Fredric Brown was a master of the short story including what is probably the shortest published science fiction short story:

“The last man on Earth sat alone in a room.
There was a knock at the door…”

The Aswer considers the question “Is there a God?”

I have include the version from “From These Ashes: The Complete Short SF of Fredric Brown”  and the version   from Baen’s short story collection “If This Goes Wrong” edited by Hank Davis.

This is the version of the story from “From These Ashes: The Complete Short SF of Fredric Brown”  Nesfa Press 2001

Dwan Ev ceremoniously soldered the final connection with gold. The eyes of a dozen television cameras watched him and the subether bore throughout the universe a dozen pictures of what he was doing.

The switch that would connect, all at once, all of the monster computing machines of all the populated planets in the universe — ninety-six billion planets — into the supercircuit that would connect them all into one supercalculator, one cybernetics machine that would combine all the knowledge of all the galaxies.

He takes a moment to regard the trillions of viewers, eyes glued to their screens for this momentous occasion. And then he throws the switch.

There was a mighty hum, the surge of power from ninety-six billion planets. Lights flashed and quieted along the miles-long panel.

As the machine whirs into life, Dwar Ev steps back and offers the first question to his partner, Dwar Reyn.

“Thank you,” said Dwar Reyn. “It shall be a question which no single cybernetics machine has been able to answer.”

He turned to face the machine. “Is there a God?”

Without a moment’s hesitation, the mighty voice answers him:

“Yes, now there is a God.”

Sudden fear flashed on the face of Dwar Ev. He leaped to grab the switch.

A bolt of lightning from the cloudless sky struck him down and fused the switch shut.

The Answer by Fredric Brown

This is the version from Baen’s short story collection “If This Goes Wrong” edited by Hank Davis.

Dwan Ev ceremoniously soldered the final connection with gold. The eyes of a dozen television cameras watched him and the subether bore throughout the universe a dozen pictures of what he was doing.

He straightened and nodded to Dwar Reyn, then moved to a position beside the switch that would complete contact when he threw it. The switch that would connect, all at once, all of the monster computing machines of all the populated planets in the universe — ninety-six billion planets — into the supercircuit that would connect them all into one supercalculator, one cybernetics machine that would combine all the knowledge of all the galaxies.

Dwar Reyn spoke briefly to the watching and listening trillions. Then after a moments silence he said “ Now Dwar Ev.”

Dwar Ev threw the switch. There was a mighty hum, the surge of power from ninety-six billion planets. Lights flashed and quieted along the miles-long panel.

Dwar Ev stepped back and drew a deep breath. The honor of asking the first question is yours Dwar Reyn.”

“Thank you,” said Dwar Reyn. “It shall be a question which no single cybernetics machine has been able to answer.”

He turned to face the machine. “Is there a God?”

The mighty voice answered without hesitation, without the clicking of a single relay.

“Yes, now there is a God.”

Sudden fear flashed on the face of Dwar Ev. He leaped to grab the switch.

A bolt of lightning from the cloudless sky struck him down and fused the switch shut.