A rogue DVD

There's a rogue DVD in the DVD drive of my laptop. I'm calling it "rogue" because it's been there, far from home, for much longer than it should have been. I need to remember to take it out and put it back in its case next time me and my laptop are in my office.

It's a DVD of the Doctor Who Xmas special from a few years ago, The Runaway Bride". This is the story that introduced Catherine Tate as Donna, who became a Doctor's assistant. Poor Donna, her wedding day didn't work out the way she expected. Instead of a honeymoon with her new husband she's been whisked off to the beginnings of the solar system by a quirky alien guy. You can watch for yourself here; head to about the two minute mark.

It's for the brief look at the beginnings of the solar system that I carried this DVD to a class. It's really well done. I think it might really have looked like that, with lots of lumps of icy rock of all sizes, banging into one another, sticking together, breaking up again, and a new Sun in the middle. The Doctor's words about this too are spot on. It's done so well I feel I can let people watch it for a minute and say, "that's probably what it would have looked like" (well, up to the point where the alien spaceship appears). From there we only need a few wee steps to start discussing questions like, "why are the gas giant planets further from the Sun?"

Science done well in TV science fiction, doesn't always happen and other Doctor Who episodes have been, let's be honest, dire.

I wanted to sing the BBC's praises for their solar system origin depiction. Other ingredients of this story really wind me up. It makes me so cross that they decided to show the Tardis flying around in full view with people hanging out of it. That's not how it works! It dematerialises and then materialises again in a different time and place. It doesn't fly around, or not in our conventional spacetime anyway. It's not a helicopter! Grrrr!

(I left the sweary words out)

It's funny, a lot of Doctor Who is so far from any sort of science that it's just fantasy. There's little need to worry about consistency. If the people who make the programme now want to change the rules a bit from those I imbibed as a kid, because they think it'll make it more amusing or visually appealing or something, it shouldn't really matter. But it does.

So, BBC, please, no more TARDIS flying around. Not clever, not funny.

Jack Bruce

I was sad to hear of Jack Bruce's passing. In Cream he was one of the creators of psychedelic and heavy rock. Every kid that picks up a bass guitar learns the riff for Sunshine of Your Love. Those sounds are all around us now, part of the everyday sonic environment.

After that he was in Tony Williams Lifetime, the band that inspired Miles Davis to explore rock music. Jazz-rock also is all around us now, even for people who don't choose to listen to it: TV show themes, film music, even in bloody elevators and when your phone enquiry gets put on hold. Lifetime was pretty much the first jazz-rock band. Full-stop. So there's Jack Bruce helping to kickstart all of that, too. His place in either of his bands would have made him one of the chief architects of the sound of the modern world. To have been in both makes him something very special indeed. We could make a really strong case that he was "Scotland's greatest musician." And that's without mentioning the very many other records and bands he contributed to, many of these really interesting, experimental (like Carla Bley; Michael Mantler; amazing gigs you can find bits of on YouTube).

Recently I'd been listening a lot to Monkjack, one of his solo records. No band, just him singing, piano, one other musician playing Hammond organ; essence of Jack Bruce. It's beautiful - deeply felt, clever, classy classy music. Here he is, not so long ago, with a lovely performance of Weird of Hermiston.

I'm sorry he's gone, a wee bit earlier than many. Our thoughts have to be with his family and close friends. But what a legacy.

"Looking at the night sky"

This time I'm using the blog as a place to assemble some bits and pieces of information about the Astronomy weekend being offered by the Centre for Open Studies, in cooperation with the Scottish Youth Hostel Association. On the weekend of 20 - 22 November, Douglas Cooper and I will be tutors for a weekend titled, Looking at the night sky. Here's the course description from the Open Studies course programme:

We will introduce the night sky, stars and constellations, telescope usage and first steps in astrophotography. Our venue will be Loch Ossian Youth Hostel, a beautiful setting distinguished by its remoteness and consequent dark, star-filled skies. Workshops, computer activities and games in the event of unsuitable weather. See Centre for Open Studies website for details.

So, a weekend introducing Astronomy, in a dark, remote location. Here are some more details:

Where is this place? Loch Ossian is at the eastern end of Rannoch Moor, marked on this map. No public road goes there. Unless you're up for a long walk from the nearest public road (which would be lovely, for those who enjoy such challenges), you get there by train to Corrour station. Corrour station is on the West Highland line, the train line that goes from Glasgow (Queen Street station) to Oban or Fort William. People coming from further south might prefer to leave a car at Rannoch or Bridge of Orchy stations, from where Corrour is just a couple of stops along the West Highland line. The Youth Hostel is about 20 minutes' leisurely walk along a "well made track" from the train station.

