Magnus
Magnus
[Cueball walks from the right towards Megan while holding up his smartphone.] Cueball: Magnus Carlsen has an app where you can play chess against a simulated version of him at different ages. Cueball: I can beat the 8½-year-old, but lose to him at 9.
[While Megan talks to Cueball he lifts his hand to his chin, while holding the smartphone down.] Megan: I want that, but for other games. Can I beat 8-year-old Serena Williams at Tennis? Swim laps faster than a 6-year-old Michael Phelps? Cueball: We should make a simulator.
[Cueball walks out left and Megan follows him. He must have pocketed his phone as it is not in his hand.] Cueball: ...Why limit it to games? Can I cook a better chicken than 11-year-old Martha Stewart? Megan: Win an election against 12-year-old JFK?
[At the top frame of this panel there is a small frame with a caption. Below lies Megan on the floor to the left in front of her laptop, while Cueball sits on the floor to the right facing her in front of his own laptop. Between them are some heavy books.] Soon... [Cueball and Megan sitting at laptops in the bottom of the panel.] Megan: Looks like 8-year-old Magnus Carlsen can swim faster than 9-year-old Martha Stewart. Cueball: But they both lose a hot-dog-eating contest to 2-year-old Secretariat. Megan: This project has gotten weird.

Cueball shows Megan an app , Play Magnus ( iOS , Android ) which claims to simulate playing chess against Magnus Carlsen at various ages. Carlsen is a chess grandmaster who is the world champion as of the date this comic was released.
The idea behind the app is that as Carlsen grows up he becomes better at chess and thus it become exceedingly difficult to beat him as he gets older. As Cueball claims he could have beaten Magnus when he was 8½-year-old, but not a half-year later, we can now estimate Cueballs strength to be that of a typical adult hobbyist, with a FIDE rating of about 1200 .
Taking the idea a step further, Megan wants such an app for other sports tennis and swimming , where skill couldn't imaginably be simulated via an app at all. She wants to compare herself to an 8-year-old Serena Williams , a top-ranked professional tennis player. Or to a 6-year-old Michael Phelps , the most decorated Olympian competitor of all time.
Cueball expands beyond sport, wishing to determine if he could cook better than an 11-year-old Martha Stewart (author of several cookbooks). Megan wonders if she'd have won an election against a 12-year old JFK ( John F. Kennedy , the 35th American President). Obviously, cooking and politics were skills acquired later in life for both figures.  Also, the U.S. Constitution prohibits anyone from serving as President before the age of 35 , so it seems unlikely that any 12-year-old candidate could win, regardless of skill level, simply because voters would not want to elect someone ineligible to serve for another 23 years. Such a contest would likely be prohibited altogether, as ineligible candidates tend to have ballot access issues.
Cueball and Megan continue speculating about an app simulating the skills of random celebrities at various ages, even beyond the talents that made them famous. They finally end up comparing 8-year-old Magnus's swimming skill against 9-year-old Martha's (he wins). But they'd both lose a hot dog - eating contest against the championship race horse Secretariat . At this point even Megan realizes (with considerable understatement) their project "has gotten weird".
The title text extends the point to even greater absurdity, e.g. the ludicrous prospect of a young Martha Stewart knocking an adult Ronda Rousey (professional wrestler and actress) unconscious, or 9-year-old Muhammad Ali (professional boxer and activist) beating a 10-year-old JFK in air hockey . The former may be a reference to the fact that professional wrestling is more entertainment than competition, and the outcomes are often pre-staged, so the victor would not depend on which contestant was more skilled. This was also referenced in the title text of 2291: New Sports System . The horse also gets re-mentioned in the title text, losing in a hot dog eating contest against 12-year-old Ken Jennings (at time of comic writing record-holder of winning streak on television game show Jeopardy! ).
Chess was previously compared to basketball in 1392: Dominant Players , which also mentioned Magnus. This is the tenth comic about chess on xkcd .
[Cueball walks from the right towards Megan while holding up his smartphone.] Cueball: Magnus Carlsen has an app where you can play chess against a simulated version of him at different ages. Cueball: I can beat the 8½-year-old, but lose to him at 9.
[While Megan talks to Cueball he lifts his hand to his chin, while holding the smartphone down.] Megan: I want that, but for other games. Can I beat 8-year-old Serena Williams at Tennis? Swim laps faster than a 6-year-old Michael Phelps? Cueball: We should make a simulator.
[Cueball walks out left and Megan follows him. He must have pocketed his phone as it is not in his hand.] Cueball: ...Why limit it to games? Can I cook a better chicken than 11-year-old Martha Stewart? Megan: Win an election against 12-year-old JFK?
[At the top frame of this panel there is a small frame with a caption. Below lies Megan on the floor to the left in front of her laptop, while Cueball sits on the floor to the right facing her in front of his own laptop. Between them are some heavy books.] Soon... [Cueball and Megan sitting at laptops in the bottom of the panel.] Megan: Looks like 8-year-old Magnus Carlsen can swim faster than 9-year-old Martha Stewart. Cueball: But they both lose a hot-dog-eating contest to 2-year-old Secretariat. Megan: This project has gotten weird.
