Minor-planet moon Herculina does not have a significant satellite. There were other similar reports of asteroids having companions (usually referred to as satellites) in the following years. Also, a letter in "Sky & Telescope" magazine at this time pointed to apparently simultaneous impact craters on Earth (for example, the Clearwater Lakes in Quebec), suggesting that these craters were caused by pairs of gravitationally-bound objects. In 1993, the first asteroid moon was confirmed when the Galileo probe discovered the small Dactyl orbiting 243 Ida in the asteroid belt. The second was discovered around 45 Eugenia in 1998. In 2001, 617 Patroclus and its
Ghost craters on Mercury planet's surface. Mercury Dual Imaging System cameras and Mercury Laser Altimeter equipment on the messenger spacecraft allowed for researchers to obtain high-resolution images of the planet's surface for analyzing Mercury's tectonics. Ghost craters are impact craters that have been filled with volcanic deposits. Ghost craters can be observed on the surface of the Moon, Mars, Mercury, and may possibly exist on Venus. On Mercury, ghost craters are most commonly found in the northern hemisphere of the planet in the smooth plains. There are three types of ghost craters on Mercury. Type one ghost craters contains a wrinkle ridge that forms