For 10 points, what matter is named because its existence can only be inferred from gravity, not observed directly by electromagnetic interaction?
The project AMANDA uses neutrino telescopes to find physical evidence of it, while the current standard model of cosmology is named for "lambda-cold" form of this substance.  Vera Rubin demonstrated that this entity can explain the flatness as distance increases of the [*] galactic rotation curve. Proposed by Fritz Zwicky, its candidates include MACHOs and WIMPs, and it accounts for more than 20% of the universe. For 10 points, what matter is named because its existence can only be inferred from gravity, not observed directly by electromagnetic interaction?
The project AMANDA uses neutrino telescopes to find physical evidence of it, while the current standard model of cosmology is named for "lambda-cold" form of this substance.  
{dark matter} [prompt on {WIMPs} until {concept}]