explain xkcd - User contributions [en]

1337: Hack

2025-01-22T20:46:00Z

141.101.76.92: Undo revision 363220 by 172.71.223.38 (talk) Except that wasn't actually a typo. See Blag...

<noinclude>:''"1337", this comic's number, redirects here. For the series of the same name, see [[:Category:1337]].''</noinclude>
{{comic
| number = 1337
| date = March 3, 2014
| title = Hack
| image = hack.png
| titletext = HACK THE STARS
}}

==Explanation==
This comic is an imagined project to re-position the {{w|International Cometary Explorer|ISEE-3/ICE}} probe, and a parody of the 1995 movie ''{{w|Hackers (film)|Hackers}}''.

The history of the probe, as laid out in the comic, is true. The probe did, indeed, return to signal range in 2014, and seemed capable of being controlled, but NASA declined to devote the resources necessary to re-establish communication. The proposed, independent project to take control of the probe and send it on a new mission didn't exist at the time of the comic, but has since [http://spacecollege.org/isee3/ become reality], as [[Randall]] noted in a [http://blog.xkcd.com/2014/05/30/isee-3/ blag post]. See [[#Background for ISEE-3/ICE|details below]].

The film ''Hackers'' was about the exploits of a group of teenage computer hackers, and their adventures in gaining unauthorized access to various systems. Like many fictional depictions of hacking, the film was heavily criticized for its lack of technical accuracy, but it did a lot to interest mainstream youth at the time in hacker culture. The primary protagonist goes by the handle "Crash Override", and his rival (and love interest) goes by "Acid Burn". The film ends with the two of them in a swimming pool, on their first date, with the lights in several nearby buildings spelling out "Crash And Burn", in Crash's latest hack/romantic gesture.

The strip depicts a scene in the satellite's control room, which plays out like many of the hacking scenes in the movie, with the system operators being shocked and flummoxed at being locked out of their own system, while an unauthorized party takes control and sends alternative instructions. The screen displays the phrase "mess with the best, die like the rest", which was Crash's signature phrase in the film.

The final row depicts a recreation of (or sequel to) the final scene of the film, with Crash and Burn once again swimming together. This time, however, Burn tells Crash to "make a wish", immediately before a shooting star appears in the sky (there's a tradition of making wishes when shooting stars appear in the sky). The implication is that Burn is the one who hacked the satellite controls and that she placed the satellite on a course for earth, causing it to burn up in the atmosphere in exactly the right time and place to create her own shooting star. This is arguably a much more impressive feat than controlling building lights, and definitely one-ups his previous romantic gesture. Since the ability to do something so dramatic by hacking computer systems depended on a very specific and rare set of circumstances, it's unlikely that he'll ever be able to top it.

The comic number is 1337, which stands for "leet", short for "elite hacker" and "leetspeek" in {{w|leetspeak}}. Leetspeak is a form of symbolic writing that substitutes various numbers and {{w|ASCII}} symbols for letters. It originates from the hacker subculture, where words were converted to leetspeek e.g., to avoid filters and triggers on chat rooms. "1337" for "leet" can most likely be explained as {{w|calculator spelling}}.

The title text "Hack the stars" is also an allusion to ''Hackers'', where the phrase "Hack the planet!" is used on multiple occasions.

==Transcript==
:[A black image shows an image of the ISEE-3/ICE spacecraft in white. Text is written in white above it]
:The ISEE-3/ICE probe was launched in 1978.
:Its mission ended in 1997 and it was sent a shutdown signal.

:[The text continues, black on white, without a frame around it, between the first frame and the next.]
:In 2008, we learned-to our surprise-that the probe didn't shut down.
:It's still running and it has plenty of fuel.
:...and in 2014, its orbit brings it near earth.

:[Megan holding up one hand and Ponytail are talking to each other.]
:Megan: We could send it on a new mission...
:Megan: Except we no longer have the equipment to send commands to it.
:Ponytail: Can't we—

:[Zoom in on Megan's head and torso as she looks towards Ponytail off-panel to the right.]
:Megan: NASA won't rebuild it. "Too Expensive"
:Ponytail (off-panel): ''Seriously?''
:Megan: I know, right?
:Megan: So the internet found the specs
:Megan: And we went to work.

:[Megan and Ponytail are walking towards right, between Hairbun facing left and Cueball (with head phones) facing right. They are sitting at desks working on their laptops. Megan speaks, as indicated both by the story line and by her hand which is lifted up, but there is not speech line from her to the text.]
:Megan: We've convinced them to give us time on the Madrid DSN transmitter and hacked the maser to support the uplink.
:Megan: And today's the big day.

:[Zoom in on Cueball's head and torso, he holds a hand up to his speaker on his head phones and watches his lit screen (as indicated by lines emanating from it).]
:Cueball: Transmitting...
:Cueball: We have a signal!
:Cueball: We have control!

