Stuart Coulson asked:
What shape would a spider web be in space?
Chris - Ooh! That’s a hard one. Dave, what do you think?
Dave - I don’t know.
Chris - In space, there is microgravity.
Dave - There's almost no gravity. There's nothing to get the spider to align itself but I don’t know whether a spider is aligning to gravity or whether it’s doing it visually.
Chris - Kat, your perspective?
Kat - I reckon, it might struggle, because they kind of fling themselves around to make their webs, so I think it might struggle with that. And also, I remember the study where they gave spiders different drugs and saw the effect on their webs, so I wonder what would be the effect of spiders on drugs in space as well?
Chris - Okay, so you answered the question with another one. Well I'm pleased to say, Alan Boyd who’s working with us at the moment as one of our interns, found a wonderful paper, which is actually doing this. NASA did this experiment aboard Endeavour, the penultimate space mission using the shuttle. It went up last May and I've got a little write-up which is in Wired magazine so I’ll just quote from this...
“A pair of golden orb spiders called Gladys and Esmerelda were shot into space on Endeavour in May. The experiment was part of a K-12 curriculum which, when school is back in session, will let students compare the behaviour of spiders kept in the classroom as well as spidernauts (as they're dubbing them).” They say, “On Earth, these spiders which are Nephila clavipes, generally spin large, circular webs, and they actually make webs that look like they have been chopped off at the top.” So they are horizontal across the top. “When they spun the webs in space, the spider’s webs ended up completely circular. The spiders, which use gravity to orient themselves seem unsure about which way to face at times, say researchers at the University of Colorado at Boulder, who were behind this study. Golden orb spiders normally use gravity when building the long lines that radiate from the web's centre - occasionally letting go to drop to the ground. But when she lets go, Esmerelda (that’s one of the spiders) doesn't have gravity to bring her down, so she just floats about instead of dropping.”
So, I think, Stuart, the answer is that the pictures they’ve got on this article and from NASA’s own website shows spiders that do seem to make quite good webs except they're very much circular. They don’t have that horizontal across the top, so the spider appears to be able to compensate for the absence of gravity and still orientates itself.
Stuart - How interesting. Obviously, it’s an odd one because it’s a very 2D-shaped and obviously now, I'm thinking of 3D shapes in space, like cocoons and things. I wonder if there would be other animals that would maybe struggle. I was thinking of the whole “caterpillar to butterfly phase” when they create the cocoon, I wonder whether they would struggle with that because if they are using gravity obviously to return themselves on that downward loop. If they can't do that, I wonder what strange shapes they would produce.
Chris - Dave?
Dave - I guess it depends whether gravity has a big effect on how they're growing because quite a lot of this sort of thing will be to do with chemical signals and electromagnetic forces. I don’t know how much gravity is important in embryology and things like that.
Chris - Certainly, NASA did do a very nice experiment a few years back looking at how plants grow in space because one of the big questions is, when you plant a seed, why does the root always grow downwards and the shoots goes upwards? How does the plant know what’s down? And it was an experiment done on the space shuttle that in fact proved it, it was on the Columbia mission, unfortunately, the one that crashed, but experiment survived, and they managed to get it from the wreckage. It revealed that in fact, in plant cells, what you’ve got are lots of tiny grains of starch bobbing around inside the cell. Under the influence of gravity, they settle inside the cell and as they settle, they push on a structure called the cytoskeleton, which is a fine network of threads and connective tissue inside the cell that holds the cell together. And the cell can sense this, so it knows what direction is downwards, and grown in space, moss, instead of growing in one direction, it grew in a funny spiral because it didn’t have that so-called geotropism.