How I built an information time machine

This is an image of the planet Earth.

It looks very much like the Apollo pictures

that are very well-known.

There is something different;

you can click on it,

and if you click on it,

you can zoom in on almost any place on the Earth.

For instancce, this is a bird's-eye view

of the EPFL Compass

In many cases, you can also see

how a building looks from a nearby street.

This is pretty amazing.

But there's something missing in this wonderful tour:

It's time.

i'm not really sure when this picture was taken.

I'm not even sure it was taken

at the same moment as the bird-eye's view.

In my lab, we develop tools

to not only travel in space

but also through time.

The kind of question we're asking is

Is it possible to build something

like Google Maps of the past?

Can I add a slider on top of Google Maps

and just change the year?

Seeing as it was 100 years before

a thousand years before,

is that possible?

Can we construct social networks of the past?

Can i Make a Facebook of the Middle Age?

So, can I build time machines?

You can just say, "No, it's not possible."

Or, maybe, we can think of it from an information point of view.

This is what I call the Information Mushroom.

Vertically, you have the time.

and horizontally, the amount of digital information available.

Obviously, in the last ten years, we have much information.

And obviously the more we go in the past, the less information we have.

If you want to build something like the Google Map of the past,

or Facebook of the past,

we need to enlarge this space,

make it like a rectangle.

How do we do that?

One way is digitization.

There's a lot of material available.

Newspaper, printed books, thousands of printed books

I can digitize all these.

I can extract information from all these.

Of course, the more you go in the past, the less information you have.

So, it might not be enough.

So, I can do what historians do,

I can extrapolate.

This is what we call in computer science, Simulation.