Why go there? At left I've included a map showing the amount of artificial light experienced across Europe (from http://www.lightpollution.it/dmsp/). Light pollution now spoils most Europeans' views of the night sky. You'll notice on that map that the biggest remaining dark areas in the continent are in Norway or Scotland. We'll be in the middle of the Scottish dark area, and a long way from even small towns. As long as the weather cooperates we will enjoy very fine views of the beautiful but elusive sights of the night sky. The Milky Way will be obvious. We'll be able to spot the Andromeda Galaxy with our naked eyes.

We're going to the Highlands of Scotland in November. Let's be honest: the weather could be awful! No telescope that you look through with your eyes can compensate for rain and clouds. Even if this happens we'll still be able to discuss the night sky, some modern ideas of planets, stars and the Universe, and telescopes and astrophotography in a remote and beautiful setting.

More on Scottish dark skies here; of course there is now a Dark Sky Park in Galloway, and the island of Coll has been designated a Dark Sky Island.

Youth hostel The SYHA website has more information on Loch Ossian Youth Hostel. You can see that it is comfortable and well managed with due attention to sustainability in a potentially fragile location. We should mention that accommodation will be in its two shared dormitories. No single rooms - sorry! We will supply more hostel information to anybody who signs up.

By the way, just in case there's any doubt, you don't need to be a "youth" to use a Youth Hostel!

What will we be doing? On the Friday and Saturday nights we will look at the sky, clouds allowing, with our own eyes and with telescopes and binoculars, and take some first steps at astrophotography. Douglas and I will help you in this. As we look we can discuss the nature of what we're seeing - some of the best conversations I've ever had about stars, planets, galaxies etc. have been as a wee group of people viewed them in a telescope. If the night is clear we'll keep going until people run out of steam, and start slow and lazy the next morning if necessary.

Bring many layers of warm clothing. You can also bring your own wee telescopes or binoculars, if you want - as long as they'll go on the train! - but Douglas and I will have a couple of telescopes with us.

During the day we'll look at a variety of telescopes and discuss their pros and cons, talk about what's in the night sky just now, how the sky changes, how to plan an observing session, and have a couple of wee talks on modern astrophysics, the natures of the objects we can see, straying a little into big or exotic topics like black holes and the Big Bang. We'll try to respond to suggestions and questions. We'll also have a close look at our very own nearest star, the Sun - "daytime astronomy" (My own research is on the Sun. Solar astronomers talk about "night-time Astronomy", meaning the whole of the rest of the subject!). We'll bring a couple of ideas for astronomical games, etc., for light relief - especially if the clouds do not cooperate and we're stuck inside in the evenings.

Fee The fee of £130 includes accommodation, all meals and tuition. You are responsible for getting there yourself. There are enrolment instructions at this link. If you go straight to enrolment, the title of the weekend is Looking at the night sky and the course code is 16973.

Tutors I work in the Centre for Open Studies, University of Glasgow. Among other duties I teach and organise courses for the public in Astronomy and Physics. I've been doing this job for a long time so I've heard lots of questions and worked out my answers to them. I believe I can speak understandably with all sorts of different people and you can maybe judge that from some of the other posts on this blog (this one, for example, or this one).

Douglas Cooper is a mainstay of several Central Scotland Astronomical societies and a skilled astrophotographer (i.e. photographer of objects in the night sky). You can see some examples of his images here and here. Some of his images of the aurora and noctilucent clouds have been featured on spaceweather.com.

I hope this sounds interesting and indeed exciting and that we might meet at Loch Ossian. I'll probably update and refine this posting over the next couple of weeks.

Credit for the light pollution map: P. Cinzano, F. Falchi (University of Padova), C. D. Elvidge (NOAA National Geophysical Data Center, Boulder). Copyright Royal Astronomical Society. Reproduced from the Monthly Notices of the RAS by permission of Blackwell Science.

