No, Earth's spacecraft have visited Mercury, but no person has ever gone into orbit around Mercury, let alone trod on its surface. Here's an article on the discovery of Mercury's liquid core. And how Mercury is less similar to the Moon than previously thought.
Mariner 10, the first spacecraft to visit Mercury, photographed around 45 percent of the surface. MESSENGER, a NASA spacecraft, sailed past Mercury three times and orbited the planet for four years before landing on its surface. In 2018, the European Space Agency launched its first mission to investigate Mercury-BepiColombo. The BepiColombo probe is composed of two separate spacecraft: one that will orbit Mercury and another that will fly by it at high speed.
Scientists have studied Mercury since 1873, when American astronomer William C. Redfield discovered that it has a faint glow from sunlight reflected off its clouds of gas and dust. This occurs because mercury has a strong affinity for oxygen, which it binds with itself to form HgO, a compound that does not burn under normal conditions. The resulting oxide layer protects it from further oxidation.
Because mercury is both flammable and toxic, it must be handled carefully. It should not be thrown into the trash or down the toilet. Instead, place any unused medication into a safe container and either throw it away or return it to your pharmacist for disposal. Do not flush medications down the toilet or they may end up in our water supply.
In the laboratory, researchers can study how chemicals in drugs react with other substances. By analyzing the products formed after these reactions, scientists can determine what compounds are produced when someone takes a drug.
However, because the surface tension of mercury is only 7 times that of water, it is implausible that a human could walk or run on mercury without breaking the surface tension (unless it is possible to devise some snow-shoe like contraption to increase the lift provided by surface tension). Indeed, it has been reported that Mercury still performs as a liquid at temperatures below -44.4 degrees Celsius, which is very close to the melting point of gold (which has a melting point of 1,085 degrees Celsius).
The common wisdom that humans can't live without air because we need oxygen to breathe is not true for mercury because mercury is a chemically reactive metal that is toxic to humans at any concentration. At low concentrations, it is white and non-toxic but above a certain threshold value, it becomes toxic and changes color. This change in behavior of mercury is used by scientists in laboratories to study how substances affect living organisms.
In fact, there are very few elements that are both poisonous and stable over time. Only three elements meet these criteria: arsenic, mercury, and uranium. Arsenic is a poison that can be found in natural gas, coal, and wood; mercury is a poison that can be found in natural gas, coal, and ore bodies; and uranium is a poison that can be found in natural gas and oil.
Mercury exploration has a tiny position in the world's space ambitions. It is the inner planet with the least amount of exploration. As of 2015, the only missions that had performed close observations of Mercury were the Mariner 10 and MESSENGER missions. The MESSENGER probe was the first to circle Mercury. Its mission ended in 2018.
Did you know that Venus has volcanoes? No, neither did we. But now there is evidence of active volcanism on Venus. Some scientists believe that Earth may have had similar-looking worlds at one time, but that they were once joined together into a single planet called Venus. Others think this idea is too simple an explanation for what we see today regarding the different types of terrain on our planets.
Venus isn't the only planet that looks like it might be full of life. There is also Mars. Scientists think that perhaps both Venus and Mars had oceans of water as their planets were forming. Maybe if we explore these planets further we will find out that they have conditions suitable for life.
In addition to these two planets, astronomers have discovered many other bodies around other stars that appear to be similar to Earth. Some of these "exoplanets" are large enough to be classified as gaseous planets like Neptune or Jupiter, but others are small enough to be classified as terrestrial planets such as Earth. Astronomers have found evidence of water on several exoplanets using various methods.
So far, two spacecraft have visited Mercury. The first was known as Mariner 10. Mariner 10 passed past Mercury three times in 1974 and 1975, mapping over half of the planet's surface. Messenger was sent into orbit around Mercury in 2011 and finished mapping of the whole planet's surface in 2013.
Scientists want to send probes to other planets in our solar system because they can provide information about the formation of our galaxy and also life on other planets. Findings from studies of planets such as Venus and Mars have helped scientists understand how Earth developed life. Scientists hope that discoveries made on these other planets will help them learn more about their own planet.
The most obvious difference between Mercury and the other planets is its distance from the Sun. Although all the planets in our solar system share a similar shape, they differ in size due to their distance from the Sun. The closer a planet is to the Sun, the hotter it becomes. The further away a planet is from the Sun, the cooler it becomes. This is why some planets such as Neptune and Uranus appear frozen solid from north and south poles, respectively.
Mercury is the closest planet to the Sun, with an average distance of 37 million km (23 million miles).