Because the Earth is tilted at twenty-three and a half degrees, the Ascendant's duration in each zodiac sign differs according to the latitude and longitude that you were born at.  In the UK, the signs of Leo to Scorpio dominate on the Ascendant, with Virgo and Libra taking nearly three hours to rise each whilst the opposite signs of Pisces and Aries take less than an hour each.  In the southern hemisphere, the reverse is true in that the signs of Pisces and Aries are the most common in Australia and New Zealand.  It could be argued that this is why most Aussie's are seen in the UK as either headbangers (Aries rising) or alcoholics (Pisces rising).  But the opposite is true once again in the UK.  Northern Europeans are either anal (Virgo rising) or indecisive (Libra rising).  The Ascendant, or rising sign as it is sometimes known, is only the superficial colouring to the chart.  It's the armour you put on as you go out of the front door.  Many people look like their Ascendant sign rather than their Sun sign.   I suppose I'd better go a bit further.  Aries rising arch their eyes, Taurus rising have strong necks, Gemini rising often have frown lines from an early age, Cancer rising have round faces, Leo rising is all about the hair, Virgo rising is just fussy about appearance, Libra rising has a line twixt lower lip and chin or on the point of the jaw, Scorp rising have the eyes, Sag rising the grin lines and big voice, Cap rising the high cheekbones, Aquarius rising the slanted eye effect and Pisces rising the goldfish bowl look.  If I go any further, I'll get into trouble again, but I bet I'm right with more than two thirds of you...