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
Craters of the Moon (geothermal site) in the region has dramatically changed, as did the geothermal activity at Craters of the Moon. The geysers at Wairakei Geyser Valley totally disappeared, but the heat output at Craters of the Moon increased. A lot of hydrothermal eruptions occurred, which formed the craters. In 1950, the total heat output at Craters of the Moon was about 40 MW (megawatts). By 1958, it had increased to about 90 MW. In 1964 it was 420 MW. After 1964 the output declined to about 220 MW in 1979. The most recent estimate being about 200 MW in 2000. Heat output from the