Archives For Fun

Scale of the Universe

February 9, 2012 — Leave a comment

This is a fantastic, scrollable Universe explorer written in Flash. Learn just how big – and small – everything is. Marvellous.

Sex in Space

February 2, 2012 — Leave a comment

Ever considered the idea of sex in space? The 100-mile high club? You know, that thing James Bond does in Moonraker. A friend of mine was musing about this on Twitter today and it got me thinking.

Astronauts spend a long time in an enclosed space with a limited number of people. They are obviously very focussed on their various experiments and mission functions, but surely they’ve gotten ‘distracted’ once in a while up there? Whether it’s the International Space Station (ISS), a possible years-long Mars mission or a future multi-generational spaceship – sex seems to inevitably crop up. Humans are programmed to seek out intimacy. We are social animals. 

So far as I can see, no one has ever had sex in space. There is a hoax report from 2007 but not much else out there. The physical act of sex in space ought to be possible but complicated. Newton’s Third Law (that every action has an equal and opposite reaction) means that sex could be pretty bumpy in zero gravity. Without gravity to keep them stable, two people could end up spinning around violently or flying off in unpredictable directions. An alternative might be some kind of tethered sleeping bag – or a 2suit? In a very light craft, it may even be the case that you’d have to the protect the ship’s balance from sex! (If this ship’s a-rocking… )

Assuming that we solve this issue by the time we embark on any future, mass exodus to the stars, I think the interesting case to look at is a potential long-term, manned Mars mission.

Imagine the scenario: a small group of intrepid, physically fit explorers board a small ship and close the door for 6 months. Their perilous journey will bring them closer together in already close-quarters. They exhaust all small talk very quickly and the repetitive nature of their task will cause their minds to wander. One day a coolant leak causes the temperature to spike and everything is getting hot and sweaty. The clothes come off and… well you get the idea.

What does sex do to a small, enclosed group like that? How does jealousy play out in such a limited space, or even a normally harmless crush? Communication with Earth is delayed, and limited, so there isn’t really anyone else to talk to. NASA has commented on such issues in the past, but generally taken the line that there is a lot of other stuff to think about when it comes to the health of the crew. Good to see sexual repression has made it to the Space Age.

Perhaps one solution would be to crew the ship with totally asexual people. Or we could go for a single-sex, entirely heterosexual crew. I know, let’s just send the crew from Star Trek: The Next Generation! (Not Riker, obviously.)   

Recently the Mars500 experiment simulated a 520-day Mars mission with a crew of 6. They emerged last year after their 18-month stint on a simulated spacecraft without much ill-effect. They were all men: one Chinese, one Italian, one Frenchman and three Russians. THe sitcom rights have likely already been sold.

There is an argument to be made for an all-female crew too. Women are more resistant to certain medical problems that may affect people living in low gravity.

There is also an entirely different concern with a mixed-gender crew: pregnancy, conception and contraception in space. Biology has evolved under gravity and we don’t understand the effects of zero-gravity enough to predict anything as complex as the gestation of a human being. There is research to suggest that cosmic rays may make long-term astronauts infertile – both by lowering sperm counts and sterilising embryos. Aside from that, can you rely on normal contraception in space? Can you afford the additional weight of thousands of contraceptive pills and lord knows how many condoms? Getting things into space is expensive.

But I will leave you with good news: although no one has had sex in space, it has been done in zero gravity. For the porno movie ‘The Uranus Experiment: Part Two’ a scene was filmed on board an aeroplane in freefall, achieving zero-gravity (and maybe more) for 20 seconds. I’ll leave you to Google it. The filming of the scene was described as ‘messy’. I think we’ll leave it at that….

…almost. One final, final link. This ion blog post about sex scenes in space includes one real-life sex movie recorded in real space. Here you go [WARNING: some of the links of this site are truly NSFW].

After a particularly awful few days of bus commuting, I have been considering the merits and pitfalls of my method of travel to work. Mostly I began by trying to figure out whether the effort put into cycling to work would be worth any saved time or inconvenience.

Rather astonishingly, my average speed on the bus works out as between 6 and 12mph. That takes the distance between each end and divides by the two extremes of travel time. I sit in traffic a lot.

According to multiple sources, cyclists travel at 12-15mph on average. That being said, I still don’t fancy cycling the 20 miles each day (twice).

My average commuting speed is similar to the world record speed for freestyle 50m swimming (5.3mph) and for marathon running (12.8mph). It is similar to the speed of transmission of sensory neurons (5-25m/s) and worryingly only 2x faster than the average walking pace.

