The phone was buzzing almost as soon as Doctor Who had finished on Saturday night. The twins were in a state of high excitement after this week's episode. And rightly so. Russell T Davies's story not only threw everything into the mix including the kitchen sink, it left us asking an unexpected question. As Planet Gallifrey put it, there were lots of squeee moments for the fans, but we already know that David Tennant has been filming the next Christmas episode, so it's unlikely that he'd leave the series before then. But we got the Doctor staring meaningfully at his hand - the one that grew back following the last regeneration. We had the bonkers Dalek ranting about "the Threefold Man" followed by Peter Davison and Sylvester McCoy appearing on Dr Who Confidential. We had the sound of drums that followed the Master around. We had Donna spacing out and listening to her heartbeat, and we had lots and lots of foreshadowing that one of the companions is going to bite the big one.

So, what do I think? I liked the Richard Dawkins cameo. It was quite right for him to appear too, as he is married to a time lord, after all. I loved the Doctor speaking Judoon - especially when he changed up a gear. I liked the return of Rose, and I loved the Dalek's retort when Bernard Cribbins paintballed it: "My vision is not impaired, I can see!" But as exciting as this week's show was to watch, it doesn't stand up to a lot of close scrutiny. It might be cool for eight-year-olds, but the rest of us want answers to a number of questions. How come the Judoon at the Shadow Proclamation snapped to attention when the Doctor addressed them, when their colleagues last season did their very best to kill him? How come the Shadow Proclamation folks hadn't looked at historical disappearances of planets? How come Rose's laptop oh-so-conveniently failed to connect when all the others did? A lot of characters did things that seemed unbelievably silly, even by Dr Who standards - in particular, the idea that Martha would try out unused technology (especially when Captain Jack was shouting at her not to) seemed wildly out of character. The whole idea of Harriet Jones sacrificing herself to call the Doctor worked well dramatically, but if the signal was actually coming from Torchwood, would the Daleks really have gone after her first, or would they simply have obliterated Cardiff? Some of the special effects were particularly wonky - yes, New York, I'm looking at you.

Which companion will die? They all got their dramatic "I may be some time" speeches this week which were presumably intended to make us think it could be any of them. Yeah, right. I'm sure K-9 will appear next week and save Sarah Jane, so she should be safe. I doubt that they'll kill off Captain Jack, because it would rather curtail the BBC's spinoff series Torchwood. I doubt that Rose will die, because RTD would be lynched within the week. Hmmm, who does that leave? My personal favourite (and Torchwood ratings-booster) Martha, and Donna. Ooops.

Mind you, even if a companion does die I'd lay money on RTD using some hackneyed plot device so that by the end of next week's episode everything has returned to normal apart from a bit of moping by the Doctor. Someone - not necessarily the Doctor - will hit the reset button, and Planet Earth will return to the state in which a character next season can still hold on to a shred of dignity when they come out with a line like "An alien? Really? They do exist then?" I'm sorry, but the scriptwriters have got to change their ways given that their world has seen miscellaneous spaceships hovering over London, assorted Daleks, Cybermen, lumps of fat and Slitheen running amok on a regular basis and flying ocean liners buzzing Buckingham Palace. That's one of the new series's biggest mis-steps, I think. As a kid I could at least convince myself that the Doctor really was out there fighting monsters, because it felt like our Earth. The fights were always low-key or set in the future, or happened in such a way as to ensure a degree of deniability thanks to UNIT. While it's a nice idea to have BBC reporters or Paul O'Grady hamming it up on a Saturday night, it takes away from the darker edge that the series had in the time of Jon Pertwee, say.

The most hackneyed plot device of the week had to be the introduction of the Osterhagen Key - which will almost certainly turn out be next week's reset button. How convenient. And if the translation of Osterhagen as Swedish for "boneyard" are accurate, some folks are even suggesting that this is how we end up with Mr Graveyard himself: the Valeyard, the Doctor's twelfth and distinctly un-cuddly evil regeneration.

But most of all, I think that the events of Turn Left haven't finished yet. And I think the future doesn't look too bright for poor Donna.

