Time Travel Thesis
Time Travel Thesis
[Cueball is facing Megan, talking to her.] Cueball: I've been reading about time travel. Megan: Cool! I did my thesis on time travel!
[Cueball is now gesturing toward Megan. An electrical charge of some sort is shown occurring outside the panel in the bottom right corner behind Megan.] Cueball: Nice! So you know about closed timelike curves? Megan: Yup. Thesis. Cueball: Apparently wormholes can use exotic matter to– Megan: I know. Like I said– Charge: Bzzzt!
[Megan has turned away from Cueball to the right. Megan from the future, wearing sunglasses, a headset and a machine strapped to her back has entered the frame from the right where the charge appeared.] Future-Megan: You can skip this conversation. It doesn't turn out to be important. Megan: Oh, thank God.
[Cueball is standing alone, the two Megans have left the panel.]

Cueball has apparently been reading about time travel . He tells Megan about this, and Megan excitedly remarks that she did her college thesis on time travel which basically means that she is supposed to know a lot more about time travel than a guy who has just been "reading" about it.
Cueball, however, continues to ask her if she knows basic facts about time travel (like closed timelike curves , wormholes and exotic matter ), like he is investigating if he has discovered facets about it that she would have overlooked while writing a thesis about it. Megan keeps trying to say that since she wrote a Time Travel Thesis , (hence the title of the comic), she already knows all of this and much, much more, and she is obviously getting frustrated by Cueball's attempts to impress her with his "knowledge".
At this point Megan's future-self arrives with a Bzzzzt , having used time travel to arrive at this exact moment in time. It seem she has continued her research and has successfully managed to make a time machine.
The reason she arrives is only to tell her younger self that this conversation with Cueball doesn't go anywhere and isn't important, and so present-Megan can leave and not waste her time anymore. Up till then, Megan was presumably reluctant to break off a conversation on the topic of time travel, since the conversation could potentially have improved, or perhaps because he at least had read about time travel which is a subject she would have a clear interest in since she wrote a thesis on it. But once the conversation began to run off track, it came as a relief to know that she could quit without the risk of missing out on anything important. Also, since Megan took the effort to time travel back to this exact moment, that must mean the conversation was so boring and uneventful she kept regretting having this conversation even far into the future to the point where she remembers it as one of the moments that need to be changed with her acquired time travel abilities.
And then she just walks away with her future-self leaving Cueball hanging in the last panel, having invented a completely new way to get out of useless/boring conversations.
Alternatively, future-Megan just makes an excuse to haul present-Megan off in order to prevent the latter from disclosing some details of time travel science to Cueball, which could have unintended consequences. However, using very advanced technology, or even violating physics law, for very mundane ends is very common in xkcd, so using time travel to prevent useless conversation is not surprising from Megan.
In either case, future-Megan finished this conversation before inventing time travel, and thus knows this conversation's outcome. So by coming back, she now changes her own (and Cueball's) future. Of course the general implications of being able to travel like this are enormous, and the paradoxes arising from such a possibility are endless, the most pressing (at the moment) being the grandfather paradox , where a time traveler creates circumstances that negate their existence (such as killing their own grandfather), in this case, Older Megan going back in time to stop Younger Megan from finishing this conversation, who will eventually become Older Megan but with no reason to go back to tell Younger Megan to stop this boring conversation. It is worth noting, however, that the comic does not inherently cause a paradox: so long as the Megan who didn't finish the conversation stills travels back in time with the knowledge that the conversation needed to be stopped and still saves her younger self from wasting her time, a time loop can be logically sustained. (It is also worth noting that a "Mobius" time loop is also perfectly possible, the grandfather paradox isn't a paradox if quantum entanglement is taken into account - something Megan would no doubt know)
It is possible that Randall may have had some conversations like this, where after having spent a lot of time getting nothing out of it himself, would have wished his future self had come back to tell him to just leave the conversation now.
In the title text present-Megan asks future-Megan about her futuristic googles and what they are for, presumably assuming they are needed for the time travel (maybe it is the backpack?). People from the future wearing weird clothing, often involving eyewear of some sort is a trope in Science-Fiction. Movies like Back to the Future Part II which tried to predict the fashion of 2015 back in 1989 didn't get it right, so this might be a commentary on those movies. However it turns out it's just some old and broken Google Glass . The only reason future Megan wears these is that she attended a party at the club that had a 2010's night theme. The fact that the Google Glass is broken and from 2010 alludes to Randall believing that the project was a fad that and that it will never pan out, even in the future. Indeed that seems to be the case. It seems generally that Randall is no fan of Google Glass, which was also shown earlier in 1251: Anti-Glass and later again in 1304: Glass Trolling . Google Glass has become a recurring theme in xkcd.
This is an indication of how far from the future she has traveled, as Google Glass was first released in the 2010s. It is not clear whether she is wearing Google Glass because it became popular in the 2010s or because it was an esoteric piece of hardware that people would readily associate with the 2010s. Also a 90s party may be thrown today, but not a 2000s party. So it is safe to assume that Megan is at least from the 2030s. Also people attending retro dress-up parties frequently make mistakes and do not dress up exactly in-style, creating some anachronisms, especially if they dress up like they did many years ago.
[Cueball is facing Megan, talking to her.] Cueball: I've been reading about time travel. Megan: Cool! I did my thesis on time travel!
[Cueball is now gesturing toward Megan. An electrical charge of some sort is shown occurring outside the panel in the bottom right corner behind Megan.] Cueball: Nice! So you know about closed timelike curves? Megan: Yup. Thesis. Cueball: Apparently wormholes can use exotic matter to– Megan: I know. Like I said– Charge: Bzzzt!
[Megan has turned away from Cueball to the right. Megan from the future, wearing sunglasses, a headset and a machine strapped to her back has entered the frame from the right where the charge appeared.] Future-Megan: You can skip this conversation. It doesn't turn out to be important. Megan: Oh, thank God.
[Cueball is standing alone, the two Megans have left the panel.]
