Weird Science Weekly: Maybe infinity isn’t as big as we thought

In this week's installment of Weird Science Weekly, we're looking at some of the strangest science around, including how adding numbers up to infinity doesn't necessarily give you what you might think, how for spiders sometimes it's 'twerk or die', and the rather disturbing realization that sponges can sneeze...

Adding numbers to infinity can actually give us a very small (and negative) answer

Infinity is a very strange concept. In principle, it's fine. Things go on and on forever, without ever stopping. Sure. That's not so hard to accept. However, if you really take a close look at infinity, it's a monster; a Nietzschean abyss that not only stares back at you ... it winks.

University of Nottingham physicists Tony Padilla and Ed Copeland are going to show just one of these 'winks' in the following video, which shows that adding up numbers to infinity doesn't necessarily give you an infinite result. It can sometimes result in a much smaller (and negative!) number instead!

For a detailed proof of the first series that Tony Padilla showed us (Grandi's Series, S = 1 - 1 + 1 - 1 ... = 1/2) click on the link that pops up in the video at 2:28, and Ed Copeland gives a longer proof (about 21 minutes) of this S = 1 + 2 + 3 + 4 + 5 ... = -1/12 series in another video (link is near the end of the above video).

As Tony Padilla says in the video, this may look like mathematical hocus-pocus, and in a way it is (check it out here), but the -1/12 result is supported by physics, and is very important for string theory. Since physics is how we describe the universe, it really reinforces just how weird of a place our universe really is!

(H/T to Phil Plait)

[ Related: Weird Science Weekly: NASA satellite reveals the rainbow sun ]

Male spiders 'twerk' to avoid being eaten

'Twerking' may be the new internet sensation these days, but researchers from Simon Fraser University have discovered that male spiders have been using this for a very good reason ... so they won't get eaten by their female counterparts.

"They take a few steps and then they stop and vibrate their abdomen, and then they take a few steps and vibrate again," Samantha Vibert, one of the study co-authors, told LiveScience.

The video first shows a male black widow spider vibrating (or 'twerking') its abdomen, then a male hobo spider walking around tapping and drumming on the web, and then tapping in the presence of a female. Lastly, it shows the standard female black widow spider response to vibrations in its web (what the male is trying to avoid) — attack! What the researchers found is that the 'twerking' of the male black widow causes vibrated 'whispers' that signal to the female that he's there to woo her, not as a meal.

"I think what really blew my mind was just how complex their signaling system is," Vilbert told LiveScience. "Spiders can be really beautiful, and they're a lot more complex than most people give them credit for. If you go past the spider fear, the phobia, there are really quite a lot of things that will make you smile."

[ Related: Weird Science Weekly: New telescope view fleshes out the ‘Hand of God’ ]

Sneezing sponges — they may have sensory organs after all

Okay, so sponges sneeze. I didn't see that coming.

That is a time-lapse video of a sponge contracting after sediment is added to the water it's in, captured by University of Alberta grad student Danielle Ludeman, which essentially shows it sneezing.

"The sneeze can tell us a lot about how the sponge works and how it’s responding to the environment,” Ludeman said in a university news release. "This paper really gets at the question of how sensory systems evolved. The sponge doesn't have a nervous system, so how can it respond to the environment with a sneeze the way another animal that does have a nervous system can?"

The full, open-access study is available on the web to read (click here for the pdf).

The really freaky thing about this ... a sponge sneeze lasts between 35 and 45 minutes, and involves its entire body. I've seen some pretty intense sneezes before, but that just sounds dangerous.

[ More Geekquinox: Time-lapse video 'Ancients' reveals the awesome splendour of our night sky ]

Keep your eyes on the wonders of science, and if you spot anything particularly strange you'd like me to check out for next week, comment below or drop me a line on Twitter!

(Image courtesy: Numberphile/YouTube)

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