The Cassini spacecraft concludes its four-year primary mission today. The good news is that it will immediately begin a two-year extended mission to investigate the planet Saturn and its moons in even more detail. It's already given us some extraordinary insights into the ringed planet, including pictures of giant hexagonal storms and colliding moons as well as the Huygens Probe's data from its descent to the surface of Saturn's largest moon, Titan.

A hundred years ago today, on June 30th 1908, something very large dropped out of the sky over Siberia. It caused an explosion over 150 times as powerful as the atomic bomb dropped on Hiroshima and the blast flattened eight hundred square miles of pine forest. A few hours later and it might have flattened Moscow instead.

The Tunguska event is now thought to have been caused by a rocky asteroid about 37 metres (120 feet) across ploughing into the atmosphere at a speed of around 33,500 miles per hour. The asteroid was going so fast that it disintegrated before it hit the ground, causing a huge shockwave which was responsible for flattening the trees and measured by barometers as far away as England. The folk at NASA's Near Earth Object program estimate that an event of Tunguska's magnitude happens about every three hundred years, but Don Yeomans, the project's manager, says he doesn't lose any sleep worrying about the next one. He can sleep more soundly these days, certainly; there are lots of people watching the skies, making sure that we know about the next one well before it blows up in our faces.

Ladies and gentlemen, I bring you... The Toast Cannon. For when pushing your burnt bread products a few inches up in the air is no longer enough. The cannon's designer Freddie Yauner is clearly a man to keep an eye on - preferably from a considerable distance and whilst wearing safety glasses and a crash helmet.

I started this blog five years ago today, which must make me officially old school or something. Actually, I didn't have a plan when I started out, I just made it up as I went along. Five years later that's pretty much how things have stayed and I don't have any immediate plans to make radical changes.

This is clever. Someone's used the BBC's subtitle service to create a database of the dialogue from Doctor Who, then used Wordle to create a tag cloud for each episode of the current series (with a few gaps). The more frequently a word is used, the larger it appears in the image. The results are rather pretty in a disconcertingly nerdy fashion, but they do show up a peculiar fact: just look how often the word "know" crops up in rather large letters. I don't know whether that's interesting or not, but it's there all the same.

I passed lorries carrying large quantities of metal railings as I headed south on the motorway this morning. That can mean only one thing - it's Glastonbury next weekend. The good news: apparently it won't be as wet as it was last year. I think I'd still take a boat with me if I was going...

Anyone who knows me will understand what I mean when I say I'm a bit of a movie nerd. Film is a bit of an obsession with me. That obsession doesn't just mean being able to name my favourite director or always going to see the latest film by a favorite actress; that stuff is for civilians. No, I also have favourite directors of photography, favourite composers, and favourite special effects technicians. For example, I was watching Beowulf this week and nodded when I saw the sound designer credit for Randy Thom, because I know what he does and how much better films are because he worked on them. Frequently, it's the people like him, working behind the scenes who turn a good movie into a truly great one, and yet their work is seldom celebrated as enthusiastically as, say, the careers of George Lucas or Steven Spielberg. This week I lost another of my heroes, someone who absolutely epitomised the backstage "magic touch" that a master can bring to the world of cinema. Stan Winston died of cancer at the age of 62.

Winston won four Oscars for his special effects work on films like Aliens, Terminator 2, and Jurassic Park. In fact his IMDB entry reads like a list of my favourite films. He designed the Predator in John McTiernan's film which ostensibly starred Arnold Schwarzenegger, although for nerds like me the monster was the real star; he messed with my head to a disturbing degree with the special effects for John Carpenter's version of The Thing, but he was also instrumental in shaping Tim Burton's vision of Johnny Depp's character in Edward Scissorhands. He created the stunning creature makeup for the alien bad guy Sarris in Galaxy Quest; he built fully-working animatronic toys for Small Soldiers; he turned Matthew Broderick into a mechanised goofball for Inspector Gadget and he even designed the kangaroo make up in Tank Girl. His passing will leave a giant hole in the industry, but his place in cinematic history is assured.

It was the summer solstice at 00:59 this morning. Revellers at Stonehenge got the date right this time and turned up in their thousands to brave a very cold and soggy midsummer dawn. As for me, I stayed in bed.