Shooting a man

I'm working on tonight's class, the second meeting of Hands-On Space Astronomy. This is a course that aims to help people to explore Astronomy in a little bit more depth once they have a little basic knowledge. It relies on the free availability of vast quantities of data from space missions and also some ground-based observatories, and simple tools for accessing, manipulating and combining these data, all tied together nowadays in so-called Virtual Observatories. Some of these tools and the interfaces to them have changed a bit since I last taught the course. Also we would always want to revise a slightly unconventional course like this each time we run it: what went well; what should have been done differently? So there's a bit to prepare and think about.

I needed a breath of air and a wee break from this work so I popped out and went to a slightly more distant sandwich shop than usual. On the way I passed a shop selling home furnishings, devices for the kitchen, etc. A sign in the window said, "No woman ever shot a man while he was doing the dishes." Now, I don't believe this. I think if a woman had decided to shoot a man, while he was doing the dishes would be one of the better moments. His attention would be on the sink, soap suds and what lay beneath them, the thorough removal of fatty grime, etc. He might not even hear the arms-bearing woman come up behind him, far less realise her intention.

You might argue that a man who regularly does dishes is less likely to find himself in the cross-hairs. That might be true but "less likely" does not mean, "never". If the woman has made up her mind to do the deed, an episode of dish-washing won't change her mind. It will only present an opportunity.

Do women themselves sometimes get shot by men while doing the dishes? A whole other, potentially fertile field of discussion is left barren.

So on the whole I will be very surprised if no man anywhere has ever been shot while doing the dishes. Now back to Hands-On Space Astronomy.

Positronium

Science continues to find that homeopathy doesn't work. I know homeopathy has sincere adherents who don't think about scientific evidence in the same way as the rest of us. I admire those people who are constantly in debate with them and I'm glad my own area of science is a long way away from this sort of topic. So I was quite taken aback to come across this account of positronium homeopathy.

Positronium is a sort of an atom but a very exotic one, with only a fleeting existence. Like an atom of hydrogen it consists of two elementary particles with equal and opposite electric charges. Like an atom of hydrogen one of these particles is an electron, familiar (as far as any subatomic particle is "familiar") as a constituent of the atoms around us. Unlike a hydrogen atom the positively charged particle is a positron. A positron has the same mass as an electron but a positive, rather than a negative charge. It is the electron's antimatter counterpart, a sort of evil twin. When an electron and a positron come together they cancel one another out (the word used is "annihilate") and the mass of both particles is converted into energy, in the form of light, according to Einstein's most famous relation E = mc².

Antimatter sounds like something out of science fiction (and one of its most famous occurrences must certainly be in the propulsion unit of the Starship Enterprise). Nonetheless it exists. The first discovery of a positively charged electron was in 1932 by the American scientist Carl Anderson. Now they are put to work every day in our hospitals (know somebody who's had a PET scan? Guess what the "P" in "PET" stands for).

Natural processes produce positrons, as do events in man-made particle accelerators. My own interest focuses on the energetic events of solar flares, in which positrons are sometimes produced. Once they exist, positrons don't hang around for very long. There's usually an electron for them to annihilate with. But before annihilating, for a ten-millionth of a second or less, the positron and the electron orbit one another as an atom of positronium. I like to think of them in a sort of dance, eyeball to eyeball, each recognising in the other its equal, its opposite and its imminent extinction. Finally they annihilate one another, producing a spectrum line in gamma-rays that we can detect and learn from.

Composed only of two very simple objects, the positronium atom gives very precise tests of the quantum theory of electromagnetism, so it has been studied in great detail in the laboratory. It lets us test very precisely elements of our basic understanding of the world.

Matter and anti-matter can both exist but there is more matter than anti-matter. If there were equal amounts of both, they would have annihilated each other very early in the history of the Universe. The Universe would be filled with light but there wouldn't be atoms and molecules i.e. ourselves. So the question, "why is there more matter than anti-matter" is a fundamental question about the Universe.

After all this I'm both sad and a bit cross to discover talk of "positronium homeopathy". In its yin-and-yang components, its brief existence, its annihilation, and the matter-antimatter asymmetry at which it hints, positronium is a very beautiful and exotic aspect of the physical world. There's more than enough real, deep beauty and weirdness there without making up a lazy, unsubstantiated fairy story.

