Characteristics of Mercury:

1. Mercury is called the "Second Earth". It is a terrestrial planet with a diameter of about 4880 kilometers and is made of rock. Its density is almost the same as that of the Earth. Likewise, its core is thought to be a huge iron core occupying three-quarters of Mercury's radius.

2. As the first human probe to enter Mercury’s orbit, MESSENGER has made many important discoveries. For example, it confirmed scientists’ speculation for many years that billions of tons of water are stored in the north pole region of Mercury. ice.

3. The temperature of Mercury in direct sunlight during the day can be as high as 430 degrees Celsius, while at night the temperature drops to minus 170 degrees Celsius. The temperature difference between day and night reaches 600 degrees Celsius.

Extended information:

Difficulties in Mercury detection:

1. Behind Mercury is the sun, which is 330,000 times heavier than the Earth. Its huge gravitational effect will affect the detection of Mercury. The spacecraft enters the orbit of Mercury and causes interference.

2. To successfully enter orbit, it is necessary to carry out 9 gravity-controlled orbit changes near the Earth, Venus and Mercury within 7 years of flight time. This will be the number of orbit changes in the history of planetary exploration. The most ever.

3. In order to withstand high temperatures, the spacecraft also uses multi-layer heat insulation technology. The outermost layer is composed of ceramic fibers. The detector is also equipped with an efficient radiator to ensure that scientific instruments and electronic equipment can work normally.

Reference: People's Daily Online - Difficulties, Highlights and Highlights of Humanity's Third Mercury Exploration