explain xkcd - User contributions [en]

2988: Maslow's Pyramid

2024-09-24T09:25:03Z

141.101.99.30: /* Explanation */

{{comic
| number = 2988
| date = September 20, 2024
| title = Maslow's Pyramid
| image = maslows_pyramid_2x.png
| imagesize = 744x422px
| noexpand = true
| titletext = The local police, building inspector, and fire marshal are all contesting my 'safety' assertion, or would be if they could reach me past all the traps.
}}

==Explanation==
{{incomplete|Created by a PHYSICAL IMPLEMENTATION OF A METAPHORICAL HEURISTIC MODEL - Please change this comment when editing this page. Do NOT delete this tag too soon.}}
{{w|Maslow's hierarchy of needs}} is a psychological model initially proposed by {{w|Abraham Maslow}} in 1943. It posits that all humans have certain requirements for a healthy and fulfilled life, and that these can be prioritized by how fundamental and foundational they are. The most basic needs are physical, such as food, water, and shelter, as humans can't survive without them in the long term. Then come things like safety, which includes physical safety, but also protection from things like emotional and economic threats. Beyond these come less urgent needs, such as love and social belonging, with the top (at least in simplified versions) being "self-actualization" or something similar.

The idea is frequently represented by a segmented triangle diagram, with basic foundational needs near the bottom creating the stability to enable {{w|self-actualization}} at the top, at least in the 'simplified' version. This diagram has become so popular that it's commonly referred to as "Maslow's Pyramid", even though Maslow himself never actually used it.

In this comic, [[Cueball]] has interpreted the concept of Maslow's Pyramid too literally. He attempts to achieve true happiness by building an actual, physical pyramid that resembles the common representation of Maslow’s hierarchy. Cueball complains that the pyramid only fulfills one of the five needs listed on its side: physical safety, as it's "highly defensible". It can also potentially provide shelter, but that's only one of multiple physical needs.

The pyramid is useless for his social and emotional needs: everyone, like [[Megan]] and [[White Hat]] whom he shows his pyramid to, thinks the pyramid was a poor idea, including Cueball himself. Despite the impressive accomplishment of constructing such an edifice, Cueball apparently feels entirely unfulfilled, and is "seriously questioning [his] life choices".

The title text calls into question the notion that it provides even physical security. It apparently fails to comply with fire and {{w|building codes}}, which is potentially dangerous to both Cueball and his community. Moreover, he implies that inspectors can't even access the building, due to "all the traps". The notion of real-life pyramids (and other ancient structures) being filled with active booby-traps commonly portrayed in fiction, and it seems that Cueball built such traps into his pyramid. Of course, in a modern structure, such traps would almost certainly be illegal on their own (particularly if they prevented authorities from accessing the property), and living in a pyramid full of traps would potentially be a danger to Cueball himself. Even if the structure provided physical safety, if it put him in legal jeopardy (and likely economic danger, considering how expensive it must have been to build), means that it doesn't even fulfill that need.

==Transcript==
:[The scene is seen from far away with the characters dwarfed by a huge pyramid in the middle of the panel. To the left we see Cueball facing White Hat and Megan while he is pointing behind him to the giant pyramid. It has been segmented into five tiers of equal height. Each tier has a labeled written on the side facing out. The segment at the tip is so small that the text needs to be written on two lines. To the right of each segment there is either a red cross (four times) or a green check mark (level two from the bottom). Next to these marks there is a comment. From top to bottom the labels, marks and comments are:]
:Self-actualization
::X Honestly questioning my life choices here
:Esteem
::X People seem less impressed by it than I hoped
:Belonging and love
::X Friends are worried about me
:Safety
::✔ Highly defensible
:Physiological needs
::X Provides basic shelter but no food, water, heat, etc

:[Caption below the panel:]
:I built Maslow's pyramid thing, but it's a total ripoff - it's only providing 20% of my needs.