Open Studies Astronomy bulletin

A few times a year I send out a wee email bulletin for people who come to some of our courses (let me know if you'd like to get these). The aim is to let them know - or remind them - of Glasgow University Open Studies Astronomy and Physics courses and day schools, and to highlight other interesting events in the Glasgow area. Here's the latest:

1. IMMINENT

   I've only just heard that the Scottish Dark Sky Observatory is hosting a visit from the science writer Stuart Clark, TOMORROW, 10 May. Stuart Clark is an excellent writer on Astronomy and Physics topics ("The Sun Kings"; "The Sky's Dark Labyrinth"; regular pieces in the Guardian). You may also have seen him interviewed by Philomena Cunk on the subject of "time" on Charlie Brooker's Weekly Wipe - clearly a man who doesn't take himself too seriously. I haven't heard him speak but I've heard good things. See http://www.scottishdarkskyobservatory.co.uk/events/dr-stuart-clark-lecture-and-stargazing/

2. The Institute of Physics are now hosting a series of talks here in Glasgow, aimed at a very broad audience. The titles so far have been really interesting, to my eye, including both pure and applied topics. The next of these will be given on Thursday 15 May, 19.00 in the Kelvin Building here in the University, by Dr Stuart Reid from the University of the West of Scotland: "Giving stem cells a good nano-kicking". More details at http://www.astro.gla.ac.uk/users/martin/ioplect/
3. Glasgow City of Science has a new website to showcase the city as a leading international destination for scientific discovery and innovation. Their words: "A diverse range of influential, partner organisations with local, national and international reach have come together through the Glasgow City of Science initiative to leverage our scientific potential as a major driver of sustainable economic development and to demonstrate the importance of communicating science as part of the region’s wider heritage and culture." So the City of Science project is about industry and companies, but also education and outreach. You'll find lots of interesting events on their Events page, and you might like to subscribe to their e-bulletin.
4. We ourselves have a couple of Astronomy events in the summer programme:

   Astronomy when the skies are bright, ideas and activities to stay involved with the wider universe even although it's difficult to see in Scotland in the summer. Douglas Cooper, Andrew Conway and myself; Saturday 24 May, 10.00 - 15.00

   Weighing the Earth on Schiehallion, Perthshire, recalling Nevil Maskelyne's fundamental experiment to determine the mass of the Earth, and taking a day to actually visit the mountain. With Andrew Conway, who in 2005 was involved in an attempt to repeat this experiment with modern equipment. Evening of 18 June and all day 21 June.

Mercury

One Sunday in the winter of, I guess, 1990, I set out for a day in the hills with my pal Douglas. We set out to climb Ben Ledi, that bold, conspicuous mountain near Callander. It was one of those warm, windy winters we were seeing then and the hills were not enticing but I was going stir crazy in the city.

The day was very windy. I think there were 80 mph gusts. At least one stride was thwarted completely because the wind blew me backwards as far as I would have stepped forwards. Douglas thought this was hilarious: "that's the first time I've seen somebody actually blown backwards through the air!"

Bizarrely for that time of year there was almost no snow. The ascent was hard work but we reached the top and made it back to the car without any undue occurrence. Then things got slightly weird.

There is a fairly big parking space at the bottom of Ben Ledi, at the Callander end of Loch Lubnaig. I had borrowed my wife's car, a white Vauxhall Astra with a great big, blue and black letter "M" on the side, logo of her employer at the time, Mercury Communications. We walked across the park towards it, past a minibus into which several men were climbing. They paused and glared at us as we walked past. There was some muttering and nudging. They didn't speak but their faces told a definite story: they hated us. Two of them were getting into another car nearer us. One of them said, "you're lucky your car's still here, mate." I peered at them, reading their tee-shirts: "British Telecom hill-walking club". "It's the wife's," I said - truthfully, although I doubt they believed me. Everybody laughed and the moment passed but for a few minutes those BT employees wanted to kill us. At Margaret Thatcher's bidding, Mercury was going to rob them of their jobs. Anybody in a Mercury car was their class enemy.

Mercury symbols on manhole covers still decorate the streets. This one is on Eldon Street, just along the road from my office. Each time it catches my eye I remember that grey, dreich winter day when the BT hillwalking club wanted to beat me up. Then I was newly married; now my children are in university. That brief moment of tension captured a larger moment in British social history but nonetheless still resonates, particularly as I cross the campus of Britain's fourth oldest university.

