Happy birthday Hubble

Both these images - the Eagle Nebula, left, and the spiral galaxy M51, also known as the Whirlpool Galaxy, right - have been released by Nasa as the Hubble space telescope marks its 15th anniversary. Hubble has taken more than 700,000 images of the universe, but Nasa says these images are among the sharpest it has produced.

Icy disagreement

The climate change debate is hedged by uncertainties, the novelist Ian McEwan wrote in Grist magazine last month (correction - I should have said that this piece originated on Open Democracy and also appeared in the Guardian newspaper).

Can we avoid what is coming at us, or is there nothing much coming at all? Are we at the beginning of an unprecedented era of international cooperation, or are we living in an Edwardian summer of reckless denial? Is this the beginning, or the end? We need to talk.
Any regular readers of George Monbiot's Guardian columns will probably be aware of his disagreements with his fellow environmentalist David Bellamy over climate change.

More than hot air required

An excellent, 30,000 word New Yorker investigation into climate change earlier this year concluded that it was curious that a technologically advanced civilisation should decide to destroy itself.

Tomorrow the Guardian is publishing a 36-page supplement explaining and examining the issue described by the prime minister, Tony Blair, as the world's most important long-term problem.

Climate change will be one of the main items on the agenda at next week's G8 meeting of world leaders in Gleneagles in Scotland and many will be watching what moves the Bush administration makes on the issue. The US has been attacked over its apparent scepticism that climate change is a grave threat and its refusal to sign the Kyoto treaty on reducing emissions of carbon dioxode.

In an interview in today's Financial Times, the environment secretary, Margaret Beckett, claims that Britain's chairmanship of the G8 has already been a success because of increased awareness of climate change in the business world.

She is today making a presentation at an insurance industry conference in which she will suggest that businesses that take action now to reduce emissions of carbon dioxide will be in a prime position to profit from the regulation of greenhouse gases.

But rather less upbeat today was former Labour cabinet minister Stephen Byers, and US Republican Senator Olympia Snowe, who are co-chairs of the International Climate Change Taskforce.

Countdown to lift-off

The Guardian's science editor Tim Radford explains the scale of the challenge facing the crew of the Discovery, which blasts into space tonight.

Right now — it's 12.30 BST — engineers in Florida are carefully pumping 256,000 gallons of superchilled hydrogen and oxygen into the external fuel tank of the space shuttle Discovery. Space.com describes it as a three-hour job.

It isn't one to hurry, because a lot rides on this mission.

End of the shuttle era

A 50ft boom extension attached to Discovery's robot arm is seen against the backdrop of the Earth as the Discovery crew prepares to search for any damage to the nose and wing. Photograph: Nasa TV/AP

Nasa's flight operations manager, John Shannon, says the bodywork of its fleet of space shuttles has suffered thousands of instances of damage over the years. But when video footage appears to show debris falling off the fuel tank and landing gear doors, Discovery begins to look far removed from the reusable space plane it was once claimed as. In fact, it looks old. This follows a two-week delay to liftoff because of a faulty fuel sensor.

There is a degree of perceptions here. Debris is a matter of concern because it ripped the hole in Columbia's wing in 2003 and caused it to disintegrate upon its re-entry to Earth. We see it because we are looking for it – likewise after Columbia and the earlier Challenger explosion, media and other observers are much more aware of safety issues. But while it is true the shuttles are space age technology, it is 1970s space age technology. Nasa plans to retire the fleet when the International Space Station is completed in 2010 and their cargo bays are of no further use. A shuttle liftoff is still awesome to watch, but some of the shininess has gone.

A piece in the Christian Science Monitor on the launch describes it as a launch into the shuttle's final era:

Few expect these last five years to be a victory lap for the shuttle era, which has extended through seven presidential administrations and 114 launches

With the president's wish to return to the moon and then strike out for Mars, the greatest goal of the shuttles now is to finish the long-delayed task of completing the space station as safely and quickly as possible, and then to disappear.