{{comic discussion}}

[[Category:Comics with color]]
[[Category:Comics featuring Cueball]]
[[Category:Comics featuring Megan]]
[[Category:Comics featuring White Hat]]
[[Category:Psychology]]

2979: Sky Alarm

2024-09-02T13:44:15Z

141.101.99.30: /* Explanation */

{{comic
| number = 2979
| date = August 30, 2024
| title = Sky Alarm
| image = sky_alarm_2x.png
| imagesize = 332x302px
| noexpand = true
| titletext = During the day it also activates for neat clouds and pretty sunsets.
}}

==Explanation==
The comic shows [[Megan]] and [[Cueball]] being alerted by a 'Sky Alarm' that a 'cool space thing' is happening. The alarm is triggered when a relatively interesting astronomical event occurs, for example, the {{w|Perseid meteor shower}} and blue {{w|supermoon}} that happened recently. Randall remarks in the caption how he wants this device and wishes it existed. Cueball and Megan (and by extension [[Randall]]) feel that they regularly miss events they'd like to see, so such a device would help prevent this.

The title text further specifies that he would want it to activate even for more common sky-related spectacles, such as interesting clouds and nice sunsets (which still can be very beautiful). In short, it would help its owner to not miss interesting outdoor sights.

Most recently before this comic, Randall referred to cool sky phenomena in [[2971: Celestial Event]]. Quite a few such references preceded this (such as the aforementioned {{w|Perseid meteor shower}}), so they may have been on Randall's mind.

==Transcript==
:[A square device with a light on top and a label on its side, is seen resting on a stool to the left. It is activated and the light on top of it is glowing and a voice is emanating from it, maybe even speaking the siren part of the sound that comes between sentences. Cueball, sitting on an office chair at his desk, looks away from his laptop so he is now facing the device while Megan is on the other side of the desk running away from it towards the right edge of the panel.]
:Label: Sky Alarm
:Sky alarm: ''Weeee Ooooo Weeee Ooooo''
:Sky alarm: ''There's a cool space thing happening!''
:Sky alarm: ''Weeee Ooooo Weeee Ooooo''
:Sky alarm: ''Go outside and look up!''

:[Caption below the panel:]
:I want this device.

{{comic discussion}}

[[Category:Comics featuring Cueball]]
[[Category:Comics featuring Megan]]
[[Category:Space]]
[[Category:Weather]]

Talk:2003: Presidential Succession

2024-08-29T17:44:34Z

141.101.99.30:

Aw, but what about Morgan Freeman? [[Special:Contributions/108.162.221.11|108.162.221.11]] 04:43, 6 June 2018 (UTC)
:And Kiefer -designated survivor- Sutherland?[[Special:Contributions/141.101.104.83|141.101.104.83]] 08:24, 6 June 2018 (UTC)
:Morgan Freeman> "I do solemnly swear / that I will faithfully execute the Office of President of the United States..." [[User:Linker|Linker]] ([[User talk:Linker|talk]]) 12:39, 6 June 2018 (UTC)

Academy awards have been won by actors playing kings / queens - of England, the United Kingdom and Siam - Princes - of Denmark - and Prime Ministers of Great Britain and even the President of the Uniter States / Member of the house of Representatives, but I do not believe it has been won by an actor playing a state govenor. Mind you it is not clear if an actor playing a prison govenor, would count. [[User:Arachrah|Arachrah]] ([[User talk:Arachrah|talk]]) 11:30, 6 June 2018 (UTC)
: Broderick Crawford, actually. I've added him. To the best of my ability to determine, the opposite group (Governors Award recipients who have played characters named Oscar) appears to be an empty set. I'll note that I don't have a really comprehensive filmography for {{w|Jean-Claude Carrière}}, but I consider it fairly unlikely that he ever played a character by that name. [[User:Squeamish Ossifrage|Squeamish Ossifrage]] ([[User talk:Squeamish Ossifrage|talk]]) 16:08, 6 June 2018 (UTC)

Bill Pullman's eldest daughter Maesa is a film composer with an IMDB page in her own right. [[User:Arachrah|Arachrah]] ([[User talk:Arachrah|talk]]) 11:30, 6 June 2018 (UTC)
:With Maesa added (turned 35 last year), addded second child (not sure of exact DOB, but he was born the right year to be now 35) and added the third (commented, so hidden) ready for his own eventual 2028 inclusion. Have not checked for possible residency disqualifications/delays. [[Special:Contributions/141.101.99.30|141.101.99.30]] 17:44, 29 August 2024 (UTC)

