Friday, September 23, 2011

The most powerful Atlantic hurricanes

One of the ways in which meteorologists assess the intensity of a hurricane is by measuring its barometric pressure. Generally speaking, the lower the pressure is in the core of the hurricane, the more quickly air will rush into the core from adjacent regions of higher pressure. Thus, as a rule of thumb, if hurricane A has a lower barometric pressure than hurricane B, hurricane A is thought to have higher top sustained winds, and is therefore the more intense of the two systems.

By that metric (and not according to wind speeds actually measured in the core of a hurricane), the most powerful hurricane ever recorded in the Atlantic basin was hurricane Wilma in October of 2005. At its peak intensity over the western Caribbean, Wilma registered an Atlantic basin record low pressure of 882 millibars. The storm had top sustained winds of 185 miles per hour, and gusts that screamed well over 200 miles per hour.

Using barometric pressure as the sole criteria for measuring intensity, here is a list of the ten most powerful Atlantic hurricanes:

Note : The list above is based on the lowest pressure recorded during the entire life of each storm,  which was not necessarily the barometric pressure of the system at landfall.

Sunday, September 18, 2011

The first land vertebrates

During the Devonian period (417 ~ 360 mya) one of the most important changes in the history of life on earth took place. It was during this time that backboned animals began to venture out of primordial bodies of water and onto terra firma, begetting a line of vertebrate land dwellers that eventually led to amphibians, reptiles, and mammals such as ourselves.


While we are descendants of the first backboned creatures to venture onto dry land, the first land vertebrates looked nothing like us. Indeed, they had a bizarre, otherworldly appearance, and resembled something of a cross between a fish and a salamander. Their fossil remains have been discovered in Devonian period rocks, many of which are located in northern Canada.

For those of you who are interested, here is a link to the Wikipedia page for the Devonian period:

 http://en.wikipedia.org/wiki/Devonian