An optical telescope with no primary lens or mirror proposed.

[Ian Robinson]

http://space.newscientist.com/article/dn13820-telescope-could-focus-light-without-a-mirror-or-lens.html?DCMP=ILC-hmts&nsref=specrt14_head_Lens-free%20telescope


Light passing through a pattern of holes in a metal foil is focused to form an image (Illustration: E Hinglais et al/CNES/OMP)

http://space.newscientist.com/data/images/ns/cms/dn13820/dn13820-2_250.jpg
The Fresnel imager would consist of two spacecraft, one holding the foil sheet, and the other holding the camera and other instruments at the focus a few kilometres away (Illustration: L Koechlin et al/OMP)

[renormalised]

Very interesting proposal....I hope it gets the go ahead at some stage.

[tbentley]

I'm always interested when scientists talk about looking for conditions necessary for life on other planets. It always seems to be based on the notion that any life must be similar to that that exists here on earth.
Things like water and oxygen are often used as signals that life could exist. I've always wondered whether it's not possible that we're the freak planet and every other life in the universe doesn't depend on hydrogen gas and mercury or something "weird" like that.
Just because all life on earth is carbon based does that mean that it's the same everywhere else? Is this the ultimate form of racial prejudice? Hello to anyone non-carbon based out there, I'm fighting for your rights brother (or sister or whatever.):hi:

[GrahamL]

yeah thats right in a way travis I guess ..but if you narrow it down a little in that the elements we know of that make up the universe as a whole arn't that complicated ,,and yeah theres no doubt more we don't know of yet .
Increase the sample size a bit and its probably likely that the
combinations of things needed for us to find similar systems that would
support life similar to what we know would be astronomicaly large.

I recall a number ? from a while back and think it was 10 to the something (very large power) :)

[bojan]

Well... Carbon-based molecules can form large and complicated structures.. and so can silicon. But you have to have the medium in which large molecules can "operate" and in carbon-based chemistry this is water. Silicon molecules are not soluble in water in general .. so you must have something else. I think that there are many papers discussing those issues and so far it seems only carbon-based chemistry, at temperatures between 0C and 50-60C can form large and stable compounds that can interact between themselves at acceptable rate.. to form life as we know it.
The future will tell, possibly otherwise.. but right now other chemistries are not likely.