In ome strange and mysterious way, the four stars that comprise the constellation Crux — better known as the Southern Cross — have come to represent the lands that lie below the equator.
Indeed, travelers in the Southern Hemisphere eagerly look for their first glimpse of the Cross, as I did in April 1986 when I led a tour to Easter Island and the Chilean Andes for a view of Halley’s Comet. Up until then, the Cross was always out of sight from my home location in the New York City area, hidden below the southern horizon. But that all changed when our tour group spent our first night on Easter Island, and at long last I could finally see the four stars of the famed Southern Cross.
From top to bottom, Crux measures just 6 degrees — only a little taller than the distance between the pointer stars of the Big Dipper. (Reminder: Your clenchd fist held at arm’s length is 10 degrees wide.) In fact, the Southern Cross is the smallest (in area) of all the constellations.
Like the Big Dipper of the northern sky, the Southern Cross indicates the location of the pole and as such is often utilized by navigators. The longer bar of the Cross points almost exactly toward the south pole of the sky, which some aviators and navigators have named the “south polar pit” because, unfortunately, it is not marked by any bright star.
Who saw it first?
It is believed that Amerigo Vespucci was the first European explorer to see the “Four Stars,” as he called them, while on his third voyage in 1501. Yet, Crux was plainly visible everywhere in the United States some 5,000 years ago, as well as in ancient Greece and Babylonia.
According to the writings of Richard Hinckley Allen (1838-1908), an expert in stellar nomenclature, the Southern Cross was last seen on the horizon of Jerusalem around the time that Christ was crucified. But thanks to precession — an oscillating motion of the Earth’s axis — the Cross ended up getting shifted out of view well to the south over the ensuing centuries.
Immediately to the south and east of the Cross is a pear-shaped, inky spot, about as large as the Cross itself, that looks like a great black hole in the midst of the Milky Way. Legend holds that, when Sir John Herschel first saw this feature from the Cape of Good Hope in South Africa in 1835, he wrote his Aunt Caroline about this “hole in the sky”
Indeed, few stars are seen within this hole, and it soon became popularly known as the “Coalsack.” People initially thought the Coalsack was some sort of window into deep space, but today we know that it’s really a great cloud of gas and dust that absorbs the light of the stars that must lie beyond it.
A cross for many nations
Interestingly, the Southern Cross has been depicted on the flags of several different antipodean countries.
Crux can be found on the national flags of Australia, New Zealand, Papua New Guinea, Samoa and Brazil. The New Zealand flag depicts only the four brightest stars of the Cross, while the banners of the other nations also include the faintest fifth star (known as Epsilon Crucis).
Additionally, Crux is not the only constellation that is represented on the Brazilian flag. This banner holds a total of 27 stars, each representative of a Brazilian state or its federal district. All of these stars are depicted on a globe, with their positions plotted for 20:30 local time on Nov. 15, 1889 over Rio de Janeiro, to commemorate the date when Emperor Dom Pedro II was deposed and Marechal Deodoro Da Fonseca declared Brazil a republic.
In addition to Crux, the stars on the flag are from eight other constellations: Canis Major, the Big Dog; Canis Minor, the Little Dog; Virgo, the Virgin; Scorpius, the Scorpion; Hydra, the Water Snake; Triangulum Australe, the Southern Triangle; Carina, the Keel of Argo, the Ship; and Octans, the Octant. A banner across the sky reads Ordem e Progresso, which means “Order and Progress” in Portuguese.