How high is Everest?

In an effort to put an end to generations of controversy, the authorities in Nepal are trying to ascertain the precise height of the world's biggest mountain. The project could take up to two years - and even then it is more than likely that not everyone will agree.

While for well over 100 years Everest has been recognised as the planet's highest point, there are differences of opinion as to the exact dimensions and even over what should actually be measured.

For more than half a century, Nepal has recognised the generally accepted height of 29,028 ft for the mountain they call Sagarmatha - despite the insistence by neighbouring China that what it refers to in Tibetan as Qomolangma (Holy Mother), is actually 29,017 ft. The mountain straddles the border and neither side wishes to back down.

"We have begun the measurement to clear this confusion," Gopal Giri, a spokesman with Nepal's land management ministry. "Now we have the technology and the resources we can measure ourselves. This will be the first time the Nepal government has taken the mountain's height."

The task of measuring the height of the world’s highest mountain was first performed during the days of British rule in the subcontinent by a Bengali mathematician, Radhanath Sikdar, employed in the office of the surveyor general, Sir Andrew Waugh.

At the time the British authorities were conducting the so-called Great Trigonometric Survey and it was believed that Kangchenjunga in Sikkim was the world's highest. But based on data collected from the field, Sikdar concluded in 1854 that another nearby peak, at the time referred to simply as Summit XV, was higher.

For two years, the team reassessed the findings and then, confident of what they had discovered a new giant, announced their news. Several years later, in 1865, Sir Andrew declared that the peak would be known as Mount Everest, in honour of his predecessor, Sir George Everest. Based on the average figure obtained from six separate surveying stations, each 100 miles from the mountain, it was said to have a height of 29,002 ft.

This height remained in accepted use for the best part of a century, including in 1953 when Edmund Hilary and Norgay Tenzing made their way to the summit and safely descended.

The following year, a survey by the Indian authorities suggested a new height for the mountain, of 29,028 ft, based on the average reading for 12 survey stations, located between 30 and 50 miles from Everest. But the availability of new technology in the subsequent years led new teams to question the estimate. In 1992 a joint Chinese and Italian expedition team was the first to use GPS technology and came up with a figure of 29,031 ft.

In 1999, a team led by the late American mountaineer Bradford Washburn spent several years working with GPS devices to make a new calculation. Washburn's climbers were able to reach the summit and use their measuring devices.

Not only did they come up with a new height, 29,035.3 ft, but they said they had also been able to measure the movement of the Everest massif, being pushed by the Eurasian continental shelf. They estimated that the mountain was moving north-east by around a quarter of an inch a year.

There the matter may have ended, but for the wishes of the Chinese to take yet another measurement. In 2005, a team of mountaineers and researchers climbed Everest from the Chinese side and announced a new reading of 29,017 ft. However, they said this only measured the actual rock formation of Everest and not the snow cap on the very top.

Nepali officials complained that during discussions about the border with their much larger neighbour, China insisted on using its own measure. But last year, the two countries agreed that both measurements might be correct.

"Both are correct heights. No measurement is absolute. This is a problem of scientific research," Raja Ram Chhatkuli, director general of Nepal's survey department, said at the time.

Mr Chhatkuli will be overseeing Nepal's own attempt at a precise assessment in which scientists will place three GPS devices on different locations on the mountain from which to obtain data.

If you are a regular reader you may be asking, why the sudden interest in Everest by the Lighthouse Keeper on a blog that has previously made its name largely covering the final two missions of the US Space Shuttle?

Well, the Lighthouse Keeper hasn’t made it any where near the top of this mighty mountain - but this autumn is the tenth anniversary of my first visit to Nepal and a high-level trek through the Everest region.

That was in the days before blogs so, come next month, the Lighthouse Keeper will be putting things right and embarking on the trip all over again - this time from the relative comforts of home.

A kind of day-by-day blog retrospective reliving the journey in words and pictures - from the excitement and heat of Kathmandu to the extreme cold and wilds of the lower reaches of Everest. Stay tuned for a great upcoming adventure!

Pictures from above

As a keen photographer the Lighthouse Keeper is always looking for a new angle or perspective on a familiar subject - but from an earthly vantage point even perched atop of a high crane is no match for the kind of views astronauts have from the orbiting International Space Station.

This night time view of India-Pakistan borderlands was one of a series of night-time shots captured recently by one of the six crew members, who often say that one of their favourite off-duty pastimes is gazing back at Earth as there is "always something spectacular to see".

Clusters of yellow lights on the Indo-Gangetic Plain of northern India and northern Pakistan reveal numerous cities both large and small.

Of the hundreds of clusters, the largest are the metropolitan areas associated with the capital cities of Islamabad, Pakistan, in the foreground and New Delhi, India, at the top. For scale these metropolitan areas are approximately 700 km apart.

The lines of major highways connecting the larger cities also stand out. More subtle but still visible at night are the general outlines of the towering and partly cloud-covered Himalayan ranges immediately to the north (left).

A striking feature of this photograph is the line of lights, with a distinctly more orange hue, snaking across the central part of the image.

