Greta Thunberg, the best-known of the young people advocating for science-based climate policies, has been called a “revolutionary” both by admirers and critics. This is because she wants change that is serious and fast.

Can it happen in the world today?

I think the answer is yes. A process of serious political change is not only possible; it has already begun. Global youth-led demonstrations are part of this process, and changing voter behaviour is another part.

We’re in a time when the wind of change is blowing, as Harold Macmillan said about Africa back in 1960.

Climate-conscious people demonstrated in…

But for most of those 2.5 billion years there was almost no free oxygen (O2) in Earth's atmosphere. (See the page "Geological history of oxygen" in Wikipedia.) This oxygen-less Earth was an environment where many forms of microbial life could emerge and flourish, but not mitochondria which are adapted to process O2.

Have you heard of the “outside-in” hypothesis of eucaryote origin proposed by David Baum and Buzz Baum? In this model, the ancestors of mitochondria originally lived just outside another, larger species of cell, with which they already had a mutually beneficial relationship. In which case there was selective pressure to keep the two species of cell close to one another. And the eventual incorporation of the mitochondria into the larger cell was not a miracle of pure chance after all.

I agree that sentiment plays a part in theorising about presence or absence of life beyond Earth… but not necessarily in the way you think. I’d suggest that sentiment, in the form of excitement about our own current and future technology, leads us to make working assumptions about our future that may or may not be true, such as the idea that we’ll soon be spreading through the galaxy as fast as our imagined future space ships can fly. …

Would colonies on Mars or in orbit be “places where whatever conflicts and disasters that threaten Earth are less able to reach”? Aren’t most of the threats we face right now due to our failure to use high technology in a sustainable way? Wouldn’t space colonists be even more dependent on high technology, therefore even more vulnerable to system collapse?

“Facts are stubborn things.” — John Adams (1735 to 1826)

“The current, best available science is not opinions — it’s facts.” — Greta Thunberg September 2019

The January 6 insurrection in Washington can be characterised several ways, for instance as an attempted self-coup and as an anti-democratic putsch.

It was also a revolt for denial—part of a larger, on-going conflict between those who take well-established facts seriously, and those who deny facts that don’t fit their narrative.

Like Donald J. Trump, the insurrectionists were in denial of Biden’s election victory, which had already been confirmed by the Electoral College and…

There are good reasons to think that Titan and Venus may have life, or something very like it. If so, it implies an awe-inspiring diversity of living worlds in the Milky Way Galaxy. For those who dream of humans colonising the Galaxy, this would be bad news, because of what it says about the Great Filter…

The recent report about Venusian phosphine is the latest in a series of surprises from that planet, and from another world with clouds, Saturn’s moon Titan.

The phosphine report by Jane S. Greaves and others was both serious and exciting, though we don’t yet…

Why Venus microbes could be as comfortable with concentrated sulfuric as Earth living things are with water…

Life in the clouds of Venus?

The recent report of phosphine there looks like a serious clue.

The apparently successful quest for phosphine was conducted because Clara Sousa-Silva and others singled out the compound as a strong biosignature — a compound whose discovery on a rocky planet would be an major indicator of life there, because it is unlikely to be produced by non-living processes.

The biggest apparent obstacle to Venusian life is neither temperature nor pressure, but the presence of sulfuric acid…