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. Mercury's tiny atmosphere and magnetic field were also identified by Mariner 10. The second visit was by NASA's MESSENGER spacecraft, which entered Mercury's orbit on April 30, 2011.
Did you know that your body produces oxygen even though you may not be breathing? Every time you breathe in air, some of the oxygen is absorbed into your blood stream through your lungs. Your body then reacts to this new information by producing more red blood cells and releasing less carbon dioxide into the surrounding air.
10th Mariner 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. The mission ended in 2015.
Why do men lead more rallies than women? Because men are given more opportunities to show their feelings through demonstrations and protests. Women are expected to be quiet and accept their fate.
Why do men smoke more in some countries than others? In most countries, men smoke more than women; this is called "male smoking". But in some countries, such as China, India, and Russia, it's the other way around. China has one of the highest rates of female smoking in the world. One reason may be that there are fewer restrictions on selling cigarettes in these countries - leading to a greater availability of cigarettes for men, who tend to smoke more than women.
China: high rate of male smoking | Source: Source
Russia: high rate of female smoking | Source: Source
10th Mariner Mariner 10 was the only NASA spacecraft to explore Mercury in 1974 and 1975. It was scheduled to fly past the planet three times in order to photograph its extensively cratered surface. However, communications problems with Earth caused the mission to abort its first two attempts at Mercury orbit insertion, and it flew by the planet for just 15 minutes on its third attempt.
It is estimated that Mariner 10 took about 50 images of Mercury during its short stay at the planet's orbit. The pictures revealed a world with craters of all sizes, many of them marked by bright material in their centers. Some of the larger holes appear to have been filled by volcanic activity.
The discovery of these features demonstrated that Mercury had a geologic history like that of Earth and the other planets in our solar system. Before Mariner 10, no evidence existed of life on Mercury because all observations were made from Earth. The new data showed that Mercury has a crust of some kind and may even have oceans under its rocky surface.
Mercury has an extremely eccentric orbit, taking 87.9 days to complete one trip around the Sun. This means that at any given time, the planet is either too close or too far away from the Sun to be able to support life as we know it.
The Point of View Mariner 10 was the only spacecraft to visit Mercury for three decades, and practically all of our understanding about the planet was based on the limited observations obtained during its three flybys in 1974–75. Mercury remained a mystery despite this initial research. It was not until much later that other missions were sent to study it in more detail.
Mariner 10 took many pictures of Mercury from an average distance of 140 million miles (225 million km). From these images, scientists were able to determine that the planet is almost entirely made up of iron with some silicon and magnesium present. It has a thin atmosphere of sulfur dioxide which is subject to severe windstorms called pateras. The temperature at the surface can reach 450° F (232° C).
The first mission to orbit another planet was the Soviet Union's Venera 4, which flew by Venus on February 14, 1982. It returned science data for over half of the planet's circumference and discovered that there is oxygen in the atmosphere. However, due to its large size (4 meters or 13 feet) and intense heat, Venus may not have been habitable for life as we know it.
America's next attempt to explore another world came four years later with the launch of the James Webb Space Telescope. This enormous telescope will be capable of looking back in time at objects such as galaxies far away from Earth.
Mariner 10 was the only NASA spacecraft to explore Mercury in 1974 and 1975. However, problems with one of the craft's fuel cells caused the mission to be terminated early.
Mercury is not as mysterious or unexplored as it once was. But it is still a very important resource for scientists who want to learn more about our solar system and galaxy.
There's still more than half of Mercury that we haven't seen before. Some regions are so dark they must be filled with lava or carbon dioxide, while others are very bright because they probably contain a lot of sulphur.
Mercury is always visible from Earth with the exception of its nightside, which faces away from us. Because of this, scientists have used cameras on board spacecraft to take pictures of the solar-powered planet over time. These images reveal changes on Mercury's surface that can be attributed to geological activity or meteorite impacts. In addition, instruments on board spacecraft have detected elements in the planet's atmosphere that were likely released when particles from the sun hit its surface.
Scientists think that Mercury may have had an ocean at one point in time. If so, it may have been completely drained when the nearby Moon formed around 4.5 billion years ago. The impact that created the Moon probably swept most of the ocean away but some would have been left behind.
In June 2008, the Japanese Akatsuki spacecraft entered orbit around Mercury.
It is the first mission to do so. Since then, it has been relaying data back to Earth via NASA's Deep Space Network (DSN).
Mariner 10, the first spacecraft to visit Mercury, photographed around 45 percent of the surface. In 2018, the European Space Agency launched its first mission to investigate Mercury-BepiColombo. The mission includes a U.S.-built Mercury Rover that will explore an area about 250 miles by 100 miles on the innermost planet.
Image credit: NASA/JHU-APL/SwRI'
Mercury is the smallest of the planets outside the Earth's orbit. It has a mass only one-third that of Earth and a radius one-fifth that of Earth. Because it is so small, any water present would be in a thin atmosphere and there might not be enough to support life as we know it. But even though it has no ocean, it was once covered in water. In fact, much of what we know about early Mercury's environment comes from studies of terrestrial fossils found in its polar craters. These fossils date back 4.5 billion years, which makes them among the most ancient physical evidence of life on Earth or any other planet then known to science.
The origin of Mercury is still a subject of debate for scientists.