Femtosecond pulses of light propagating along photonic-crystal bres can generate a broad optical supercontinuum.This striking discovery has applications ranging from spectroscopy and metrology to telecommunication and medicine.Among the physi-cal principles underlying supercontinuum generation are soliton emission, a variety of four wave mixing processes, Raman-induced soliton self-frequency shift, and disper-sive wave generation mediated by solitons.Although all of the above eects contribute to supercon tinuum generation, none of them can explain the generation of blue and violet light from infrared femtosecond pump pulses.In this talk I will argue that the most profound role in the shaping of the short-wavelength edge of the continuum is played by the eect of radia tion trapping in a gravity-like potential created by accel-erating solitons.The underlying physics of this eect has a straightforward analogy with the inertial forces acting on an observer moving with a constant acceleration.This observation allows to use ber solitons as ecient tools for targeted frequency conversion and for emulation of light bending and trapping by gravity in the ber optics experiments.