These stats are taken from Wikipedia. A special shutout to Stagecoach Oxford or being so appallingly bad and wasting hours of my life each week!

This post was written on the A40 at an average of 2mph. Ugh.

Solar System by Numbers

September 18, 2011 — Leave a comment

Had a bit of fun this weekend creating these oh-so-factual images of the Sun and Planets. There are up to 10 numbers used to create each image – each one giving a characteristic of that particular world, such as the orbital period in years or the mean surface temperature.

These were all made on my iPhone too. Yeah that’s right: I geeked out.

The Sun: create using SOHO image found at

Mercury: created from NASA Messenger image at

Venus: created from Magellan image at

Created using NASA’s Blue Marble (

Mars: created from Hubble image at

Jupiter: created using Voyager image found at

Saturn: created using Cassini image found at

Uranus: created using Voyager image found at

Neptune: create using Voyager 2 image found at

These image are all on Flickr too.

Ways to End the World

October 22, 2009 — Leave a comment

A friend recently asked me how I think the world might end. It’s a good question – lots of fun too, as a scientist. There seem to be countless ways to bring the world to an end – but here are some of the best ones we came up with. Feel free to add your own in the comments.



Roughly every 30 million years something very bad seems to happen – life on Earth seems to die in vast quantities and a large percentage of all Earth’s species go extinct. Why do these mass-extinction events occur? Not sure – but it does seem to have happened with a reasonably regular interval for over 250 million years.

One hypothesis for this is that there is something ominous circling around us, at the edge of the Solar System. Some think it could be a large planet, other suggest a dead star – it has been given names like Planet X and Nemesis. Whatever it is, the theory goes that it is orbiting our Sun in a highly elliptical fashion. Once every orbit it plunges very close to the Sun, just scraping the edge of the Solar System: the Oort Cloud.

The Oort cloud is home to countless rocky bodies – it is the home of many comets – and such a massive gravitational nudge would send potentially thousands of these objects hurtling into the inner Solar System – one of which might hit us and cause a catastrophic global disaster. This might what killed the dinosaurs, and it’s possibly what will kill us.


Magnetic Switch

Since the mid-nineteenth century humans have been monitoring the Earth’s magnetic field. The same magnetic field that guides migratory birds and makes a compass work also protects us from harmful radiation from the Sun and gives us the beautiful Northern Lights. But here’s the thing – it is gradually weakening. According to some researchers, this could mean that something is about to change.

We also know – and this where it gets disturbing – that the Earth’s magnetic field has historically flipped over from time to time. In fact this usually happens every 250,000 years. It has been almost 800,000 years since the last flip so perhaps we’re overdue. Of course no one was around to witness the last one and so we don’t know what effect it would have. Things could get very ugly though.

If the magnetic field that protects the Earth did flip it would mean that somewhere along the way we wouldn’t be protected from space for a while! We might be bombarded with harmful radiation or cosmic rays. The lovely aurora would perhaps be slightly more menacing if they gave you cancer. If the flip is sudden then it would wreak havoc on the world’s electric systems – potentially frying them.

Infinite Loop

The Singularity

We are now able to make ever-smarter machines. What happens when we make a machine that is smarter than us? The answer surely is that it will be able to built an even better, smarter machine and that in turn will build an even better one too. Within a few cycles we will be faced with a machine so clever that we seem puny and irrelevant by comparison. The world could quickly be controlled and organised by such a machine and we will have ended our reign here.

We are also extending the human lifespan faster all the time (in the West) – what happens when we extend it by more than a year each year? We will then live indefinitely. Technological progress advances exponentially. This means that world-changing advancements come along at shorter and shorter intervals – eventually you reach a mathematical singularity, at which point things can no longer be thought of the way they used to.

The theory goes that some singularity is coming in the next century and although it may not be quite as we imagine it, it will possibly end the world as we know it. It may bring an end to our lives as we know them – in the machine case for example – why not download ourselves into super-intelligent machines and go onto bigger and better things? At our current rate of progress we will make more progress in the next century than in the past 10,000 years. The world as we understand it will surely cease to be.



Gamma Ray Bursts (GRBs) are distant but gargantuan explosions that take just a few seconds and release more energy than the Sun will in its entire lifetime! Some are 100s of times more powerful than that. Needless to say, you don’t need to be very close to one of these things to be more than a little singed. It could be almost anywhere in our galaxy and still devastate the planet.

