Solar System Chatter

A hundred satellites, all talking at once. Here’s the intel.

Earth Your World in High Def
Commercial satellite imagery company DigitalGlobe just released the first photo from WorldView-4, which was launched November 11. The company boasts that the Lockheed Martin-built satellite has the highest resolution of any commercial satellite, resolving detail down to 30 centimeters. The image, which we’ve abused here by posting in low-res (you can see the original here), is of Yoyogi National Gymnasium in Tokyo, Japan, which was built for the 1964 Olympics and will be used again for the 2020 Games. DigitalGlobe markets its imagery for mapping, security, and humanitarian response purposes, but also collects its own set of images for its ongoing 16-year time-lapse image library.  Image: DigitalGlobe / WorldView-4. December 2, 2016

Planets A New Camera at Mars
Although the lander half of the ExoMars mission didn’t make it, the European Space Agency is very pleased so far with the Trace Gas Orbiter, which sent back its first images of the Mars surface this week. The orbiter is going to take another year to get into its final orbit, but that doesn’t mean mission scientists can’t get its instruments up and running. The image at right is from the Colour and Stereo Surface Imaging System, or CaSSIS, showing a crater a bit smaller than a mile wide that’s on the rim of a much more massive crater at about 23 feet per pixel, taken as the orbiter did a low pass just 155 miles altitude. The camera is able to take short exposures extremely rapidly (one of the pictures it sent down this week took an exposure lasting 700 microseconds every 150 millisecond). Eventually, scientists at the Astronomical Observatory of Padova in Italy will be able to take CaSSIS data and create stereo images, with which they can make 3D reconstructions of Martian features. Image: ESA/Roscosmos/ExoMars/CaSSIS/UniBE. November 29, 2016

Earth GOES is Up
Weather forecasting is about to take a big leap forward after the successful launch of NOAA’s GOES-R satellite. It’s the first of four satellites in the next generation upgrade for the Geostationary Operational Environmental Satellite series (the first one was launched in 1974). The satellite will reach its final orbit in a couple of weeks, when it will be renamed GOES-16, and spend the next year testing its six instruments that will collected data significantly faster and in more detail than any previous incarnation. Scientists will have access to the first lightning-mapper in geostationary orbit and improved space weather sensors. GOES-16 will also be connected with a constellation of satellites that can detect distress signals from boats and aircraft. Image: NASA. November 19, 2016

Planets New Moons for Uranus?
Voyager 2 is the mission that keeps on giving. Scientists at the University of Idaho think they’ve discovered two moons orbiting Uranus that have never been seen before. They noticed patterns in the waves of the planet’s rings that indicate an object creating a disruption. The two moons, which haven’t been observed yet, only hypothesized from the math, would be tiny: two to nine miles in diameter. Scientists have always wondered why Uranus’ thin ring structure doesn’t spread out more, and already know that two of the planet’s 27 known moons act as “shepherds” to the Epsilon ring. If these two new moons exist, they may help add to the explanation of the planet’s dynamics if they act as shepherds to other parts of the ring system. Image: NASA/Erich Karkoschka (Univ. Arizona). October 21, 2016

Planets Mars in Ultraviolet
The MAVEN spacecraft, which has been orbiting around Mars since 2014, recently sent back ultraviolet images of the entire globe. By studying the UV light, scientists can now detect the dynamic wind behavior at high altitudes on Mars, how the ozone concentrations change over the course of a year, and how clouds form around the planet’s four largest volcanoes, which can help explain energy distribution in the atmosphere as the seasons change. The volcano Olympus Mons appears in the dark spot near the top of the image at right, with a dot of white clouds in the center, at its peak. The three other volcanoes appear in the diagonal line, and their cloud cover often merges into a formation thousands of miles long. Click through here to watch a video that stitches together the global UV images from MAVEN. Image: NASA/MAVEN/University of Colorado. October 17, 2016

Universe Cannonball Fire
A bizarre star system is lobbing out superhot plasma blobs at blazing speeds every 8.5 years. The Hubble Space Telescope located their starting point at a red giant star, which couldn’t be generating them. More likely, an unseen companion swings by closely, gathering material from the red giant and flinging it into space. Image: NASA, ESA, and A. Feild (STScI). October 6, 2016

