Rare, all-red auroras are produced by high-altitude oxygen, at heights of up to 200 miles. Nitrogen produces blue or purplish-red aurora. The connection between the Northern Lights and sunspot activity has been suspected since about 1880.
In developed countries, the average birth weight of a full-term newborn is approximately 3.4 kg (71â2 lb), and is typically in the range of 2.7â4.6 kg (6.0â10.1 lb).
1 The median birth weight in the period 1989-1991 was 3,372 grams, compared to 3,434 grams in the period 2004-2006.  The average total body length of the newborn infants ranges from 14-20 inches (35.6-50.8 cm), although premature newborns may be much smaller.