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

When an object from outside our star system zooms through our neighborhood in the solar system, it provides a rare opportunity to study the raw material from which distant worlds are made. The ...

The universe’s accelerating expansion has long puzzled physicists. For decades, dark energy, an unseen force thought to make up nearly 70% of the cosmos, has been the leading explanation. But a new ...