:[Zoom in on Megan's head and torso. She has turned away from Cueball to the right towards Hairbun.]
:Megan: OK, transmit the new comet rendezvous maneuver sequen—
:Cueball (off panel): What ''the hell?''
:Megan: What?

:[Same setting as when Megan and Ponytail entered the control-room, but Ponytail just stands there and Megan puts a hand out towards Cueball.]
:Cueball: My console went dead!
:Hairbun: ''Mine too!''
:Megan: What's happening?!

:[Another zoom in on Cueball's head and torso and glowing screen. He has both hands down.]
:Cueball: There's a new signal going out over the transmitter!
:Megan (off panel): A bug?
:Cueball: ''Someone else is in the system!''

:[Zoom in on Hairbun's head and torso. She is also working on her laptop, with the glowing screen visible.]
:Hairbun: Kill the connection!
:Cueball (off panel): ''I can't find it!''
:Hairbun: ''They're firing the probe's engines!''
:Cueball (off panel): ''No!!''

:[Back to a zoom in on Cueball. He points at his screen.]
:Megan (off panel): ''Who's '''doing''' this??'' Stop them!
:Hairbun (off panel): ''I'm trying!''
:Cueball: ''Look! My screen!''

:[Same setting as when Megan and Ponytail entered the control-room, but Ponytail has a hand to her mouth and she and Megan stand close to Cueball who has taken his hands off the keyboard. The text on Cueball's laptop screen is shown above the setting, indicated with zigzag lines:]
:M-E-S-S-W-I-T-H-
:T-H-E-B-E-S-T

:D-I-E-L-I-K-E-
:T-H-E-R-E-S-T

:[The last four panels is outside night scenes with a black sky above. In the first of these a woman (Burn) with long hair (Megan like) and a hairy man (Crash) is seen in a swimming pool with blue water.]

:[A zoom out reveals that the pool is on top of a skyscraper in a vertically developed, downtown setting with lots of light in all the skyscrapers, one of which is even taller than the one with the pool. From the top of the central skyscraper speech lines come which indicate that the two from the pool is up there speaking, and we get their names from this panel.]
:Burn: Crash?
:Crash: Yeah, Burn?

:[Same setting but only one speech line.]
:Burn: Make a wish.

:[The last panel shows the same setting, but with the spacecraft streaking across the sky as it enters the Earths atmosphere and burns up in a way that is indistinguishable from a meteoroid.]

==Trivia==

===Background for ISEE-3/ICE===
The {{w|International Cometary Explorer|ISEE-3/ICE}} probe was launched in August 12, 1978 and tasked to study Earth's magnetic field and the solar wind. Before completing its original mission the probe was repurposed on June 10, 1982 to study the interaction between the solar wind and a cometary atmosphere. By flying through the comet {{w|21P/Giacobini–Zinner|Giacobini-Zinner}}'s tail, it became the first probe to do so. This put ISEE-3 in a {{w|heliocentric orbit}}. Its trajectory will bring it close to Earth on August 2014.

The Deep Space Network (DSN) detected the probe again in 2008 because NASA mistakenly left its transmitters on. However, the probe was only transmitting the carrier signal at that time. A status check of the spacecraft has revealed that many of its instruments are still working and that it contains plenty of fuel.<ref>Lakdawalla, Emily (2014-02-07). [https://www.planetary.org/articles/02070836-isee-3 "ICE/ISEE-3 to return to an Earth no longer capable of speaking to it"]. ''The Planetary Society''. Retrieved 2024-06-17.</ref>

It was reported that the hardware to communicate with ISEE-3/ICE had been decommissioned. The Madrid DSS complex still has the special filter required to communicate with the ICE satellite, but because of frequency conflicts S-band uplink is not supported.<ref>{{W|Jet Propulsion Laboratory}}. [https://deepspace.jpl.nasa.gov/dsndocs/810-005/101/101E.pdf "70-m Subnet Telecommunications Interfaces"] (PDF). {{w|Deep Space Network}}. 810-005, 101, Rev. E.</ref>

On March 1 and 2, 2014 radio amateurs were able to detect the beacon signal from the retired NASA deep space probe ICE (International Cometary Explorer) using the 20 m radio telescope at the Bochum Observatory (Germany).<ref>[https://amsat-uk.org/2014/03/09/radio-amateurs-receive-nasa-isee-3ice-spacecraft/ "Radio amateurs receive NASA ISEE-3 / ICE Spacecraft"]. ''AMSAT-UK''. 2014-03-09. Retrieved 2024-06-17./</ref>