Top 5 US astronauts? I only count three. Who are the other two? [[Special:Contributions/172.68.150.76|172.68.150.76]] 12:15, 6 June 2018 (UTC)

As of September 3, 2017, the 5 US astronauts with the most total time in space are Peggy Whitson (665 days), Jeff Williams (534), Scott Kelly (520), Mike Fincke (382), and Mike Foale (374), according to https://www.nasa.gov/feature/nasa-station-astronaut-record-holders. Michael Lopez-Alegria has the second-most time in space for a single spaceflight (215 days, compared to Scott Kelly, 340). [[User:The Dining Logician|The Dining Logician]] ([[User talk:The Dining Logician|talk]]) 12:59, 6 June 2018 (UTC)

Mike Foale was born in Louth - so ineligible. Michael Lopez-Alegria was born in Spain ditto [[User:Arachrah|Arachrah]] ([[User talk:Arachrah|talk]]) 15:26, 6 June 2018 (UTC)
:Foale was born to an American mother and should hence be a natural-born American. --[[User:Ycthiognass|Ycthiognass]] ([[User talk:Ycthiognass|talk]]) 09:40, 7 June 2018 (UTC)
::There is actually legal question about whether someone born on foreign soil to US citizens count as "natural-born" (or whether courts would just say it's a political question and pass the buck to Congress), though I will add Foale back to the list. [[Special:Contributions/162.158.62.207|162.158.62.207]] 14:04, 7 June 2018 (UTC)

The non-US-citizen-being-in-line-for-the-Presidency thing has already been cleared up IRL - several Presidential cabinets have had non-natural-born-US citizens on them (current Transportation Secretary Elaine Chao was born in Taiwan; in the past Madeline Albright was born in the then-Czechoslovakia). All the serious succession lists I've ever seen just list them and skip over them. [[Special:Contributions/162.158.62.51|162.158.62.51]] 13:19, 6 June 2018 (UTC)

How do we decide who gets a bye in the jousting tournament? [[Special:Contributions/162.158.74.147|162.158.74.147]] 13:30, 6 June 2018 (UTC)
:Random draw, probably. There's no jousting rankings AFAIK to enable any kind of seeding like in tennis. [[Special:Contributions/162.158.62.51|162.158.62.51]] 15:16, 6 June 2018 (UTC) There is a USA chapter of the International Jousting Association. I didn't spend enough time to track down a rankings list, but there are 3 levels of competition, which would be a start in seeding. To further seed I'd suggest using the Europa Tiebreaker.[[Special:Contributions/162.158.62.15|162.158.62.15]] 18:14, 18 June 2018 (UTC)

Anyone with a jousting ranking would not need a bye. [[User:Arachrah|Arachrah]] ([[User talk:Arachrah|talk]]) 15:26, 6 June 2018 (UTC)

Anyone else think it's interesting that Kate gets a "if available" but Tom Hanks doesn't? [[Special:Contributions/172.69.62.184|172.69.62.184]] 16:23, 6 June 2018 (UTC)
: Also, why doesn't Tom Hanks kids get to be in line, like Bill Pulman's? Colin Hanks is old enough. [[Special:Contributions/162.158.122.210|162.158.122.210]] 03:59, 7 June 2018 (UTC)

I assume, but am too lazy to do all the maths, that the person born closest to Europa would be the one closest in time to the point Sun Earth and Jupiter are in line.
I found a table of opposition distances here: http://www.ianridpath.com/jupiter.htm
[[User:Arachrah|Arachrah]] ([[User talk:Arachrah|talk]]) 18:26, 6 June 2018 (UTC)That would seem to be the overwhelmingly dominant factor, the only other factors would be which side of the Earth someone is born on (up to 7915miles difference, or about 7 minutes of the Earth's orbit), and Elevation/Altitude,since as of yet no one has been born in space(citation required), this factor is trivial, equivalent to less than 1 second of Earth's orbit.[[Special:Contributions/162.158.62.15|162.158.62.15]] 18:14, 18 June 2018 (UTC)

