Professor Dave Explains
Classification of Igneous Rocks: Intrusive vs. Extrusive
Now that we know how igneous rocks form, what are the types of igneous rocks? This depends on precisely where they form, and we can call them either intrusive or extrusive. These can also be called either plutonic or volcanic. What do...
NASA
Gravity Assist: Fire Fountains on the Moon, with Dave Draper
Early in its history, the Moon was molten, with “fire fountains” erupting from its surface. How did the Moon cool down and become the quiet, cratered world we know today? NASA’s Chief Scientist Jim Green chats with NASA’s Deputy Chief...