Ceres is the king of the asteroid belt, being the largest object in that region of the Solar System, and the Dawn spacecraft has shown it to be a very interesting world. While it is relatively small, classified as a dwarf planet, and very cold being so far from the Sun, there are hints that it has been surprisingly geologically active in the past and perhaps still is. Superficially it resembles the Moon or Mercury, gray and covered in craters. But there are also canyons, hazes, and unusual bright spots. Those spots have become a focus of much interest for scientists, and now new studies indicate that they appear to change in brightness from day to night, and may be evidence of ongoing activity inside Ceres.
The Martian rover Opportunity has become famous for its amazing longevity, but it is not the only one; orbiting spacecraft also usually enjoy long lifespans, and today the Mars Reconnaissance Orbiter is celebrating its 10th year exploring Mars from above. It has helped to revolutionize our understanding of Mars and its complex geological history as well as, of course, sending back thousands of incredible high-res images of the Martian surface.
It has been a year now since the Dawn spacecraft first reached the dwarf planet Ceres in the main asteroid belt between Mars and Jupiter, and during that time has shown Ceres to be a unique and complex little world. At first glance, Ceres just seems to be a heavily battered place, covered in craters like the Moon or Mercury, but a closer look reveals something more interesting: a small rocky world with large fractures, unusual “bright spots” randomly dispersed across the surface and an odd conical “mountain” which sits in isolation with nothing else like it around. Dawn has already acquired an enormous amount of data about Ceres, but now, in its lowest possible orbit, will continue to do for some time to come.
As the data from New Horizons continues to come in, we are learning more about what an incredible little world Pluto really is, with tall mountains of rock-hard water ice, as well as glaciers and vast icy plains composed of nitrogen ice. In some ways, these features are visually reminiscent of similar ones on Earth, and now this week another cool discovery was revealed: methane snow on some of Pluto’s mountain peaks.
NASA’s Curiosity rover on Mars may have been stealing the spotlight in recent years, but the other rover, Opportunity, is still going strong after 12 long years. Opportunity has survived the harsh environment and various challenges for much longer than anyone anticipated, and now is taking on a new task: climbing slopes as steep as 30 degrees while searching for deposits of clay minerals which had already been detected by orbiting spacecraft. The region where Opportunity landed, Meridiani Planum, is mostly flat plains, but now on the rugged edge of the huge Endeavour crater, the rover is becoming something of a mountain climber.
This coming September, a new NASA spacecraft, OSIRIS-REx, will be heading toward an asteroid to collect samples which will later be brought back to Earth. This is the first time for such a sample return mission to an asteroid by a U.S. spacecraft, but there’s also another unique aspect to this mission – artists, and space enthusiasts in general, are being invited to submit some of their work to be included onboard the spacecraft.
One of the most surprising discoveries in recent years in the outer Solar System is that there are small moons which have oceans inside them. Jupiter’s moon Europa and Saturn’s moon Enceladus are now known to have global oceans of water beneath their icy crusts, and others are thought to as well, including Ganymede, Titan, and possibly others. These moons have a lot of ice and rock as well, and gravitational tugging and heating from the large gas giant planets helps maintain a deep layer of liquid water inside them, where otherwise they would most likely be frozen solid in the deep cold so far from the Sun. Now it seems that another moon also once had an ocean, although in this case it is thought to now be solid ice: Pluto’s largest moon, Charon.
Exoplanets are now being discovered by the thousands, but most are so far away that determining anything specific about their composition or atmosphere is currently very difficult. But technology keeps advancing, and scientists are now starting to be able to learn more about them, at least ones which are a bit closer to our own Solar System. One of the most common types of exoplanets are the “super-Earths,” which are larger and more massive than Earth but smaller than Uranus or Neptune. Now, astronomers have been able to analyze the atmosphere of one of these worlds for the first time.
Pluto is a tiny world and incredibly distant from the Sun, so it was a pleasant surprise for scientists last summer when the New Horizons spacecraft found that it is such a geologically active and dynamic place, with vast “seas” of nitrogen ice and glaciers, tall mountains of rock-hard water ice, and possible ice volcanoes. A new update this week focuses on some of the most interesting features discovered: iceberg-like blocks of water ice which “float” in the “seas” of softer nitrogen ice.
The recently announced new mission to Jupiter’s moon Europa, a highly anticipated return to this ocean world, may face a launch delay from 2022 to the late 2020s. The news comes amid the release yesterday of NASA’s fiscal year 2017 budget request, which provides substantially less funding than Congress had mandated last year.