All of this talk about ''where'' people were born is very misleading. The general opinion is that you have to have been a citizen from birth, not born in the U.S. (or a U.S. territory or whatever). Ted Cruz was born in Canada, but he would have been eligible had he won the nomination and the election. See http://www.politifact.com/truth-o-meter/article/2015/mar/26/ted-cruz-born-canada-eligible-run-president-update/ for discussion. —[[User:TobyBartels|TobyBartels]] ([[User talk:TobyBartels|talk]]) 20:56, 6 June 2018 (UTC)
*Yes, Kate Brown (governor of Oregon) should be restored to Randall's line of succession, because she was born in Spain while her father was serving in the U.S. Air Force. Presumably she's a U.S. citizen by birth and thus eligible for the presidency. --[[Special:Contributions/172.68.150.52|172.68.150.52]] 22:44, 6 June 2018 (UTC)
** Added her. [https://en.wikipedia.org/wiki/List_of_foreign-born_United_States_politicians#Governors This page says she's a natural-born citizen]. --[[User:Ycthiognass|Ycthiognass]] ([[User talk:Ycthiognass|talk]]) 08:49, 7 June 2018 (UTC)

I read #7 being that we would have 5 people as co-president. [[Special:Contributions/162.158.122.210|162.158.122.210]] 03:59, 7 June 2018 (UTC)
:Would that also hold for other entries where multiple people are listed (e.g., multiple league MVPs meet the criteria)? Also, there is the "ties broken by born closest to Europa" title text. [[Special:Contributions/162.158.62.207|162.158.62.207]] 13:31, 7 June 2018 (UTC)

For the 'List of Specific Individuals', should it be maintained by who currently holds those positions, or left as who held them when the comic was posted? [[Special:Contributions/172.69.70.71|172.69.70.71]] 12:14, 7 June 2018 (UTC)
:If you want to come back and update the line as things change in the weeks, months, and years ahead, you're welcome to do so. If you do, I would recommend that both lists (the one accurate as of comic publishing and the one "updated") be maintained, perhaps as one table for fun comparison (adding blank spots as necessary if a current spot falls out of eligibility or a new one becomes eligible for whatever reason. [[Special:Contributions/162.158.62.207|162.158.62.207]] 13:29, 7 June 2018 (UTC)

Tom Hanks is probably a reference to the June 4 Last Week Tonight episode, see http://time.com/5298479/john-oliver-last-week-tonight-guardianship/ {{unsigned ip|162.158.123.85}}

Oh! Question regarding Serena Williams - does it count if her latest match was in a ''doubles'' tournament? She pretty much always teams up with sister Venus in doubles. [[Special:Contributions/162.158.62.207|162.158.62.207]] 14:52, 7 June 2018 (UTC)

Anyone else curious about the apostrophe in "Governor's award"? The current notes imply that it is simply a mistake in "Governors Awards" (the Academy Awards similar to the Oscars), but Governor's awards (i.e., an award by a state Governor) for other areas are quite common (e.g. Clemson University Governor's Award for Excellence in Science and Pennsylvania's Governor's Award for the Arts). Rearranging Oscar and governor from the preceding criterion certainly makes sense, but wild speculation is always more fun... {{unsigned ip|172.68.211.28}}

1933: Santa Facts mentioned Santa being 9th in the presidential line of succession. [[Special:Contributions/162.158.111.7|162.158.111.7]] 08:56, 8 June 2018 (UTC)

To me, #17 (Pullman '''and''' his descendants) seems to imply that we'd abolish the 4-year term and be presided by the Pullman clan for as long as there are eligible successors. #18 might imply that too. [[Special:Contributions/162.158.74.21|162.158.74.21]] 20:14, 8 June 2018 (UTC)
:Presidential elections are mandated in the Constitution every four years - Bill or any of his descendants, or any qualifying member of the UK royal line of succession, would only serve until the current term ends. (Whether a crisis that knocked so many people ahead of them out of the line would allow a reputable and accepted election is another story.) [[Special:Contributions/173.245.52.139|173.245.52.139]] 15:37, 11 June 2018 (UTC)

I note that if Donald Trump wasn't already holding the office of President, he could only qualify from positions 7 and 20 on Randall's list. And not at all from the actual list. [[User:These Are Not The Comments You Are Looking For|These Are Not The Comments You Are Looking For]] ([[User talk:These Are Not The Comments You Are Looking For|talk]]) 01:09, 10 June 2018 (UTC)
:He wouldn't have been the only one - Obama's and JFK's previous job title before becoming President was US Senator, and Eisenhower was President of Columbia University. [[Special:Contributions/173.245.52.139|173.245.52.139]] 15:37, 11 June 2018 (UTC)

There are two problems with this explanation:
The line of succession applies only when the office of president becomes vacant. If the president is incapacitated, the vice president acts as president. If that office is vacant, or the vice precident is also incapacitated, the US will have to do without a president.

