Mercury is the closest planet to the Sun and because of its proximity, it cannot be seen during daylight. Mercury completes three rotations around its axis for every two orbits that our Earth makes, which means that up until 1965 we believed that only one side of Mercury faced away from the sun.
Mercury is the smallest planet in our solar system that doesn’t have any moons or rings. Mercury, being so close to the Sun and small size wise, has very different features than other planets like Earth; your weight would be 38% of what it would on earth for instance! The time taken by a day (a single rotation about its axis) on surface of mercury lasts 176 days – one year’s worth which takes 88 days. It was discovered in 1859 by two astronomers from Cambridge University Observatory who spotted it just appearing as an object without detail when looking through their telescope while doing some observations at night.
Clocking in at 176 days per solar day, Mercury’s sidereal time is significantly slower than Earth. Tidal locking to the Sun has caused this planet’s rotation and orbit around it to almost synchronize over time; however, its distance from the sun ranges anywhere between 46-70 million kilometers.
One of five planets visible with the naked eye, Mercury is just 4,879 Kilometers across its equator, compared to 12,742 for Earth.
The planet Mercury is small, but it’s super dense!
In fact the density of every cubic centimetre reaches 5.4 grams- twice as heavy when compared to Earth’s 3.5g/cm3 makeup of mostly soil and rock Although this may be because its surface mainly consists out earthy metals like iron and lead, in truth we are not sure what could account for such a high number
Scientists from NASA have come to believe the core of Mercury is in fact molten. Normally, a planet’s solid iron core cools rapidly when it enters Earth’s atmosphere and becomes hotter around its surface as heat escapes through convection; however, this was not observed with small planets like Mercury where only 42% of their volume comprises an iron-based material. The scientists now believe the answer lies in light elements such as sulphur which would lower the melting temperature while still retaining enough gravity for orbit stability since Mars has almost no metal at all except what they picked up over time after hits by asteroids or other planetary debris that left them bone dry before water filled most Martian canyons during floods creating life on earth billions of years ago!
In 1974 and 1975, the Mariner 10 probe flew by Mercury three times. Nearly half of the planet’s surface was mapped during this time span. In 2004, a new spacecraft named Messenger launched from Cape Canaveral Air Force Station for its first visit to Mercury since 1970s – but it wasn’t easy!
In 1974 and 75, NASA’s MARINER 10 visited ʺMercury-the hard way.” (The Sun’s proximity makes visiting difficult). Three flybys in two years yielded just under HALF of our knowledge about one side – or hemisphere–of MESSENGER’S destination; with only 43% coverage on that side we can say much less about what lies beneath some other regions not seen at all