Archive for the ‘Science’ Category

Ten days ago, I spotted a new visitor in our garden: a couple of long-tailed tits stopped by and sampled the peanuts. Wikipedia says that they are not exactly scarce, so I hope to see them more often.

A long-tailed tit feeding in our garden

A long-tailed tit feeding in our garden
(click for a larger version of the picture)

PS. In Dutch the long-tailed tit is called a “staartmees“.


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Science never sleeps, new discoveries are made every day, new technologies help refine or review existing knowledge – based on evidence.

Having fallen under the spell of Australia in 2015 I cannot help but pay attention to (scientific) news about this continent and its people. No wonder then that this title caught my eye: “Buried tools and pigments tell a new history of humans in Australia for 65,000 years“.

The result is that we have a convincing age for the settlement of Madjedbebe, and Australia, of 65,000 years ago.

The arrow next to the green plus sig points to the approximate location of Madjedbebe, halfway between Jabiru and Ubirr

In the words of the abstract in Nature:

Human occupation began around 65,000 years ago, with a distinctive stone tool assemblage including grinding stones, ground ochres, reflective additives and ground-edge hatchet heads. This evidence sets a new minimum age for the arrival of humans in Australia, the dispersal of modern humans out of Africa, and the subsequent interactions of modern humans with Neanderthals and Denisovans.

I wanted to know where Madjedbebe was located, having been in Jabiru when we visited Kakadu. It took a bit of searching, since Google Maps has no reference to the place. However, the Megalithic Portal website knows the rough coordinates, and that allows me to imagine that Madjedbebe is a bit over half way on a straight line from Jabiru to the Ubirr site. The arrow next to the green plus sign on the map above should be near the real spot (I have taken the liberty of copying part of a Google Maps satellite photo to create the 32km by 32km map view) .

But much more important than knowing where to find the place is what this knowledge will do to our understanding of how humans colonised the whole world. Not yet a year ago, mitochondrial DNA research pointed to a period about 50.000 years ago for the settlement of Australia (see the references on my page about Aboriginal Art). It remains to be seen how the results of these (and other) studies can be used to compose a coherent view Australian prehistory.

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Ars Technica introduced me to the inventor of the equals sign. I was surprised to read that it was a 16th century Welsh scholar who came up with this symbol, since so much of our algebraic foundations was passed on through and from Arab scholars in the Middle Ages. Anyway, here’s a quote from the man we’re talking about:

And to avoide the tediouse repetition of these woordes: is equalle to: I will sette as I doe often in worke use, a paire of paralleles, or Gemowe lines of one lengthe, thus: = , bicause noe .2. thynges, can be moare equalle..

More about the life of Robert Recorde can be read in the Wikipedia, of course. He must have been quite a character: he taught mathematics in Oxford in his youth, went on to study medicine, then became a “controller of Mint” in several places. He also wrote the first English book on Algebra, called “The Grounde of Artes“, and later followed up with a book that introduced the equals sign (his invention) as well as the symbols for plus and minus that were already in use in Germany.

Click on the image to go to the original text of Robert Recorde

Click on the image to go to the original text of Robert Recorde

One of the commentators on the Ars article says the text of this 1557 work is transcribed in the Gutenberg Project; unfortunately, that’s wrong. A copy of “The Whetstone of Witte” can be found in the Internet Archive.

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Ars Technica published a nice overview of the current state of solar power technology: “The future of solar power technology is bright“. As owner and user of a solar panel installation I am happy to see that research on this topic has not halted. The current weather here in Belgium makes it clear, to me at least, that we will also need panels – or something else – to generate electricity when the skies are cloudy.

I wonder: having technology is one thing; making sure it is applied in the best way is something else. If we want more solar energy here in Western Europe, we will need to find a way to turn our rooftops and perhaps even south-facing walls and windows into solar panels. If we want developing countries to avoid a dependency on coal and petrol, then we’ll have to help them install appropriate systems for generating electricity rather than exporting our old cars and trucks to them.

Talking about cars: our family currently owns/uses two cars, both more than 10 years old but still in good working order. We are contemplating replacing one of them by a small hybrid or even full electric car. But that market is still immature, and many of the cars offered are still quite expensive. Replacing my diesel-powered car by an electric will make me feel good, but what will happen to the old car? If it’s moved to another part of the world and continues polluting the environment, does that really improve the world?

Is this part of the long-term future?

How hard would it be (or is it) to replace the petrol engines in current cars with something more environment-friendly, like an electric engine? Can petrol engines be converted into hydrogen engines? Could I add a solar panel on top of my car to help the battery? Or… well, you get my drift. I assume that the “economics” of such transformations have already been calculated by car manufacturers. Of course, they will not like such an operation, because it would result in less sales of new cars. The cost of doing nothing (and just continuing what has been done for a long time now) is becoming more apparent every day – even China is now committed to do something about air pollution.

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On December 23rd, 2016, I bought a few books, as I am accustomed to do every year in the holiday season. One of those books is a second-hand copy of Brian Green’s “The Elegant Universe“. I have already read some of his other books, and I am – since a long time – quite interested in the origin and evolution of the universe as well as fundamental physics. So this buy was a no-brainer.

For some reason I could not put the book down once I started reading (although I had not yet finished William Gibson’s “The Peripheral“, but that one has to wait). Green writes about the development of superstring theory from an insider viewpoint, and that makes the story much more interesting. Even if your mathematics isn’t that great (like mine) this book can help you understand the essence of string theory, so I recommend it strongly.


To start his story, Green clearly explains Special Relativity and General Relativity. As it should, Albert Einstein features prominently in his exposé. From there on, Green explains, one after the other, the problems encountered by theoretical physicists and the solutions devised to solve them. Einstein is mentioned regularly in most of the chapters.

And then, a few days ago, an online news site extensively mentioned Einstein as an author on a completely different subject: politics. Hence I discovered that Einstein was more than “just” a brilliant physicist. Already in 1909 (!) Albert Einstein wrote:

Nevertheless, it is necessary to remember that a planned economy is not yet socialism. A planned economy as such may be accompanied by the complete enslavement of the individual. The achievement of socialism requires the solution of some extremely difficult socio-political problems: how is it possible, in view of the far-reaching centralization of political and economic power, to prevent bureaucracy from becoming all-powerful and overweening? How can the rights of the individual be protected and therewith a democratic counterweight to the power of bureaucracy be assured?

(Source: Monthly Review)

I have not yet found the time to read more about Einsteins views on politics, but it says something about the man that he was already quite outspoken on this subject even before he rose to fame (after all, his paper on Special Relativity saw the light four years later, in 1912). At the same time, I can only see that we have not yet found an answer to his questions, let alone a solution to the problems posed…

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xkcd: Earth Temperature Timeline

Visit XKCD’s website for the full, long version
(Just click on the picture).

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Yes, that’s how Julldozer describes his digital sundial: he uses “programmable pixels inside a shadow” to make the sundial “print” the time on a flat surface. This is the result (there’s more of this in a time-lapse video on his website):

The Mojoptics Digital Sundial in use

The Mojoptics Digital Sundial in use

In a video Julldozer explains the science behind this remarkable object. The complexity of the sundial object is reduced, according to Julldozer, by using an open-source tool called OpenSCAD to program the design instead of designing it manually. And then all you need is a 3D printer and lots of time… Or you can presumably buy one in his gift shop.

All in all, I like this contraption. It’s an ingenious build, and it’s a nice display of what 3D printers are capable of.

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