And the Hello,

welcome to the Naked Scientists with me Chris Smith and also with Dave and Soher Dave. Hello and this week scientists discover a planet wandering through space all on its own

but where did it come from? We take a look at this year's Nobel Prizes and we dig deep

to explain the engineering behind tunneling.

How did early engineers first dig under the Thames?

How did they indeed?

And another question, person this week, our scientific teaser.

Can you tell us what's 50 kilometers long?

In fact, the longest of its type in the world

first used in 1994 took six years to build

and cost nearly 5 billion pounds?

If you know the answer, or you would like to get in touch for any

other reason with the program you can email Chris at the naked scientist.com you can

tweet at naked scientist or you can find us via our Facebook page.

The Naked Scientists Podcast is powered by UKfast.co.uk.

First let's take a look at what's been making the science headlines this week.

Chris what have you got for us?

Well Dave a very interesting study which was published this week looks at the subject of multiple sclerosis.

Multiple sclerosis is one of the most common degenerative diseases of the nervous system.

It's where the immune system attacks something called the myelin sheath, which is almost like the electrical insulation you see around wires, which are around nerve cells in the brain.

We don't know why this happens, but the immune system, for some reason moves into certain parts of the nervous system, destroys the myelin in there, and as a result, nerve fibers short out, they also don't conduct information properly and this can have

deleterious effects on people's vision, on their sensation and also on their motor

...