The BBC had a story on their website yesterday about a Welsh police helicopter crew who reported seeing an unusual aircraft flying over the Vale of Glamorgan last weekend. It's the first time I've seen the BBC carry a UFO story for quite a while - interest in the subject is not what it was and these days man-made aircraft can look every bit as weird as those reported by flying saucer buffs back in the fifties. Hmmm, I wonder if something from West Wales drifted a little too far afield?

You know it's the twenty first century when the twins are able to hold a teleconference with you from a tent in the back garden.

Rob and Ruth have each got wicked new laptops ready for the start of university in the autumn, so they have been trying them out. They've already got them up and running with the applications they need - I love Skype. Mind you, they then completely one-upped me and everyone else I know by ordering pizzas online. Truly, we are living in a connected world.

Needless to say I got back from Sweden and promptly came down with a sore throat which turned into a humdinger of a cold. I've spent most of the last few days asleep, and most of the last few nights drenched in sweat; it has not been pleasant.

Before I completely succumbed to airline bugs, I was treated to a very nice meal out on Saturday night by Rebecca and the twins. They got me father's day cards and a present of a Top Gear DVD which was a lovely surprise, and completely unexpected. The six bottles of real ale were also a pleasant surprise, and just as welcome. Thank you all very much, folks.

So what has happened in the last week or so? Well, if you've spent more than a cursory amount of time on the web this week you've probably already noticed that Firefox 3 was released. The launch appears to have gone well - I was up and running within a couple of hours. I like the page zoom feature, which enables you to magnify a web page by zooming in and then scrolling around. This comes in particularly useful when your eyesight isn't what it used to be. I like the "most visited" drop down list and the extra functionality of the location bar, and I like the new ways to bookmark things. I haven't really investigated tagging yet but I can see it being one of FF3's more interesting features. The browser seems to load faster and so far it hasn't fallen over on me, which is a good sign. There is much talk of improved memory management, faster JavaScript, and a smaller memory footprint; these are Good Things, of course. But cosmetically at least, FF3 doesn't feel like the great leap forwards that FF2 was. I suspect that the benefits will mainly become apparent as I use the software over the coming days and weeks.

I spent most of last week inside a very large exhibition hall in Stockholm, the Stockholmsmässan. It was a busy show, so unfortunately I didn't really get that much time to explore the city until the evenings. I was surprised how early things shut down there, given that it was still light at one o'clock in the morning. It's probably just as well, otherwise I would never have gone to bed.

Special mention has to be made of the Stampen Jazz Club, however, which we discovered on our second day there. Good music, good beer, and friendly staff make all the difference when you're away from home so if you're ever in Gamla Stan that's the place to go.

I've been in Sweden for most of the week - I got home last night. More details will follow soon.

A scientific theory is a wonderful thing. It describes how things work in such a way that you can predict things, and then see if the world actually works like that or not. If x is true, a theory says, then y should happen. A good theory allows you to predict y happening under lots of different conditions, which is a good indicator that the theory is an accurate representation of what really happens. I've read three mind-boggling articles in the last week which concern the nature of reality, and if they don't make your head spin, you probably haven't understood the implications.

You've probably already heard of Heisenberg's Uncertainty Principle. I'm going to try and explain it in a single paragraph, but bear in mind that there are issues on subjects like Complementarity that mean this is a grossly oversimplified version of nearly a hundred years of theoretical discussions. Okay? So - take something as small as an electron. An electron is so small that if a single photon of light collides with it, its physical state will be profoundly affected. The trouble is, that to get information about the state of that electron, we depend on receiving at least single photon's worth of light that has interacted with it. The quantum mathematics which we use to describe how the photon and electron have interacted mean that the more accurately you define one property of the electron (its position, for example) then the less you know about its other properties (such as its momentum). This is down to the mathematics that are used, it doesn't matter how accurate your measuring instruments are. You can have the most accurate microscope in the history of science, but if you nail down one property really well, you lose the information about the other property. The mathematics mean that there is a fixed amount of uncertainty inherent in your observations.