The constitution places no restrictions on who can act as president. The current law of succession stipulates that only those elegible to become president can act as president, the constitution does not.
--[[Special:Contributions/162.158.134.154|162.158.134.154]] 08:30, 10 June 2018 (UTC)
:Point 1, the office of President may be vacant but the powers of the Acting President execute the same by whomever the line falls to, and in times of crisis people will nearly certainly just consider them the new President (conflicting claims aside). Point 2 is just false - Article 2 of the Constitution stipulates natural-born citizen at 35 years old and having lived in the US for the last 14 years. Unless you're arguing that "President" and "Acting President" aren't the same? That sure as hell didn't stop John Tyler from refusing to acknowledge anyone who didn't acknowledge him as the new President after William Henry Harrison died a month into his term. [[Special:Contributions/173.245.52.139|173.245.52.139]] 15:17, 11 June 2018 (UTC)
::Point2: That is exactly what I am saying. Only the vice president can succeed to the presidency. The others would execute the powers of the president. What would most likely happen is that the acting president would appoint a vice president, who would succeed immediately when approved by congress.--[[Special:Contributions/162.158.134.34|162.158.134.34]] 07:50, 12 June 2018 (UTC)
::Point 1: There would be no acting president. Only the vice president can become acting president when the president is incapacitated. This and the office of president being vacant are covered in entirely separate parts of the constitution. The line of succession applies only in the latter case.
::Point 2: That was established in congressional legislation. Only the Vice President can become President when the President is incapcaitated, the rest act using the powers of the president but are not themselves the president.

;The Queen
Shouldn't the Queen come before Charles of Windsor? She is 0th in the British succession line. [[Special:Contributions/172.68.27.246|172.68.27.246]] 20:48, 17 June 2018 (UTC)
::It would violate Royal Oath. [[User:Erkinalp|Erkinalp]] ([[User talk:Erkinalp|talk]]) 13:53, 19 June 2018 (UTC)

Since jousting can be a lethal sport (especially if you don't know what you're doing, or like, not wearing armor), I'm left to wonder if part of the whole single-elimination aspect of the competition, where EVERY American is participating, is basically a strategy to literally eliminate everyone there is to be subject to the government's rule (literally eliminate every citizen so the last one left alive is left to be in charge sort of thing) - [[User:Brettpeirce|Brettpeirce]] ([[User talk:Brettpeirce|talk]]) 18:10, 31 December 2018 (UTC)

[[Special:Contributions/172.69.135.184|172.69.135.184]] 07:43, 27 February 2019 (UTC) Foresee a problem with the Billboard Year End chart-toppers: What if a band has anonymous or pseudonymous members and/or deliberately avoids letting one of them assume leadership?
What about the MVPs, should the awards not be given prior to the line of succession reaching them?

;Updates to List of Individuals

Note that this list is supposed to be '''as of the date of the comic''' and should not be updated with changes due to events after that date. [[User:Ianrbibtitlht|Ianrbibtitlht]] ([[User talk:Ianrbibtitlht|talk]]) 17:31, 5 January 2019 (UTC)

I challenge the idea that a version of a legend can be "incorrect". [[User:Nitpicking|Nitpicking]] ([[User talk:Nitpicking|talk]]) 15:22, 4 April 2023 (UTC)
:It's downright factually wrong enough. As a Briton (perhaps, if not a colonial Roman left-over of some kind, the exact details obscured by time and creative reimagining/conflation from the mists of time being several centuries thick by the time he was extensively "chronicled") he was likely a key figure ''opposing'' the arriving Anglo-Saxons of his time, so to be king of the later-constituted "England"/land-of-the-Angles (which was not even a practical neologism, during his supposed reign, across his supposed realm) is an inconsistency that can't even be logically explained by mystical happenings like however such a warrior gets to wield a wet woman's weapon. The celtic fringes (leastwise the P-Celtic bits, on this main island of ours) have far more claim to him than those who eventually spread out from Norfolk/Suffolk/etc and nudged/subsumed them into their current pockets, never mind the post-Hastings mix of transplanted vikings who took over that ruling mantle and went on to shape and solidify the current form of the home-nations. [[Special:Contributions/172.70.90.35|172.70.90.35]] 19:21, 4 April 2023 (UTC)

