Tuesday, 6 July 2010

An egg in space - or an egg in a vacuum - what would happen?

This is a question that has been bugging us at work.

What would happen to a chicken egg in space? Equally interesting is the question what would happen to a chicken egg if placed in a vacuum chamber?

Eggshells are able to withstand quite large forces from the outside because of their dome structure, but are not so strong from the inside. This makes sense - they need to be strong enough to withstand the force of the mother chook sitting on them, but need to be fragile enough from the inside for the baby chick to escape. If placed into a vacuum, would the pressure of the small amount of air inside the egg be enough to break the shell? Let's assume for the sake of argument that the egg was laid at normal atmospheric pressure.

Other things to consider include temperature. Would the egg white and egg yolk freeze and therefore expand? This could break the shell. Is there enough empty space inside the egg into which the mainly water interior could expand? Or would this happen too suddenly? Is temperature actually a factor?

Or perhaps a sudden change in pressure might cause the interior to rapidly boil, exploding the egg? Water only boils at 100 degrees at normal atmospheric pressure - the more you lower the pressure, the lower the temperature that water boils at. For instance, at the top of Mount Everest, the boiling point of water is 69 degrees. Human blood would boil in space except for the fact that our skin is strong enough to protect our blood from the rapid drop in pressure. Is an eggshell similarly strong, or is it too permeable?

Is there a difference between the scenario where the egg is in space - let's say at about the Earth's orbit - and so is heated by the Sun (or at least half of it), and in a vacuum chamber where there is no heat source?

As much as we like to ponder these questions, we don't have an answer. What do you think? Please feel free to speculate and throw ideas into the mix.

For extra reading, check out the references for work conducted on hatching chickens in low gravity, and also hypergravity.

References:
SUDA, T., ABE, E., SHINKI, T., KATAGIRI, T., YAMAGUCHI, A., YOKOSE, S., YOSHIKI, S., HORIKAWA, H., COHEN, G., & YASUGI, S. (1994). The role of gravity in chick embryogenesis FEBS Letters, 340 (1-2), 34-38 DOI: 10.1016/0014-5793(94)80168-1

Jones SM, Warren LE, Shukla R, Browning A, Fuller CA, & Jones TA (2000). The effects of hypergravity and substrate vibration on vestibular function in developing chickens. Journal of gravitational physiology : a journal of the International Society for Gravitational Physiology, 7 (3), 31-44 PMID: 12124183

8 comments:

  1. So an egg can stand pressure from outside pushing in, is this the opposite of what you'd get in a vacuum? I'd expect a vacuum to exert a sucking pressure pulling all sides of the egg outwards.

    My guess, omlette.

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  2. Eggs generally don't explode when you boil them (when you think the high temp might expand the air pocket inside). In saying this, if you put an egg into a microwave, it makes a very gooey mess!

    It might depend how quickly the pressure changed. I think there's a fair degree of permeability through the shell. We have chooks and our older chook lays thinner egg shells too so shell thickness might be a factor too.

    My question is what is the egg doing in space (or a vacuum) in the first place. I did see pea soup put in a vacuum on Masterchef last night (apparently to remove the air in the soup) and that looked impressive. Perhaps you can ask the chef from last night to put an egg into his machine...

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  3. David BofingerMay 01, 2011 8:55 pm

    I don't know much about eggs, you should ask a biologist. Here's a guess:

    Air leaks in and out through the egg, but only slowly. I don't know if water does.

    If the egg is suddenly put in a vacuum or if water can't get out then the egg breaks open, goopy stuff leaks everywhere, the chicken if any dies, the liquids boil away.

    If the pressure is reduced slowly and water can get out - and I don't know how long that would take, maybe hours or days? - the internal vacua of the egg rupture, the chicken if any dies, the liquids boil away, the egg is left dry and lifeless.
    None of this is much fun, especially for the egg. There's no good way for this to end.

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  4. From a colleague:

    "I don't know much about eggs, you should ask a biologist. Here's a guess: Air leaks in and out through the egg, but only slowly. I don't know if water does. If the egg is suddenly put in a vacuum or if water can't get out then the egg breaks open, goopy stuff leaks everywhere, the chicken if any dies, the liquids boil away.

    If the pressure is reduced slowly and water can get out - and I don't know how long that would take, maybe hours or days? - the internal vacua of the egg rupture, the chicken if any dies, the liquids boil away, the egg is left dry and lifeless. None of this is much fun, especially for the egg. There's no good way for this to end."

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  5. Thank you Mr Science for bringing this pressing national security issue to the public's attention. For too long the threat of chickens dropping eggs on us from space has been denied its due consideration as a genuine menace to the security of our peace-loving, but somewhat blinkered nation.

    As a specialist Defence Chickenologist, I have been monitoring the global arms race in chickens. Third world nations were quick to recognise the equivalence of chickens and fighter jets and have been active in the chicken/fighter sphere for many years (read our Minister for Defence's statement on the topic here: http://www.minister.defence.gov.au/gregCombetSpeechtpl.cfm?CurrentId=10522).

    Our former Prime Minister, Mr Rudd was keenly aware of the issue, although he tended to focus on the defence implications of Chinese chickens and the stragic threat they posted to first wrld countries (see http://news.ninemsn.com.au/national/1044339/rudd-ups-civilian-effort-in-afghanistan).

    It was a sad day for both Australia and Defence Chickenology when the fowl Julia Gillard stole, yes, stole the highest office in the land. Ms Gillard's ascension to the Prime Minister's Office has set the defence chicken movement back decades. She has turned the whole debate into a farce (see for example: http://www.abc.net.au/news/stories/2010/07/05/2944534.htm?section=features).

    I look forward to your next post on this critical topic.

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  6. My first thought was that something would happen, but nothing too exciting or explosive. People don't really explode in space, after all! We and the egg are used to one atmosphere, and we can withstand several atmospheres (as in deep sea diving) without injury if you're careful. By contrast, you can't have negative pressure, only lower pressure - down to zero. An egg in a vacuum has one less atmosphere of pressure on it than it usually would, and I don't think the pressure inside is so great as to make it explode.

    The pressure might not make as much difference here as it would for water, say; at high altitudes on Earth, it can apparently take longer to cook eggs - possibly because the boiling water is at a lower temperature. So my guess is that in space, the white and yolk would probably freeze, and even on Earth this cracks the shell. I don't think the egg will become the egg equivalent of steam; it's made of complex proteins and won't behave the same way as a simple, pure substance like water.

    The other variable is that while the inside may have less strength than the outside, a chick using its egg tooth or beak to peck a hole by applying force at a single point isn't the same as equal force on the entire shell. Probably the force wouldn't be uniform, though, since the distribution of yolk and white inside isn't uniform either.

    So, to sum up all my musings and lunchtime Google research: I think the egg would freeze and the shell would crack, but I don't think it would explode.

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  7. I wonder what would happen if you took an egg in the vacuum of space, empty it via a tiny hole, and somehow perfectly seal the hole. If you were to take it back to earth, would it shoot up on its own or would it implode?

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