===Updates for ISEE-3/ICE===
After this comic was published, it was established that an 18-meter satellite dish at the Johns Hopkins Applied Physics Laboratory does still have the right hardware.
*April 4, 2014: Volunteers started a crowdfunding project on RocketHub to contact the probe and put it back into a {{w|halo orbit}} orbit around {{w|Lagrangian point}} L1.<ref>Wingo, Dennis; Cowing, Keith. [https://web.archive.org/web/20140417052853/https://www.rockethub.com/42228 "ISEE-3 Reboot Project"]. ''RocketHub''. Space College, Skycorp, and SpaceRef. Archived from [https://www.rockethub.com/42228 the original] on 2014-04-17. Retrieved 2024-06-17.</ref>
*May 23, 2014: First contact to the probe was established.
*May 29, 2014: NASA gave them approval to try to achieve contact.
*May 30, 2014: The project, led by [http://www.rockethub.com/profiles/68340-dennis-wingo Dennis Wingo] and {{w|Keith Cowing}}, had taken control of the spacecraft.
*July 2, 2014: The reboot project successfully fired the thrusters for the first time since 1987. The engines on ISEE-3 performed a successful spin-up burn. The spin rate was changed to 19.76 rpm which is inside of the original mission specifications at 19.75 +/- 0.2 rpm.
**Further attempts to change the trajectory into an earth bound orbit did fail. Despite the effort from experts and amateurs via the internet<ref>[https://spacecollege.org/isee3/we-are-borg-crowdsourced-isee-3-engineering-and-the-collective-mind-of-the-internet.html "We Are Borg: Crowdsourced ISEE-3 Engineering and the Collective Mind of the Internet"]. ''Space College''. 2014-07-14. Retrieved 2024-06-17.</ref> it was determined that the spacecraft had run out of nitrogen pressurant.
*Since the device was still communicating, and many of the instruments were still working, the ISEE-3 was intended to be used for the first citizen science, crowd funded, crowd sourced, interplanetary space science mission.<ref>[https://spacecollege.org/isee3/announcing-the-isee-3-interplanetary-citizen-science-mission.html "Announcing the ISEE-3 Interplanetary Citizen Science Mission"]. ''Space College''. 2014-07-24. Retrieved 2024-06-17.</ref>
*{{w|International_Cometary_Explorer#Contact_lost|Contact was finally lost}} on 2014-09-16.

See [http://spacecollege.org/isee3/ Space College: ISEE-3 Reboot Project Archives] for the coverage of this amazing project.

== References ==
{{reflist}}

{{comic discussion}}

[[Category:Comics with inverted brightness]]
[[Category:Comics with color]]
[[Category:Comics featuring Cueball]]
[[Category:Comics featuring Megan]]
[[Category:Comics featuring Ponytail]]
[[Category:Comics featuring Hairbun]]
[[Category:Space probes]]
[[Category:Astronomy]]
[[Category:Computers]]

Talk:3038: Uncanceled Units

2025-01-15T20:45:48Z

141.101.76.92:

DUDE I'M STILL IN SCHOOL RN, WHAT?
(also, the joke is that energy is power*time, so kWh is kJ/s... in an hour [[User:CalibansCreations|'''Caliban''']] ([[User talk:CalibansCreations|talk]]) 13:27, 15 January 2025 (UTC)

I guess not every comic can be a winner. Talking about an appliance using a certain amount of kWH per day is clear and normal. Power gets billed by the kWh, not the Joule. While technically not wrong, wanting "cancel" a sub-part of the commonly-used energy unit kWh and leaving it in deliberately-obscured units most people are less familiar with is the sort of insanity I'd more expect from White Hat than Cueball. [[Special:Contributions/172.70.35.171|172.70.35.171]] 13:39, 15 January 2025 (UTC)
:Maybe that is a meta-joke? To frame kWh/day as something crazy by giving that line to whitehat --[[User:Lupo|Lupo]] ([[User talk:Lupo|talk]]) 13:52, 15 January 2025 (UTC)
:There's a difference between instantaneous power draw, and the total "volume"(/area, really) of power over time. Though a fridge is "always on", it is still only irregularly at full-draw. But, to the power company (or to the gas company, who will generally give a kWh measure of 'energy taken from the network'), they don't (generally) care whether you used twice as many kW over half the time or half as many over twice the time, within any given total billing period, even if it affects what you think. [[Special:Contributions/172.70.163.46|172.70.163.46]] 14:39, 15 January 2025 (UTC)
::Using joule as if it was an everyday unit of energy would be weird but I don't agree that watt is crazy. It's a normal unit of energy consumption that does mean something to people, e.g. 1000W microwave, 100W (incandescent) light bulb. Don't get me wrong kWh/day is also useful to translate it to your energy bill, but I do feel slightly uncomfortable every time I see that time divided by time :-) [[User:Mtcv|Mtcv]] ([[User talk:Mtcv|talk]]) 14:40, 15 January 2025 (UTC)

