This paper investigates the constraints on dark energy from cosmic age limits and supernova observations. Using the cosmic age limit derived from globular clusters and white dwarfs ($t_0 > 12$ Gyr) and recent high-redshift supernova data from the HST/GOODS program, the authors estimate the equation of state for dark energy. They find that the cosmic age limit significantly reduces the upper bound on the variation amplitude of the dark energy equation of state. The authors propose a new scenario called Quintom, which has an equation of state greater than $-1$ in the past and less than $-1$ today, satisfying current observations. Additionally, they consider the implications of recent X-ray gas mass fraction data, which suggests a negative running of the equation of state. The paper discusses the challenges and implications of these findings for dark energy theories, particularly the cosmological constant and dynamical dark energy models.This paper investigates the constraints on dark energy from cosmic age limits and supernova observations. Using the cosmic age limit derived from globular clusters and white dwarfs ($t_0 > 12$ Gyr) and recent high-redshift supernova data from the HST/GOODS program, the authors estimate the equation of state for dark energy. They find that the cosmic age limit significantly reduces the upper bound on the variation amplitude of the dark energy equation of state. The authors propose a new scenario called Quintom, which has an equation of state greater than $-1$ in the past and less than $-1$ today, satisfying current observations. Additionally, they consider the implications of recent X-ray gas mass fraction data, which suggests a negative running of the equation of state. The paper discusses the challenges and implications of these findings for dark energy theories, particularly the cosmological constant and dynamical dark energy models.