With most smartphones now having GPS, it’s easy to take navigation for granted. Just fire up Google Earth and you can get satellite images of your location, accurate to within a few metres. There are times, however, when using GPS is difficult – if not impossible. Try going on an Antarctic expedition, for example – you’ll soon run into trouble. At temperatures of -40°C, the chemical reactions within all but the most powerful of batteries will slow to a snail’s pace – making them pretty useless for powering your electronic devices for very long. The next best thing might seem to be to whip out your trusty map and compass… except that even a compass stops being accurate as you approach the magnetic pole. No, for finding your way to the North or South Pole requires some truly old-school navigation techniques.
The trick to knowing where you are when trekking near the Poles is to use a sextant. These are ancient navigation devices that have been used by seafarers for eons. (Many sailors continue to carry them today.) They are pretty simple (battery-free) contraptions that measure the angle between the horizon and an object in the sky, like the sun or the moon. By recording the angle of the sun at a specific time (e.g. noon on 1st December 2014) then it is possible to work out where you are using navigation data tables. (You can see examples of these here).
Another trick for hiking across the snowy wastelands is to use shadows created by the sun. By facing away from the sun and using your body’s shadow like a sundial, it is possible to make sure that you are walking in a straight line with the use of an accurate clock. For a rough example, to head toward the South Pole then you will want to keep your shadow pointing to your right in the morning (when the Sun is in the east sky), straight ahead of you at noon (when the sun is in the north) and left in the afternoon.
If you are brave enough to try it, then know that it is a very long way. Wrap up warm and get good at singing, for that iPod certainly won’t help to while away the hours…
Answer by Dr Stu with thanks to Veronica Shaw, previous South Pole explorer.
Technology really is a modern day wonder – we can check emails while on the go, teenagers can message on their mobiles, and pretty much anyone can see their loved ones thousands of miles away on apps such as Skype and Viber. Of course, things weren’t always that way and long before the silicon chip, technology was rather more basic. And some of it involved solving problems with twigs and pendula.
Nowadays, water engineers can use a variety of hi-tech technologies to find underground water. For example, acoustic doppler current profilers detect water movement within a pipe; electrical resistivity tomography devices detect groundwater by through electrified wires dropped into the ground, and magnetic resonance sounding equipment finds underground water using the technology of MRI scanners.
But before all this wizardry existed, people depended on dowsing (otherwise known as water divining) to ‘see’ into the ground and locate things such as water wells, hidden metal, oil, buried treasure and even lost golf balls! And rather than using equipment that costs a bucket load, modern day dowsers use the dame technology: simply placing either two bent rods or a forked stick in front of them and walk over a target area to ‘find’ water. When the stem of the twig pulls towards the ground or the two rods cross over, it indicates that water is near. This process can then be repeated from a different direction to pinpoint the location.
Dowsing has been practiced for millennia and, as with anything with such a history, there are many enthusiasts who swear that it works; some water engineers even use it in their professional work. Dowsing is a practice that has also been extended to finding missing people (although a few more items are needed, namely a map and a pendulum) and is described as map dousing.
But finding underground water relies not just on technology, but on an understanding of the land – a realisation that certain areas are more likely to accumulate water than others. Such knowledge of geology and the landscape is used by hydrologists and dowsers alike – whether they realise it or not. And so most scientists argue that the dowser’s twigs or rods move not through detection of ‘earthrays’ (the force that dowsers believe exist) but through the ideomotor effect, whereby the dowser unknowingly moves the device. Much like how tears can be brought on emotions, tiny ideomotor movements and twitches are driven by unconscious beliefs, in just the same way that involuntary hand movements drive an Ouija board reading.
It is likely that an experienced water dowser will have learnt from previous failures and successes in which areas underground water commonly occurs – in the same way a hydrologist can make a best guess from their understanding of geology. And so while a hydrologist may say that they have a hunch about underground water, a dowser will let it come out in their sticks.
Answer By Dr Stu and Chloe Westley
Read more: Water Dowsing by USGS (a thorough appraisal)
When I was at school all the kids loved Star Wars. The girls in my class saw Princess Leia as their no-nonsense role model, while the boys all dreamed of piloting an ‘X-wing’ spaceship and destroying the Death Star – just like Luke Skywalker. The sophisticated children, however, knew that roguish Han Solo’s Millennium Falcon was the VW campervan of interstellar cool.
In the movies, the Millennium Falcon looks like a big ship. But as Stan (five years old) asked us (via their parent) – just how big is it really? Or more specifically, is it bigger than a blue whale? Kids truly ask all the best questions…
The blue whale is a good thing to compare the ship with as it is the largest animal to have ever existed on planet Earth (dinosaurs included). Fully grown they are 30 metres / 100 feet long and weigh an almighty 170 tonnes. By comparison, the original Millennium Falcon was rather teeny – the model used in the original Star Wars film was 5 feet long (1.5 metres) – which, while making it taller than a five-year-old, was small enough to easily fit inside a blue whale’s gaping mouth.
For the 1997 movie set, a bigger version of the Millennium Falcon was also built, set in a secret hangar in Pembrokeshire, Wales. It measured a more respectable 70 feet (21 metres) from one edge to the other – making it closer to the size of a fully grown blue whale, but still falling short in comparison.
But of course, these are only models and not the ‘real’ Millennium Falcon (wink!). According to the geek-tastic Wookiepedia online encyclopaedia, the Millennium Falcon is actually a ‘Modified YT-1300f light freighter’ measuring 34.4 metres long and 25.6 metres wide. (Apparently the sizes were worked out by measuring the images in Dorling Kingsley’s book Star Wars Blueprints: The Ultimate Collection.) If accurate, this calculation makes the real Millennium Falcon ever so slightly larger than a blue whale!
So there you have it – while the replica Millennium Falcons are all smaller than a blue whale, the actual space ship is a bit bigger (by about 4 metres). That said, Han Solo would be disappointed to know that his ship still isn’t big enough to carry an adult blue whale in its cargo hold. Stowing a large T-Rex would be easy, however; but then dinosaur space transport is a completely different issue altogether…
Question sent from Stan, aged 5.
Answer by Dr Stu