# Factual Questions **URL:** https://boards.straightdope.com/c/factual-questions/9.md?page=954 [Latest](https://boards.straightdope.com/latest.md) · [Categories](https://boards.straightdope.com/categories.md) · [Tags](https://boards.straightdope.com/tags.md) **Page:** 955 --- ## [What is the "21 foot rule?"](https://boards.straightdope.com/t/what-is-the-21-foot-rule/745119)
**Author:** [@Chihuahua](https://boards.straightdope.com/u/Chihuahua)\ **Replies:** 72\ **Last updated:** [February 11, 2016, 7:32pm UTC](https://boards.straightdope.com/t/what-is-the-21-foot-rule/745119 "2016-02-11T19:32:54Z")
So I read this article http://news.sky.com/story/1633328/scots-police-teach-us-cops-how-to-avoid-gun-use) and there’s a part I don’t understand. This doesn’t really seem to tie in to the rest of the article. If it is … --- ## [Experts: Mac Mini having a hardware or software problem?](https://boards.straightdope.com/t/experts-mac-mini-having-a-hardware-or-software-problem/741319)
**Author:** [@edwardcoast](https://boards.straightdope.com/u/edwardcoast)\ **Replies:** 25\ **Last updated:** [February 11, 2016, 7:19pm UTC](https://boards.straightdope.com/t/experts-mac-mini-having-a-hardware-or-software-problem/741319 "2016-02-11T19:19:38Z")
I have a Mac Mini (late 2012 model). It has an internal SSD and 16 GB of RAM. The entire thing was built by Apple and has never been opened since I bought it. It is running the latest Mac OS. A few months ago, I started… --- ## [Using a lens to get hotter than the source's temperature - true for the Moon?](https://boards.straightdope.com/t/using-a-lens-to-get-hotter-than-the-sources-temperature-true-for-the-moon/745750)
**Author:** [@TroutMan](https://boards.straightdope.com/u/TroutMan)\ **Replies:** 13\ **Last updated:** [February 11, 2016, 7:17pm UTC](https://boards.straightdope.com/t/using-a-lens-to-get-hotter-than-the-sources-temperature-true-for-the-moon/745750 "2016-02-11T19:17:37Z")
This week’s xkcd What If asked if a magnifying glass can be used to start a fire with only moonlight. Randall’s answer is no, the primary reason being that lenses and mirrors can’t make something hotter than the surface … --- ## [Why are people suddenly referring to the "Lunar New Year"?](https://boards.straightdope.com/t/why-are-people-suddenly-referring-to-the-lunar-new-year/745690)
**Author:** [@Jragon](https://boards.straightdope.com/u/Jragon)\ **Replies:** 21\ **Last updated:** [February 11, 2016, 6:24pm UTC](https://boards.straightdope.com/t/why-are-people-suddenly-referring-to-the-lunar-new-year/745690 "2016-02-11T18:24:42Z")
I’m a bit confused, this year it seems like everyone is referring to the “Lunar New Year” happening a couple days ago. I haven’t heard this usage for Chinese New Year before. I can’t say it makes much sense to me since y… --- ## [How many human sperm have ever lived?](https://boards.straightdope.com/t/how-many-human-sperm-have-ever-lived/745771)
**Author:** [@WF\_Tomba](https://boards.straightdope.com/u/WF_Tomba)\ **Replies:** 8\ **Last updated:** [February 11, 2016, 5:47pm UTC](https://boards.straightdope.com/t/how-many-human-sperm-have-ever-lived/745771 "2016-02-11T17:47:37Z")
I was trying to figure out how many human spermatozoa have ever lived. Estimates for the number of humans who have ever lived vary, but I’ve seen numbers around 100 billion. We can assume that about half of these humans… --- ## [Salt therapy?](https://boards.straightdope.com/t/salt-therapy/745720)
