## xkcd: What If?

Off topic discourse and banter encouraged.
neufer
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### Re: xkcd: What If? #136 - Spiders vs. the Sun

bystander wrote:Spiders vs. the Sun
• Which has a greater gravitational pull on me: the Sun, or spiders?
Granted, the Sun is much bigger, but it is also much further away,
and as I learned in high school physics, the gravitational force is
proportional to the square of the distance.
— Marina Fleming

One could argue that the true gravitational force is the tidal spaghettification force which drops off as the cube of the distance. This drop-off nicely cancels the mass/volume growth of large distance objects like the Sun such that the the tidal spaghettification forces of the (apparent) equal sized Sun & Moon are comparable (except for the fact that the Moon is somewhat denser).

Hence, if a thread dangling spider is close enough to you to block out the Sun (or Moon) then the gravitational tidal spaghettification force on your head due to that spider exceeds that of the Sun (or Moon).
Art Neuendorffer

Chris Peterson
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### Re: xkcd: What If? #136 - Spiders vs. the Sun

bystander wrote:Spiders vs. the Sun
• Which has a greater gravitational pull on me: the Sun, or spiders?
Granted, the Sun is much bigger, but it is also much further away,
and as I learned in high school physics, the gravitational force is
proportional to the square of the distance.
— Marina Fleming
It's disappointing to find so much spider fear voiced by a curious, scientifically minded person (the article author, not the questioner).
Chris

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bystander
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### Re: xkcd: What If? #136 - Spiders vs. the Sun

Chris Peterson wrote:
It's disappointing to find so much spider fear voiced by a curious, scientifically minded person (the article author, not the questioner).

Phobias are not rational or reasonable. Even educated, normally rational people may be affected by them. Your disappointment in another's phobia may be as unreasonable as their phobia.
Know the quiet place within your heart and touch the rainbow of possibility; be
alive to the gentle breeze of communication, and please stop being such a jerk.
— Garrison Keillor

neufer
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### Re: xkcd: What If? #136 - Spiders vs. the Sun

bystander wrote:
Chris Peterson wrote:
It's disappointing to find so much spider fear voiced by a curious, scientifically minded person (the article author, not the questioner).

Phobias are not rational or reasonable. Even educated, normally rational people may be affected by them. Your disappointment in another's phobia may be as unreasonable as their phobia.
http://en.wikipedia.org/wiki/Arachnophobia_%28film%29 wrote:
The [1990 Arachnophobia film starring Jeff Daniels and John Goodman] drew protests from some people interested in spiders, as they believed the film tarnished the public image of spiders.
• Arachnophobia [last lines]
Doctor James Atherton (Julian Sands): [while drawing out the general spider] Suppers ready! Come and get it. [said general spider screeches and leaps onto his neck sinking it's fangs into his throat]

Delbert McClintock (John Goodman): [minutes later cries out as James drops from the rafters, cocooned and covered in spiders] They got the professor!
Art Neuendorffer

Chris Peterson
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### Re: xkcd: What If? #136 - Spiders vs. the Sun

bystander wrote:
Chris Peterson wrote:
It's disappointing to find so much spider fear voiced by a curious, scientifically minded person (the article author, not the questioner).

Phobias are not rational or reasonable. Even educated, normally rational people may be affected by them. Your disappointment in another's phobia may be as unreasonable as their phobia.
Phobias may not be rational, but the decision to incorporate them (or perpetuate false natural facts) is, and doesn't belong in this explanation. The disappointment in a very poor explanation is strong here. As is the failure to consider tidal impact, which is much more significant (as Art has pointed out).

This "What If?" is a fail.
Chris

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### Re: xkcd: What If? #136

Big ugly spiders do have the tendency to make me gravitate towards a can of RAID. But the effect does wear off shortly after the interaction of the spider and i.
To find the Truth, you must go Beyond.

geckzilla
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### Re: xkcd: What If? #136 - Spiders vs. the Sun

bystander wrote:
Chris Peterson wrote:
It's disappointing to find so much spider fear voiced by a curious, scientifically minded person (the article author, not the questioner).

Phobias are not rational or reasonable. Even educated, normally rational people may be affected by them. Your disappointment in another's phobia may be as unreasonable as their phobia.
It is not unreasonable or impossible to at least greatly reduce a phobia, though. All you need is a shift in public perception. Homophobia, racism, and human xenophobia are largely unacceptable in our society these days. So if we want to move away from arachnophobia then we must publicly express our disappointment.
Just call me "geck" because "zilla" is like a last name.

Chris Peterson
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### Re: xkcd: What If? #136 - Spiders vs. the Sun

geckzilla wrote:
bystander wrote:
Chris Peterson wrote:
It's disappointing to find so much spider fear voiced by a curious, scientifically minded person (the article author, not the questioner).

