[Update 11/12/2016: Is it all an optical illusion? Read the follow-up.]

[Update 11/7/2016: Visually, fast drops in a time series, like those of D140 and D260, will tend to appear to squash any noise and periodicity. For that reason, analysis of presence of periodicity needs to be mathematical.]

The recent crash of the ExoMars Schiaperelli lander on Mars highlights how difficult it is to land there. So why is that? Why are landings on Mars so complex? And why do they fail so often? ESA is getting somewhat bad press for this. In my view it validates the foresight of their approach, to send a test lander first. It also highlights the risk for manned missions to Mars and the planetary protection issues with humans to the Mars surface, which I've written about many times.

Since President Kennedy, the Pesident by tradition sets long term objectives for human spaceflight for NASA. President Bush's vision was a return to the Moon. President Obama's vision treats the Moon as of so little interest, that the next step on the way to their long term goal of Mars is to pluck a boulder from an asteroid to create a new moonlet orbiting the Moon for astronauts to visit. With a new President, there is often a change of human space flight policy. The Moon is far more scientifically interesting than we realized at the time of Apollo, not only more interesting than a boulder from an asteroid, as we will see, you could go as far as to say that the level of science interest for the Moon is not dissimilar from that of Mars.

Mars' largest moon, Phobos, has captured public imagination because the dominant feature on its surface (22-kilometers across) is Stickney crater (9-km across), a mega crater that spans nearly half the moon. 

The crater lends Phobos a physical resemblance to the planet-destroying Death Star in the film "Star Wars." But over the decades, understanding the formation of such a massive crater has proven elusive for researchers. For the first time, physicists at Lawrence Livermore National Lab have demonstrated how an asteroid or comet impact could have created Stickney crater without destroying Phobos completely. The research, which also debunks a theory regarding the moon's mysterious grooved terrain, was published in Geophysical Review Letters.

President Obama, if you love science,
 Please protect Mars life from contamination from Earth
For Future of Exobiology - MOON FIRST

The nearby star Proxima Centauri hosts an Earth-sized planet (called Proxima b) in its habitable zone but the star seems nothing like our sun. It's a small, cool, red dwarf star only one-tenth as massive and one-thousandth as luminous as the sun. However, new research shows that it is sunlike in one surprising way: it has a regular cycle of starspots.

Starspots (like sunspots) are dark blotches on a star's surface where the temperature is a little cooler than the surrounding area. They are driven by magnetic fields. A star is made of ionized gases called plasma. Magnetic fields can restrict the plasma's flow and create spots. Changes to a star's magnetic field can affect the number and distribution of starspots.

You may have heard that the Moon is hopeless for gardening and for growing crops, and that Mars is the "go to" place for a prospective astronaut gardener. But is it? As it turns out, the Moon has some advantages over Mars, especially if you can plant your garden in a habitat or greenhouse on its summits of sunlight at the poles.

Yes, it is rather chilly there, at -30° C (-22 °F), but there is no weather, good or bad, and the vacuum of space is a good insulator (like a thermos flask). The temperature at the poles is steady, varying by only 10 °C (18 °F) up or down. That's warm enough to keep a well insulated habitat or greenhouse at a comfortable temperature of 20° C (68 °F) year round with sunlight piped in from solar collectors.

When I wrote my kindle and online book Case for Moon First, I was surprised to find that the Moon is resource rich, and often beats Mars in habitability comparisons.  Yet photos of Mars released to the press look so much more Earth-like than the Moon, because of the brightening of the landscape and boosting of blue in the scene (white balancing) done to help geologists read the rocks.

This is a news story that broke recently, on the idea that Elon Musk's plans would violate the Outer Space Treaty. The articles I've read so far focus on property rights and the  provisions in the OST that rule out ownership of territory. But that can be fixed with future legislation, especially since it's not really the land but the habitats that are of most value, and ownership of those is already covered in the OST . So far none of them have mentioned by far the toughest legal and practical obstacle, which is planetary protection of Mars from Earth microbes to preserve its science value for the future of mankind. That can't be fixed by passing new laws. Elon Musk says the mission would be dangerous, with colonists risking death, especially the first ones.

I've just been listening to Elon Musk's much anticipated talk about his vision for colonization of our solar system. Many find this idea inspiring, that by technological means, we can become a multiplanetary species. 

Here is the talk, in case any of you haven't seen it yet.

For a summary of the technical details he revealed in the talk, see this article on