NASA Is Developing A Rover For Venus That Could Survive The Planet’s Tumultuous Atmosphere.

Ten Interesting facts about Mercury

Mercury is the closest planet to the sun. As such, it circles the sun faster than all the other planets, which is why Romans named it after their swift-footed messenger god. He is the god of financial gain, commerce, eloquence, messages, communication (including divination), travelers, boundaries, luck, trickery and thieves; he also serves as the guide of souls to the underworld

Like Venus, Mercury orbits the Sun within Earth’s orbit as an inferior planet, and never exceeds 28° away from the Sun. When viewed from Earth, this proximity to the Sun means the planet can only be seen near the western or eastern horizon during the early evening or early morning. At this time it may appear as a bright star-like object, but is often far more difficult to observe than Venus. The planet telescopically displays the complete range of phases, similar to Venus and the Moon, as it moves in its inner orbit relative to Earth, which reoccurs over the so-called synodic period approximately every 116 days.

Mercury’s axis has the smallest tilt of any of the Solar System’s planets (about ​1⁄30 degree). Its orbital eccentricity is the largest of all known planets in the Solar System; at perihelion, Mercury’s distance from the Sun is only about two-thirds (or 66%) of its distance at aphelion.

Its orbital period around the Sun of 87.97 days is the shortest of all the planets in the Solar System.  A sidereal day (the period of rotation) lasts about 58.7 Earth days.

Mercury’s surface appears heavily cratered and is similar in appearance to the Moon’s, indicating that it has been geologically inactive for billions of years. Having almost no atmosphere to retain heat, it has surface temperatures that vary diurnally more than on any other planet in the Solar System, ranging from 100 K (−173 °C; −280 °F) at night to 700 K (427 °C; 800 °F) during the day across the equatorial regions. The polar regions are constantly below 180 K (−93 °C; −136 °F). The planet has no known natural satellites. 

Unlike many other planets which “self-heal” through natural geological processes, the surface of Mercury is covered in craters. These are caused by numerous encounters with asteroids and comets. Most Mercurian craters are named after famous writers and artists. Any crater larger than 250 kilometres in diameter is referred to as a Basin.

The largest known crater is Caloris Basin, with a diameter of 1,550 km. The impact that created the Caloris Basin was so powerful that it caused lava eruptions and left a concentric ring over 2 km tall surrounding the impact crater.

Two spacecraft have visited Mercury: Mariner 10 flew by in 1974 and 1975; and MESSENGER, launched in 2004, orbited Mercury over 4,000 times in four years before exhausting its fuel and crashing into the planet’s surface on April 30, 2015.

It is the smallest planet in the Solar System, with an equatorial radius of 2,439.7 kilometres (1,516.0 mi). Mercury is also smaller—albeit more massive—than the largestnatural satellites in the Solar System, Ganymede and Titan.  

As if Mercury isn’t small enough, it not only shrank in its past but is continuing to shrink today. The tiny planet is made up of a single continental plate over a cooling iron core. As the core cools, it solidifies, reducing the planet’s volume and causing it to shrink. The process crumpled the surface, creating lobe-shaped scarps or cliffs, some hundreds of miles long and soaring up to a mile high, as well as Mercury’s “Great Valley,” which at about 620 miles long, 250 miles wide and 2 miles deep (1,000 by 400 by 3.2 km) is larger than Arizona’s famous Grand Canyon and deeper than the Great Rift Valley in East Africa. 

The first telescopic observations of Mercury were made by Galileo in the early 17th century. Although he observed phases when he looked at Venus, his telescope was not powerful enough to see the phases of Mercury.

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images: Joseph Brimacombe, NASA/JPL, Wikimedia Commons

Why We Need to Get Back to Venus

Paul Byrne explains why we need to get back to our cosmic neighbor.

Thoughts on revisting Venus

So NASA won the internet today…

ASTEROID DAY 2018

On 30 June 1908, 110 years ago, a 40 m asteroid struck the Earth over Tunguska, Siberia.

Destroying an area of forest the size of Greater London, this was the most significant impact event in Earth’s recent history.

Now recognised by the United Nations as Asteroid Day, 30 June marks a global opportunity to raise awareness of the threat and opportunity posed by the numerous rocky bodies traversing space.

Since 2009, ESA has played a leading role in the global hunt for risky asteroids and comets – known formally to astronomers as near-Earth objects (NEO) – and is currently developing cutting-edge widefield telescopes that will have the ability to scan the entire sky in just 48 hours.

ESA also carries out crucial analysis as part of its Space Situational Awareness (SSA) programme and mobilises observatories and astronomers worldwide through its SSA NEO Coordination Centre at the Agency’s ESRIN facility in Italy.

Each year, Asteroid Day is broadcast live across the globe with a packed programme that brings together astronauts, rock stars and scientists.

Highlighting our potentially vulnerable place in space, the live event also describes the many ingenious and yet not-far-from scifi potential solutions to these dangerous roaming rocks.

Each year hundreds of regional events also take place, with 78 countries so far having hosted concerts, community events, lectures and much more.

'Sail-Rover' could make Venus exploration possible.

NASA’s Innovative Advanced Concepts program is funding a study into the possible use of a sail powered rover to explore the 500°C surface temperatures of Venus.

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Image of the clouds of Venus via the European Space Agency

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TODAY IN HISTORY: Planet Venus, observed by NASA’s Pioneer 12 space probe on February 26, 1979.

Venus is the second closest planet to the Sun and has the highest surface temperature of any planet in our solar system, with an orbital period of about 225 Earth days. Because of its similar gravity and size, it is sometimes known as Earth’s “sister planet.” However, besides these two aspects, the two planets have almost nothing in common. With the densest atmosphere on any terrestrial planet in the solar system, the surface pressure on Venus is about 92 times that of Earth; the same pressure one kilometer beneath Earth’s oceans.

Even though Venus is comparatively much further away from the Sun than Mercury, it is the hotter planet with a surface temperature of around 462 °C; this is because of its dense atmosphere of greenhouse gases such as carbon dioxide and sulfur dioxide. One remarkable aspect of the atmosphere of Venus is the precipitation of liquid sulfuric acid. The surface geology of the planet has been observed by NASA for over twenty years now, and it is seen that there is extensive and violent volcanism at the surface.

(image sources: NASA; http://www.the8planets.com/wp-content/gallery/planet-venus/venus-atmosphere.jpg, http://www.boskowan.com/blanensko/)