Stargazers will be treated to a rare seven-planet alignment in February. This is what scientists hope to learn.

All seven of the other planets in our solar system are about to become visible at once in a great planetary alignment – here’s how to spot the celestial show ...

With a radius of 2,106 miles, Mars is the seventh largest planet in our solar system and about half the diameter of Earth. Its surface gravity is 37.5 percent of Earth’s. Mars rotates on its ...