Nobel season for the year 2011 opens today with the announcement in Stockholm of the Medicine Prize, to be followed over the course of a week by the awards for physics, chemistry, literature, economics and peace.
The Medicine Prize is scheduled to be announced at 11:30 am (0930 GMT) at the earliest.
The winner of the Nobel Peace Prize, perhaps the most watched of the prestigious awards, will be revealed Friday in Oslo, and the five-member Norwegian Nobel committee has a record 241 nominees to choose from, the list of which is kept a well-guarded secret.
Nobel watchers say however the nod could this year go to activists involved in the Arab Spring uprising, which led to the overthrow of autocratic regimes in Tunisia, Egypt and Libya and rattled the ones in Syria, Yemen and Bahrain.
If that were the case, among those mentioned as possible winners is Tunisian blogger Lina ben Mhenni, who chronicled her country's revolution on the Internet.
Another possibility is Israa Abdel Fattah of Egypt and the April 6th youth Movement that she co-founded with Ahmed Maher in 2008.
The movement, which began on Facebook, "played a key role in maintaining the direction and non-violent character of the uprisings in Egypt," Kristian Berg Harpviken, the head of the Peace Research Institute of Oslo, told AFP.
He also mentioned Google executive Wael Ghonim, "a principled non-violence activist" who was a central inspiration to the protests in Cairo's Tahrir Square.
Other names circulating are Afghan human rights activist Sima Samar, Russian human rights organisation Memorial, Liberian activist Leymah Gbowee, Zimbabwean Prime Minister Morgan Tsvangirai, Germany's ex-chanceller Helmut Kohl and the European Union.
Last year the prize went to jailed Chinese dissident Liu Xiaobo.
For the other closely-watched prize, that for literature which last year went to Peruvian-Spanish author Mario Vargas Llosa, literary circles suggest the situation in the Middle East could also play a role in the Swedish Academy's choice, with Syrian poet Adonis tipped as a favourite.
In June, Adonis, whose real name is Ali Ahmed Said and who lives in France, published an open letter to Syrian President Bashar al-Assad in a Lebanese newspaper urging him to end the bloody repression.
Online betting site Ladbrokes tipped Adonis as the favourite on September 30, just ahead of Swedish poet Tomas Transtroemer.
Kenya's Ngugi wa Thiong'o, Somalia's Nuruddin Farah, Hungary's Peter Nadas, Korean poet Ko Un, Japan's Haruki Murakami, India's Vijaydan Detha and Australia's Les Murray also figure among the favourites for this year's Literature prize, which will most probably be announced on October 6 but could come any Thursday in October.
The field is meanwhile seen as wide open for the prizes for Medicine, Physics and Chemistry, to be announced on October 3, 4 and 5, although they have in the post-war period been dominated by American researchers.
The Economics prize, which will wrap up the season on October 10, is meanwhile not expected to be heavily coloured by the debt crises currently raging in Europe and the United States.
Nobel laureates receive 10 million Swedish kronor ($1.48 million, 1.08 million euros) which can be split between up to three winners per prize.
The prizes will be handed out at formal ceremonies in Oslo and Stockholm on December 10, the anniversary of prize founder Alfred Nobel's death in 1896.