A number of hypotheses have been advanced as to the source and nature of the Wow! signal. None of them have achieved widespread acceptance. Interstellar scintillation of a weaker continuous signal—similar in effect to atmospheric twinkling—could be an explanation, but that would not exclude the possibility of the signal being artificial in origin. The significantly more sensitive Very Large Array did not detect the signal, and the probability that a signal below the detection threshold of the Very Large Array could be detected by the Big Ear due to interstellar scintillation is low. Other hypotheses include a rotating lighthouse-like source, a signal sweeping in frequency, or a one-time burst.