Meteorite hunters are combing Ohio for fragments of a space rock that streaked across the sky earlier this week.
For more than 60 years, nearly every large rocket used some combination of the same liquid and solid propellants. Refined kerosene was favored for its easy handling and non-toxicity, hydrazine for its ...
A cosmic explosion with an energy equivalent to the output of a billion suns went unnoticed by astronomers until they caught the "echo" of this gamma-ray burst.