We all know what a kilogram is, right? It’s the mass of a bag of sugar. Thank goodness for the bag of sugar. Without it we’d be forced to imagine 1/7000th of an African bull elephant or 1/14560th of a double decker bus or God only knows what fraction of the weight of Wales.
Having a clear visualisation of the kilogram is important for all sorts of reasons, not least because it’s one of the seven SI units, the fundamental alphabet of symbols which can be combined in a variety of ways to express any physical quantity. Speed, for instance, is measured in metres per second, whereas force can be expressed in terms of kilogram metres per second squared.
The kilogram was accepted into this metrological pantheon alongside the metre 125 years ago today, when the value of both units was defined at the first General Conference on Weights and Measures organised by the BIPM. As a consequence of that meeting, three identical kilograms were cast by the firm Johnson Matthey out of a mass of platinum-iridium alloy. This alloy was chosen because of its density and chemical stability, meaning that the kilograms would be both small and resistant to rust. One of the kilograms was kept at the BIPM offices in Sevres, and two were sent for safekeeping in America. Rumours that a further three were subsequently distributed to the elven-kings under the sky have no foundation in truth.
As anyone who has ever attempted to buy wallpaper with a loved one will know, colours are notoriously difficult to define. One man’s Burgundy is close enough to another woman’s Maroon for Red to be a dangerously ambiguous catch-all term.
But what if more were at stake when choosing colours than marital happiness. What if the choice of one particular shade of blue over another constituted a religious sin. And – as if that weren’t bad enough – what if nobody had actually set eyes on the colour in question since the days of Ancient Rome.
This chromatic grey area is not a hypothetical situation. The disappearance of the colour t’khelet (pronounced with a properly phlegm-filled ‘kh’, if you please) was a pressing question in Jewish theology for well over a millennium. It took generations of rabbis, dye-makers and chemists to bring the dye back from the dead, and in the process explain just how it was that the Jews first got the blues.
In the Old Testament’s Book of Numbers (chapter 15, verse 38), the Lord tells Moses to instruct the Children of Israel to “make for themselves fringes on the corners of their garments, throughout their generations, and affix a thread of t’khelet on the fringe of each corner.”
What’s the largest animal ever to live on planet Earth? Whether you’re measuring in double decker buses, swimming pools or African elephants, any budding naturalist will be able to tell you that the answer is the blue whale. At 31 metres long and weighing 146 tonnes, this enormous cetacean easily exceeds the paltry dimensions of such pretenders as diplodocus and Tyrannosaurus rex. In London’s Natural History Museum, one of the rare institutions where life-sized models of both animals exist side-by-side, the blue whale has a good three metres on Dippy the beloved Diplodocus.
The blue whale has had to fend off another challenger this week, in the form of Dreadnaughtus schrani, a behemoth from 77 million years ago thought to measure 26m from tip to tip. Dreadnaughtus has made headlines as the most complete sauropod skeleton ever discovered, a body of evidence which provides ample confirmation of its titanic size.
But the absence of such complete remains has never stood in the way of scientists looking to predict an animal’s length and height. The dimensions of the largest dinosaurs have often been extrapolated from just a few fragments of their enormous skeletons. In one notable case, the discovery of a single vertebra led to the prediction of an entirely new species of dinosaur, larger than any that had come before or since. A dinosaur that would make the blue whale look like small fry: Amphicoelias fragillimus.
Chances are, the screen you’re currently looking at is capable of displaying over 16 million different and uniquely identifiable colours. As those of you who’ve done digital design work will probably know, each of these colours can be represented by a Hex code – a six-character string of letters and numbers.
But where do these odd symbols come from? And what do they mean? And – most interestingly of all – is it possible to work backwards from the Hex code to correctly identify the colour?
Today is “Internaut Day”, marking the 23rd anniversary of the World Wide Web’s public unveiling. While working at CERN in 1991, computer scientist Tim Berners-Lee invented “hypertext” – virtual content with embedded links to other text – and revolutionised the way we use computers. Continue reading →
37 years ago today, the Big Ear telescope in Ohio picked up the first and only strong signal from outer space that could be from extra-terrestrials.
Rather embarrassingly for humanity, we behaved like school kids who just received a text from someone they fancied. We spent ages debating whether or not the message was for us; and then we got our mates to help us write a reply which is looking pretty cringey in hindsight. Continue reading →
This week I decided to look up Tycho Brahe’s nose. After all, it is the title of our blog. And as you’d expect when looking up someone’s nose, you come across a fair amount of useless gunk. But keep poking around for long enough and those itchy fingers start uncovering some really fascinating nuggets.
The first thing everyone knows about Brahe – even before they know what he looks like or even how to pronounce his name – is that he had a gold prosthetic nose. Now I don’t know about you, but that strikes me as rude. It’s also mistaken, incidentally, but more than anything else it’s rude. So here’s a picture of Tycho Brahe (Brah, Bra-hay or Bra-hee, depending on how wrong you mind being) for you to look at while you think about just how rude you’ve been.
Forget the nose – why doesn’t anyone remember those moustaches?!
Brahe’s original nose (not shown in the above) was cut off to spite his face by a fellow Dane named Manderup Parsberg while the two were students at the University of Rostock in Northern Germany. Many have claimed the duel was inspired by a mathematical disagreement, which is a cute story, but Tycho seems like the sort of person who would have challenged you to a duel if you looked the wrong way at his moose (don’t worry, we’ll come back to the moose).