Awesome giant anvil-shaped cloud photographed by Space Station

A giant, anvil-shaped cloud bubbles up towards the Earth's stratosphere, looming over West Africa.

The amazing formation would be invisible to anyone on the ground and would even be obscure from a regular passenger jet since they can reach up to 75,000ft.

But astronauts captured the astonishing picture from hundreds of miles up as they orbited the globe on the International Space Station.

Anvil clouds are formed mostly from ice and normally form in the upper parts of thunderstorms. They get their shape from the fact that rising warm air in thunderstorms expands and spreads out as the air bumps up against the bottom of the stratosphere.

Streaks of snow are often seen falling out of the edges of anvils. This light snow usually evaporates as it falls through the relatively dry air surrounding the upper part of the thunderstorm.


Images released today showed Tom Marshburn and Christopher Cassidy doing final maintenance work on the exterior of the complex ahead of their departure today.

The four-hour and 54-minute procedure involved rewiring, camera setup, tidying cables and installing handrails and a portable foot restraint to aid future spacewalkers.

The five spacewalks together spanned a total of 30 hours.

The team from the visiting Endeavour shuttle fitted Japan's new outdoor experiments platform with television cameras, completing the final task for the £1.45 billion Kibo complex.

'Congratulations, you guys just completed the ... assembly,' Mission Control radioed once the second camera was secured.

'I can verify from up close it is, indeed, a beautiful laboratory.'

Space shuttle Endeavour's astronauts are inspecting their ship to make sure it's safe for Friday's landing.

The survey of the wings and nose, being conducted Wednesday morning, is standard before a shuttle returns to Earth.

Nasa wants to make sure Endeavour's heat shield was not pierced by micrometeorites or space junk during its two weeks in orbit. The astronauts used a laser-tipped boom to check for damage.

Endeavour and its crew of seven left the international space station Tuesday.

As the inspection was under way, an unmanned Russian vessel carrying several-thousand pounds of supplies docked at the station. Commander Gennady Padalka had to manually guide the craft in because of a problem with its automatic system.

Awesome Aurora Seen from Space

Why beaming messages to aliens in space could destroy our planet

Thanks to the foolish antics of a downmarket TV company and a website favoured by self-obsessed teenagers, planet Earth could be in for a nasty shock towards the end of this century.

For if, in the decades to come, a fleet of flying saucers arrives with malicious intent, they will be the culprits.

This week it was announced that documentary-maker RDF and Bebo, a 'social networking site' for dippy youngsters, are to use a big radio telescope in Ukraine to send a powerful focused beam of information - 500 messages from the public in the form of radiowaves - to a nearby star called Gliese 581.

A 'mere' 20 light years (120 trillion miles) away, Gliese not only lies in our cosmic backyard but astronomers think it is also home to one or possibly two Earth-like planets which could be home to life.

The Gliese 581 solar system is, in other words, probably the likeliest home for our cosmic next-door neighbours.

Surely this is a harmless piece of nonsense? What danger could there possibly be from sending a big 'Hello' from Earth to a nearby star system?

After all, aliens are probably just a myth and if they are out there they will come in peace. That's the idea anyway.

Let's get one thing straight: I am not part of the UFO brigade. I have seen no convincing evidence whatsoever that aliens have yet visited the Earth in person.

I know The X Files is a work of fiction, not a documentary, and I accept that those who claim to have seen flying saucers and even to have been abducted by strange little aliens are either sincerely mistaken, mendacious or mad.

I have no truck with crop circle mystics and those who believe the pyramids were built by little green men from the Planet Tharg.

We have been looking for alien life for several decades now, sending probes to Mars and Venus, and listening out for radio messages from the stars.

And, so far, we have found nothing. Not even a microbe.

And yet, I also accept that absence of evidence is not evidence of absence. We have been looking for extraterrestrials for only a very short time.

We have really considered the possibility of their existence for a few centuries at most - a tiny proportion of the time that we humans have been around.

Most of all, I accept that although we have not found aliens yet, the statistical probability that there are intelligent lifeforms somewhere out there must be very high.

There are, after all, a hundred thousand million stars in our galaxy - and more than a hundred billion galaxies besides.

Astronomers now think that most of these stars - more stars than there are grains of sand on all the beaches of Earth - have retinues of planets around them.

So far, they have discovered only about 250 of these potentially life-bearing worlds or 'exoplanets' but there are many hundreds of thousands of millions more out there.

Not all of them will be habitable, but many millions will probably be 'Goldilocks worlds' - not too cold, not too hot, not too big and not too small, but just right, in theory, for life to have evolved.

Indeed at least one of the planets orbiting Gliese 581 is maybe such a Goldilocks world.

And even if we accept that life will not evolve everywhere it can, we must also accept that on the one world we know life has emerged - our own - it did so with startling rapidity.


Life on Earth is very nearly as old as Earth itself, and this suggests that if conditions are right then biology of some form will come into being.

Of course 'life' is not the same as 'intelligent life'. The galaxy could be swarming with microbes and algae, shrubs and lichen, even rabbits, lizards and fish (or their alien equivalents).

