Planets do not take much longer to form after stars have formed. For example, the Sun formed 4.6 billion years ago, and the Earth about 4.5 billion years ago. However, scientists now say it is not necessarily the only possibility. ...

Astronomers have identified a strange planet not present in our solar system orbiting other stars. It is neither too large nor too tiny but falls between the Earth’s and Neptune’s radii. Dense “super-Earths,” more prominent than Earth, are found near ...