We humans often notice the passage of time by observing our watches; the movement of the Sun, Moon, and stars across the sky; or by the records left by our ancestors in diaries or other historical records—but these are just fleeting moments in the eyes of geological time. We are used to thinking about recorded history. But recorded history is just a blink when compared to the length of time called pre-history. Recorded history only goes back a few thousand years. The Earth is far older.

It’s hard for humans to grasp just how long the Earth has been here. Using a variety of methods, geologists have been able to put together many pieces of a very complicated puzzle. After all, how do you assemble a puzzle when you’re not sure what the finished picture should look like? From studying processes that are happening today, such as geological composition, rates of deposition, weathering, climatology, biology, and Earth’s magnetic field, geologists can extend these processes back to ancient times and learn what the Earth was like billions of years ago. When combined with data points such as those found in the fossil record, these extrapolations can be constrained, and the picture starts to emerge from the puzzle. More »

Yesterday an earthquake with a magnitude of 8.0 struck the South Pacific, near the Samoan islands. Wolfram|Alpha’s earthquake feed immediately brought information on that quake into the system, and continues to pick up data on aftershocks in the region. Here’s the latest 24-hour view of earthquake activity within 250 miles of Upolu, one of the Samoan islands devastated by the resulting tsunami.

(The image below reflects activity within the 24 hours before this post was written; click the image for current information.)

That earthquake in the South Pacific was the largest quake in the past 24 hours, but not the only one. Today there have been several other major quakes near Indonesia, including one of magnitude 7.6, and smaller quakes near China.

(The image below reflects worldwide earthquake activity within the 24 hours before this post was written; click the image for current information.)