Discovery DIY

In a shot from his helmet cam, astronaut Steve Robinson holds a piece of protruding gap filler he has removed from between the thermal tiles on the underside of Discovery, revealing the red adhesive that was used to hold it in position. Photograph: Nasa TV/Reuters

2.30pm update: In the end, he didn't need the homemade hacksaw. With just his fingers, astronaut-turned-repairman Steve Robinson has just performed an audacious in-flight fix to the space shuttle Discovery, allowing Nasa and the nation the chance to catch breath for the first time today, writes Richard Luscombe in Florida.

Stunning pictures from Robinson's "helmet-cam" broadcast live on the web and on Nasa's own TV station showed him pulling out the two protruding fragments of ceramic-cloth 'gap fillers' from Discovery's belly. "It looks like the patient is cured," he declared after the second rectangular strip came away easily with just a gentle tug.

Mission Control in Houston declared it "a great job" as Robinson, still dangling from the space station's robotic arm, headed back to the shuttle after an unprecedented spacewalk lasting more than four hours, but not before fellow space-walker Soichi Noguchi managed to snap a few pictures for the Robinson family album of a new national hero.

"You'll spend the next four years signing autographs," teased astronaut Andy Thomas, who choreographed Nasa's first in-orbit repair to a spacecraft. Despite the light mood, the relief aboard Discovery, and among the space agency's beleaguered engineers, is enormous as a potential danger to the shuttle's safe return to Earth is eliminated.

'We can still do this dangerous business'

The space shuttle Discovery touches down safely at the Edwards air force base in California. Photograph: Nasa TV/AP

It wasn't quite the homecoming Nasa had in mind for the shuttle Discovery and its seven astronauts, but after the troubles they've had during the 14-day adventure, the space agency is just happy to have it back on the ground safely, writes Richard Luscombe in Cape Canaveral, Florida.

Florida's notoriously unreliable weather, low clouds and rain, forced four landing attempts at the Kennedy Space Centre to be scrubbed so Nasa sent it instead to a remote air force base in California's Mojave desert, where it touched at 5.12am (1.12pm BST), 53 minutes before sunrise. It's a disappointment for commander Eileen Collins and her crew, who won't now be reunited with their families for another day, and also for Nasa itself, which will have to shell out the best part of a million dollars to fly Discovery back to Florida on the back of a jumbo jet.

Even so, mission managers will still be celebrating tonight over the successful completion of America's first manned spaceflight since the Columbia disaster in February 2003. Highlights were astronaut Steve Robinson's audacious spacewalk to perform the first external repairs to a spacecraft in orbit and the most detailed imagery ever obtained of a shuttle in flight from a sensor on its robotic arm. Lead flight director Paul Hill said it proved "we can still do this dangerous business".

As for the space shuttle's future, Nasa's task now is to fix the falling foam problem that has plagued the last two missions and which led to the fleet being grounded again. The agency says it's a short term glitch and remains hopeful a fix can be found in time for the shuttle Atlantis to take off in September as planned. But there are plenty of independent experts who say it will be next year before Nasa will be ready to fly again. The shuttle, due for retirement in 2010, is crucial to the completion of the International Space Station. The clock is ticking.

'It's a little scary', says Hillary

An iceberg melts in Kulusuk, Greenland. Photograph: John McConnico/AP

There was some rare good news today for those of us who are terrified at what you might describe as humankind's decision to destroy itself by failing to heed the warnings about global warming.

Two of the leading contenders to contest the 2008 presidential elections in the US, Hillary Clinton and John McCain, have been on a climate change fact-finding mission to Alaska and Canada's Yukon territory.

The struggle for public opinion

A declaration today by more than 700 scientists who support animal experimentation appears to be taking on animal rights extremists, writes David Fickling.

