Mercury is the smallest of the first eight planets, with a radius around 2440 km, which is only slightly bigger than the Moon. A desolate, cratered terrestrial world with no Earth-like atmosphere, active volcanoes, moons, or life, Mercury has a rocky surface much like the Moon and is the second densest of the planets at 5.43 g/cm3
Space and Astronomy Wiki – the planets in the solar system –
Mercury is the fastest moving planet, traveling through the solar system almost 50 km (31) miles per seconds faster than any other planet. Every day is 59 Earth days long and a year – the time it takes the planet to orbit the Sun – takes only 88 days, a combination resulting in daylight temperatures reaching 800 degrees Fahrenheit (420 degrees Celsius) and a brisk night at around -290 degrees Fahrenheit (-180 degrees Celsius).
Mercury was visited by Mariner 10 during 1974-1975 and MESSENGER orbited the planet three times between 2008-2009, before going into orbit in March 2011 for an extended analysis. On Thursday, April 30, 2015, MESSENGER ended its mission by creating a new crater on the surface of Mercury.
You can learn more facts & figures about Mercury here.
Geophysical data from Messenger illuminates internal structure of Mercury
Astronomy news (December 02, 2013) – NASA’s Messenger Spacecraft answered many questions concerning the innermost planet in the solar system during its two-year mission to Mercury. Messenger took around 80,000 high-definition images of about ninety percent of the surface of Mercury. It also took around 10,600,000 laser ranging shots using the Mercury Laser Altimeter (MLA) in order to map the topography of the planet surface. In addition, astronomers tracked the spacecraft using radio waves in order to gather data on how the spacecraft reacted in the planet’s gravity field.
Mercury’s generates a magnetic field
Astronomers combined the gravity and topographical data from Messenger to learn interesting things about the interior of Mercury. They found the core of Mercury spans about eighty percent of the diameter of the planet, compared to the fifty percent the Earth’s core spans. They also think Mercury has a solid silicate crust and mantle atop a layer of solid iron. Beneath these layers, astronomers believe lies a liquid layer and possibly a solid inner core. Astronomers need this information in order to better understand how the planet generates a magnetic field.
Mercury’s has surface features astronomers at NASA want to take a closer look at
Astronomers looking at Mercury’s surface also found areas with interesting features they want to take a closer look at in the future. They found a ridge in Mercury’s northern region they think formed after the volcanic plains had cooled. They also viewed an altered portion of the Caloris Basin were part of the basin floor is higher than the ridge. This could indicate more recent geophysical activity on the surface of Mercury than first thought.
Astronomers also used the topographical data collected on Mercury to determine the largest height variation on the planet is just 6.2 miles (10 km). This seems unusual since this distance is less than the greatest height variation on both Mars (19 miles [30 km]) and the Moon (12 miles [20 km]).
The Messenger Spacecraft taught us a lot more about Mercury than just the items above. Astronomers announced a lot more interesting things they discovered about Mercury through Messenger recently and you can read about many of these items on the NASA website.
NASA’s Messenger spacecraft continues to study Mercury
Messenger is still in orbit about Mercury taking images and providing astronomers with the data they need to delve even deeper into the mysteries of the innermost planet of our solar system. The spacecraft is presently closer to the surface of Mercury than ever and is taking a closer look at some of the interesting regions and features we mentioned.