Showing results for "Legacy" in Earth Sciences

Scientists have long attempted to understand Earth’s past, and in service to that effort, they have divided the world’s history into eons, eras, periods, epochs, and ages. For example, the current eon is called the Phanerozoic Eon, which means “visible life”. This is the eon in which multicellular life has evolved and thrived. Before this, life was microscopic (single cells).

The early history of Earth covers such vast stretches of time that years, centuries, and even millennia become virtually meaningless. Instead, paleontologists and scientists who study geochronology divide time into periods and eras. What humans commonly refer to as the “Ice Age” is actually a series of fluctuating climate events that have occurred throughout the planet’s history. These ongoing historical phenomena are difficult to conceptualize because of both the time frame involved and the natural process by which they cyclically unfold.

Serendipity placed David Johnston on Mount St. Helens when the volcano rumbled to life in March 1980. Throughout that ominous spring, Johnston was part of a team conducting scientific research that underpinned warnings about the mountain. Those warnings saved thousands of lives when the most devastating volcanic eruption in U.S. history blew apart Mount St. Helens but killed Johnston on the ridge that now bears his name. Melanie Holmes tells the story of Johnston's journey from a nature-loving Boy Scout to a committed geologist.

They say that one is subjected to a sobering sample of what can only be described as an existential crisis when traversing the golden and seemingly infinite terrain of the Sahara Desert. If one climbed any of the countless sand dunes and twirled around in a place, particularly under the starlit sky, they would scarcely be able to tell east from west without a compass, for there would be nothing but dizzying carpets of indistinguishable sand hills unfurling into the distant horizon.