Bitcoin soared to fresh records Tuesday, putting it on course for $10,000, but the virtual currency's stratospheric rise has fuelled fears of a bubble after a 10-fold increase this year. 

The cryptocurrency, launched in 2009 as a bit of encrypted software written by someone using the Japanese-sounding name Satoshi Nakamoto, has had a roller-coaster ride that has taken it from just a few US cents to its current sky-high valuation.

Traded on specialist platform, with no legal exchange rate and no central bank backing it, Bitcoin is monitored and regulated by its community of users, and is used to buy everything from pizza to a pint in a London pub.

But it has attracted widespread criticism, from financial industry titans to governments.