P. (2010). On the properties of ten strong-lensing systems found in the Sloan Digital Sky Survey. Master's thesis, Northern Illinois University.
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