The processes set in motion then are still in play. The current government seems to place a religious faith in markets, that kind of faith which evidence leaves unshaken. That the state should be almost the only provider of higher education is intolerable to them, so they are determined to "bring greater diversity to the higher education sector". Companies, the entities that make up markets, do not exist to nurture fully informed citizens capable of thinking critically and playing a full role in society; nor to curate and transmit existing knowledge and create new. Companies exist to maximise profits. We only have to look at for-profit higher education in the USA to see how badly things can go wrong, how completely the profit motive can undermine any value that higher education could have had for students and the rest of society. It's extremely disappointing that our government seems to be encouraging companies linked to bad practice in the USA. It's almost as if big companies are automatically a Good Thing, no matter how they actually behave. I'm glad to see our union opposing this trend. Unfortunately all the media now relegate such discussions to the Politics or Education sections, well away from the eyes of anybody who's not already interested. See "NHS privatisation".

You thought this was going to be about Mercury, didn't you, planet closest to the Sun, smallest of the terrestrial planets, whose orbit evolves in a way that needs General Relativity for its complete explanation? Possibly the very exciting MESSENGER mission? Sorry. But as I criss-cross the campus between my various roles, those little souvenirs of Margaret Thatcher's Britain keep reminding me of a windy day on Ben Ledi.

Whisky

I am enraged by those age check things when you look at Scotch whisky distillery websites (example). Will looking at pictures of seaweed and highland cows and distilleries and peaty hillsides make 12 years olds more likely to hit the booze? Will they be saving their pennies to try the latest port cask expression? Will they say, "well, I didn't enjoy Frosty Jack's very much, but that 21 year old Old Pulteney with its tastes of engine oil and smoke looks just the thing for me"? Is there scientific evidence that febrile young minds exposed to boozy images will be turned from the path of light, corrupted, set on the path to a diseased relationship with alcohol, bibulous futures sealed as certainly as if they had crossed the event horizon of a black hole?

And if they're old enough to look at a distillery website, aren't they also old enough to choose a fake date of birth?

What good can this possibly do? Bah.

I was looking for work reasons, by the way. More of that soon.

An evil tree

Probably it is not evil. In Pollok Park it must see so many passers-by that any routine evil-doing would have become well-known. Of course it might choose shrewdly its victims and the moments to take them. A park in a big city will supply them fairly regularly: alone and melancholy, remote from or devoid of friends and family. Nobody will notice if they never return from some restless nocturnal stravaig. The end of unrest might even be a kindness.

Probably it is not evil. Nothing happened to me. I was able to photograph it. But I was there in daylight; other people were around; I am not unloved.

Probably it is not evil. It is not after all an ill-favoured Ash Tree. Still, Let's hope they chop the thing down. Yes, Let's hope they chop the thing down.

Fort William

I spent last weekend at the Fort William Mountain Festival. Jane Magill and I were there with the Cosmic Way roadshow. The Cosmic Way aims to spread the word about the Scottish scientist CTR Wilson, the invention of the cloud chamber which earned him a share of the 1927 Physics Nobel Prize, and the study of radiation from space. Wilson always traced a very direct line to the cloud chamber from his stay on the summit of Ben Nevis in 1894. He also speculated that immensely penetrating radiation from space might arrive all the time at Earth and carried out a wee experiment to test this idea, in the Neidpath railway tunnel on the edge of Pebbles. In our minds we thought of a squiggly line on the map like a cloud chamber track, with Ben Nevis at one end and Peebles at the other. It could be a long distance journey, like the West Highland Way or the Southern Upland Way: the Cosmic Way!

By the way, I have ventured out into the world beyond the farm and I know there are Fort Williams and Peebles's in other parts of the world. In this Scottish story I'm talking about the Scottish versions.

Fort William is one of the obvious venues for the Cosmic Way. We meet people who know Ben Nevis and its summit very well (our stand was next to the John Muir Trust, who own Ben Nevis above 700m) and who love the outdoors and nature, just as CTR Wilson did himself. For some of them this esoteric science might become a bit less forbidding when they learn that it starts with a love of the natural world and its beauties.

On Sunday I took some time and walked up Glen Nevis a little bit. I hadn't really expected to have - or to take - any time during the weekend so I didn't have proper gear for long, rough walks or snow but I did start up the Ben Nevis path from Achintee, that thousands of people follow to the summit every year. I turned back when I came to a burn running down over the path. This is the same track that was constructed in 1883 so that the Ben Nevis Observatory could be built and operated. And in turn the Observatory gave Wilson a couple of weeks' work in September 1894, inadvertently starting him on the road towards the cloud chamber. So, in the absence of an ice axe or even decent boots, this wee toddle was exactly the right one for Cosmic Way reasons.

