Key concepts

• global climate

• asteroid impact

• supernova

Introduction

Can space weather have ismpacts on global climate? We know that the amount of energy striking Earth from the Sun is the main driver of weather and climate. Temperature differences from day to night and from season to season are explained by the intensity of sunlight falling onto the surface and into Earth's atmosphere. For the most part, variation in intensity of sunlight is due not to changes in the luminosity or brightness of the Sun, but instead due to the daily rotation of Earth and the regular annual variation in hemispheric tilt toward or away from the Sun. In northern hemisphere summer, the Earth's axis and the northern hemisphere are tilted toward the Sun. Six months later, northern hemisphere winter occurs – Earth is on the opposite side of the Sun, and the northern hemisphere is tilted away from the Sun.