Phobias are not rational or reasonable. Even educated, normally rational people may be affected by them. Your disappointment in another's phobia may be as unreasonable as their phobia.
It is not unreasonable or impossible to at least greatly reduce a phobia, though. All you need is a shift in public perception. Homophobia, racism, and human xenophobia are largely unacceptable in our society these days. So if we want to move away from arachnophobia then we must publicly express our disappointment.
Well, the "phobias" you mention are seldom phobias in the clinical sense, but more like examples of societally driven hatred or dislike. Arachnophobia is something that runs quite deep in our species, so eliminating it could take more than simple social pressure. My objection isn't so much to arachnophobia as to its reinforcement by a science educator, who should be taking every opportunity to celebrate the natural world and emphasize the wonder, not the fear.

(I recognize that some of the arachnophobia displayed in the article is an attempt at humor which takes advantage of this widespread fear, but I think the strategy is a poor one in this case.)
Chris

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neufer
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### Re: xkcd: What If? #136 - Spiders vs. the Sun

http://en.wikipedia.org/wiki/Herpetophobia wrote:
<<Herpetophobia is a common specific phobia, which consists of fear or aversion to reptiles, commonly lizards and snakes, and similar vertebrates as amphibians. It is one of the most diffused animal phobias, very similar and related to ophidiophobia. This condition causes a slight to severe emotional reaction, as for example anxiety, panic attack or most commonly nausea.>>
geckzilla wrote:
<<It is not unreasonable or impossible to at least greatly reduce a phobia, though. All you need is a shift in public perception. Homophobia, racism, and human xenophobia are largely unacceptable in our society these days. So if we want to move away from arachnophobia then we must publicly express our disappointment.>>
Art Neuendorffer

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### Re: xkcd: What If? #136

I used to be arachnophilic when I was seven. I used to love letting them crawl all over my hand. When we moved to Boise and I had a basement bedroom where crawly things (especially black widows) were rampant, I learned that I didn't want anything to do them any longer. For me it was a learned response.

I supposed if they had venom that was euphoric - their species would thrive. Evolution might yet prevail. Or it might be from the hand of a cleaver geneticist? No telling what the future holds
Make Mars not Wars

bystander
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### xkcd: What If? #137 - New Horizons

New Horizons
• What if New Horizons hits my car? — Robin Sheat
Know the quiet place within your heart and touch the rainbow of possibility; be
alive to the gentle breeze of communication, and please stop being such a jerk.
— Garrison Keillor

Markus Schwarz
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### xkcd: What If? #138 - Jupiter Submarine

Jupiter Submarine
• What if you released a submarine into Jupiter's atmosphere? Would it eventually reach a point where it would float? Could it navigate? — KTH

bystander
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### xkcd: What If? #139 - Jupiter Descending

Jupiter Descending
Know the quiet place within your heart and touch the rainbow of possibility; be
alive to the gentle breeze of communication, and please stop being such a jerk.
— Garrison Keillor

neufer
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### Re: xkcd: What If? #139 - Jupiter Descending

xkcd wrote:Jupiter Descending
• What would you smell before you melted or burned up?
http://what-if.xkcd.com/139/ wrote:
<<Jupiter's upper atmosphere has three main layers—an upper layer of haze and ammonia clouds, similar to cirrostratus clouds on Earth. Below that is a thick, reddish-brown ammonium hydrosulfide cloud layer. The lowest layer consists of white water clouds, which occasionally rise into towering thunderstorms that occasionally push through the middle layer.>>
https://en.wikipedia.org/wiki/Ammonium_hydrosulfide wrote:
<<Ammonium hydrosulfide is the chemical compound with the formula (NH4)SH. On Earth the compound is encountered mainly as a solution, not as the solid, but (NH4)SH ice is believed to be a substantial component of the cloud decks of the gas-giant planets Jupiter and Saturn, with sulfur produced by its photolysis responsible for the color of some of those planets' clouds. The common "stink bomb" consists of an aqueous solution of ammonium sulfide. The mixture easily converts to ammonia and hydrogen sulfide gases. Both ammonia and hydrogen sulfide (rotten egg smell) have a powerfully unpleasant smell.>>
https://www.gutenberg.org/files/3190/3190-h/3190-h.htm wrote:
Title: 1601, Conversation as it was by the Social Fireside in the Time of the Tudors
Author: Mark Twain

<<Martial, too (Book XII, Epigram LXXVII), tells of the embarrassment of one who broke wind while praying in the Capitol,
• "One day, while standing upright, addressing his prayers to Jupiter, Aethon farted in the Capitol. Men laughed, but the Father of the Gods, offended, condemned the guilty one to dine at home for three nights. Since that time, miserable Aethon, when he wishes to enter the Capitol, goes first to Paterclius' privies and farts ten or twenty times. Yet, in spite of this precautionary crepitation, he salutes Jove with constricted buttocks.">>
Art Neuendorffer

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### Re: xkcd: What If? #139

I would rather send a probe with a detachable Chute and a Self inflating Helium Balloon to float along in the atmosphere.