Discovering that this is so would be interesting and marvellous, but it would not be the same as discovering fellow intelligent beings out there.

And even intelligent life does not mean 'spacefaring life'; it took us thousands of years to get from the invention of the wheel to the first space rockets and radio telescopes.

But the sheer size and age of our galaxy suggests that at least some other worlds should be inhabited by creatures at least as bright as us - creatures able to build radio telescopes and pick up messages and think about doing something about it when they do.

And herein lies the problem. One of the most plausible reasons that we have seen of no signs of aliens may be simply that they haven't found us yet.



Which brings us to the fact that the most likely means of our discovery by alien life is by sending radio waves announcing our presence through space.

Indeed, there are those who point out that radio and TV signals from Planet Earth have been leaking inadvertently into space since the dawn of the radio age 86 years ago.

Surely intelligent alien lifeforms - if they are out there - would have detected these Earthly signals by now, they argue.

After all, the signals travel on through space at the speed of light, so all star systems closer than about 80 light years away could, in theory, have picked up hints of our transmissions by now.

But in reality, picking up these signals will be hard, even for the most advanced civilisation.

Weak and undirected, ordinary television and radio transmissions become almost undetectable at cosmic distances. Yet powerful, focused signals such as the one to be sent by RDF/Bebo are different - they are far easier to detect.

So far, just a handful of such signals have been sent, the first message fired out by the Arecibo radio telescope in 1974. And these have generated immense controversy.

Some scientists, notably the physicist and writer David Brin, have pointed out the danger of shouting 'we are here' to a potentially hostile cosmos.

The fact is that if a civilisation even a few centuries in advance of ours (in technological terms) were to get wind of our existence then the results could be catastrophic.

For what if Gliese is home to a belligerent lifeform with infinitely superior technology to ours? After all, the history of Earth tells us that when advanced civilisations meet technologically backward ones, the results have been, almost without exception, disastrous for the people with bows and arrows.

If we are unlucky, the inhabitants of Gliese could send an invasion fleet. Since they are 20 light years away, the signal will not reach them until 2028 and it will be some decades after that before the fleet arrives here.

It is important to remember that any aliens capable of flying across the great voids between the stars will be in possession of technology so advanced that fighting them would be like taking on a modern army with spears.

We would have no chance. So the best thing may be to keep shtum.

Or to hope that the inevitable self-obsessed triviality that is bound to comprise any message sent by the Bebo community will be enough to convince any purple-tentacled aliens who are on Gliese 581 that there is no intelligent life on Earth whatsoever - and to leave us well alone.

Bizarre ball of twisted metal space junk falls from the sky into farmer's backyard

It might not be much to look at, but this ball of twisted metal has been all the way into space - and back again.

James Stirton, who found it in his backyard, was initially mystified by the object's appearance. The 20kg heap of tangled carbon fibre and steel stuck out like a sore thumb from the dry scrubland of his cattle farm in Queensland, Australia.

"I was just riding along on my bike and it was beside the road, beside a track out in the paddock," Mr Stirton said.

"I just wondered what it was so I went over and had a look at it and I figured it must have fallen from the sky because there's no tracks or traffic or anything out here."

He added: "I know a lot about sheep and cattle but I don't know much about satellites. But I would say it is a fuel cell off some stage of a rocket."

Brisbane Planetarium curator Mark Rigby was asked to examine the object, which landed in the small town of Cheepie, west of Charleville in November last year.

He said there was "no doubt" it was a helium or nitrogen tank from a rocket, probably one that had been used to blast a U.S. solar satellite into space more than 18 months ago.

"I looked at what had been coming down around that time and orbits and things like that and managed to narrow the time frame based on when the farmer found it," he told the Sydney Morning Herald.

"This particular object was predicted for re-entry (into the Earth's atmosphere) at 11.47am Australian Eastern Standard time on November 1, 2007, which would have put it near Indonesia.

"I don't know why, but I think it has just sort of limped on a bit and ended up in Charleville."

After checking space flight records, Mr Rigby said the rocket had likely been launched from Cape Canaveral in Florida on October 26, 2006.

It was used to send up one of two Stereo satellites into orbit to study the sun.

Helium or nitrogen tanks are used to pressurise the rocket's fuel systems and also to manoeuvre the spacecraft.

Mr Rigby said falling space junk was not as uncommon as people might think.

Nasa scientists estimated last year that more than 9,000 pieces of space debris are orbiting the Earth - and the hazard will only get worse in the next few years.

Much of the debris results from explosions of satellites, especially old upper stages left in orbit with leftover fuel and high-pressure fluids inside.

"There is about 5,000 tons' worth of operational and non-operational satellites and space junk in orbit at any one time," Mr Rigby added.

"There are things like this re-entering the Earth's atmosphere every week. The predictions can be quite uncertain about where it is going to come down."

Indeed, the remote area where Mr Stirton lives, around 500miles (800km) west of the northern Queensland state capital of Brisbane, is something of a magnet for so-called "space junk".

In 1979, large parts of the Skylab space station famously fell to earth near a tiny outback town in the west of Australia.

The local council sent Nasa a ticket for littering and the U.S. President at the time, Jimmy Carter, rang a local motel to apologise.