A few weeks before Venus passes in front of the Sun, what would be its phase as observed from Earth? Quarter phase (half illuminated). Thin waxing crescent phase. Waxing gibbous phase. Thin waning crescent phase. Full phase. Waning gibbous phase. None of the other answers- planets do not go through phases like the Moon's. In physics, changing velocity over time as measured in meters/second/second is called acceleration. gravity. velocity. mass. force.