A few months ago I commented about the effect on reflecting heat that painting roofs with white paint could have.

I was therefore interested to see via Everything Popular is Wrong that there is now a group set up specifically to promote the idea.

The organisation – Paint the Globe – promotes the idea, although its website is rather light on supporting facts, and rather heavy on presuming that the reader is based in the USA – which is ironic for an organisation with the word “globe” in its title. That quibble aside, in terms of total impact on climate change, this is mere tokenism, but quite often tokenism leads to bigger and better changes and more awareness of the issues. Which can only be a good thing.

As it is difficult to persuade people to get out the white paint after a building is constructed – maybe the planning system should encourage upward facing surfaces to be painted white as part of the process of getting planning permission?

One of the areas where I agreed with the former London Mayor, Ken Livingstone is when he commissioned a report on promoting green roofs in London, although I am not sure if it was pushed as an important issue for planning controls.

In the meantime, I am off to buy shares in the makers of Dulux paints.

…until September.

Hampstead Observatory, the 100-year old telescope observatory in North London is open to the general public for free during the winter months – but has to close for summer due to the annoyance of a lack of darkness in the evenings.

This Saturday (15th May 2010) marks the final evening of operations until the evenings start to get dark enough again in September.

Saturn is currently the best sight in the night sky for visitors, and the observatory will be open 8pm-10pm on Friday and Saturday evenings.

The observatory is only open if the sky is clear enough to see anything, and weather forecasts suggest that Friday will be a write-off, with partial cloud on Saturday – so it could be working that night.

Will also open 11am-1pm on Sunday, but obviously not possible to use the telescope.

Web site of the HSS Observatory

Entrance to the "field" the Observatory sits in

The Observatory

Main Telescope - photo taken during daylight hours

One of the worrying aspects about climate change is the melting ice in the Arctic, but not because all that melted ice would cause a rise in sea levels.

In fact, about 90% of the ice is below sea level, and as water expands when frozen, by around 9%, it is quite possible that the Arctic melting would have zero impact on sea levels.

However, ice is also very reflective and a lot of solar energy hitting the earth is reflected back into space by the Arctic ice. No ice, and all that heat gets absorbed by the sea, warming it – and in turn causing sea volumes to expand and sea levels to rise.

So, how about increasing the amount of the earth’s surface that reflects the solar radiation? It’s something I have occasionally pondered about, but lacked the resources/skills to work out the maths.

Some boffins have also thought about similar ideas – such as seeding clouds over oceans or even more brazenly, putting mirrors in space.

Now another report appears on my mailing list – where some boffins have actually looked at what would happen if you liberally splashed white paint on the roofs of city buildings.

Asphalt roads, tar roofs, and other artificial surfaces absorb heat from the Sun, creating an urban heat island effect that can raise temperatures on average by 2-5 degrees Fahrenheit (about 1-3 degrees Celsius) or more compared to rural areas. White roofs would reflect some of that heat back into space and cool temperatures, much as wearing a white shirt on a sunny day can be cooler than wearing a dark shirt.

Their simulations, based on an idealized view of different types of cities around the world, indicate that, if every roof were entirely painted white, the urban heat island effect could be reduced by 33 percent.

I was reminded of the issue today though, as someone has had an accident outside the flat and most of the road is now covered in whitewash. I wonder what the impact would be if every road was also covered in whitewash – presuming one can be developed that lasts more than a few days.

I am as it happens, quite a fan of green roofs, where the tops of buildings are given over to garden spaces for the residents or shrub-land for the local wildlife and it is a pity that so few new buildings in London are thus designed.

Obviously, the Gherkin might have a bit of a problem!

A slightly introspective posting – but as a fairly avid user of Twitter, I have been following the account being managed by the people at the particle physics lab at CERN.

A fairly quiet account, things livened up considerably on Friday as the place started testing the Large Hadron Collider (LHC), and the person behind the CERN twitter account provided a live commentary of the evening’s events.

The excitement of the event could be very clearly felt through the stream of tiny comments that flowed out of Geneva that evening.

However, what was interesting for me to see was how much interest it was generating on Twitter, and at one point the LHC was in the top-10 of most talked about topics on Twitter. Even accepting that the average user of Twitter is reported to be older and more (ahem) intelligent than the average MySpace user, it was still surprising to see a rather obscure aspect of particle physics being of so much interest to so many people.

Or maybe it is just the “big machine” thing?

Also noticeable though was how many people started “following” CERN on Twitter on Friday and Saturday so that they could also follow the live feed of information. They went from 17,400 to 33,000 followers in just two days.

As I have commented in the past about how science on TV is increasingly dumbed down, it was refreshing to see how many people were demonstrating a clear interest in physics, even on a Friday evening.

A note for BBC2′s Horizon – go back to the glory days and start producing decent science programmes again. There is an audience out there!

On a personal note, a few years ago I was able to join a small group for a guided tour of CERN a few years ago and saw the ATLAS detector when it was still in pieces above ground. It was a visit I am unlikely to forget. Below is a picture I took (with icky camera) of one of the huge magnetic rings that run around the detector – and a diagram showing what a tiny component they are within the whole machine. Humbling.

Oh, CERN is also where the origins of what we today call the World Wide Web started, and in their rather good museum is the original document submitted by Tim Berners-Lee, with the famous scribble, “vague, but interesting” from his boss.

Possibly one of the greatest understatements of all time?

Just had an email from the nuclear fusion research centre just outside Reading with the dates for their 2010 open evenings.

The dates are: 19th May, 13th July, 15th September, 20th October, 24th November.

All are on Wednesday evenings and start at 7pm. To reserve places, call 01235 466608 or email deniese.willis@ccfe.ac.uk stating how many tickets and the date you want.

The tours start are free – and is a really fascinating view of a potential replacement energy supply for, well – almost everything – gas, coal, oil – and it could get rid of the ugly side of nuclear power – nuclear fission.

My previous visit can be read about here.

I would strongly advise booking asap, as places tend to “sell out” fairly quickly.