The umbrella term for the 68 percent of the universe that we can't detect and know nothing about has been given the umbrella term "dark energy." Like wormholes 30 years ago, it is more MacGuffin than science. You could call it aether or magic or any deity name and be just as valid.

But inference says something, or a variety of somethings, must be causing the universe to expand when gravity says it should contract. So dark energy it is.

Except maybe it isn't

This is an update to my article: How A "Dwarf Planet" Gas Giant Could Challenge IAU Definition - Pluto, Ceres, Haumea Etc Can All Be Planets. That article pointed out that we could discover a gas giant in our own solar system that satisfies the IAU definition of a "dwarf planet" as it wouldn't clear its orbit if it was far enough away. First, I should have pointed out there that the WISE search has not ruled out gas giants in the remote parts of our solar system.

I think the chances of the SpaceX mission around the Moon going ahead on schedule in 2018 is tiny. But on the remote chance it does, I would not fly on that mission, if you paid me a billion dollars. The problem is that they have to rely on many innovations working just right that are hardly tested. Their current Dragon spacecraft is only rated for re-entry from LEO (Low Earth Orbit) and not for the much faster re-entry from a trip around the Moon. That’s why they plan to use the larger Dragon 2 which has its first flight in 2018.

Ethan Siegel has just written an article, "The Science Has Spoken: Pluto Will Never Be A Planet Again", so this is a response to it. I'll argue that far from "story over", actually we could make a discovery tomorrow that would turn the whole thing on its head and make their definition untenable.  This will become particularly acute if we ever find a gas giant in the outer reaches of our solar system, too far away to clear its orbit. And we could find such a planet.

Vera Rubin who helped to discover one of the greatest mysteries of nature has died.    She was the mother of astronomical dark matter investigation.  I won't write about her accomplishments at length ...

This is something you hear said so often - that we risk being hit by an asteroid that could make humans extinct. But do we really? This is the article I’m commenting on, a recently breaking news story: Earth woefully unprepared for surprise comet or asteroid, Nasa scientist warns. Some are already worrying that it means that we are all due to die in the near future from an asteroid impact. Well, no, it doesn't mean that. So, what is the truth behind it? 

The source of all this is a comment by Dr Joseph Nuth who warns:

I had previously discussed the amplitude of the ~0.88-day signal of Boyajian's star (or KIC 8462852.) If you look at the amplitude series alongside gradual dimming of the star throughout the Kepler mission (Montet and Simon, 2016), it appears there's a relationship, even though amplitude changes are real and not an artifact of dimming. Montet dimming is thought to be very unique to Boyajian's star. It follows that if the 0.88-day signal is independent of major dips, our peculiar star happens to be affected by two unique but independent mechanisms.
Data visualization is a key tool in Data Science. You should always look at your data. Invariably, you will discover aspects of the data you might not notice if you just blindly run algorithms on it. That said, another important rule of thumb in Data Science is that you should not only rely on what you think you are seeing. You should always follow up and confirm any graphical analysis with Math.
The giant planets in our solar system have very diverse rings. Observations show that Saturn’s rings are made of more than 95% icy particles, while the rings of Uranus and Neptune are darker and may have higher rock content. Since the rings of Saturn were first observed in the 17th century, investigation of the rings has expanded from earth-based telescopes to spacecraft such as Voyagers and Cassini. However, the origin of the rings was still unclear and the mechanisms that lead to the diverse ring systems were unknown.

If Elon Musk and Robert Zubrin have their way, we may get migrations of hopefuls setting off from Earth to Mars to colonize what they believe to be a "New World". If so, what they find there will be far more like the nineteenth century Antarctica than the seventeenth century "New World". Indeed, even the climbers who tackled Mount Everest in the twentieth century explored a far more hospitable place than Mars. You could breathe the air on the summit with only the need for an oxygen mask. It's also bitterly cold on Mars - a night in the Martian tropics is colder than the coldest night on Everest in the middle of winter. It's so cold that the air often starts to freeze out as dry ice at night.