Nagasamir

"Confirm our position, Major. Nagasamir's system doesn't have an asteroid belt." "Position confirmed, Sir. The asteroid belt IS Nagasamir."

- Colonel Steven Caldwell and Major Kevin Marks

Nagasamir was a planet in the Pegasus galaxy, which held a Stargate.

History
The planet's natives, the Nagasamirians, were friends and trading partners of the Atlantis expedition.

2009
In 2009, the planet was visited by Janus, who gave the natives Lantean level technology to defend them against the Wraith, and an advanced Zero point energy reactor, that would power way more then the people would need at their amount of consumption. He had the Unknown Aliens install the upgrades to the peoples city.

Colonel John Sheppard and his team visited the planet with what they had discussed to trade previously, however with their newfound technology from the Ancient, they no longer required it. When it was revealed to AR-1 that the advancements were from Janus, Sheppard warned the planet's leader that he couldn't be trusted.

The leader respected Sheppard's warning, and politely rejected the continued support of Janus. As a result, he destroyed the planet by releasing uncontrolled Zero point energy from their new reactor.

After it's destruction, when Atlantis couldn't dial the planet, Woolsey had Amelia Banks contact the Daedalus to pick up AR-1, then together they went to investigate why.

They found the remains of the planet had become an asteroid belt. Dr. Rodney McKay figured out what destroyed the planet and noted the damaged caused by the uncontrolled Zero point energy had severely damaged subspace, to point that opening a Hyperspace window would be really bad.