Last week, Planetaria reported on why NASA should return to Venus, and new technology being developed to help make that happen, especially as in longer-lived landers or rovers. With its extremely hostile conditions, Venus has been much less of a priority in more recent years, at least in terms of surface missions, despite it being Earth’s closest planetary neighbour. But now there may be more impetus towards a new mission – not one that NASA would do alone, but rather a joint mission with Russia, known as Venera-D.
The Solar System has been a busy place in recent years, with missions to a diverse range of worlds, from Mars, Jupiter and Saturn to distant Pluto and even comets and asteroids. Most of these have been NASA spacecraft, which continues to lay the path to exploring such distant places. There are, however, some places which have been visited in the past, decades ago, but now are seemingly no longer a priority, such as Uranus and Neptune. But there is another planet which is actually Earth’s closest neighbour, yet was only last visited in the 1970s and 1980s, by American and Soviet spacecraft – Venus.
Meteors flashing across the sky are a common sight here on Earth, but of course they are not limited to only our planet; these bits of rocky debris, smaller pieces of asteroids and comets known as meteoroids, can be found just about everywhere in the solar system (becoming meteors when entering and burning up in the atmosphere). Now, the Cassini spacecraft has observed similar impacts occurring in another very different and far-away place: the rings of Saturn!
For any future astronauts who land on Mars, there is one piece of advice that shouldn’t even need to be said: keep your helmet on! Mars has an atmosphere, like Earth, but it is much thinner than ours (and mostly carbon dioxide), and so is unbreathable by humans. However, evidence has continued to grow that Mars’ atmosphere was once a lot thicker than it is now, early on in the planet’s history. Recent findings from the Curiosity rover have added to that evidence, as well as showing not only how Mars has lost most of the atmosphere that it once had, but also that the atmosphere which remains is still very active.
You may be familiar with the phrase “follow the water” when it comes to the search for life on Mars, and for good reason – any place on Earth where there is liquid water, there is life. So, logically, the best places to look for evidence of past or present life on Mars would be where there has been liquid water in the past (or perhaps even still is, underground). But now there is also another approach being taken, in terms of possible present-day habitability in particular: follow the salt.
The Dawn spacecraft left behind the giant asteroid Vesta last September, and is now en route to the even bigger dwarf planet Ceres, but scientists are still busy studying all of the data that was sent back to Earth while it was orbiting Vesta for over a year. And as often happens while exploring these new worlds, they have made a surprising discovery: long, sinuous gullies on the walls of geologically younger craters.