**Author:** [@Anny\_Middon](https://boards.straightdope.com/u/Anny_Middon)\ **Replies:** 9\ **Last updated:** [February 11, 2016, 5:39pm UTC](https://boards.straightdope.com/t/salt-therapy/745720 "2016-02-11T17:39:30Z")
My cousin gave me a salt crystal lamp for Christmas. A friend gave me a trip to a salt cave for Christmas. We’re going next week. All of a sudden salt therapy seems to be the trendy thing. Supposedly breathing in dry… --- ## [Is there a word to mean, e.g., "divisible by three"?](https://boards.straightdope.com/t/is-there-a-word-to-mean-e-g-divisible-by-three/486581)
**Author:** [@foolsguinea](https://boards.straightdope.com/u/foolsguinea)\ **Replies:** 48\ **Last updated:** [February 11, 2016, 5:34pm UTC](https://boards.straightdope.com/t/is-there-a-word-to-mean-e-g-divisible-by-three/486581 "2016-02-11T17:34:17Z")
“Even” numbers are evenly divisible by two. “Round” numbers, in the common sense, are a bit more vaguely defined, but can often be understood to mean something like, “divisible by a power of ten no more than two orders … --- ## [Help with Skype and my MacBook, please](https://boards.straightdope.com/t/help-with-skype-and-my-macbook-please/745788)
**Author:** [@harmonicamoon](https://boards.straightdope.com/u/harmonicamoon)\ **Replies:** 2\ **Last updated:** [February 11, 2016, 4:38pm UTC](https://boards.straightdope.com/t/help-with-skype-and-my-macbook-please/745788 "2016-02-11T16:38:53Z")
About a month ago, the Skype caller couldn’t hear my voice. I did a restart and all was good. On Monday, I had a normal call, everything okay. Well, Mondays are my daughter’s Skype night date. She couldn’t hear me. … --- ## [No male heir](https://boards.straightdope.com/t/no-male-heir/745623)
**Author:** [@drewder](https://boards.straightdope.com/u/drewder)\ **Replies:** 20\ **Last updated:** [February 11, 2016, 3:49pm UTC](https://boards.straightdope.com/t/no-male-heir/745623 "2016-02-11T15:49:07Z")
It seems like England had a lot of troubles whenever a king died without a son to take over. Why is it after Edward the 6th’s death that it was suddenly ok for women to take over the throne? We had a Jane Grey, Mary Tudo… --- ## [Historical inaccuracies in \[b\]The Patriot\[/b\]](https://boards.straightdope.com/t/historical-inaccuracies-in-b-the-patriot-b/42543)
**Author:** [@light\_strand](https://boards.straightdope.com/u/light_strand)\ **Replies:** 23\ **Last updated:** [November 28, 2000, 6:48am UTC](https://boards.straightdope.com/t/historical-inaccuracies-in-b-the-patriot-b/42543 "2000-11-28T06:48:38Z")
I watched the movie The Patriot last night (a good Thanksgiving movie) and wondered how historically accurate it was. I know Mr Gibson is known for “poetic license” when it comes to history. So how 'bout it history buff… --- ## [Why wasn't the bill of rights part of the original consitution?](https://boards.straightdope.com/t/why-wasnt-the-bill-of-rights-part-of-the-original-consitution/745810)
**Author:** [@bomberswarm2](https://boards.straightdope.com/u/bomberswarm2)\ **Replies:** 6\ **Last updated:** [February 11, 2016, 3:35pm UTC](https://boards.straightdope.com/t/why-wasnt-the-bill-of-rights-part-of-the-original-consitution/745810 "2016-02-11T15:35:20Z")
Wouldn’t these have been pretty simple things? Why would they need to be amended? And ifcthey were amended so soon afterwards, why not just have them in the original consitution? --- ## [Fatal meteorite](https://boards.straightdope.com/t/fatal-meteorite/745521)
**Author:** [@dtilque](https://boards.straightdope.com/u/dtilque)\ **Replies:** 28\ **Last updated:** [February 11, 2016, 3:13pm UTC](https://boards.straightdope.com/t/fatal-meteorite/745521 "2016-02-11T15:13:16Z")
News reports such as this one, say that a meteorite hit a college campus in India and killed a bus driver. If true, it’s the first known human casualty by a rock from space. The thing that I’m wondering about is that th… --- ## [Any chance they can get the grounded Italian ship back upright?](https://boards.straightdope.com/t/any-chance-they-can-get-the-grounded-italian-ship-back-upright/609541)
