Maurizio – Omnologos

Where no subject is left unturned

Our Past Is In The Sky

with one comment

Far-fetched as it might seem (and be!), we might be literally surrounded by information about the Earth’s, Sun’s, Galaxy’s past. By looking in the right direction with the right instruments, we could even be able to see how things were at different times, even billions of years ago.

By looking where? This idea is based on a little-known characteristics of black holes, namely the large amount of incoming light that is back-scattered, i.e. sent back more or less in the direction it came from. This phenomenon is visible as a halo around the black hole (see picture to the left).

Think then: by looking at a black hole 20 million light years away, we will be getting some light first emitted by our galaxy 40 million years ago, as the photons will have had to travel to the black hole and back. Correcting for the optical properties of the region around the black hole that we see as a halo, we would even be able to get a picture of our galactic surroundings.

Analogously for black holes nearer to us, eg 20,000 light years away, the halo will literally contain pictures of our neighborhood as of 40,000 years ago.

All of the above is unlikely to be easy, still any information in the back-scattered photons will be extremely valuable.

Written by omnologos

2010/Dec/08 at 15:32:23

One Response

Subscribe to comments with RSS.

  1. Wow, a photo of a black hole!
    Or … “Artists impression”?
    I love the way NASA talks about black holes as if they had actually seen one. 🙂

    tallbloke

    2012/Jan/06 at 11:22:19


Leave a Reply

Fill in your details below or click an icon to log in:

WordPress.com Logo

You are commenting using your WordPress.com account. Log Out / Change )

Twitter picture

You are commenting using your Twitter account. Log Out / Change )

Facebook photo

You are commenting using your Facebook account. Log Out / Change )

Google+ photo

You are commenting using your Google+ account. Log Out / Change )

Connecting to %s

%d bloggers like this: