Scientists may have found a hint of dark matter and could have started to unravel one of the universe's greatest mysteries.
Initial results from the Alpha Magnetic Spectrometer (AMS) have revealed tantalising evidence from fast moving particles.
They seem to bear the signature of collisions between atoms of dark matter, the mysterious "stuff" that cannot be seen or detected directly, yet which somehow binds the cosmos together.
However, the possibility that the particles have some other origin cannot yet be discounted.
Over the next few months, further analysis will show whether the "smoking gun" of dark matter really has been discovered.
The seven ton AMS is a super-sophisticated particle collector is attached to the outside of the International Space Station and is the most expensive experiments ever conducted in space, the AMS cost £1.32 billion.