This diagram shows the approximate relative sizes of the terrestrial planets, from left to right: Mercury, Venus, Earth and Mars. Distances are not to scale. A terrestrial planet is a planet that is primarily composed of silicate rocks. The term is derived from the Latin word for Earth, “Terra”, so an alternate definition would be that these are planets which are, in some notable fashion, “Earth-like”. Terrestrial planets are substantially different from gas giants, which might not have solid surfaces and are composed mostly of some combination of hydrogen, helium, and water existing in various physical states. Terrestrial planets all have roughly the same structure: a central metallic core, mostly iron, with a surrounding silicate mantle. Terrestrial planets have canyons, craters, mountains, volcanoes and secondary atmospheres.
Source.

This diagram shows the approximate relative sizes of the terrestrial planets, from left to right: Mercury, Venus, Earth and Mars. Distances are not to scale. A terrestrial planet is a planet that is primarily composed of silicate rocks. The term is derived from the Latin word for Earth, “Terra”, so an alternate definition would be that these are planets which are, in some notable fashion, “Earth-like”. Terrestrial planets are substantially different from gas giants, which might not have solid surfaces and are composed mostly of some combination of hydrogen, helium, and water existing in various physical states. Terrestrial planets all have roughly the same structure: a central metallic core, mostly iron, with a surrounding silicate mantle. Terrestrial planets have canyons, craters, mountains, volcanoes and secondary atmospheres.

Source.

First Image Ever Obtained from Mercury Orbit
At 5:20 am EDT on Mar. 29, 2011, MESSENGER captured this historic image of Mercury. This image is the first ever obtained from a spacecraft in orbit about the Solar System’s innermost planet. Over the subsequent six hours, MESSENGER acquired an additional 363 images before downlinking some of the data to Earth. The MESSENGER team is currently looking over the newly returned data, which are still continuing to come down.
Source: NASA.

First Image Ever Obtained from Mercury Orbit

At 5:20 am EDT on Mar. 29, 2011, MESSENGER captured this historic image of Mercury. This image is the first ever obtained from a spacecraft in orbit about the Solar System’s innermost planet. Over the subsequent six hours, MESSENGER acquired an additional 363 images before downlinking some of the data to Earth. The MESSENGER team is currently looking over the newly returned data, which are still continuing to come down.

Source: NASA.

MESSENGER Begins Historic Orbit Around Mercury
NASA’s MESSENGER spacecraft successfully achieved orbit around Mercury at approximately 9 p.m. EDT Thursday. This marks the first time a spacecraft has accomplished this engineering and scientific milestone at our solar system’s innermost planet.
For the next several weeks, APL engineers will be focused on ensuring the spacecraft’s systems are all working well in Mercury’s harsh thermal environment. Starting on March 23, the instruments will be turned on and checked out, and on April 4 the mission’s primary science phase will begin.
Source: NASA.gov

MESSENGER Begins Historic Orbit Around Mercury

NASA’s MESSENGER spacecraft successfully achieved orbit around Mercury at approximately 9 p.m. EDT Thursday. This marks the first time a spacecraft has accomplished this engineering and scientific milestone at our solar system’s innermost planet.

For the next several weeks, APL engineers will be focused on ensuring the spacecraft’s systems are all working well in Mercury’s harsh thermal environment. Starting on March 23, the instruments will be turned on and checked out, and on April 4 the mission’s primary science phase will begin.

Source: NASA.gov

Venus, Mercury, and MoonCredit & Copyright: Pete Lawrence (Digital-Astronomy)

Explanation: Earlier this month, Venus and Mercury climbed into the western twilight, entertaining skygazers around planet Earth in a lovely conjunction of evening stars. Combining 8 images spanning April 4 through April 15, this composite tracks their progress through skies above Portsmouth, UK. Each individual image was captured at 19:50 UT. The sequential path for both bright planets begins low and to the left. But while Venus continues to swing away from the setting Sun, moving higher above the western horizon, Mercury first rises then falls. Its highest point is from the image taken on April 11. Of course on April 15, Venus and Mercury were joined by a young crescent Moon.
(via APOD)

Venus, Mercury, and Moon
Credit & Copyright: Pete Lawrence (Digital-Astronomy)

Explanation: Earlier this month, Venus and Mercury climbed into the western twilight, entertaining skygazers around planet Earth in a lovely conjunction of evening stars. Combining 8 images spanning April 4 through April 15, this composite tracks their progress through skies above Portsmouth, UK. Each individual image was captured at 19:50 UT. The sequential path for both bright planets begins low and to the left. But while Venus continues to swing away from the setting Sun, moving higher above the western horizon, Mercury first rises then falls. Its highest point is from the image taken on April 11. Of course on April 15, Venus and Mercury were joined by a young crescent Moon.

(via APOD)

A Double Ringed Basin On Mercury
What created the internal second ring of this double ringed basin on Mercury? No one is sure. The unusual feature spans 160 kilometers and was imaged during the robotic MESSENGER spacecraft’s swing past our Solar System’s innermost planet last week. Double and multiple ringed basins, although rare, have also been imaged in years past on Mars, Venus, Earth, and Earth’s Moon.
Image credit: NASA/JHU APL/CIW
(via APOD)

A Double Ringed Basin On Mercury

What created the internal second ring of this double ringed basin on Mercury? No one is sure. The unusual feature spans 160 kilometers and was imaged during the robotic MESSENGER spacecraft’s swing past our Solar System’s innermost planet last week. Double and multiple ringed basins, although rare, have also been imaged in years past on Mars, Venus, Earth, and Earth’s Moon.

Image credit: NASA/JHU APL/CIW

(via APOD)

No, it’s not Lawrence of Arabia’s troop of bodyguards. The seven original Mercury astronauts used parachute pieces to make hats and clothes during a 1960 training exercise in the Nevada desert. The idea was to prepare the men to survive in the event of an emergency landing in the wilderness. Pictured here, from left to right, at Stead Air Force Base: Gordon Cooper, Scott Carpenter, John Glenn, Alan Shepard, Virgil Grissom, Walter Schirra and Donald Slayton.

(via wired.com)
No, it’s not Lawrence of Arabia’s troop of bodyguards. The seven original Mercury astronauts used parachute pieces to make hats and clothes during a 1960 training exercise in the Nevada desert. The idea was to prepare the men to survive in the event of an emergency landing in the wilderness. Pictured here, from left to right, at Stead Air Force Base: Gordon Cooper, Scott Carpenter, John Glenn, Alan Shepard, Virgil Grissom, Walter Schirra and Donald Slayton.
(via wired.com)