  Early-type stars are predicted to excite an entire spectrum of internal
gravity waves (IGWs) at the interface of their convective cores and radiative
envelopes. Numerical simulations of IGWs predict stochastic low-frequency
variability in photometric observations, yet the detection of IGWs in
early-type stars has been limited by a dearth of high-quality photometric time
series. We present observational evidence of stochastic low-frequency
variability in the CoRoT photometry of a sample of O, B, A and F stars. The
presence of this stochastic low-frequency variability in stars across the upper
main-sequence cannot be universally explained as granulation or stellar winds,
but its morphology is found to be consistent with predictions from IGW
simulations.
