“Lyman-alpha blobs” is just a cool way of saying “massive, distant, early-universe collections of hydrogen gas”. There have been several of them seen. Since they’re billions of light-years away, and therefore billions of years old, they tell us a lot about how the galaxies we know today evolved.
A new Lyman-alpha blob has been found, though: Himiko. It’s very far away, 12.9 billion light-years. And it’s big. Very big. Much (like, 10 times) bigger than similar blobs are, and than our models say are likely to exist.
It’ll be interesting to find out why it’s so huge. Is there a supermassive block hole at its centre? Are our models of galaxy formation wrong? Is it just a big ol’ freaky space blob?
Stay tuned. I, for one, welcome Himiko, our new Lyman-alpha Overlord.