**Author:** [@aceplace57](https://boards.straightdope.com/u/aceplace57)\ **Replies:** 226\ **Last updated:** [February 11, 2016, 12:31pm UTC](https://boards.straightdope.com/t/any-chance-they-can-get-the-grounded-italian-ship-back-upright/609541 "2016-02-11T12:31:21Z")
Based on the photos, can they ever get this ship back upright? Maybe lots of tugboats? Its grounded on a sandbar and can’t sink. What would be the procedure for recovering the ship? I’m assuming they won’t wait a 100 ye… --- ## [Why is the cerebral cortex folded?](https://boards.straightdope.com/t/why-is-the-cerebral-cortex-folded/745147)
**Author:** [@Machine\_Elf](https://boards.straightdope.com/u/Machine_Elf)\ **Replies:** 27\ **Last updated:** [February 11, 2016, 5:43am UTC](https://boards.straightdope.com/t/why-is-the-cerebral-cortex-folded/745147 "2016-02-11T05:43:56Z")
The folds and fissures of the cerebral cortex are typically explained as a way to fit all that surface area (a couple of square feet, I’ve heard) inside a nice, compact skull. But why is surface area a necessary feature… --- ## [Can you eat black powder?](https://boards.straightdope.com/t/can-you-eat-black-powder/656065)
**Author:** [@Sicks\_Ate](https://boards.straightdope.com/u/Sicks_Ate)\ **Replies:** 21\ **Last updated:** [February 11, 2016, 3:31am UTC](https://boards.straightdope.com/t/can-you-eat-black-powder/656065 "2016-02-11T03:31:26Z")
If so, how much? Let’s say that I was making a recipe and wanted to use it as an ingredient. I don’t, but for example’s sake. This board thread tries to answer the question, but it’s…well…not the Dope. And don’t tell… --- ## [Using light from the sun to heat something above temperature of the sun?](https://boards.straightdope.com/t/using-light-from-the-sun-to-heat-something-above-temperature-of-the-sun/713140)
**Author:** [@DaveBfd](https://boards.straightdope.com/u/DaveBfd)\ **Replies:** 98\ **Last updated:** [February 10, 2016, 10:08pm UTC](https://boards.straightdope.com/t/using-light-from-the-sun-to-heat-something-above-temperature-of-the-sun/713140 "2016-02-10T22:08:10Z")
This is a question I stole from another source. The answer given was that it was impossible. This seems counter-intuitive to me, could somebody explain what the answer is, and why? Lets use ideal circumstances of an u… --- ## [If humans developed faster than light travel, how far back in time could we see with space telescope](https://boards.straightdope.com/t/if-humans-developed-faster-than-light-travel-how-far-back-in-time-could-we-see-with-space-telescope/745436)
**Author:** [@Wesley\_Clark](https://boards.straightdope.com/u/Wesley_Clark)\ **Replies:** 20\ **Last updated:** [February 10, 2016, 8:59pm UTC](https://boards.straightdope.com/t/if-humans-developed-faster-than-light-travel-how-far-back-in-time-could-we-see-with-space-telescope/745436 "2016-02-10T20:59:49Z")
If humans developed faster than light travel and decided to set up space telescopes to see historical earth, how car back could we see the planets history? I once heard if you tried to develop a lens big enough to see th… --- ## [Contempt of court vs. contempt of Congress (Martin Shkreli)](https://boards.straightdope.com/t/contempt-of-court-vs-contempt-of-congress-martin-shkreli/745163)
