Path: csiph.com!news.mixmin.net!newsreader4.netcologne.de!news.netcologne.de!newsfeed0.kamp.net!newsfeed.kamp.net!fu-berlin.de!uni-berlin.de!individual.net!not-for-mail From: Sylvia Else Newsgroups: sci.physics Subject: Re: Eight things you might not know about light Date: Fri, 22 Apr 2016 11:50:28 +1000 Lines: 32 Message-ID: References: <5717c080$0$27711$c3e8da3$fdf4f6af@news.astraweb.com> Mime-Version: 1.0 Content-Type: text/plain; charset=utf-8; format=flowed Content-Transfer-Encoding: 8bit X-Trace: individual.net ZP8GUwbz19hGIPHflkehEQ3FJ0LQe+PRHbT105Za1VsfZ7Fld0 Cancel-Lock: sha1:tz+lTTxYMGovpz05FXE0iKDdx7s= User-Agent: Mozilla/5.0 (Windows NT 6.1; rv:38.0) Gecko/20100101 Thunderbird/38.3.0 In-Reply-To: <5717c080$0$27711$c3e8da3$fdf4f6af@news.astraweb.com> Xref: csiph.com sci.physics:572267 On 21/04/2016 3:46 AM, benj wrote: > On 04/20/2016 12:09 PM, Sam Wormley wrote: >> On 4/19/16 9:07 PM, Sylvia Else wrote: >>> On 20/04/2016 2:21 AM, Sam Wormley wrote: >>> >>>>> 2. Most types of light are invisible to our eyes. >>> >>> That's a rather loose definition of the word "light". Indeed, can light >>> be even divided into types, other than arbitrarily? >>> >>>>> 8. You can collide photons to make particles. >>> >>> What particles can you make by colliding the photons emitted by a VHF >>> radio antenna? >>> >>> Sylvia. >>> >> >> X-ray have enough energy, E = hν = hc/λ , to create electron-positron >> pairs. Gamma, more massive particles. >> > Sam, sam, Sammy! Pairs are NOT made by colliding photons! They are > created from a single photon. Won't you ever learn not to try to post > science here? Journalists know no science. Why do you keep C&P their > screed? A single photon cannot convert into particles (being particles that do not move at the speed of light), because it's impossible for both energy and momentum to be conserved. Sylvia.