There are other ways to be irradiated: the Sun could go nova, releasing massive quantities of dangerous material and radiation; a stray pulsar could accidentally spin around and fry us like an massive, errant laser pointer.

However it might happen, it remains remotely possible that in a brief instant the Earth could find itself totally irradiated on one side. Every living thing, every molecule of anything would be vapourised and instantly! Half the population – more or less – would be gone in a microsecond. And they’re the lucky ones. If you’re unfortunate enough to live on the other side of the Earth during this high-energy blast then you have the pleasure of gradually rotating around into the radiation – if it is still there. Worse still you could experience the awful, apocalyptic nightmare that is a shockwave of plasma – made up of every living thing from one half of the planet – sweeping across the world, incinerating everything as it goes.



We’ve  all heard the old wives tale about the Sun dying and swallowing up the Earth as it becomes a red giant, right? Well let me tell you you don’t need to worry about it. That will take 6 billion years to happen – that’s ages! Especially whn there’s something much worse heading for us much faster.

The Andromeda Galaxy, the Milky Way’s friendly galactic neighbour and virtual twin sister is heading right for us. Pulled in by gravity, Andromeda and the Milky Way are on a collision course and  in 2 or 3 billion years Andromeda will rip our galaxy apart like cotton wool. Shockwaves will ripple through the two galaxies, triggering supernovae and star formation at an incredible rate.

The Solar System will be lucky to survive such an event. Gravitational forces could tear us apart, radiation could fry us to a crisp or if we’re really unfortunate we could be gobbled up by one of two very big black holes as they coalesce and merge.

snowball_earthSnowball Earth

Periodically, many times over the course of the Earth’s history ice has covered the world and then gone again. I’m not talking about ice ages – no this is something even more dramatic. 600 million years ago the Earth was a giant snowball – entirely covered by ice. It also happened 100 million years before that and over two billion years ago. This ‘Snowball Earth’ is the result of a runaway cooling effect where the ice covering the surface of the planet increases the reflectivity (or albedo) such that a lot of the incident radiation from the Sun bounces back into space, thus cooling the planet further.

As man-made climate change warms up the Earth, key processes may shut down due to changes in the freshwater/salt water balance – the gulf stream, the ocean currents. If this happens and the poles are cut off from sources of warm air or water, then they may refreeze rapidly and the runaway ‘Snowball’ process can begin.


Evolving Out of Style

With all this talk of things that might happen in millions and billion of years it is probably prudent to mention that we almost certainly won’t be around anyway. If by the end of the world, you mean the end of civilization or the end of the human race, then even looking a million years ahead is foolish.

Even the most well-adapted and long-lived species seem to only last a few million years or so before evolving out of style. The ones that do are not exactly like us – crocodiles, sharks, cockroaches. The human race, like any other, is subject to the environment around it and will evolve and adapt with it. It only takes one big volcanic eruption or viral outbreak to change our circumstances dramatically.

In a million years we could have become plankton-eating aquamen or tree-loving, hairy cannibals. We may not even live on Earth anymore…


Big Crunch/Rip/Freeze

Our universe has been around for 13.7 billion years – Earth has been around for just over 4 billion. We’ve been here for a few hundred thousand – depending on what we you call ‘we’. If we do manage to secure our existence indefinitely – perhaps by uploading ourselves into machines or spreading ourselves far and wide enough into the cosmos – then can we really be here forever? Time it seems could be eternal but also it could not.

Following the Big Bang – the beginning of the universe – we can either live in an ever-expanding universe that eventually rips itself apart (the Big Rip), an ever expanding universe that gradually slows down (Big Freeze) or a universe that reaches some extremely large size and then begins to fall back in on itself (Big Crunch). It all depends on how the Universe is made up and how much dark energy there is.

If we’re heading for a Big Rip then eventually there will be no Universe left as we understand it – so we die. If it’s a Big Crunch then everything ultimately smashes back together and time end – so we die. If the Big Freeze happens then sooner or later all the energy in the universe gradually becomes so diluted and spread out that nothing energetically useful can ever happen – everything freezes out – (thoughts, movement, calculations) – so we die.


Heisenberg Uncertainty Principle

Nothing is impossible – just highly improbable. As fans of the Hitchhiker’s Guide are aware. That is what Heisenberg ended up stating about the Universe thanks to quantum mechanics. It is possible, though not very likely that a giant cat will appear one day and give the Earth a lovely hug and magic up some tea and cake. It is also equally unlikely that one day a giant death ray will appear and destroy our whole planet.

