We don't know when the first stars appeared in the universe, but we can safely say it was a really long time ago: Scientists have found the remnants of what could have been one of the first stars ever to shine, over 13 billion years ago.
A team of astronomers in the United States and United Kingdom, using telescopes in Hawaii and Chile, observed a gas cloud, illuminated from "the brilliant light coming from the surroundings of a distant black hole." The cloud is composed of carbon, oxygen and iron. According to IndiaTalkies.com:
The cloud's atoms occur in abundances that are quite unlike that found in the nearby cosmos today and are more what one would expect from stars that were originally made only of hydrogen and helium.
This discovery may alter our perception of the age of the universe: Because we can't carbon-date the universe, one way to determine its age is to work the math based on the age of stars.
Although NASA says the universe is between 12 and 14 billion years old, this star's remains can now skew their dates accordingly.
Other stars also challenge NASA's timeline: One of the oldest observable stars (with a telescope, that is) is HE 1523-0901, which astronomers say is a venerable 13.2 billion years old. Curious astronomers can view HE 1523-0901 from the Southern Hemisphere or from southern countries in the Northern Hemisphere (think Venezuela).