In other words, it's physically impossible to know everything about the current state of the Universe - to the point where if you manage to define the exact position of every particle in the Universe with totally exact precision, there is an infinite amount of uncertainty about the direction and speed in which those particles are travelling. If that is true, Heisenberg said, how can you possibly hope to predict the future? At best, you can only provide a range of possiblilites. The Copenhagen Interpretation of Heisenberg's work with Niels Bohr developed these ideas into a formal philsophy which effectively says that how you observe an object affects the physical properties of that object. The end result is that we define reality by choosing the way in which we observe it. Most people find that idea ok at the subatomic level, but if you suggest that the effects of uncertainty scale up into the world around us, they start looking worried. Although he agreed with the reasoning, Einstein's reaction to this suggestion was one of profound discomfort. He found it abhorrent to suggest that reality can't exist in a way that is independent of how it is observed.

Scientists in Austria have been performing experiments to establish whether reality really does work like this. Do objects exist regardless of whether they are observed, or does the act of observation actually influence reality in the way suggested by quantum mechanical theory? In simple terms, the question is this: is reality something that has been "there" all the time, before we look at it, eat it, or stub our toe on it - or does it only adopt a defined state after we've noticed it? The new experiments show that the classical model of reality disagrees with experimental results by over 80 orders of magnitude. The quantum model is accurate; our senses just do not have the sensitivity to observe the quantum effects around us. In essence, we create the classical world we perceive and there could be other classical worlds completely different from ours.

Things get even more interesting when a theory predicts y, but z happens instead. And these are interesting times for cosmology. The second item is in this week's New Scientist magazine discussing the work of Benjamin Wandelt, a cosmologist at the University of Illinois. He recently delivered a talk about how gravitational waves triggered by an event known as inflation (which is thought to have taken place shortly after the Big Bang) should have affected the polarisation of the Cosmic Microwave Background (CMB). The trouble is that the equipment used to detect this polarisation is getting better and better, but the polarisation has still not been detected. Wandelt also discussed temperature fluctuations which have been measured in the CMB, and he appears to have found that there are more cold spots than hot spots. This isn't what inflation predicts either, and people are beginning to suspect that the inflation theory is in trouble.

The last item is a paper entitled A Hemispherical Power Asymmetry from Inflation by Adrienne L. Erickcek, Marc Kamionkowski, and Sean M. Carroll of the California Institute of Technology. This paper also discusses the temperature fluctuations in the CMB. Their analysis shows that the fluctuations are approximately 10% larger in one direction than they are in the other - again, not something that the inflation theory predicts. The explanation they have come up with is an alternative process to inflation that relies on an energy field called a curvaton. At a conference this week, Dr Erickcek suggested that this theory would allow our universe to bubble off from a previous one - so the fluctuations in the CMB might have been inherited from our parent universe, before the Big Bang. Let me just type that again, in case it didn't sink in: before the Big Bang.

Erickcek also suggested that further universes could have been spawned by our own - and we might never know they existed. Sean Carroll suggested that such an event might happen in your living room and you'd never notice. Has this team come up with observations and maths to back up Andrei Linde's bubble universe theory? It looks like it to me.

There's a bit in the latest Indiana Jones movie where Jim Broadbent says to Harrison Ford, "We seem to have reached the age where life stops giving us things and starts taking them away." I know how he feels, because death took one of my heroes away at the weekend: Alton Kelley died at the age of 67.

Together with Stanley "Mouse" Miller, Alton Kelley created some of the most iconic graphics in the history of popular music. As members of The Family Dog collective in San Francisco, the two men pretty much defined the look of psychedelia in the sixties with a string of striking and brightly coloured concert posters for gigs by artists like Bo Diddley, the Moody Blues, Jefferson Airplane, Big Brother and the Holding Company, and of course the Grateful Dead. Mouse and Kelley went on to design some of the Grateful Dead's most memorable album covers and later produced artwork for albums by the US rock band Journey as well.

When I was doing a lot of cartoons and graphic design, Mouse and Kelley were a huge influence, rivalled only by Rick Griffin. I was obsessed by the beautiful chromed lettering and fluid imagery that they created. That obsession was fuelled by an appreciation of the craftsmanship that was required to produce it. When I bought an airbrush twenty years ago one of my main reasons for doing so was to emulate the look of their work; once I had attempted to create my own art in the same style I began to realise just how talented they really were. These days anyone with a graphics tablet and Photoshop can achieve the same look in a fraction of the time, making it all too easy to dismiss the skill and ability involved, but the creativity and drive that Alton Kelley and his colleagues showed us deserves to be celebrated.

