"The best match for today's outer Solar System that we found with our simulations ... along with all other lines of evidence for Planet 9, will soon face a rigorous test with the operational ...

For a few evenings around 28 February, every planet in the solar system will be visible in the night sky, thanks to a rare ...

Stargazers will be treated to a rare alignment of seven planets on 28 February when Mercury joins six other planets that are already visible in the night sky. Here's why it matters to scientists.