It appears to be more continuous and brighter than most highways in the view and is actually the fenced and floodlit border zone between the countries of India and Pakistan. The fence is designed to discourage smuggling and arms trafficking between the two countries.

This image was taken on a digital SLR camera with a 16 mm lens to provide a wide field of view, as the Space Station was tracking towards the southeast across the subcontinent of India.

The distinct, bright zone above the horizon (visible at top) is produced by airglow, a phenomena caused by excitation of atoms and molecules high in the atmosphere (above 80 km altitude) by ultraviolet radiation from the Sun. Part of the ISS and a solar panel array are visible at right.

This photograph below, taken from the Space Station at the end of July 2011, shows the Moon with the limb of Earth near the bottom, transitioning into the orange-coloured troposphere, the lowest and most dense portion of Earth's atmosphere.

The troposphere ends abruptly at the tropopause, which appears in the image as the sharp boundary between the orange and blue-coloured atmosphere. The silvery-blue noctilucent clouds extend far above the Earth's troposphere.

Faith and fragrance

Warm rain poured out of a dark sky on a typically humid evening in Hyderabad, India. But along the Hussainsagar lake it was a cacophony of noise and light, a carnival atmosphere as the climax of the boisterous Hindu Ganesh festival was in full swing.

People had been arriving all day for the traditional ending which involves immersing carefully prepared Ganesh idols in the murky waters of the lake. A series of cranes lined the lakeside, lowering each Ganesh on a platform into the water to be received by holy men.

Trucks and vehicles of all shapes and sizes, decorated with flowers and flags and stacked with families and Ganesh idols began arriving early in the day and continued throughout the evening as people poured into the city to experience the religious fervour.

Ganesh is one of the best-known and most popularly worshipped deities in Hinduism and, although known by many other attributes, Ganesh's elephant head makes for easy and familiar identification.

The Ganesh festival for 2011 - an occasion on which Lord Ganesh, the son of Shiva and Parvati, is believed to bestow his presence on earth for all his devotees - has just ended.

It is the birthday of Lord Ganesha and is observed in the Hindu calendar month of Bhaadrapada, starting on the shukla chaturthi (fourth day of the waxing moon period), typically between 20 August and 15 September.

The Lighthouse Keeper’s own and unexpected eye-witness experience of the Ganesh festival came during a stay several years ago in Hyderabad for a business conference and exhibition, which was hijacked for the day as police closed roads and access across the city.

As it happened the city's Marriott hotel was just across the road from the Hussainsagar lake so, being ‘confined to quarters’ for a day and night was not such a bad option, as the thick of the action was just a ‘stroll’ across the road and offered a great opportunity for photography.

The Ganesh festival is completed only with the immersion of the idols but civic bodies in many Indian cities are becoming increasingly concerned with the ecological issues surrounding the festival and the environmental impact on the bodies of water that are a focus of the ceremony.

This year an estimated 1,300 tonnes of rubbish has already been lifted from the main spots around the Hussainsagar lake as more than 100 vehicles and 2,500 municipal staff were pressed into service during a massive clean-up operation.

Misty mellowness

There seems to be no doubt that the seasons are advancing and arriving earlier each year. And it is becoming a rather peculiar thing.

September is traditionally renowned as the genteel easing from summer into the golden days of autumn, a calm, collected and wonderfully settled time of year when the harvest is finally gathered.

So, here we are in the very first week of the month experiencing fearsome gales and storms associated more with the unpredictability of October. Perhaps there has been some kind of shift in the matrix?

We know from the changing habits of migrating birds and tree records that in recent years spring has been arriving at our shores considerably earlier than in the past - some three or four weeks compared with even 20 years ago.

If spring is around the corner as we’ve barely closed our curtains on the winter calendar surely the other seasons are marching forward apace too.

Even before the UK’s most recent late summer public holiday at the end of August a farmer friend was delighted to tell me during a chat in the local pub that he had already completed the annual harvest - some three to four weeks earlier than normal.

And the very next day, as if to prove a point, a low morning mist hung in the dewy autumnal early morning air. It certainly seemed that the ‘season of mists and mellow fruitfulness’ as portrayed so eloquently by John Keats back in 1820 was well and truly upon us.

The powers that be already preform minor adjustments to our calendar and time-keeping to hold our days and time in check - every four years we have a leap year. Infact, it’s actually more like a ‘leap day’, inserted at the end of February.

So, to combat our rolling seasonal disorder why not introduce a leap month? It could be just the solution governments have been looking for. A cheeky way to ignore the vagaries of encroaching climate change - a kind of turning back the clock.

But would it really be a good alternative to buckling down and getting to grips with excessive power and energy consumption, which might at least slow down the man-made acceleration to climate change in the first place?

Questions, questions. I guess in the end it comes down to a personal level - how which are we all prepared as individuals to change our lifestyles, if at all?

In today’s quick fix society having a ‘leap month’ every now and then might just prove more politically attractive. A solution without solving the actual problem. And instead of ‘climate change’ we could rebrand it ‘season change’.

The only thing then to decide is which month should we skip to bring things back into alignment? We might all have our favourites - which one would you pick?