In the bright evening twilight of 14, 15 and 16 July, observers in the British Isles and Western Europe can see the waxing gibbous Moon pass by Mars, first-magnitude star Antares in Scorpius, then Saturn. This series of conjunctions occurs very low in the southern sky for UK-based astronomers, while Australasian observers are ideally placed to view the spectacle almost overhead.
Overall, about 1 kg of material is escaping our atmosphere every second. Every day, around 90 tonnes of material escapes from our planet’s upper atmosphere and streams out into space. Although missions such as ESA’s Cluster fleet have long been investigating this leakage, there are still many open questions. How and why is Earth losing its atmosphere?
Where did the two natural satellites of Mars, Phobos and Deimos, come from? For a long time, their shape suggested that they were captured asteroids. However, the shape and course of their orbits contradict this hypothesis. Two independent and complementary studies now provide an answer: these satellites formed from the debris of a gigantic collision between Mars and a protoplanet one-third its size.
Mars lies highest in the sky to the south soon after sunset at the beginning of July for observers in the UK, so you should not waste any opportunities to view the Red Planet while it is close and still relatively large in size. Tharsis, the great Martian volcanic plateau that is home to the largest volcanoes in the solar system, is turned toward Earth in the first week of the month.
Planetary scientists have discovered pieces of opal in a meteorite found in Antarctica, a result that demonstrates that meteorites delivered water ice to asteroids early in the history of the solar system. Opal, familiar on Earth as a precious stone used in jewellery, is made up of silica (the major component of sand) with up to 30 percent water in its structure.
The space environment around a planet plays a key role in determining what molecules exist in the atmosphere – and whether the planet is habitable for life. New research shows that Venus has an “electric wind” strong enough to remove the components of water from its upper atmosphere, which may have played a significant role in stripping Earth’s twin planet of its oceans.
We may be losing Jupiter in the west at dusk, but two other planets are well placed in the late evening. Skywatchers in the UK and Western Europe should look low in the southern sky around 12am local time on 17, 18 and 19 June to see the waxing gibbous Moon in the vicinity of planets Mars and Saturn, plus first-magnitude star Antares in the constellation of Scorpius.
On the evening of Monday, 30 May, Mars is closer to Earth than at any time since 30 October 2005. This begs the question: just how close can Mars get? Ade Ashford gives you an overview of close Martian oppositions past, present and future. Also, Friday, 3 June sees the opposition of Saturn, the other planet visible low in the south around midnight.
Using radar data collected by NASA’s Mars Reconnaissance Orbiter, researchers have found evidence of an ice age recorded in the polar deposits of Mars. Measurements show that about 87,000 cubic kilometres of ice have accumulated at the poles since the end of the last ice age about 370,000 years ago; the majority of the material accumulated at the Martian north pole.
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