**Author:** [@Donnerwetter](https://boards.straightdope.com/u/Donnerwetter)\ **Replies:** 19\ **Last updated:** [February 10, 2016, 8:58pm UTC](https://boards.straightdope.com/t/contempt-of-court-vs-contempt-of-congress-martin-shkreli/745163 "2016-02-10T20:58:01Z")
Today, Martin Shkreli appeared before the Committee on Oversight and Government Reform of the U.S. House of Representatives to answer questions concerning the pricing policy for a drug his company manufactures (see also t… --- ## [Banana and Its Peel](https://boards.straightdope.com/t/banana-and-its-peel/745731)
**Author:** [@Jinx](https://boards.straightdope.com/u/Jinx)\ **Replies:** 5\ **Last updated:** [February 10, 2016, 7:48pm UTC](https://boards.straightdope.com/t/banana-and-its-peel/745731 "2016-02-10T19:48:55Z")
Does the banana draw nutrients (even if just sugar) from the peel as it ripens? I noticed my over-ripened, now black banana peel is painfully thin. And while the banana itself is edible (catching it just before it turn… --- ## [How many spare planes do airlines have?](https://boards.straightdope.com/t/how-many-spare-planes-do-airlines-have/745364)
**Author:** [@Bijou\_Drains](https://boards.straightdope.com/u/Bijou_Drains)\ **Replies:** 40\ **Last updated:** [February 10, 2016, 4:37pm UTC](https://boards.straightdope.com/t/how-many-spare-planes-do-airlines-have/745364 "2016-02-10T16:37:09Z")
I noticed both Super Bowl teams took chartered airliners to the game last weekend. Broncos took a United plane, Panthers took American. How many planes do the big airlines have available for charters? ( On average,… --- ## [Voodoo/Psychogenic Death: Credible?](https://boards.straightdope.com/t/voodoo-psychogenic-death-credible/745465)
**Author:** [@Earl\_Snake-Hips\_Tucker](https://boards.straightdope.com/u/Earl_Snake-Hips_Tucker)\ **Replies:** 7\ **Last updated:** [February 10, 2016, 2:03pm UTC](https://boards.straightdope.com/t/voodoo-psychogenic-death-credible/745465 "2016-02-10T14:03:47Z")
I saw Ashley Montagu on a 1970s ‘Johnny Carson’ rerun and he made mention of something he called ‘voodoo death.’ This is something other than sticking pins in a doll made to resemble that certain despised aunt, but some… --- ## [Pain Tolerance](https://boards.straightdope.com/t/pain-tolerance/745686)
**Author:** [@Mrdeals](https://boards.straightdope.com/u/Mrdeals)\ **Replies:** 5\ **Last updated:** [February 10, 2016, 1:07pm UTC](https://boards.straightdope.com/t/pain-tolerance/745686 "2016-02-10T13:07:54Z")
Kind of stemming from my other question about whether bacteria avoidance had anything to do with immunity. I seem to have a pretty high pain tolerance compared to others i know. I have been using my hands in extreme wor… --- ## [The evolution of the B-17.](https://boards.straightdope.com/t/the-evolution-of-the-b-17/745682)
**Author:** [@chacoguy](https://boards.straightdope.com/u/chacoguy)\ **Replies:** 7\ **Last updated:** [February 10, 2016, 12:31pm UTC](https://boards.straightdope.com/t/the-evolution-of-the-b-17/745682 "2016-02-10T12:31:06Z")
Aviation Buffs, please be gentle. If I remember correctly, there was the top turret, the ball turret, two waist gunners and a tail gunner. The enemy figured out pretty quickly that there was a blind spot directly to the… --- ## [Does the weight of Earth change](https://boards.straightdope.com/t/does-the-weight-of-earth-change/745544)
**Author:** [@Nansbread1](https://boards.straightdope.com/u/Nansbread1)\ **Replies:** 15\ **Last updated:** [February 10, 2016, 11:36am UTC](https://boards.straightdope.com/t/does-the-weight-of-earth-change/745544 "2016-02-10T11:36:50Z")
Has the planet gained or lost weight over time. --- ## [Microsoft Edge Start Page Questions](https://boards.straightdope.com/t/microsoft-edge-start-page-questions/745639)