Chris Peterson
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### Re: xkcd: What If? #139

BMAONE23 wrote:I would rather send a probe with a detachable Chute and a Self inflating Helium Balloon to float along in the atmosphere.
You'd still need that big bullet-shaped heat shield.
Chris

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neufer
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### Re: xkcd: What If? #139

Chris Peterson wrote:
BMAONE23 wrote:
I would rather send a probe with a detachable Chute and a Self inflating Helium Balloon to float along in the atmosphere.
You'd still need that big bullet-shaped heat shield.
• A "Self inflating Helium Balloon" would sink like a lead balloon in Jupiter's hydrogen atmosphere:
https://en.wikipedia.org/wiki/Atmosphere_of_Jupiter wrote:
<<The atmosphere of Jupiter is mostly made of molecular hydrogen and helium in roughly solar proportions [i.e., hydrogen 74% / helium 25%].
https://en.wikipedia.org/wiki/Aerobot wrote:

<<An aerobot is an aerial robot, usually used in the context of an unmanned space probe or unmanned aerial vehicle. Balloon designs for possible planetary missions have involved a few unusual concepts. One is the solar, or infrared (IR) Montgolfiere. This is a hot-air balloon where the envelope is made from a material that traps heat from sunlight, or from heat radiated from a planetary surface. Black is the best color for absorbing heat, but other factors are involved and the material may not necessarily be black.

Aerobots might be used to explore the atmosphere of Jupiter and possibly the other gaseous outer planets. As the atmospheres of these planets are largely composed of hydrogen, and since there is no lighter gas than hydrogen, such an aerobot would have to be a Montgolfiere. As sunlight is weak at such distances, the aerobot would obtain most of its heating from infrared energy radiated by the planet below.

A Jupiter aerobot might operate at altitudes where the air pressure ranges from one to ten atmospheres, occasionally dropping lower for detailed studies. It would make atmospheric measurements and return imagery and remote sensing of weather phenomena, such as Jupiter's Great Red Spot. A Jupiter aerobot might also drop sondes deep into the atmosphere and relay their data back to an orbiter until the sondes are destroyed by temperature and pressure.

One of the trickier aspects of planetary balloon operations is inserting them into operation. Typically, the balloon enters the planetary atmosphere in an "aeroshell", a heat shield in the shape of a flattened cone. After atmospheric entry, a parachute will extract the balloon assembly from the aeroshell, which falls away.>>
Art Neuendorffer

Chris Peterson
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### Re: xkcd: What If? #139

neufer wrote:
• A "Self inflating Helium Balloon" would sink like a lead balloon in Jupiter's hydrogen atmosphere:
Well, there's plenty of other stuff in the atmosphere besides hydrogen. But even in a pure hydrogen atmosphere, I think the terminal velocity of a lead balloon is going to be quite a bit higher than that of a helium one!
Chris

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neufer
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### Re: xkcd: What If? #139

Click to play embedded YouTube video.
Chris Peterson wrote:
neufer wrote:
A "Self inflating Helium Balloon" would sink like a lead balloon in Jupiter's hydrogen atmosphere:
Well, there's plenty of other stuff in the atmosphere besides hydrogen. But even in a pure hydrogen atmosphere, I think the terminal velocity of a lead balloon is going to be quite a bit higher than that of a helium one!
Art Neuendorffer

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### Re: xkcd: What If? #139

When I hear "lead balloon" I imagine a piece of solid lead and not a lead foil balloon. Cool project, though. Mythbusters is always fun.
Just call me "geck" because "zilla" is like a last name.

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### Re: xkcd: What If? #140 - Proton Earth, Electron Moon

Proton Earth, Electron Moon
• What if the Earth were made entirely of protons, and the Moon were made entirely of electrons? — Noah Williams
Know the quiet place within your heart and touch the rainbow of possibility; be
alive to the gentle breeze of communication, and please stop being such a jerk.
— Garrison Keillor

bystander
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### xkcd: What If? #141 - Sunbeam

Sunbeam
• What if all of the sun's output of visible light were bundled up into a laser-like beam
that had a diameter of around 1m once it reaches Earth?
— Max Schäfer
Know the quiet place within your heart and touch the rainbow of possibility; be
alive to the gentle breeze of communication, and please stop being such a jerk.
— Garrison Keillor

neufer
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### Re: xkcd: What If? #141 - Sunbeam

Click to play embedded YouTube video.
bystander wrote:
Sunbeam
• What if all of the sun's output of visible light were bundled up into a laser-like beam that had a diameter of around 1m once it reaches Earth? — Max Schäfer
Art Neuendorffer

geckzilla
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### Re: xkcd: What If? #140

I have a hard time believing the reflected moonlight would also kill...
Just call me "geck" because "zilla" is like a last name.

neufer
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### Re: xkcd: What If? #140

geckzilla wrote:
I have a hard time believing the reflected moonlight would also kill...
The Moon would be at least as bright as the Sun...but it would almost all be in gamma rays
Art Neuendorffer