The Green Bank telescope (R) listened to Oumuamua (L) across four radio frequency bands
It is the first object discovered in the solar system that appears to have originated from another part of the galaxy.
Although thought to be an asteroid, Oumuamua’s elongated cigar shape hundreds of metres in length but only one tenth as wide is highly unusual for a typical space rock.
Travelling at up to 196,000 mph, the object’s high speed also suggests that it is not gravitationally bound to the sun but is destined to head back out of the solar system.
The object is currently about two astronomical units (AU) from Earth, or twice the distance between the Earth and sun.
Breakthrough Listen aims to survey a million nearby stars and 100 nearby galaxies looking for alien signals.
Since the 1960s, there have been more than 98 Seti projects around the world, none of which have turned up any convincing evidence of extraterrestrial civilisations.