What's up in
For decades, astronomers debated whether a particular smudge was close-by and small, or distant and huge. A new X-ray map supports the massive option.
We don’t know why the universe appears to be expanding faster than it should. New ultra-precise distance measurements have only intensified the problem.
The result highlights a fundamental tension: Either the rules of quantum mechanics don’t always apply, or at least one basic assumption about reality must be wrong.
A team in Paris has made the most precise measurement yet of the fine-structure constant, killing hopes for a new force of nature.