“The Cow and CSS161010 were very different in how fast they were able to speed up these outflows,” said Northwestern astrophysicist Raffaella Margutti, about a bright burst in a tiny galaxy 500 million light years away from Earth, a new astronomical transient in the universe, that launched 1 to 10 percent the mass of the sun at more than half the speed of light — evidence that this is a new class of transient. CSS161010 is vastly faster, heavier and brighter at radio wavelengths than its mysterious predecessor, AT2018COW (“The Cow” above). “But they do share one thing — this presence of a black hole or neutron star inside. That’s the key ingredient.”