Interstellar travel

Alien was shown on telly over the Xmas period. What a great movie! I saw it when it came out in 1980, a day or two after the last examination of my BSc degree. With those big exams behind me I was in a bit of a black mood but Alien really lifted my spirits. My only real disappointment was that one of the humans survived.

It's amusing how quickly images of future technology date. One of the crew interacts with a computer via a 1980s keyboard and a CRT monitor, for instance - not even a touch screen, far less by speaking, and in text, no GUI. In many other ways it's far-sighted, however.

Interstellar space is such a potential playground for science fiction. It's quite irresistible to authors and film-makers but the enormous distances have always been a huge problem: how could you make these journeys in a human lifetime, far less a time short enough for the action of space battles and political intrigues? Einstein's Theory of Special Relativity shows that the speed of light is a sort of ultimate speed limit of the physical world. As accelerated objects move at speeds closer and closer to the speed of light, they get more and more massive, so it gets harder to accelerate them further. Worse, some invented method for faster-than-light communication would open up the most horrible paradoxes: you could receive the answers to questions before you decided to ask them, for instance. Most people prefer to believe it's just not possible, rather than allowing that the normal sequence of cause and effect might sometimes break down. So we're stuck with travel no faster than the speed of light which means four years at least to the nearest star, even supposing we can make our spaceships move close to the speed of light, and many thousands of years to most others.

The normal solution of science fiction is to assume some advance in physics that will enable a way round this problem. For example, you can learn probably more than you ever wanted to know about Star Trek's "warp drive" in Memory Alpha, the Star Trek wiki. I still remember the gasps in the cinema when the Millenium Falcon entered hyperspace for the first time. There are probably very few Britons who don't know about Doctor Who's TARDIS, especially with the hugely successful reboot of recent years (but I need to get something off my chest here: I HATE it that they now show the TARDIS flying about like some sort of helicopter. It's WRONG. WRONG.). From thousands of science fiction novels that casually invoke such unknown physics, let me mention one personal favourite: M John Harrison's brilliant Light, in which the inventor of faster-than-light travel is also a serial killer.

Let's face it. There is every chance that the physical world just doesn't work this way. No faster-than-light travel is possible and all our Star Treks and Star Wars and Doctors are just fantasies, not even "science fiction". Don't cry.

I like it that Alien takes the less preferred but more likely solution. The human crew are placed in suspended animation for most of their enormously long journeys and only revived after the many years of travel - unless, of course, they intercept signals of intelligent life that turn out to be warning them to keep away from beasties that will use them as incubators for a few hours before bursting fatally out of their stomachs. Anyway this device allows recognisable humans to make interstellar journeys although it does raise interesting questions beyond the scope of the movie, about the maintenance of a culture when communication involves such long intervals of time.

We're not really adapted for interstellar travel. Our individual lifespans are so short. But interstellar travel might eventually make sense if we evolve or, more likely, engineer ourselves into beings that live for, say 1,000 years. Then a 10 or 20 year journey to a nearby star would be a fine way of spending a little bit of your life. This might become possible with our existing bodies through bio-engineering, as imagined so excitingly by Freeman Dyson, or we might even find some way of divorcing consciousness from the body and supporting it in machines: "uploading" a person into a computer. Then the "person" would keep working as long as the machine did.

Of course science fiction has tackled these ideas as well. A student on one of my courses handed me a copy of Diaspora by Greg Egan. The protagonists in this book are our cultural and, umm, mechanical descendants but they have long since moved beyond organic bodies. As minds existing within machines they can contemplate journeys of thousands of years; they are effectively immortal. Most of the interest and possibly the deterrent value of this book lies in the nature of its protagonists, their motivations and relationships. In a time after biology these transhumans are not exactly people we can imagine having a beer and a chat with.

I haven't even mentioned Alcubierre and so on, attempts at identifying a road to faster-than-light travel based on known physics (which, so far, involve using a sort of matter not known to exist as well as demanding the generation of infeasible amounts of energy). Even if these technologies ultimately prove to be possible I believe they belong to an extremely distant future. I think changes to the physical nature of humanity will make thousand-year journeys feasible and attractive first.

So, Alien notwithstanding, I think the future of interstellar travel is summed up in a couple of phrases often heard in Scotland: "ye canna change the laws o' physics, Captain"; and "it's not for the likes of us".