681: Gravity Wells

2014-02-13T10:46:30Z

141.101.99.30: /* Outer Planets */

{{comic
| number = 681
| date = December 28, 2009
| title = Gravity Wells
| image = gravity_wells.png
| titletext = This doesn't take into account the energy imparted by orbital motion (or gravity assists or the Oberth effect), all of which can make it easier to reach outer planets.
}}

The xkcd page links to [http://xkcd.com/681_large/ a much larger version].

==Explanation==
{{incomplete|Fix Grammar}}

The comic shows the solar system gravity field of each planet and some of their satellites, in a simplified form. Each well is scaled such that rising out of a physical well of that depth in constant Earth surface gravity would take the same energy as escaping from that planet's gravity in reality. Each planet is shown cut in half at the bottom of its well, with the depth of the well measured down to the planet's flat surface.

This is a simplified method of comparing the escape velocities of the various planets and satellites: since, in reality, the strength of gravity decreases the further you get from the planet, it's harder to do a direct comparison when seen in a more realistic format.

Besides the eight planets, several moons are also included: Earth's moon is included; Mars' tiny moons Phobos and Deimos are shown in an inset panel (at the appropriate distance up Mars' gravity well for their orbits). Jupiter's moons Ganymede, Io, and Europa are included, as well as Saturn's moon Titan.

The {{w|Sun}} gravity well is not shown in it entirety, but is just indicated on the far left as ''"Very very far down"'' -- had it been shown in its full extent it would have made the rest of the drawing so small in comparison that it would have been unreadable.

==== Inner Planets ====

* Mercury -- no facts listed

* Venus -- no facts listed

* Earth & Moon -- listed with the depth of the gravity well of 5,478 km for Earth and 288 km for the Moon. Calculations of depth is explained in the Saturn insert.

* Mars -- listed with the depth of gravity well of 1286 km

==== Cut outs ====

* The Mars cutout shows how small mars moons really are, specifically in terms of gravity -- {{w|Deimos_(moon)|Deimos}} is so small that a bike jump would be sufficient to escape and on {{w|Phobos_(moon)|Phobos}} you could launch a baseball into space simply by throwing...

* The drawing next to Jupiter is playing on the classic "Yo Mama" joke, combining the aspects of your mom being very fat (having a huge gravitational pull) and very slutty (having sex with the entire football team), represented by them being attracted to, and falling into, her gravity well.

* The Earth/Moon cutout shows the significant difference in the {{w|gravity well}} between the two and explain why the moon landing needed such a {{w|Apollo_Lunar_Module|small vehicle}} to return to earth. The drawing shows that most space explanation like the {{w|International_Space_Station|space shuttle}}, {{w|GPS_satellite|GPS satellites}} and {{w|Geostationary_orbit|geo-stationary satellites}} are in fact still within the {{w|Gravity_well|gravity well}} of earth and has not really escaped.

==== Outer Planets ====

The fascinating fact about {{w|Jupiter}}'s mass is that it is border line in mass to have ignited as a {{w|Brown dwarf}} which is the smallest kind of star. Saturn, while similar in size, is composed of much lighter gas material and hence the mass is much smaller and the gravitational pull is smaller. Large gravity is a significant factor in igniting fusion, as the gravity pull the matter together to increase the pressure and temperature to the degree where the {{w|Nuclear_fusion|nuclear reactions}} can start. Had that happen at the creation of our solar system, i.e. had a few more Saturns dropped into Jupiter, then we would had two {{w|Sun}}'s and our solar system would have been a {{w|Binary star}}.

The figures on {{w|Titan_(moon)|Titan}} are sirens, a reference to Kurt Vonnegut's ''{{w|The Sirens of Titan}}''.

