Travelling light

In the 1990s, the Hipparcos satellite enabled scientists to use triangulation techniques to calculate the distance of the Pole Star, Polaris, from Earth. Their answer was 434 light-years (a light-year is a tad under 6 trillion miles). But in 2012, astronomer David Turner analysed the spectrum of its light and concluded that the star was ‘only’ 323 light-years away. Polaris fluctuates in brightness, however, and the Hipparcos team think that Turner might not have taken this adequately into account, using a higher value which would have made the star appear closer. Someone has set out to decide who’s right:

I am a light ray, and I’m well on my way
From Polaris towards your blue planet.
I have used the ‘straight’ lines that space-time defines
On my journey, since first I began it.

When shall I arrive? Well, I’d better contrive
To work out the timings involved:
I’m travelling at c1 on my trajectory –
But one problem still has to be solved.

I need your assistance to find out the distance
From Polaris to Earth: but oh dear!
It seems you’re not sure what it is any more,
And the error’s not  just a light-year.

The problem’s Polaris, for this sort of star is
The sort whose brightness keeps changing.
If you measure it wrong, it’ll not be too long
Till your sums will all need rearranging.

If Dave Turner’s correct, well then I’d expect
To arrive a whole century sooner.
But I trust Hipparcos2 to measure my star, ’cos
It’s been such a great cosmos-tuner:

It’s clocked the positions, with milliarcsec3 precisions
(And motions and parallaxes, too),
Of 60K-score of our galaxy’s store
Of stars (which leaves billions to do!)4

If Hipparcos is right, and the time of my flight
Is four-three-four years, it’ll show
That Dave Turner was wrong (as I guessed all along).
If you doubt it, ask me – I should know!

1 ‘c’ is the usual symbol for the speed of light in a vacuum, which is about 670,616,629 mph.
3 A very precise measure of angle: there are 3.6 billion milliarcseconds in just 1 degree!
4 Wikipedia reckons the estimated total number of stars in our Milky Way galaxy to be “between 200 and 400 billion”

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Probing Popo

Volcanic eruptions are notoriously unpredictable. But analysis of thin sections of crystals in lava from Mexico’s Popocatépetl has enabled researchers to probe the subterranean travels of magma as it flows from one chamber to another on its convoluted journey to the vent. It’s too late, though, to be of any help to the early inhabitants of nearby Tetimpa, who migrated to a new settlement further north, leaving remains that were found by archaeologists nearly two millennia later.

Though Popocatépetl looks like a boiling kettle,
With steam escaping from its open spout,
You must be on your mettle, or Popocatépetl
Will do its level best to catch you out.

(Tetimpa’s folk knew well that it wasn’t wise to dwell
When old Popo was about to blow his top:
For they had learned to tell when to stay or run like hell
And sacrifice to Popo their corn crop*.)

Now researchers are learning what keeps old Popo churning:
Using petrographic microscopes, they’ve found
That a greyer crystal section means a rapid, hot injection
Of magma hit a chamber underground;

And each crystal’s grey-scale banding provides some understanding
Of mineral diffusion rates, which show
How long the magma took (you can read it like a book!)
To travel through the labyrinth below.

Of course, diffusion stops when old Popo’s crater pops
And magma hits the cooler outside air–
That’s how you can assess how long (well, more or less)
The magma had remained entombed in there.

Some six and forty years is the answer, it appears*,
Which suggests eruptions here, my source reports,
Will not be quite as bad as what killed Young Pliny’s dad –
A ‘Plinian’ eruption – fame of sorts!

* See papers by Plunkett & Uruñuela, on Tetimpa, and Petroni et al, on timing pre-eruptive magmatic processes

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Intelligent design?

You couldn’t really apply that term to the location of the prostate gland.

Here’s this week’s competition: design a prostate gland
In such a way that there is room to let the thing expand.
The current one works well, initially, at least.
But when the blooming thing gets fat, the prostate is a beast.

I mean, it’s wrapped around a vital piece of plumbing,
So, when it grows, it slows the flow! It really is mind-numbing.
And that’s not all: it pokes into the nearby bladder,
Thereby preventing emptying. It’s not just mad, it’s madder!

It’s in the wrong place, really. Intelligent design?
If so, the guy who planned it should rapidly resign.
No, it was evolution (which has no long-term plan)
That put the prostate where it is and made things tough for Man.

[Image: British Association of Urological Surgeons]
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Sophie’s weigh

‘Sophie’ is the most complete set of Stegosaurus bones at the Natural History Museum. The experts there have used them to estimate what she would have weighed.

Poor Sophie Stegosaurus! In Wyoming, USA,
She might have either starved to death or fallen ill one day.
She died while adolescent, a death quite undeserved,
And yet her bones – well, most of them – were luckily preserved.