This is especially funny with US units. My car needs about 5l/100km, or 0.05mm². Now I am wondering how many ft^(-2) my car does... --[[User:Lupo|Lupo]] ([[User talk:Lupo|talk]]) 13:49, 15 January 2025 (UTC)
: You make a good point about the units (at least in one instance). Shouldn't the reduced units for fuel economy be inverse area? Effectively, it is a measure of the distance the vehicle could travel while consuming a column of fuel with a specific height and specific top (or bottom) surface area. Or, The better the fuel economy, the less the surface area that is necessary to move a specific distance. SammyChips 20:41, 15 January 2025 (UTC)
:: More usefully imagined as the front (or back) end of a horizontal column (or, twisting as it may, a pipeline) that traverses the journey made by the vehicle. As if (instantaneous variations excepted) you consume precisely the fuel that your vehicle passes 'through/around'. [[Special:Contributions/141.101.76.92|141.101.76.92]] 20:45, 15 January 2025 (UTC)

fridge [[Special:Contributions/172.70.126.147|172.70.126.147]] 14:22, 15 January 2025 (UTC)

The late [https://en.wikipedia.org/wiki/David_J._C._MacKay Sir David MacKay] wrote an excellent book, [http://www.withouthotair.com/ Sustainable Energy – without the hot air] (which is available free online).
On [http://www.withouthotair.com/c2/page_24.shtml this page] he talks about the units he uses in the book: kWh for energy ("one unit") and kWh/day for power - becuase it's simple for lay-people to understand - how many units does this appliance use per day.
It's a good book if any of you are interested in sustainable energy (although it was written in 2008, so some bits might be out of date by now) {{unsigned ip|172.70.85.33|14:33, 15 January 2025}}

If anyone's curious, I found an online gallons per square foot calculator: https://www.omnicalculator.com/construction/gallons-per-square-foot [[Special:Contributions/172.71.223.6|172.71.223.6]] 15:54, 15 January 2025 (UTC)

The answer to Cueball's question is likely NO in the US and YES in the UK, due not just to gallon size but also fridge size (a model like that is a particularly large fridge, when I bought one 10 years ago going for the smallest available I had to modify my cabinet above the fridge as there wasn't one less than 6'8"- the fridge hole was 6' previous).[[User:Seebert|Seebert]] ([[User talk:Seebert|talk]]) 16:02, 15 January 2025 (UTC)

I disagree with this comic, and I think the final paragraph in the explanation about Hubble's constant best explains why. [[User:Beanie|Beanie]] [[User talk:Beanie|talk]] 15:57, 15 January 2025 (UTC)

Technically, kWh should be written as kW⋅h or kW h, because it literally means "kilowatts multiplied by one hour", not "kilowatts per hour" as many people assume. However, almost nobody writes it correctly. (kW/h is sometimes also seen, but egregiously incorrect.) Also, particularly now that electric vehicles are becoming more popular, people often get confused between kW and kW h. The car can charge at a peak or average rate expressed in kW, but energy billed by a charging service provider is expressed in kWh. People frequently either add or remove the "h" incorrectly because they don't understand the difference. In some places like India, a kilowatt-hour is simply referred to as a "unit" to avoid confusion. In my opinion, it was an enormous mistake to use kWh when we could be using mJ instead, which I think is probably something close to the point Randall may have been trying to make. Anyway, I wasn't sure if there was a place for any of this random trivia in the article itself, but feel free to use it. [[User:Equites|Equites]] ([[User talk:Equites|talk]]) 17:11, 15 January 2025 (UTC)

Relevant XKCD… I mean relevant YouTube video: "Cursed units" 1 and 2: https://www.youtube.com/watch?v=kkfIXUjkYqE https://www.youtube.com/watch?v=Zg7xe8MkJHs [[User:Fabian42|Fabian42]] ([[User talk:Fabian42|talk]]) 17:31, 15 January 2025 (UTC)

: Highly relevant, in fact. The first video referred to the kilowatt-hour as "cursed", which became a highly polarizing issue in the comments, something that was addressed at the beginning of part 2. Assuming these responses weren't cherry-picked, I get the impression that there are a lot of people on both sides of this. It seems like the same kind of thing we're seeing in this very comment section. [[User:ISaveXKCDpapers|ISaveXKCDpapers]] ([[User talk:ISaveXKCDpapers|talk]]) 18:10, 15 January 2025 (UTC)

I always wonder why people here prefer liter/m^2 for the amount of rain. Where the same number as mm is way easier to imagine. [[Special:Contributions/172.68.50.99|172.68.50.99]] 18:14, 15 January 2025 (UTC)
: You would rather have it in microliters/mm^2? At least something like mL/cm^2 might be nice considering the density of water, even though the value would be different by a factor. SammyChips 20:35, 15 January 2025 (UTC)