A decade before Adolf Hitler rose to power in Germany, famed physicist Albert Einstein was already sensing imminent peril for his country and his own welfare, as a newly discovered letter reveals.
Astronomers have found evidence that the supermassive black hole thought to lurk at the heart of our galaxy displays the gravitational properties dictated by the general theory of relativity.
It would be hard to overstate how resilient the theory of general relativity has been. In its hundred-plus-year history, it’s managed to predict things far beyond the capabilities of 1910s experiments, and it withstands every new test scientists throw at it.