But a closer look at the statement - and a similar declaration made exactly 15 years ago - makes it seem as though pro-experimentation body the Research Defence Society is running scared of its opponents.

A good bite of the sun'

The eclipse of the sun by the
moon as seen from Minsk, Belarus.
Photograph: Maxim Malinovsky/EPA
Anyone looking out of their window in London at 10:01am this morning may have wondered why the sky was a bit darker than usual. Well, it was because at precisely that moment, 57% of the sun was obscured by the moon, writes Kearan Ramful.

An annular solar eclipse took place today - the moon appeared to sweep across the face of the sun, casting a shadow over a swath of Europe, Africa, Asia and the Middle East. Unlike a total eclipse, when the moon is at its closest to Earth, an annular eclipse occurs when the moon is near its apogee, its furthest point away from our planet.

Over London, the phenomenon took place from 8.48am to 11.18am. Astronomers gathered to observe it in Hyde Park, but cloud cover meant most people witnessed only a murky gloom. Those in Aberdeen fared better, seeing a 44% eclipse, and in Plymouth 64% of the sun was covered.

The best views were to be had on the Iberian peninsula, where the skies were clear and the eclipse moved through its annular stage, virtually blotting out the sun, and observers in Madrid were amongst the first to see the phenomenon. Spanish bloggers have been following it online, noticing that the moon took a "good bite" of the sun.

Britain last saw a solar eclipse - a total one - in August 1999. The next one will be in March 2006.

Complementary and controversial

Many people swear by herbal remedies, writes Sarah Boseley. They are passionately grateful to their acupuncturist, and the osteopath is spoken of in reverent tones.

There is no doubt that a huge number of people think complementary medicines work. It's very likely that they do work - for them. It does not follow that the NHS should be adopting them wholesale.

This is a hugely touchy area. Christopher Smallwood, the economist and former SDP policy director asked by the Prince of Wales to take an independent lookat what complementary medicines could do in the context of the NHS, has produced a report that attempts to be calm and rational, but still has an aftertaste of capture by the complementary medicines lobby.

It's Tooting, Jim, but not as we know it

The snootier variety of north Londoner has a well known penchant for making disparaging remarks about not daring to go "south of the river".

The idea among these snobs is that south London lacks some of the sophistication of the north of the capital, which they contend is a paradise of ciabattas and cappuccinos.

So, news today that a scientist has named a desolate crater on Mars after Tooting, south London, may not do a lot to lessen the prejudice of the south-bashers.

Just a second

On time. Photograph: Sergio Dionisio/APLondoners who are familiar with the "Underground minute", or the phenomenon of time actually slowing down as a train approaches a tube station, will have no trouble grasping the concept of the "leap second". Briefly, 2006 will arrive a second later on Sunday because the earth is not keeping up with our system of timekeeping.

The friction of the tides means that the rate at which the world is spinning on its axis is slowing. Days are now about two milliseconds longer than they were at the beginning of the nineteenth century. So the International Earth Rotation and Reference Systems Service occasionally deploys a leap second in order to regulate "sun time" with "clock time".

Before considering exactly how to use that extra second - and bear in mind it represents only 1/3,600th of the "extra" hour we enjoy every year when the clocks go back - you might like to ponder what exactly a second is.

Bird flu: should we start worrying?

How alarmed should we be that scientists analysing Turkish bird flu samples have found evidence that the virus has mutated? Could this be the mutation that we've feared could lead to the virus spreading from people-to-people and triggering a flu pandemic?

How did it all start?

A group of eminent scientists are spending two days discussing the origins of life on Earth. The Guardian's science correspondent, James Randerson, joined them.

The first morning of a two-day meeting at the Royal Society on the origins of life on Earth was dominated by the search for it on Mars. Studying the red planet is useful because it shares some characteristics with the early Earth and so might give scientists clues about what happened here.

So what does Martian life have going for it? Water for starters, the scientists say. The dry channels and flood plains seen by Nasa's unmanned Viking missions in the 70s confirmed that the apparently parched surface of Mars must once have been abundant in water.

