# Can some metals reflect... **URL:** \ **Category:** Factual Questions\ **Created:** [May 21, 2010, 11:18pm UTC](https://boards.straightdope.com/t/can-some-metals-reflect/540316 "2010-05-21T23:18:06Z")\ **Posts on this page:** 7\ **Page:** 1
**Author:** ![vanadium-i-ching](https://avatars.discourse-cdn.com/v4/letter/v/ea5d25/32.png) [@vanadium-i-ching](https://boards.straightdope.com/u/vanadium-i-ching)\ **Post date:** [May 21, 2010, 11:18pm UTC](https://boards.straightdope.com/t/can-some-metals-reflect/540316/1 "2010-05-21T23:18:06Z")
…radiation from the entire electromagnetic spectrum? Or rather, anything with sufficient energy to excite the electrons, i.e. visible light and beyond? ---
**Author:** ![beowulff](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/beowulff/32/542_2.png) [@beowulff](https://boards.straightdope.com/u/beowulff)\ **Post date:** [May 21, 2010, 11:25pm UTC](https://boards.straightdope.com/t/can-some-metals-reflect/540316/2 "2010-05-21T23:25:09Z")
What, like X-Rays? No, unless you are talking reflection at very slight incident angles. This is one of the reasons that X-Ray lasers aren’t practical at this time. ---
**Author:** ![Chronos](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/chronos/32/134_2.png) [@Chronos](https://boards.straightdope.com/u/Chronos)\ **Post date:** [May 21, 2010, 11:27pm UTC](https://boards.straightdope.com/t/can-some-metals-reflect/540316/3 "2010-05-21T23:27:31Z")
It’s extremely difficult to reflect x-rays; the only way they can do it in x-ray telescopes is to have the mirrors at a grazing angle (about a degree) to the incoming rays. And even that doesn’t work for gamma rays, for which you can’t really produce optics at all. ---
**Author:** ![Lumpy](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/lumpy/32/446_2.png) [@Lumpy](https://boards.straightdope.com/u/Lumpy)\ **Post date:** [May 22, 2010, 2:59am UTC](https://boards.straightdope.com/t/can-some-metals-reflect/540316/4 "2010-05-22T02:59:14Z")
Above a certain energy level, the way photons interact with matter changes. Visible light and most of what we call ultraviolet can temporarily raise the energy level of an electron’s binding state to an atom, and then be reemitted again. Beyond the energy level of where a photon ionizes an atom, knocking an electron away altogether, the rules change. ---
**Author:** ![njtt](https://avatars.discourse-cdn.com/v4/letter/n/ecd19e/32.png) [@njtt](https://boards.straightdope.com/u/njtt)\ **Post date:** [May 22, 2010, 4:13am UTC](https://boards.straightdope.com/t/can-some-metals-reflect/540316/5 "2010-05-22T04:13:01Z")
> [@beowulff](#): > > What, like X-Rays? > No, unless you are talking reflection at very slight incident angles. > This is one of the reasons that X-Ray lasers aren’t practical at this time. 😕[X-Ray laser](http://en.wikipedia.org/wiki/X-ray_laser) ---
**Author:** ![beowulff](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/beowulff/32/542_2.png) [@beowulff](https://boards.straightdope.com/u/beowulff)\ **Post date:** [May 22, 2010, 4:22am UTC](https://boards.straightdope.com/t/can-some-metals-reflect/540316/6 "2010-05-22T04:22:25Z")
> [@njtt](#): > > 😕[X-Ray laser](http://en.wikipedia.org/wiki/X-ray_laser) I didn’t say that they didn’t _exist_ - I said they weren’t practical. > [@](#): > > Most of today’s X-ray lasers require so much power that they rely on fusion laser facilities the size of football stadiums or larger, making their use impractical. From [here](http://blog.taragana.com/science/2010/02/22/ultra-fast-tabletop-x-ray-laser-may-be-used-for-high-resolution-imaging-6889/). ---
**Author:** ![vanadium-i-ching](https://avatars.discourse-cdn.com/v4/letter/v/ea5d25/32.png) [@vanadium-i-ching](https://boards.straightdope.com/u/vanadium-i-ching)\ **Post date:** [May 22, 2010, 10:49pm UTC](https://boards.straightdope.com/t/can-some-metals-reflect/540316/7 "2010-05-22T22:49:40Z")
> [@Lumpy](#): > > Beyond the energy level of where a photon ionizes an atom, knocking an electron away altogether, the rules change. What happens then?