Given enough time – say an infinitely long time – eventually each of these things will happen. The problem is that since we already exist, it doesn’t matter if something good pops into existence alongside us. If something bad randomly blurts out of the vacuum – even for a brief moment – and destroys us then that does matter. The longer we hang around, the more chance there is for something like that to happen.

It isn’t likely, but is worth thinking about.

Glowing Samples

July 4, 2008 — Leave a comment

I’ve not much to say about this other than that it is a very cool image. I took it on Wednesday during Cardiff University’s Dragonfly Day. As well as making our own spectrometers there was also an experiment to deduce the contents of several mystery cups. All were white or see-through liquids. Using just their sense of smell and a UV blacklight, participants had to figure out what was inside each cup.

Just so you know, the contents were:

  • A Suncream
  • B Washing Power (for clothes)
  • C Shampoo
  • D Toothpaste
  • E PVA Glue
  • F Lemon Juice
  • G Double Cream
  • H Tonic Water
  • I UV Sensitive Body Paint

Note: This experiment involves sharp objects and should only be performed by children if under supervision. As long as care is taken, this is a fun experiment with effective results. It can be done without the razor blades, but the results are not as good.

Spectrometers are used, like prisms, to spread light out into the component colours. This enables us to understand the compositions of everything from stars to streetlights. Here I show you how to make your own spectrometer and give you a few examples of what you can see with it.

What You Need:

  • A cardboard tube (toilet roll or kitchen roll tubes are just perfect, in the pictures here, I have used more black card to make a tube myself.)
  • 2 square pieces of black card (approx 8cm x 8cm)
  • Black tape or masking tape (something that blocks out light)
  • Razor blades (nothing fancy just cheap blades that are not attached to anything)
  • A stanley knife
  • An old CD

Make a Diffraction Grating:

Cut a small square hole (approx 1cm across) in the middle of one of your 8cm x 8cm black cards. Break the CD into pieces, just snap it. You’ll need a section of the broken CD that can nicely cover the 1cm hole in your card.

Using a bit of sticky tape, peel away any cover remaining on the piece of CD, so that it is transparent. Use tape to stick it over the hole, creating a sort of window. This will be our diffraction grating.

Make a Very Fine Slit:

Using a stanley knife, cut a slit in the middle of the other piece of 8cm x 8cm black card. This slit should be about 2cm long and just a few millimetres wide. Tape the the two razor blades either side of the slit. They should make an even narrower slit, just 1mm or less if possible!

The aim is create a very fine, narrow slit though which light can travel. Make sure the blades are securely attached with tape for safety.

Make the Spectrometer:

This is the easy bit! You now attach the two square cards to either end of the tube using the dark tape. You have to attach it in such a way that no light is let into the tube accidentally (hence the dark tape). When you look through the diffraction grating, you only want to see light coming from the slit.

Testing Out Your Spectrometer:

The best way to see how this works is to use daylight. Just point the spectrometer toward a window during the day or up at a cloud if you’re outside. You should not ever look directly at the Sun. You should see a nice, smooth spectrum (rainbow) somewhere in your field of view in the tube. Here is a photo of a cloud taken through my own spectrometer. The bright white light is the slit and spectrum is just off to one side.

What’s Happening?

When light enters the tube though the slit it spreads out – all waves do this when passing through small slits. The CD then makes the separate colours visisble to your eye. You see a nice, even spectrum from daylight sources because daylight is made up of all the colours of visible light from the Sun. Once you can see this pattern, you can start trying to find the spectra of other things.

In our physics lab we have lamps of different chemical make-ups. These let us see pure light from different sources. Here are a few I took today, all photos taken by my own camera through my own, homemade spectrometer.

Here is the spectrum for Zinc, which you can see contains some red and blue but very little green.

Cadmium is very distinctive, with short sections of each of the three primary colours and very little between them. It is less spread out than Zinc. There is a big gap between the green and red sections.

Krypton is seen to be fainter than the others here, but the spectrum is still visible. The blue section has become much more violet or indigo here and the green is greener than it was in Cadmium.

The Astronomy Connection:

This is how astronomers know what stars are made of. They use advanced spectrometers to measure the spectrum of stars and pull out the ‘fingerprint’ patterns of colour that you see above. Each element has a unique set of spectral lines (colours) and these can identify the presence of different chemicals in stars, nebulae and just about everything else.

This is the whole spectrum of the Sun. It is so detailed that it had to spread onto multiple lines to see it properly! You’ll see that in fact it is not perfectly evenly spread out as I suggested earlier. This was taken with a very advanced spectrometer that has a greatly increased sensitivity compared to one made here, but its based on the same principles.