The meme-ing of life

The American Academy of Forensic Science's annual meeting is under way in Seattle, writes James Randerson. It is a truly huge get-together of everyone who is anyone in forensics - nearly 4,000 scientists from all over the world and more than 500 talks and events.

The meeting is themed around "Mass disasters: natural and man made", but there will be plenty else on offer, from drug crime and identity theft to a session titled "Is your daughter trolling for paedophiles on the internet?" and the bizarre-sounding "Tom Krauss memorial bite mark breakfast".

I'll be keeping you posted with regular updates, but first, something much more trivial. Toilet paper. Stay with me on this - there is a point, I promise.

Evil, depravity and beetle poop: a case report

I have come to the conclusion that many of the scientists, lawyers and law enforcement officers at the annual meeting of the American Academy of the Forensic Sciences are severely damaged people, writes James Randerson. Years of contact with the most depraved, gruesome, sickening and evil of human acts have, I think, changed them in frightening ways.

Forensics and families: lessons from Lockerbie

A single image often becomes newspaper shorthand for a tragedy. Think of the blasted 7/7 bus or the ragged facade of the Grand Hotel in Brighton after the IRA bombing, writes James Randerson.

When Pan Am flight 103 was destroyed on December 21 1988, it was the image of the aircraft's cockpit ploughed into the ground that would forever say "Lockerbie bomb". But that image was a source of great pain to the wife of one of the victims.

"For 12 years she had suffered, thinking that the body in the photo under a sheet was her husband," Kathryn Turman, director of the office of victim assistance at the FBI, told the American Academy of Forensic Science (AAFS) conference in Seattle yesterday.

Ms Turman was in charge of liaising with the families of the victims and passing on information as the forensic effort unfolded. She is still in contact with some of them now. In the Lockerbie widow's case, Ms Turman was able to put her mind at rest by telling her the body in the photo was actually one of the cabin crew.

Pi-eyed

A calculator, as not used by planet-brain mathematicians working out pi to billions of decimal points

Today is pi day, a celebration of one of the most-used yet bizarrest numbers in all of mathematics, writes Alok Jha.

Pi (which begins 3.14, hence the celebration today) represents the ratio of a circle's circumference to its diameter. It goes on forever, and there are no patterns in the order of the digits. Little wonder mathematicians call it an irrational number. It has its uses in countless physics equations, endless mathematical formulae and near-infinite engineering problems.

Before this starts sounding like a maths lesson, we should point out that the number is rooted in plenty of popular culture. Kate Bush sang the first 137 digits in a song, titled π, on her recent album, Aerial (although some people accuse her of getting the numbers wrong); Carl Sagan wrote about the possibility of findig a fingerprint of God in a version of pi; and Professor Frink (of The Simpsons fame) shouts "pi is exactly 3" to get the attention of a bunch of scientists.

Scribblings at the birth of science

The Robert Hooke folio. Photograph: Bonhams / PA


As the streaming sun sparkled off Rolexes and pocket watches, the auctioneer strode on to the lectern like a public school headmaster about to take assembly, writes science correspondent James Randerson. "Settle down now, boys. First, congratulations to Bradbys for their victory in the inter-house rugby tournament ... "

Even with 189 lots to go before the big draw, the tension in the auction room is almost unbearable. "This thing is of huge historical significance - of national significance," I overhear a man behind me whisper.

The sale everyone is waiting for is described by Bonhams auctioneers, in Mayfair, as a manuscript "that marks the beginning of the modern world". And it has a price tag to match - £1m to £1.5m.

"Few memorials of the scientific revolution can have greater resonance. The Hooke folio - lost for some 300 years - is a remarkable survival from the heroic age of science," says the sale catalogue. The documents are notes taken by the brilliant scientist Robert Hooke in the early days of the Royal Society, the UK's premier scientific academy.