Main Page
Welcome to the explain xkcd wiki! We already have 12 comic explanations!
(But there are still 3247 to go. Come and add yours!)
Latest comic
| Asteroid Threat |
 Title text: Paleontologists have long worried that the dinosaurs blasted into space 66 million years ago will one day complete their orbits and fall back down. |
Explanation
It's generally agreed by scientists that most dinosaurs went extinct primarily as a result, either directly or indirectly, of the Chicxulub asteroid impacting the Earth near the Yucatán Peninsula 66 million years ago. This comic posits that another asteroid is soon going to hit the Earth again. Because the impact location will be on the exact opposite side of the planet (the antipode), the comic takes the absurd notion that it will act the 'opposite' way, reversing all the original effects and bringing dinosaurs back from extinction.
The general consensus is that most dinosaurs that weren't in the immediate vicinity of the impact itself went extinct as a result of the environmental effect it had. Other factors have been proposed to explain the extinction, and the relative contributory effect of these has been a matter of some debate. The title text suggests that the initial Chicxulub event actually resulted in the dinosaurs' disappearance because it involved the dinosaurs launching, or being launched, alive into space. Either the shock of the asteroid strike somehow threw them loose from the planet, or the geology has been misinterpreted and is actually the result of the dinosaurs intentionally engineering a massive rocket blast. They have since been on a long path, most likely circling the Sun, that will some day intersect with the Earth again, and they will land still alive and take control again.
This is ridiculous, for a number of reasons. Firstly, they would they have to somehow survive, and potentially arrange, the initial event. There is no evidence that the dinosaurs developed rocketry techniques, while an impact strong enough to have knocked them into space would have subjected them to violent forces that they were not adapted to withstand. Secondly, they would need to sustain a breeding population in the airless vacuum of space through to the present day. Again, dinosaurs do not seem to have had the technology for space travel, and such a long journey would require extra complications in that they would need to also breed and grow food for the duration, requiring them to maintain an entire ecosystem. Lastly they would need to survive their presumably meteoric re-entry through the Earth's atmosphere and the impact with its surface - a thoroughly impossible feat.
Because Earth rocks have been found on the Moon, there has been some speculation that microscopic fragments of fossils from the era of dinosaurs or earlier may have landed on the moon, but no such fragments have been collected.
This could also be seen as a joke referencing the second law of thermodynamics, that entropy can only rise (i.e. you cannot undo destruction by doing the original action in reverse).
Transcript
- [Two images of Earth are shown. At the top left is a small one, centered on southern West Africa, showing the Atlantic Ocean and the east coast of South America, with a dotted line through the Earth entering at the Yucatán Peninsula and exiting at the east-central Indian Ocean. Taking up most of the rest of the panel is a large Earth image centered on the Indian Ocean and containing a target symbol, comprising a circle and four spokes, aimed at a location in the east-central Indian Ocean.]
- [Caption below image:]
- Dire news: An asteroid is on course to hit the earth exactly opposite the Yucatán Peninsula, bringing back the dinosaurs.
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.
- If you're new to wikis like this, take a look at these help pages describing how to navigate the wiki, and how to edit pages.
- Discussion about various parts of the wiki is going on at Explain XKCD:Community portal. Share your 2¢!
- 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!
Rules
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.
Logo
Explain xkcd logo courtesy of User:Alek2407.