The "Rings" in {{w|Saturn}}'s gravity well are Saturn's rings: The farther you get from a planet, the weaker the effect of its gravity on you, so, at some point, when climbing out of Saturn's gravity well, you've reached the point equivalent to starting your climb from the rings of Saturn, or, in fact, from specific rings of Saturn: Saturn's rings start fairly near the planet and extend out fairly far, hence why there's several stripes..

{{w|Uranus}} -- notably absent is any "your-anus" jokes.

{{w|Neptune}} -- Megan's quote is a paraphrase of {{w|Carl_Sagan|Carl Sagan}}'s quote, "...but from a planet orbiting a star in a distant globular cluster, a still more glorious dawn awaits, not a sun-rise, but a galaxy rise." [[http://www.youtube.com/watch?v=zSgiXGELjbc Video here]]

==== How to interpret gravity wells ====

To escape a planet or satellite's orbit, you need merely climb to the highest of the two peaks to ''either''the left or right of the object. So, for example, to escape Venus, you need merely reach the peak left of it, the slope right of it is part of the Sun's gravity well, and shows how much further you'd need to climb out of the Sun's gravity well to get from Venus to Earth. Likewise, the peak left of Jupiter is slightly lower than the one to the right; this is because the rightmost peak includes the difficulty of moving away from the sun to get to Saturn, the next planet along.

The text explains that the depth of the well is mass-of-planet over radius-of-planet with newtons constant and 9.81 m/s² as constants, where 9.81 m/s² is the {{w|Gravity_of_Earth|acceleration of a free falling body at earths gravity}}.

The calculation for a gravity well is:
:depth = (G * Planet-mass ) / (9.81 m/s2 * Planet-radius)
::where G is {{w|Isaac_Newton|Newton}}'s {{w|Gravitational_constant|gravitational constant}}, and
::9.81 m/s2 is the {{w|Acceleration|acceleration}} rate of a {{w|Gravity_of_Earth|free falling body on earth}} at sea level (g).

==Transcript==
:'''Main Text'''
:Gravity Wells scaled to Earth surface gravity
:This chart shows the "depth" of various solar system gravity wells.
:Each well is scaled such that rising out of a physical well of that depth — in constant Earth surface gravity — would take the same energy as escaping from that planet's gravity in reality.
:Each planet is shown cut in half at the bottom of its well, with the depth of the well measured down to the planet's ''flat'' surface.
:The planet sizes are to the same scale as the wells. Interplanetary distances are not to scale.
:Depth = (G × PlanetMass) / (g × PlanetRadius)
:G = Newton's constant
:g = 9.81 m/s2

:'''Planetary Descriptions'''
:To Sun, very very far down
:Mercury
:Venus
:Earth - 5,478 km
:Moon - 288 km
:Mars - 1,286 km
:Ganymede
:Io
:Jupiter
::[A drawing of a "very deep" gravity well, "Your mom" at the bottom, several member of "local football team" falling down towards her.]
::Jupiter is not much larger than Saturn, but much more massive. At its size, adding more mass just makes it denser due to the extra squeezing of gravity.
::If you dropped a few dozen more Jupiters into it, the pressure would ignite fusion and make it a star.
:Europa
:Titan
::Two figures: Weeoooeeoooeeooo
:Saturn
::Rings
:Uranus
:Neptune
::Megan: An even more glorious dawn awaits!

:'''Mars Inset'''
:[Mars gravity well, the Pathfinder probe on its surface, with its moons Deimos and Phobos as smaller gravity wells.]

:[Figure of a man (to scale) in Deimos's gravity well.]
:You could escape Deimos with a bike and a ramp.

:[Figure of a man (to scale) in Phobos's gravity well.]
:A thrown baseball could escape Phobos.

:'''Earth Inset'''
:[Zoomed-in view of Earth/moon gravity well, featuring the relative locations of the atmosphere, Low Earth Orbit, the International Space Station, the Space Shuttle, GPS satellites, and satellites in geosynchronous orbit.]
:Cueball: This is why it took a huge rocket to get to the moon but only a small one to get back.

:It takes the same amount of energy to launch something on an escape trajectory away from Earth as it would to launch it 6,000 km upward under constant 9.81 m/s2 Earth gravity.

:Hence, Earth's well is 6,000 km deep.

{{comic discussion}}
[[Category:Comics with color]]
[[Category:Large drawings]]