Avi Loeb, a Harvard astrophysicist, has suggested that the interstellar object 3I/ATLAS could be composed of antimatter, a form of material that releases nearly total energy on contact with ordinary matter.
Loeb described antimatter as
"the most efficient fuel" in the universeand argued that its interaction with solar particles could account for the object's unusual brightness and apparent acceleration.
Author's summary: Avi Loeb proposes antimatter composition for 3I/ATLAS.