The Variability of solar IRradiance and Gravity Oscillations (VIRGO) experiment contains two types of active cavity radiometers for monitoring of the solar constant, two three channel sunphotometers for the measurement of spectral irradiance at 335, 500 and 865 nm and a low resolution imager with 12 pixels. The main scientific objective is probing the solar interior by helioseismology with p and g mode solar oscillations determined from spectral irradiance and radiance variations on time scales of minutes to the mission time. Information about the convection zone is thus obtained. The comparison of the amplitudes and phases of the oscillations as manifested in irradiance and radiance (from VIRGO) and velocity as measured by the GOLF (global oscillations at low frequencies) experiment are also used in analyzing the convection zone.