A sampling of items regarding planetary science, astronomy, and solar science:
** A solar cycle update from Bob Zimmerman: Sunspot update January 2019: The early solar minimum | Behind The Black
January saw a slight uptick in sunspot activity, but the overall activity remains comparable to mid-2008, when the last prolonged solar minimum began. If you go to my October 2018 update, you can see the graph when it included data going back to 2000 and see the entire last minimum.
That last minimum started in the last half of 2007, and lasted until mid-2009, a full two years. If you look at the red line prediction of the solar science community, it appears that they are expecting this coming minimum to last far longer, almost forever. I expect this is not really true, but that they have simply not agreed on a prediction for the next cycle. Some in that solar science community have hypothesized that we are about to enter a grand minimum, with no sunspots for decades and thus no solar maximum. Others do not agree.
** Mark Showalter, New Horizons Hazard team lead and SETI Institute Senior Scientist, discusses “the spacecraft’s flyby of Ultima Thule, what it’s like working on the Hazards team, and even the naming of some of Pluto’s surface features” with SETI Institute chief Bill Diamond:
*** Ultima Thule has flat lobes according to further analysis of the image data from the fly-by of the Kuiper Belt object: New Horizons’ Evocative Farewell Glance at Ultima Thule: Images Confirm the Kuiper Belt Object’s Highly Unusual, Flatter Shape – New Horizons
This animation depicts a shape model of Ultima Thule created by the New Horizons science team based on its analysis of all the pre-flyby images sent to Earth so far. The first half of the movie mimics the view from the New Horizons spacecraft as it approached Ultima Thule and has the “snowman” shape that was so frequently mentioned in the days surrounding the New Year’s 2019 flyby.
The movie then rotates to a side-view that illustrates what New Horizons might have seen had its cameras been pointing toward Ultima Thule only a few minutes after closest approach. While that wasn’t the case, mission scientists have been able to piece together a model of this side-view, which has been at least partially confirmed by a set of crescent images of Ultima Thule (link). There is still considerable uncertainty in the sizes of “Ultima” (the larger section, or lobe) and “Thule” (the smaller) in the vertical dimension, but it’s now clear that Ultima looks more like a pancake than a sphere, and that Thule is also very non-spherical.
NASA’s Curiosity Mars Rover has already descended from Vera Rubin Ridge, a region of Mount Sharp that it has been exploring for more than a year. But before it left, the rover took a 360-degree panorama of the area depicting its last drill hole on the ridge (at a location called “Rock Hall”), a new region it will spent the next year exploring (the clay unit) and its last view of Gale Crater’s floor until it starts ascending in elevation again.
At high resolution there does not appear to be much difference between the darker and lighter areas. The lighter areas in general seem less rough and at a slightly lower elevation, but both areas are dominated by ridges and dunes trending southwest-to-northeast.
Why is this slightly higher region darker? Let’s assume that this darker material was a lava flow overlaying the surface. Over eons wind erosion, trending southwest-to-northwest, roughly eroded both it and the lower layers around it, leaving behind this rough corroded terrain. The different make-up of the darker material allows it to erode in a rougher manner.
While possibly correct, I would not bet much money on this guess. It is not clear it is lava. It is not clear that it is a flow. It does not explain why there are two areas of different darkness. And it certainly not clear what the make-up of any of this stuff is.
This is simply another cool mystery on the Martian surface.
- Stunning new images show what the Chang’e-4 mission has been up to | The Planetary Society – “ewly released images and video from the Chang’e-4 mission, extracted from a longer Chinese New Year celebration video posted by CCTV”.
NASA’s Hubble Space Telescope has snapped the latest weather pictures of our solar system’s frigid outer planets, and UC Berkeley astronomers have jumped in to interpret them.
The new images, taken as part of a yearly monitoring program, show that a dark storm has appeared in Neptune’s northern hemisphere, the fourth seen on the planet since 1993, all of which appear and fade within a few years. UC Berkeley undergraduate student Andrew Hsu, who led a study of the latest images with associate research astronomer Michael Wong, estimates that the dark spots appear every four to six years at different latitudes and disappear after about two years.
It’s unclear how the storms form, Hsu said, but like Jupiter’s Great Red Spot, the dark vortices swirl in an anti-cyclonic direction and seem to dredge up material from deeper levels in the ice giant’s atmosphere. The latest storm was captured by Hubble in September 2018 and is roughly 6,800 miles across.
The new snapshot of Uranus gives a fresh look at a long-lived storm circling around the north-pole region of Uranus, a planet that is usually thought of as featureless and boring.
** Asteroids – The DART mission will smack an asteroid with a spacecraft to test deflection capabilities: The DART Mission: Learning How to Swat Dangerous Asteroids | The Planetary Society
Why did the dinosaurs die? They didn’t have a space program! The upcoming DART mission will test our best thinking about how we may someday deflect a Near Earth Object that is speeding toward fiery Armageddon on Earth. Nancy Chabot of the JHU Applied Physics Lab is the mission’s Coordination Lead.
** Science news is included in the latest TMRO.tv space news report: SpaceX Engine Tests, ISRO Spaceflight, Lunar Craters and SpaceIL