The accelerating expansion of the universe is usually explained by an invisible force known as dark energy. But a new study suggests this mysterious ingredient may not be necessary after all. Using an ...

When NASA launched the Pioneer probes, they were met with an intriguing mystery. At around 20 astronomical units, both ...

Katina Tibbetts is determined to hold all her students to high standards. But she also knows that different kids need different kinds of help to get there. Tibbetts, who teaches 1st, 3rd, and 5th ...

You see this all the time in textbooks: This is often described as "the acceleration due to gravity". Is this really the best thing to call this? No. A better name would be "the local gravitational ...