A solar eclipse occurs when the Moon passes between the Sun and the Earth, allowing the Moon's long, thin shadow to intersect the Earth's surface. The shadow comprises two concentric cones called the umbra and the penumbra. Observers on the Earth who are within the smaller, central umbra see the Sun completely blocked.
Within the larger
penumbra, the Sun is only partially blocked. In this visualization, the Earth,
Moon, Sun, and shadow cones are viewed through a telescopic lens on a virtual
camera. Long focal lengths like the one used here appear to compress the distance
between near and far objects. Despite appearances, the geometry of the scene is
to scale. The Moon's umbra cone is roughly 30 Earth diameters long, barely
enough to reach the Earth, while the Sun is both 400 times larger than the Moon
and 400 times farther away.
The virtual camera
flies from the night side of the Earth and Moon to the day side, revealing the
path of the Moon's shadow during the April 8, 2024, total solar eclipse. The
umbra sweeps across the surface at more than 1500 miles (2400 kilometers) per hour
along the path of totality, shown in red. The shadow would move even faster if
the Earth weren't rotating in the same direction. The shadow tracks the
west-to-east motion of the Moon in its orbit.
The outline of the
penumbra is shown in purple, and the northern and southern edges of the path it
sweeps out are drawn in yellow. This shows the part of the Earth where people
will see at least a partial eclipse. Orange loops at either end of the eclipse
path are sunrise and sunset lines, points on the Earth where the eclipse either
begins or ends at sunrise or sunset.
The umbra is over
land for just an hour and forty minutes before moving into the North Atlantic
and then skipping off the edge of the Earth.
No comments:
Post a Comment