New Delhi, April 24 -- The comet that rambled past us from another star last year likely originated in a cold, isolated corner of the galaxy that had yet to gel into its own solar system, astronomers reported Thursday.

Comet 3I/Atlas is only the third interstellar visitor to be confirmed and quite possibly the oldest. Scientists estimate it could be up to 11 billion years old, more than twice as old as the sun.

A team led by the University of Michigan used the ALMA observatory in Chile's Atacama Desert to examine the comet last fall. The errant but harmless iceball was discovered last summer, giving NASA and the European Space Agency plenty of time to aim multiple space telescopes at it as it zoomed past Mars in October and made its clo...