Tom Womack

I've often heard arguments like 'the cost of flying should reflect its externalities', where the clear implication was that this would make it so expensive that people would stop doing it, or so expensive that it would clearly be cheaper to take a train.

On the whole I'm strongly in favour of air travel - at least, I'm strongly in favour of at most one-level-vicarious personal experience of strange far-off places, and air travel is the only realistic way to get anyone there; going over land to Bangkok is significantly more expensive than Thai Air even if time and ludicrous inconvenience are not a constraint, the price of the return plane ticket won't get me a train beyond about Moscow.

Yes, it takes a lot of energy to remove one ton of CO2 from the air: http://nextbigfuture.com/2009/06/co2-removal-from-atmosphere.html says fifty kilojoules per mole which is 1.2 gigajoules per ton, http://www.futurepundit.com/archives/005592.html is optimistic and says a third of that.

A gigajoule is about 300 kilowatt-hours, so about thirty pounds worth of electricity at the price I pay for it as a domestic user on a not-terribly-good-value tariff. Say the cost-of-capital and depreciation for CO2-removal equipment is about the same as the electricity; so the total cost for taking CO2 out of the atmosphere would be sixty pounds a ton.

Even people strongly against CCS no-net-CO2 coal-fired electricity generation argue that the efficiency cost of doing the CCS would be about 30%, the currently-4GW facility at Drax would produce 2.5GW; say this doubles the price of the electricity and we're talking a hundred pounds a ton.

One of Easyjet's A319 planes burns 850 gallons of fuel an hour to transport say 120 people (capacity is around 150); jet fuel produces about a ton of CO2 per hundred gallons burned, so taking your 120 people two hours to Berlin has produced about twenty tons of CO2. Removing which would put £17 a head on the cost of the flight; Easyjet is nothing if not cheese-paring, so it probably wouldn't put £30 a head on the price of the ticket. +30%. The last time I compared the prices, Easyjet to Berlin was £100 return and rail was £400 one way.

A Eurostar train carries 750 people two hours from London to Paris and uses 12.5 megawatts of electricity to do so; 25 megawatt-hours at a kilo of CO2 per kilowatt-hour for UK electricity generation [yes, I know most of the French electricity is fission-produced] is 25 tons, so about the same amount of CO2 as the A319 to get six times as many people about half as far. I don't have the figures for slower trains.

A 747 with its 400 passengers burns about a gallon of fuel a second, say produces 36 tons of CO2 per hour, it's eleven hours to San Francisco so that's 400 tons, £24000 to remove. A hundred pounds per passenger per direction; say £250 on the price of the return ticket. +30% again, maybe a bit worse if you're flying at very off-peak times and can get a cheaper base ticket.

Flights aren't the overwhelming part of the cost of foreign holidays now; making them 30% more expensive doesn't seem likely to stop people travelling, and if doubled electricity bills and somewhat more expensive holidays are the price I have to pay to keep London (and incidentally Bangladesh, for there is only one sea level) above water, I'll pay gladly.

Hmm. I've noticed a few gaps in my bookcase, and I can't quite remember to whom I've lent what.

cartesiandaemon has my copies of "The Well of Ascension" and "The Hero of Ages"

ceb has the two Cat Valente books

pseudomonas has quite a lot of books and I didn't keep a record of exactly which; certainly includes "Red Seas Under Red Skies" and "Snake Agent".

Somebody must have my Sarah Monette books, but I'm not sure who.

I ought to lend hilarityallen "Dragonfly Falling", the second volume of "Empire in Black and Gold"

In the other direction, I have and have read naath's "Glorifying Terrorism" and despotliz's "The Graveyard Book" and "The Gone-Away World"; I have and have not read Jon Amery's "The Twilight Watch" and Liz's "The Fortress of Solitude".

If you have borrowed books from me, or have lent me books which aren't on my list, would you mind leaving a comment?

Yesterday, finally finding a time that fitted after my brother Ben had suggested this several times, we cycled to the source of the Cam at Ashwell Springs.

It's a nice bike ride, about twenty miles each way over countryside that gets a little rolling as you pass Haslingfield: http://www.gmap-pedometer.com/?r=2913585 is the route. There's an unexpected war memorial with a P-51 propeller sticking out of it just off the road into Steeple Morden: there was a USAAF air base there in 1942-1945

The source of the Cam is a shallow gravel-bottomed pond with two springs flowing into it; the water that nourished Newton, Darwin, Rutherford and Wittgenstein tastes very much like water, and the pond is chilly and pebbly enough that your feet feel tingly and warm after you've stopped paddling.

Cycling back via the road that passes Wimpole, you get a rather nice view of the vista that the builders of Wimpole Hall arranged, to capture which something better than a telephone might have been good:

With my hair as it is now, I really need to wear a wide-brimmed hat when cycling six hours in the sun: ran out of steam badly on the way back - I had to lie down at the top of Chapel Hill for a few minutes until my heart stopped pounding and the grampus in my lungs stopped puffing - and ended up with quite a headache in the evening despite carefully rehydrating with tea and ginger ale at the Orchard in Grantchester.

