# Hawking radiation **URL:** \ **Category:** Factual Questions\ **Created:** [March 15, 2010, 5:30pm UTC](https://boards.straightdope.com/t/hawking-radiation/532560 "2010-03-15T17:30:46Z")\ **Posts on this page:** 3\ **Page:** 3
**Author:** ![Rysdad](https://avatars.discourse-cdn.com/v4/letter/r/7cd45c/32.png) [@Rysdad](https://boards.straightdope.com/u/Rysdad)\ **Post date:** [March 23, 2010, 12:56am UTC](https://boards.straightdope.com/t/hawking-radiation/532560/41 "2010-03-23T00:56:12Z")
Kind of a follow-on question… When a pair of virtual particles are created, how far apart are they (inches, centimeters, cubits, whatever), or do they just appear from a single point traveling in opposite directions (or something)? ---
**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:** [March 23, 2010, 4:39am UTC](https://boards.straightdope.com/t/hawking-radiation/532560/42 "2010-03-23T04:39:09Z")
That’s not really an answerable question, since particles don’t have well-defined positions to begin with. But to the extent that there’s any relevant length scale, it’d be the Compton wavelength, which for an electron is [in the vicinity of 10[sup]-12[/sup] meters](http://www.google.com/#hl=en&source=hp&q=hbar%2F%28%28electron+mass%29*c%29&aq=f&aqi=h1&aql=&oq=&gs_rfai=&fp=1dc62da33e2ff469). ---
**Author:** ![ZenBeam](https://avatars.discourse-cdn.com/v4/letter/z/3ab097/32.png) [@ZenBeam](https://boards.straightdope.com/u/ZenBeam)\ **Post date:** [March 23, 2010, 4:23pm UTC](https://boards.straightdope.com/t/hawking-radiation/532560/43 "2010-03-23T16:23:48Z")
Could there be a spread in separation? In pair production, lower energy pairs are formed more than higher energy pairs, so lower frequency photons are formed more than higher frequency photons, and for electron-positron pairs, relatively slow-moving pairs are more likely than pairs with high velocity. Is there a similar spread in position, with pair production more likely for pairs with a small separation as compared with pairs formed farther apart? [Previous page](https://boards.straightdope.com/t/hawking-radiation/532560.md?page=2)