Mercury is the smallest planet in our solar system. Explore its size, extreme temperatures, core structure, and comparison ...

The 1.5-day-old moon will be in close conjunction with Mercury on Feb. 18. You may be able to spot Venus in binoculars about ...

Late last July, a University astrophysicist helped discover the smallest planet ever detected outside the solar system — without even seeing it. Using a planet-finding technique called "gravitational ...

Mercury stands stationary at 3 A.M. EDT amid the stars of Cancer. The solar system’s smallest planet will now start sliding westward, or retrograde, appearing to “fall” back toward the Sun as it moves ...

NASA bragged Tuesday that its Kepler Space Telescope had discovered the two smallest planets ever found orbiting a distant star, but a UA astronomer and colleagues may have discovered even smaller ...

From dazzling Jupiter high in the evening sky to elusive Mercury low at sunset, February 2026 offers one of the year's best planetary lineups.