Himiko (Lyman-alpha blob)
Himiko is a large gas cloud found at redshift of z=6.6 that predates similar Lyman-alpha blobs. At the time of its discovery in 2009, researchers said it "may represent the most massive object ever discovered in the early universe". It is located in Cetus at redshift z=6.595, about 12.9 billion light years from Earth, or about 75×1021 miles (122×1021 kilometers).