Planets More Evidence for Europa’s Water Plumes
New observations from the Hubble Space Telescope lend even more evidence that Jupiter’s moon Europa may have water plumes shooting from the surface. Unlike Enceladus, where the Cassini spacecraft has directly observed—and flown through—the sprays from Saturn’s moon, plumes from Europa’s underground ocean are still an educated guess. Scientists explained today that they’ve been using Hubble at the limits of its capabilities to study our neighboring planet’s moons. They gathered these observations in 2014 with a technique that’s being perfected by exoplanet scientists: Hubble observed Europa as it transited Jupiter, using the bright background to better highlight any thin plumes. They also credit the Space Telescope Imaging Spectrograph, or STIS, the instrument that got a big upgrade during the last Hubble servicing mission in 2009, for having the sensitivity to collect this data. The resulting image—at right, with an image of Europa from Galileo and Voyager superimposed over the Hubble background observation—shows what may indeed be water vapor plumes coming out at the lower left. If they’re real, that means that a Europa lander could study the plumes for signs of life while it sits directly on the surface, rather than drilling down through potentially miles of ice to reach the ocean. The team noted that although Juno is in the system studying Jupiter right now, it won’t be able to help confirm the plume data because they “took great pains” to keep it as far away from Europa as possible to prevent contaminating it with any Earth-life that may have hitched a ride. Image: NASA/ESA/W. Sparks (STScI)/USGS Astrogeology Science Center. September 26, 2016

Planets An Ocean Under Pluto’s Heart
Could it really be possible that Pluto, orbiting so far from the warmth of the sun, might have a liquid ocean? Scientists at Brown University have come up with a fantastic scenario that helps explain some characteristics of the dwarf planet observed by NASA’s New Horizons. The team, using computer models from New Horizons data, suggest that a massive impact created Sputnik Planum, a 900-km basin that makes up the western lobe of the “heart” seen in the first photos returned from the spacecraft. The impact would have been so hard that when the surface rebounded, it pulled up material from Pluto’s interior—not just any material, but liquid water, which is denser than the ice that had been on the surface and largely blasted away from the impact. If enough water was pulled up, it would create a “positive mass anomaly” at Sputnik Planum—precisely what the data suggests, because Pluto is tidally locked with its moon Charon along an axis that goes through the basin. If this is all correct—that a liquid ocean sits underneath Pluto’s heart—it would be about 100-km deep.  Image: NASA/APL/SwRI. September 23, 2016

Planets Mars Was Wet More Recently Than Previously Thought
Using data collected by NASA’s Mars Reconnaissance Orbiter, scientists have discovered that flowing water existed on Mars much more recently than previously thought. Scientists had already found evidence that Mars had a wet period about three to four billion years ago before most of the atmosphere was lost and the remaining water froze. New evidence from MRO’s HiRISE camera, however, shows craters and valleys that were likely lakes and streams that appeared a few hundred million years after that period. Teams at the University of Virginia, NASA, and the Smithsonian are now focused on how the climate on Mars would have warmed up enough during the interim period to liquify the planet’s water, suggesting one possibility is an extreme change in the planet’s tilt.  Image: NASA/JPL-Caltech/ASU. September 15, 2016

Planets What’s Pluto Emitting Now?
Two reports came out today that describe the interesting things coming from Pluto’s direction. The first one explains why its moon Charon has that strange reddish tint at its north pole region (see photo). It turns out that Pluto is a bit of a “graffiti artist,” says Will Grundy from NASA’s New Horizons’ team. Methane gas escapes the dwarf planet’s atmosphere, gets trapped by Charon’s gravity and freezes. Ultraviolet light from the sun turns the methane into hydrocarbons, and finally into reddish-colored organic material called tholins. Meanwhile, another team of scientists are perplexed by X-rays coming from Pluto. NASA’s Chandra X-ray Observatory observed Pluto four times while New Horizons was en route and measured a somewhat surprisingly high amount of radiation coming from the planet. All solar system objects with atmosphere emit some level of X-rays, because of the way the gasses interact with solar wind. While New Horizons did discover Pluto had more atmosphere than predicted—scientists thought it would have a thin atmosphere similar to a comet—it still does not account for the level of radiation given how weak the solar wind is that far away from the sun. Image: NASA/JHUAPL/SwRI. September 14, 2016