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How can impact debris in the atmosphere lead to an impact winter?

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four impact craters — Meteorite crater Four impact craters of the same size (30 km [20 miles] in diameter) imaged by spacecraft on different solid bodies of the solar system and reproduced at the same scale. They are (clockwise from upper left) Golubkhina crater on Venus, Kepler crater on the Moon, an unnamed crater on Jupiter's moon Ganymede, and an unnamed crater on Mars. The images are oriented such that the craters appear illuminated from the left; the Venusian crater is imaged in radar wavelengths, the others in visible light.

When a massive asteroid or comet strikes Earth, the resulting collision can trigger an impact winter by ejecting vast quantities of fine debris high into the atmosphere. This material, once lofted into the upper atmosphere, acts as a barrier that significantly reduces the amount of sunlight reaching the planet's surface.1

The reduction in solar radiation leads to a prolonged, global depression of surface temperatures. This cooling effect disrupts the environment by hindering photosynthesis in plant life, which can cause widespread starvation and disease across the globe. Such catastrophic environmental perturbations are believed to be a primary mechanism by which large-scale impact events contribute to mass extinctions, such as the event at the end of the Cretaceous Period that resulted in the demise of the dinosaurs.12