**Author:** [@Zeke\_N.Destroi](https://boards.straightdope.com/u/Zeke_N.Destroi)\ **Replies:** 3\ **Last updated:** [February 10, 2016, 5:39am UTC](https://boards.straightdope.com/t/microsoft-edge-start-page-questions/745639 "2016-02-10T05:39:05Z")
Hi y’all :slight\_smile: I’m one of the gullible masses who have had the unrestrained pleasure of upgrading (HA!) to windows 10 complete with Edge. I’ve fixed most of the problems that I was having with it but I’m still… --- ## [Options on installing a restroom in a barn?](https://boards.straightdope.com/t/options-on-installing-a-restroom-in-a-barn/745529)
**Author:** [@Urbanredneck](https://boards.straightdope.com/u/Urbanredneck)\ **Replies:** 29\ **Last updated:** [February 10, 2016, 3:02am UTC](https://boards.straightdope.com/t/options-on-installing-a-restroom-in-a-barn/745529 "2016-02-10T03:02:03Z")
In one of our outbuildings we have a water supply and are thinking about adding some sort of toilet/restroom. The problem is it’s not hooked to sewer and are considering options. If we put in a normal flushing toilet wo… --- ## [Scientific name for boogers](https://boards.straightdope.com/t/scientific-name-for-boogers/676954)
**Author:** [@EmilyG](https://boards.straightdope.com/u/EmilyG)\ **Replies:** 24\ **Last updated:** [February 10, 2016, 1:59am UTC](https://boards.straightdope.com/t/scientific-name-for-boogers/676954 "2016-02-10T01:59:02Z")
A “booger” is a dried piece of nasal mucus (snot), as opposed to the more slimy liquidy snot. But is there an actual scientific/medical term for boogers? --- ## [Becoming a US Citizen -- how much have the rules changed over time?](https://boards.straightdope.com/t/becoming-a-us-citizen-how-much-have-the-rules-changed-over-time/745578)
**Author:** [@Anny\_Middon](https://boards.straightdope.com/u/Anny_Middon)\ **Replies:** 5\ **Last updated:** [February 10, 2016, 1:47am UTC](https://boards.straightdope.com/t/becoming-a-us-citizen-how-much-have-the-rules-changed-over-time/745578 "2016-02-10T01:47:16Z")
My mother was born in Italy in 1921. She came to the US in 1931. Recently I found her Certificate of Citizenship, dated in 1962. It states, “having proved to the satisfaction of the Commissioner that she is now a citi… --- ## [What does a CEO or corporate president know about his companies bills?](https://boards.straightdope.com/t/what-does-a-ceo-or-corporate-president-know-about-his-companies-bills/738919)
**Author:** [@Urbanredneck](https://boards.straightdope.com/u/Urbanredneck)\ **Replies:** 22\ **Last updated:** [February 10, 2016, 1:15am UTC](https://boards.straightdope.com/t/what-does-a-ceo-or-corporate-president-know-about-his-companies-bills/738919 "2016-02-10T01:15:41Z")
I work in building maintenance. I know our 400,000 square foot building with up to 300 employees uses an enormous amount of heat, electricity, and water and I wonder, does the company president know what those bills are… --- ## [Math Question](https://boards.straightdope.com/t/math-question/745432)
**Author:** [@HoneyBadgerDC](https://boards.straightdope.com/u/HoneyBadgerDC)\ **Replies:** 19\ **Last updated:** [February 10, 2016, 12:13am UTC](https://boards.straightdope.com/t/math-question/745432 "2016-02-10T00:13:23Z")
I will do my best posing this question. I hope you can understand it. When measuring the stored energy on an archery bow we normaly draw the bow back and take a force reading every 1 " increment, we add those up usually… [Previous page](https://boards.straightdope.com/c/factual-questions/9.md?page=953) [Next page](https://boards.straightdope.com/c/factual-questions/9.md?page=955)