Growing up, I took E.T.’s fortuitous, last-minute revival for granted as down to the fact that E.T. just did that sort of thing purely because he was awesome. Having read sci-fi authors like Vernor Vinge and others in more recent decades, I can now set aside such childish notions and offer a better theory.

E.T. is a member of a hive mind species who share consciousness via a communal telepathic link. The utilization of this link varies depending on the circumstances, and sufficiently intense bursts of communication are accompanied by a red/infrared glow emanating from their chests and other body parts, perhaps as a means of radiating waste heat. This is evident in the first scene of the film, in which we see a group of alien researchers react to danger in near-perfect synchronization.

The link, besides enabling shared conscious thought, facilitates the ongoing repair and regeneration of damaged tissues by distributing the computational workload required for those repairs over many brains. It could be theorized that this is an adaption gained in their evolutionary past, but given that this is a space-faring civilization, this could just as easily be a technology that they’ve since integrated into their own biology in order to survive in hostile environments. The film gives us no further clues.

In any case, what’s clear is that E.T. could function independently for short amounts of time, but ultimately depended on others of his kind for continued survival. We also see that the other end of the telepathic link needn’t be a member of E.T.’s species. In fact, almost any life form can fall under its influence, as evidenced by the chrysanthemums. Nor is the flow of information over a cross-species link uni-directional, as shown below.

Furthermore, the range of this telepathy appears to have limits comparable to—or slightly beyond—the scale of planetary orbit. Thus, when E.T. is first stranded on Earth, his situation is more dire than it appears. Separated by a vast distance from his fellows, his physical deterioration begins immediately.

In order to survive, E.T. quickly establishes an ad hoc hive mind with the first conscious being he encounters; a young boy named Elliot. This link is of course evident throughout the film, particularly when Elliot shows symptoms of intoxication after E.T. ingests alcohol. The connection is nevertheless weak, and has the unfortunate side effect of taxing Elliot’s own vitality, but by repurposing Elliot’s brain as a surrogate computer, E.T. buys himself enough time to build and deploy a distress beacon.

As we know, E.T.’s rescue doesn’t arrive in time, and E.T.’s physical deterioration culminates in a state indistinguishable from human death. Elliot is freed from the link at this moment. His physical condition had been apparently deteriorating in sympathy with E.T.’s, but he quickly regains full health once the link is severed, thus revealing the cause of his illness as nothing more than an over-taxed brain.

This also explains why, earlier in the film, Elliot’s first response to the newly-established connection between himself and E.T. was to fall asleep. Deprived of a connection for several days, E.T. was badly in need of a another mind — any mind — to draw strength from.

Shortly afterward, E.T.’s rescue party arrives in orbit. Once again within telepathic range of his own kind, an intense burst of data transmission occurs as E.T. uplinks to the hive mind, effecting his immediate and apparently miraculous “resurrection”.