- Menkent (stars.astro.illinois.edu)
MENKENT (Theta Centauri). Centaurus is dominated by its two brightest stars, Rigil Kentaurus (Alpha Centauri, third brightest star in the sky and the nearest star to the Earth) and first magnitude Hadar (Beta Centauri). Though these two shine brilliantly to the lucky residents of the southern hemisphere, neither is visible from mid-northern latitudes, so if those that live there wish to know Centaurus, they must begin with the third brightest star in the constellation, Menkent, to which is assigned the rather lowly letter Greek letter Theta (Gamma Centauri rather oddly coming in second).
- Laurentia (Wikipedia)
Laurentia or the North American craton is a large continental craton that forms the ancient geological core of North America. Many times in its past, Laurentia has been a separate continent, as it is now in the form of North America, although originally it also included the cratonic areas of Greenland and the Hebridean terrane in northwest Scotland. During other times in its past, Laurentia has been part of larger continents and supercontinents and consists of many smaller terranes assembled on a network of early Proterozoic orogenic belts. Small microcontinents and oceanic islands collided with and sutured onto the ever-growing Laurentia, and together formed the stable Precambrian craton seen today.