Things to Look At With Your Spectrometer:

  • Sodium streelights
  • Compare daylight to a lightbulb.
  • Different light bulbs look different (that’s why energy saving bulbs light up the room in a different way).
  • Neon signs.
  • TV  and computer screens.
  • LEDs from computers or remote controls (these give very pure spectra, often only one colour).

Have fun with your spectrometer and why not try and take a photo through it? It worked fairly well for me. I’d love to see any photos you take with it, or of it. Let me know how you get on. Thanks to the Science Made Simple team for this great idea!



Astronomers studying star formation, like myself, use telescopes that can see though the pretty, optical exteriors of nebulae into the dark interiors where very cold dust radiates in the submillimetre and microwave regimes.

Microwaves, fall on the electromagnetic spectrum, between radio waves and infrared waves. They are usually around the size of a few centimetres and you may well be very familiar with them as they are produced by the microwave oven that might just be sitting in your kitchen.

Microwave ovens use a particular microwave frequency to excite molecules of water. Since water is present in lots of food and drink, this means that microwaves heat up lots of useful stuff – and they do it quickly. The fact that microwaves are now readily available to most of us in the western world and they are only a few centimetres in length, means that you can measure the speed of light in your very own home.

What You Need:

Mallow Science

The quickest and tastiest way to perform this little experiment is with marshmallows, but chocolate chips also work. You’ll obviously need a microwave oven as well, and a large, microwaveable dish. You will need a ruler, too.

What to Do:

Get your large, microwaveable dish and place a layer of marshmallows at the bottom of it.Remove the turntable from the bottom of the microwave oven. If you don’t, then this experiment will not work at all. If your microwave doesn’t have a turntable, it means that the turning mechanism is elsewhere and you’ll need to find a regular microwave oven to try this experiment.

Cook the marshmallows on a low heat for a couple of minutes, or until you see parts of the marshmallows starting to bubble. When you do, remove the dish and take a look at the marshmallows.

Melting Marshmallows

You ought to see that they have not melted evenly. In fact you should be able to see a regular pattern has formed, drawn out in melted-mallow. It depends on your microwave oven, but you should see a melted/unmelted pattern across the dish in some direction. When I tried it at home, my oven created long melted strips next to long unmelted strips (see above).


This regularity is caused by the same mechanism that heats up the food you place into your microwave oven. The appliance generates microwaves which very quickly form standing waves (see animation above) inside the cavity inside, where you put food. As the food rotates around, it passes through the standing wave nodes and this excites the water molecules, heating the food.

Measure the Microwaves:

Take your ruler and measure the distance between the melted parts of the marshmallows. You should find that there is an even pattern of melting and that the distance between them is something like 5 or 6cm. Why? Because that is the distance between the nodes of the standing waves.

Measuring Microwave Melted Marshmallows

Without the rotating mechanism, the food does not move around and cook evenly, instead it just heats at the nodal points. Using your marshmallows you have created a ‘map’ of the microwaves in your microwave oven!

Find the Frequency:

Finally you need to know the frequency at which your microwave oven operates. It is usually written on the back somewhere in small writing. Most standard microwave ovens operate at 2450 MHz. If you cannot find the value on the back of the oven, you can take it for granted that 2450 MHz is about correct.

Measure the Speed of Light:

Now you have what you need to measure the speed of light. You just need to know a very fundamental equation of physics:

Speed of a Wave (c) = Frequency (f) x Wavelength (L)

The distance between the melted sections of the marshmallow is in fact L/2, because there are two nodes for each wave (see animation). So if you have measured 6cm and your oven operates at 2450 MHz, then your measured speed of light is (0.12 x 2450,000,000) 294,000,000 metres per second.

Microwave Frequency 2450 MHz

The agreed value of the speed of light through a vacuum is 299,792,458 metres per second. See how accurately you can measure it? what could you do to make the experiment better, and thus get a closer answer?

Now You Can Eat the Gooey Melted Marshmallows:

…and make yourself sick. Yay!

Line Up

May 24, 2007 — Leave a comment

Here’s a great image of all the bodies in the Solar System in order of size. It only goes down to a diameter of 200 miles – otherwise it would get very silly indeed. Note that several planets fall after several moons in the rankings. also note the small collection of dwarf planets and transneptunian objects from Eris onward. Also, for the sake of my own blog, I have rotated the image by 90 degrees. Get the correct orientation here.


From Bad Astronomy and Universe Today’s forums, via the Bad Astronomy blog.