I have a membership at Constitution (this year's Unicon, held at Murray Edwards College in Cambridge on 31 July - 2 August; Sean Punch, Steph Swainston, Harry Gee and Sib Machat as guests of honour), and a membership at Satellite 2 (a convention to celebrate the 40th anniversary of the first moon landing, to be held in Glasgow on 25 - 26 July; Iain Banks is guest of honour).

However, in both cases I will be in Canada at the time.

So, the memberships are for sale. The Constitution one has gone, but the Satellite 2 one is still available for 40 pounds.

[Poll #1406125]

The American Crystallographic Association have their annual conference in Toronto 25-30 July; Worldcon is 6-10 August; flights are cheaper at weekends, Canada is a nice country and my boss is generous with holiday allowance, so I'll be flying to Toronto on 24 July and flying back from Montreal on 15 August.

Which gives me most of two weeks at liberty in Canada. Inspired by Stan Rogers, I was planning after Worldcon to get on a train and head to Halifax, rent a bicycle and spend a few days cycling along bits of the Nova Scotian coast before heading back to Montreal airport; is this sensible, or are the small roads of Nova Scotia built (like the small roads of eastern coastal Norfolk) carefully out of sight of anything scenic, and used only by bears and badly-driven eighty-ton coal trucks ?

I assume I can amuse myself happily for a week in Toronto, Ottawa, Montreal and intermediate parts, travelling on trains and sleeping in youth hostels; what should I be sure not to miss in that region? I had a short but intense trip to Toronto a few years back which took in Niagara Falls, Casa Loma and such parts of the Royal Ontario Museum as weren't being rebuilt; I've spent some time in Montreal but only in the deep mid-winter.

Also, are there likely to be useful things I can do if I turn up at the Worldcon venue a day or so early?

Alimentum, opposite the cinema just after the perpetually-roadworked bridge on Hills Road, have a pudding made out of marshmallows, honeycomb, toffee, banana icecream and caramel mousse, served in a smoke-filled preserving jar. It tastes of bonfire night with bananas.

I convinced the Geek Pizza People to be Geek Elaborate-Restaurant People this week, and a good time and fantastic food seems to have been had by all. Maybe leave a few weeks to recover from the shock of the new, then propose sushi.

After two hours and ten minutes on this bus from Cambridge, we have finally reached Milton Keynes temporary coach stop.

(it's the Cambridge to Oxford bus and was enormously delayed in St Neots; even running to time it takes an hour and three quarters to get to MK, which is forty-five miles by a direct route)

http://hla.stsci.edu

is the Hubble Space Telescope archive. Type in a target name (M57 is a pretty one; planetary nebulae work very well, the big Messier galaxies and globular clusters are a bit too big for the Hubble field of view), click on 'footprints' to get a picture of the sky with little boxes showing where the photo was taken, click on a footprint and go to 'images' to get a set of little pictures with the ones under the footprint highlighted in green, click on 'view online' to get a Google Maps-type zoomable view of the image.

This is more science data than it is pretty pictures, though it's not the rawest level - most of the images have been made from three exposures by a process that takes out the cosmic-ray hits, and (as you'll see in M57) some script has noticed that images have been taken of the same field in several filters and made a colour-combined version of that.

Selecting something like Cygnus A and seeing that the best pictures from the best instrument ever orbited still look like a slightly dirty orange blob, or looking at an ACS picture of a star-cluster in M33 (870,000 parsecs away) which looks rather like the photo I took of the Perseus double cluster (2300 parsecs away) with a 30mm wide-field lens last Saturday gives me a much stronger feeling that the universe is a very big place of which we know little than usual awe-driven articles about Hubble provide. The image-browser also makes it very clear that WFPC is a 2.4-megapixel camera; WFC3, being launched in about a fortnight, will be 16 megapixels and produce rather less noisy pictures.

I know HST time is insanely competed for, but I am a little surprised that people are so confident that galaxies are radially symmetric that they'll publish a paper on the distribution of star clusters in M33 having taken pictures of a dozen random non-overlapping fields covering maybe 15% of the galaxy. There's clearly sensible science behind 'we will take pictures of this elliptical galaxy in three UV bands to see if anything unexpectedly energetic is happening', but the UV detector is rather noisy and the galaxy doesn't emit much in the UV, so NGC4627 (picked as a random small galaxy from Saturday's APoD) is rather disappointing.

(if you want a large panorama, it's here. You can count battlements on the castle and see tiles on roofs in the middle distance, but it is 7MB long)

Here's sunset, viewed from the Miradour da Gloria in the west. The castle is at the right-hand edge, the square right in front is the Praca dos Restauradores and the little patch of trees behind it is the Miradour da Graca on the other side of the city. Avenida Liberdade is the first set of trees above the railings, and on the far left you see some of the big modern buildings around Parque Eduardo VII.