Lyman-alpha blob 1 (LAB-1) is a giant cosmic cloud of gas located in the constellation of Aquarius, approximately 11.5 billion light-years from Earth with a redshift (z) of 3.09.

It was discovered unexpectedly in 2000 by Charles Steidel and colleagues,[2] who were surveying for high-redshift galaxies using the 200 inch (5.08 m) Hale Telescope at the Palomar Observatory.

[3] It is also one of the largest of its kind, measuring 300,000 light years across, three times larger than the Milky Way.

[4] Imaging with the European Southern Observatory's Very Large Telescope showed that much of the light from the blob is polarized, the proportion increasing and peaking at around 20% at a radius of 45 kiloparsecs (145,000 light-years), forming a huge ring around the blob.

[4] An alternate theory is that the light is from cooling gas falling into early galaxies, which has possibly come from cosmic filaments (as galaxies are thought to form at the intersections of these filaments); however, the pattern of polarization found argues against this.