They’ve photographed her bones from her tail-spikes to her noddle,
Then stitched them all together in a 3-D computer model.
And why, I hear you ask? Well, in her digital state,
These folk can tweak their algorithms to estimate her weight.

They ‘convex-hulled’ poor Sophie – pulled a ‘skin’ around her, tight,
Then added 21% to get the volume right.
With a crocodilian density, her mass could then be sought:
Some sixteen hundred kilograms, or half what once was thought!

Now here’s an intriguing postscript:
Although, throughout this tale
I’ve called its heroine Sophie,
‘She’ could, in fact, be male . . .

[Image: Natural History Museum, London]
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Mending things

It’s very frustrating . . .

I used to be good at mending things
In the old days when all things were mendable.
When things go wrong now, you can’t take them apart,
You must throw them away – they’re expendable.

It started with valves (the electrical sort):
You had to replace them with new.
And likewise transistors; but it soon became clear
This was not economic to do.

So next a whole circuit board had to be swapped
(Who cared which part was defective?)
Now, sometimes the entire bit of kit must be ditched,
For to mend it is not cost-effective.

You used to be able to see how things worked
By getting inside them to see;
Now modern technology’s hidden the works
That interested people like me.

I used to be good at mending things
In the old days when things were repairable.
So bring me your old stuff that’s ground to a halt.
I will mend it, and life will be bearable!

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I wouldn’t say no . . .

It’s the sort of thing you might say if offered a tasty treat – unless you really thought about the words you were using.

I wouldn’t say “no” to a custard tart.
(I wouldn’t say “yes” to one either:
To talk to a custard tart would be silly
Or sad, and I reckon I’m neither.)

I wouldn’t say “Boo!” to a goose. (Just as well –
Geese don’t understand English, they say;
And “Boo!” might mean, into Gooseish translated,
Attack – he must not get away!”)

The moral of this, if moral there be,
Is: make sure that you say what you mean.
For that is the best way, I think, to avoid
Consequences you hadn’t foreseen . . .

[Images: Wikimedia]
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Unwanted gifts?

Did the truelove of the writer of the eighteenth-century carol forget what he’d sent her the day before? The unfortunate recipient (whom I thought most likely female) received a total of 376 items over the pre-Christmas period. But, necessity being the mother of invention, she had hatched a cunning plan . . .

On the first day of Christmas, my truelove sent to me
A partridge in a pear tree.

So I emailed my truelove: “What am I s’posed to do
With a partridge and a pear tree? My love, I thought you knew
I haven’t got a garden to plant the pear tree in;
And that partridge in the hallway is making such a din!”

On the second day of Christmas, my truelove sent to me
Two turtle doves
And a partridge in a pear tree.

He hadn’t read my email! They’re clogging up the hall,
Those partridges and pear trees which I didn’t want at all!
I’ll ring him up . . . he’s out. That leaves me pretty vexed:
I hope he’s not gone shopping – who knows what he’ll buy next?

On the third day of Christmas, my truelove sent to me
Three French hens,
Two turtle doves
And a partridge in a pear tree.

Now this is getting silly. Where shall I put them all?
The French hens weren’t too happy when I shoved them in the hall
With three partridges in pear trees, and four doves – I think that’s it . . .
(I had to prune the trees a bit, to make sure they would fit.)

By the seventh day of Christmas, can you guess what I had got?
Despite all my pleas,
Twelve turtle doves,
Fifteen French hens,
Sixteen calling* birds,
Fifteen go-old rings;
Twelve geese a’cackling,
Seven swans a’swimming,
And some partridges in some pear trees.

On the two next days of Christmas, my truelove sent to me
The usual, and some girls:

Sixteen maids a’milking, in a rustic sort of way,
And nine ladies dancing – what is he trying to say?
By now, my house was full, jam-packed to overflowing;
What would he send me next? There was no way of knowing . . .

On next two days of Christmas, my truelove sent to me
The usual, and some blokes:

Twenty lords a’leaping, eleven pipers piping –
The neighbours heard the racket, from behind their curtains peeping,
But soon came out to join the fun, and now the street was humming!
And then – my truelove’s master stroke – came twelve drummers drumming!

I saw a chance to make some cash (my truelove wouldn’t know):
I’d charge them all to watch it – my Festive Christmas Show!

And then I’d sell the pear trees, set free a turtle dove
And a calling bird or two to fly to my truelove.
I’d flog, for Christmas dinners, those geese and fat French hens –
But I’d give the swans back to the Queen, so we could still be friends.
And, finally, I’d auction off each lovely golden ring.
Then I will thank my truelove. What will next Christmas bring!

* Originally, ‘colly’ birds – a regional word describing a black colouring.

[Images: Perry/Acclaim Images (pear tree); RSPB (turtle dove); pintrest (French hen); (calling bird – a blackbird); (gold ring); (goose); (swan, milkmaid and dancer); Evening Standard (leaping lords); Wikimedia (bagpiper); (drummer)]
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