Mercury Has No Moons

Mercury does not possess any natural satellites – none, nada, zip and zilch!

Reason being, Mercury lies so close to the Sun that its gravity could disrupt any potential moon’s orbit and pull it directly into Mercury or even into its atmosphere.

Mercury formed approximately 4.5 billion years ago from swirling gas and dust that formed into a dense metallic core, rocky mantle, and solid crust.

Mercury’s orbit

Mercury, due to its proximity to the Sun and small Hill sphere (the radius of its circular orbit around Earth), cannot form or retain natural satellites of any sort. While early astronomers speculated about Mercury having natural satellites, scientific observations have since confirmed it to be an isolated planet without any natural satellites.

Mercury can reach temperatures as high as 800 degrees Fahrenheit (430 degrees Celsius) during the daytime hours, due to a lack of an atmosphere to retain heat, reaching 800 F at day and as much as 180F or lower at night – this extreme range makes Mercury one of the least hospitable planets to visit in our Solar System – its direct overhead sun can blind visitors without proper eye protection during daytime hours and make an otherwise pleasant visit unwelcome.

Mercury’s surface is covered by craters and landforms, similar to that found on the Moon; however, Mercury is denser, with a metallic core covering 60% of its volume (versus only 4 percent for Moon).

Mercury is marked by unique landforms that reflect its differences, such as long, narrow scarps that span hundreds of miles and up to one mile in height. Furthermore, there are deep troughs and valleys on its surface; its Great Valley extends for over 600 miles along its entire path and two miles deep at its center.

Like its rocky planet counterparts, Mercury is formed through the action of molten material on its core-mantle boundary, whereby interior heat escapes and causes its planet to contract as it cools off.

Mercury, as one of the inner planets in our Solar System, stands out as one of the least accessible planets to study due to its lack of moons and thin atmosphere. Yet thanks to NASA’s MESSENGER spacecraft and the joint venture bepiColombo JAXA/ESA spacecraft scheduled to launch in 2021, scientists are finally uncovering more information about this mysterious world.

Scientists have recently discovered that parts of Mercury’s north and south poles remain permanently shaded, suggesting they may contain water ice from either comet impacts or the Sun’s intense heat.

Mercury’s surface

Mercury, as one of the smallest rocky planets in our Solar System, is extremely dense with little atmosphere allowing sunlight to reach its surface, making the day side one of the hottest in our galaxy and its night side one of the coldest. Furthermore, as one of only two planets with liquid cores (known as “molten or liquid cores”) it also features its own magnetic field – something MESSENGER has been studying to better understand how it functions and what insights this provides into how planets form in our Universe!

Mercury’s surface is heavily cratered and similar to that of the Moon. It is covered by a thin layer of dust called regolith, made up of lunar rock powder mixed with elements such as water, oxygen, nitrogen, argon carbon dioxide sodium hydrogen helium potassium xenon and krypton.

The surface is characterized by impact craters and some smooth plains regions, with deep impact craters taking precedence. Their shadows extend far into the terrain beneath, often being named for deceased artists or authors like children’s author Dr. Seuss and dance pioneer Alvin Ailey.

Mercury, like other planets, is shaped by internal forces that push and pull at its crustal materials in an evolutionary process known as tectonics, leading to the creation of mountains, valleys, canyons and volcanoes as well as bright streaks called “crater rays”, caused by tremendous amounts of energy released during impacts that form bright streaks composed of crushed rock particles reflecting sunlight back onto their surfaces.

Mercury stands in stark contrast to Earth in that its thin atmosphere cannot trap heat or moderate its temperature; solar wind constantly strips away what little solar energy Mercury does collect, leaving its harsh rays exposed for exposure as one of the Solar System’s hottest and coldest planets.

Mercury stands alone among rocky planets in having its own magnetic field, as evidenced by its massive core. When its fluid core begins churning, its inner workings produce an atmosphere with magnetic qualities roughly equivalent to Earth’s.

Mercury’s atmosphere

Mercury does not possess an atmosphere in the sense that we typically understand, yet there exists an extremely thin layer of gas enveloping its surface. This gas is trillions of times thinner than Earth’s and undetectable without precise measuring instruments. Because of Mercury’s low surface gravity and closeness to the Sun, any gas that might exist at any one point is quickly lost into space or combined with rocks on its surface and evaporates before becoming detectable again.

Mercury lacks an atmosphere, leading to daytime temperatures reaching 800 Fahrenheit or 430 Celsius (water boils at 100 Kelvins). At night however, temperatures drop down to approximately minus 290 Fahrenheit or 180 Celsius – similar extremes of temperature can also be experienced on the Moon due to lack of an atmospheric layer that traps heat or traps cold air.

Mercury experiences many solar-related phenomena due to its close proximity to the Sun. Not only are its surface temperatures affected by intense solar rays; radiation and photon bombardment from solar wind is also prevalent due to Mercury’s highly eccentric orbit that encompasses it at such close distances.

Mercury has an expansive polar region that remains permanently shadowed from sunlight, and researchers have suggested the presence of ice there. Though the exact origin is uncertain, researchers believe it may have come from either comets or volcanic activity on the planet itself. In 2012, the MESSENGER probe detected small quantities of water near Mercury’s north pole; its source may have come from solar wind interaction with mineral compounds.

Mercury, the rocky, dusty planet is heavily cratered with two major types of land: maria (dark areas) and highlands (lighter-colored regions). Maria areas may represent lunar crust while highlands could contain both maria and regolith from inside Mercury; these features have likely been created by meteoroids impacting on its surface. Mercury also features numerous craters caused by meteoroids impacting on its surface.

Mercury’s moons

Mercury, named for a fast-moving Roman god, is one of only two planets in our Solar System without natural satellites – possibly due to its proximity to the Sun which causes gravitational field changes which make capturing moons difficult or impractical for Mercury; other factors may play a part, including lack of atmosphere and higher surface temperatures.

Mercury’s surface is covered in craters and rough terrain shaped by the impacts of asteroids and meteors over billions of years, creating its unique topography. Craters stand out due to their bright streaks made up of finely crushed bits from impacts that reflect light more effectively than surrounding materials, appearing much brighter. Over time these bright streaks may become darkened from dust buildup.

Although Mercury is currently very hot, astronomers have discovered evidence of its previous habitability with ice. Polar craters that remain shaded from sunlight may hold water ice within their depths. Radar observations also have revealed patches with high radar reflection – likely caused by frozen patches on Mercury’s surface.

Scientists speculate that Mercury likely formed larger than it currently is and that a massive impact stripped away much of its silicate mantle to form its core, composed mainly of iron. Furthermore, they suspect that metal concentration from protoplanetary disk formation also helped enriched Mercury’s core over time.

Mercury orbits with great ellipticism, shifting in distance between itself and the Sun as it circles around. At perihelion every 88 days, Mercury reaches its closest approach before moving further away during aphelion every 174 days; at speed 29 miles per second it makes Mercury the fastest planet.

Mercury’s surface is littered with craters, but scientists have also discovered tectonic features on its flanks and interior that scientists call thrust faults, which push up parts of Mercury’s crust and turn them over each other resulting in high peaks and deep valleys. Mariner 10 images display features like Santa Maria Rupes which extends across one crater on Mercury.