Hurricane Dorian was advancing at the pace of a slow crawl when it struck the Bahamas on Monday, September 2. Homes, schools, and hospitals in its path were no match for the 185 mph winds surrounding the eye. Flooding brought on by powerful storm surges overwhelmed the many low-lying islands that comprise the northern Bahamas, submerging the worst affected areas almost entirely.
If you’ve ever found yourself mesmerized by that v-shaped bow wave created by the hull of a ship as it pushes through the water, you might be interested to learn that it doesn’t actually matter whether it’s the ship or the water that’s moving. If one were to, let’s say, replace the ship with a 2,500-foot-high dormant volcano and the water with a moist air mass, you might end up with something that looks like this.
When this image was captured by Astronaut Ricky Arnold on September 10, 2018, Florence was still four days from landfall. Seen here at the peak of its intensity, the storm weakened gradually as it approached the Carolina coast. By the time it came ashore at Wrightsville Beach, NC, the wind speeds within the storm had dropped from Category 4 to Category 1 levels. That’s the good news.
You can thank atmospheric refraction for this droll little optical illusion.
In this image from August of 2016, sunlight reflected off of the Moon’s surface is bent as it passes through Earth’s atmosphere. By the time it arrives at the camera lens peering through the space station’s cupola window, something’s off.
Misshapen, yes. Permanent, no. Light travels fastest through a vacuum, slower through a medium – like air, for example. Where the atmosphere is denser its velocity is somewhat slower, and the light is bent, or refracted. Atmospheric refraction displaces stars from their expected location, and warps the shape of larger objects like the Sun and Moon. These ‘altered states’ are most noticeable just above the horizon, where the atmosphere is densest.