It looks like the secret to clinching a business deal is simple: chocolate digestives.

The Guardian has an article today on the new sport of tower running, a rather strenuous pursuit which involves finding a suitably tall skyscraper and then running up the stairs to the top.

The quotes from competitors aren't exactly what you'd call inspiring: "After my first race, I puked in a garbage can. Everyone high-fived me," "Think about the most painful thing you've ever done, then multiply by 10," and "I had never experienced so much pain in my life."

Somehow, I don't think it's the sport for me.

Boing Boing informs us that the inventor of the Pringles Can, Dr. Fredric J. Baur, has died. In accordance with his wishes, his family buried him in one.

Also stolen from Boing Boing: a post-modern examination of the Ladybird Book of the Policeman.

Damn. We've lost Bo Diddley.

I saw him play live, many years ago, as the special guest of some heavy metal band or other. I can't remember when it was, where it was, or even who brought him on stage, but my memory of seeing him play that riff with that guitar will stay with me.

I really don't feel like I've been on holiday for a week. Partly it's because I was gadding about all over the country, but I suspect that this it's mostly due to getting to bed late on Saturday night. Very late; all the shenanigans on the tube meant that Dave and I walked from the Emirates Stadium down to The Angel to get on the Northern Line; we didn't get back to Oprington until after midnight and I didn't get back here until three in the morning. I didn't mind the walk, though. It was a warm, calm evening and there was a strong smell of honeysuckle coming from people's gardens as we walked through Islington.

The HiRISE camera on the Mars Reconnaisance Orbiter has returned pictures of the Phoenix Lander sitting on the Martian surface, its solar panels glinting in the sun. The wider angle view shows the backshell and the parachute as well. The lander has started to deploy its robotic arm, ready to dig for ice below the surface. A patch underneath the lander is generating quite a lot of interest, as it indicates that Phoenix may be sitting right on top of a big lump of ice. If it is, they couldn't have picked a better spot.

I was over at Mum and Dad's for a couple of days this week. It was planned at pretty short notice, and I spent most of my time there doing things for them like putting loads of stuff in the loft, staking out the raspberry plants in the back garden and clearing the gutters. My parents are both getting rather frail and they can't do as much as they used to - it was good to be able to help them out a bit.

Mum and Dad do live out in the sticks: no broadband, borderline television reception, questionable mobile coverage from Orange, and not even any street lights in the road where they live. That means I'm pretty much offline while I stay there. While it's nice to unplug every now and again, it really makes me appreciate all the creature comforts I have here at home.

I came home via London, so I've been doing a fair bit of driving again. My brother Dave and I went to see Bruce Springsteen at the Emirates Stadium (the home ground of Arsenal FC) yesterday evening, and we had a good time. It was the first time I'd seen Springsteen live, and I was very impressed. He had the E Street band with him, too - they were the main reason I went. I've seen Nils Lofgren live before, but he certainly raises his game when he gets onstage with The Boss. Bruce doesn't need to work these days but he still gets out there and pays his dues, sliding across the stage on his knees and whipping the crowd up until they were roaring along with the band and nearly drowning them out with a wall of noise. I guess that's part of Springsteen's secret - he drives both the band and the crowd to work really hard, and it pays huge dividends. All the same, I left without buying a programme or a t-shirt; £22 for a cotton shirt seemed a bit excessive, especially when Dave and I reckoned that the takings from the box office for yesterday would have been somewhere in the order of £3.6 million.

All the same, I was impressed by the way he interacted with the audience - he could have been playing songs in the local pub with his mates rather than standing on a stage in front of 30,000 people. He stopped to accept requests from the audience, who held up cardboard placards asking for particular songs. "Don't know if we know that one" and "no man, that one's too hard" got laughs, too. But although he played for the best part of two and a half hours, there was no Dancing in the Dark and no Born in the USA. I can see where he's coming from by omitting the latter, but missing out DITD seemed like a mistake - if it was, it was the only one he made all night. I'm on fire was delivered crouching down with the front row of the audience, and made the hairs on the back of my neck stand on end. Badlands was awesome. And of course they did Born to Run. A good night.