Main Page

Explain xkcd: It's 'cause you're dumb.
(Difference between revisions)
Jump to: navigation, search
m (Waldir moved page Explain xkcd to explain xkcd: page titles are case-sensitive now)
m (Waldir moved page explain xkcd to Main Page: revert move)

Revision as of 19:57, 12 August 2012

Welcome to the explain xkcd wiki! We already have 11 comic explanations!

(But there are still 1690 to go. Come and add yours!)

Latest comic

Go to this comic

Speed and Danger
NASCAR removed the passenger seats because drivers hated how astronauts kept riding along with them and loudly announcing "Ahh, what a nice and relaxing drive."
Title text: NASCAR removed the passenger seats because drivers hated how astronauts kept riding along with them and loudly announcing "Ahh, what a nice and relaxing drive."


Ambox notice.png This explanation may be incomplete or incorrect: More on the speed of sport cars and the race cars. How much faster does it feel for a human to see a regular sports car on a high way and then a formula one car. More on why a rocket seems slow?

In this scatter plot Randall plots the speed of several vehicles (including people on foot for "normal sports") and how disastrous a crash would be. The punchline is that space rockets travel so dangerously fast, and crashes are so utterly catastrophic, that it pushes literally every other kind of crash to the "slow and safe" corner by comparison.

With the plot Randall makes the observation that the danger of a crash is greatly influenced by its speed and highlights the concept of relativity between what we perceive as 'fast', normal sports and two different types of racing cars, vs. a much faster vehicle, a rocket during launch. A rocket may appear to ascend slowly (and of course it begins its ascent slowly), but on the way to orbit it ends up moving very fast. But before it reaches the more extreme speed regime it will be far away from the ground (and the casual observer), where there is nothing to compare this speed to as opposed to a race car speeding by a spectator during a race. (Of course rockets are slow compared to the speed of light...)

Apart from the high speed, there is also the altitude to take into account for the rocket launch, and the vast amount of fuel needed to get into orbit, and any sort of failure is almost certainly fatal.

Racing cars are often involved in crashes, but at that speed it is possible to construct them so even serious crashes may not be fatal. Although rockets are also made as safe as possible, it is a completely different regime of speed and danger, and the risk of something going wrong during a take off is much higher, and it is impossible to prevent a lethal disaster if the launch fails during the ascent. This results in a much higher mortality rate for each crashed rocket (probably 100%) vs. crashed sports/race cars.

Rocket launches is compared to normal sports, NASCAR (which reaches speeds of 320 km/h (200 mph)), and Formula One, where the fastest race cars go 380 km/h (240 mph).

A rockets launched to reach the ISS needs to eventually match the speed of the space station which moves at 27,600 km/h (17,100 mph), and a rocket that needs to escape from Earth (like in going to the Mars) needs to reach 40,270 km/h (25,020 mph). The lowest of these speeds divided by the highest of the cars is still more then 70 times as fast...

The title text serves to further emphasize the point, as an astronaut (used to the several G's of acceleration during takeoff and overall much higher speeds) would likely find a NASCAR car moving at ~200mph paltry compared to what they're acclimated to and has supposedly aggravated NASCAR drivers by making a point of saying so. And thus this is used to explain why there is no passenger seats in NASCARS, to prevent astronauts in joining the drivers for a nice slow ride.

Of the many charts in xkcd this one is notable for containing the fewest samples of point of any scatter plots in xkcd.


[A two-axis diagram with two double headed arrows centered in the middle of the panel. Each arrow is labeled. There are four large dots in the diagram, three close together in the top left corner and one in the bottom right corner. Each dot is labeled.]
[Y axis:]
Top: Crashes are safe
Bottom: Crashes are dangerous
[X axis:]
Left: Slow
Right: Fast
[Dots from top left to bottom right:]
Normal sports
Formula One
Rocket launches

New here?

Feel free to sign up for an account and contribute to the explain xkcd wiki! We need explanations for comics, characters, themes, memes and everything in between. If it is referenced in an xkcd web comic, it should be here.

  • List of all comics contains a complete table of all xkcd comics so far and the corresponding explanations. The red links (like this) are missing explanations. Feel free to help out by creating them!


Don't be a jerk. There are a lot of comics that don't have set in stone explanations, feel free to put multiple interpretations in the wiki page for each comic.

If you want to talk about a specific comic, use its discussion page.

Please only submit material directly related to—and helping everyone better understand—xkcd... and of course only submit material that can legally be posted (and freely edited.) Off-topic or other inappropriate content is subject to removal or modification at admin discretion, and users posting such are at risk of being blocked.

If you need assistance from an admin, feel free to leave a message on their personal discussion page. The list of admins is here.

Explain xkcd logo courtesy of User:Alek2407.

Personal tools


It seems you are using noscript, which is stopping our project wonderful ads from working. Explain xkcd uses ads to pay for bandwidth, and we manually approve all our advertisers, and our ads are restricted to unobtrusive images and slow animated GIFs. If you found this site helpful, please consider whitelisting us.

Want to advertise with us, or donate to us with Paypal?