Science Questions

Could we send all the plastic to the Sun?

Tue, 12th Jan 2016

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Enzamul Haque asked:

I think we should stop using plastics because it will make our world worse. I have an idea about how we can destroy every inch of plastic, why don't we put all plastic in a largest space rocket & send this to sun. This will destroy all the plastic.


Kat Arney put this question to physicist Stuart Higgins...the sun

Stuart - Well we can.  Occasionally old spacecraft and things,  maybe not towards the sun, but are bashed into planets all the time to get rid of them.  But in terms of plastic - the problem is the sheer quantity of plastic that we have.  So last year, the Earth produces about three hundred million tons of plastic.  A million tons is about the weight of  of 750 Empire State Buildings - it’s a massive quantity.

Kat - So okay.  In terms of like the jet fuel that we’d need to get a rocket made of that much plastic up there would - it’s not economic is it?

Stuart - It’s not.  So I did a quick back of the envelope calculation, I must stress…

Chris - It wasn’t a plastic envelope?

Stuart - It wasn’t a plastic envelope.

Kat - A little plastic window in it though.

Stuart - So the heaviest rocket - the heaviest lifting rocket that we’ve had was Saturn 5.  It was the rocket that took astronauts to the moon and that had the capability of lifting 50 tons-ish to the moon.  So if we think, actually, it would take 6 million rocket launches to get all the plastic from just one year up towards the moon, not even to the sun.  And if we think there are only about 85 rocket launches a year - that’s about 70,000 years it would take just to shift last year’s plastic.

Kat - And Enzamul does goes on to say that this use of plastics is clearly bad and that we should stop using them - are they all plastics bad?  Maybe Ben as well, you’d like to come in on this. Are all plastics bad and there any really viable alternatives to get us off our fossil fuel plastics?

Ben - So plastic’s a material called polymer, sort of formed from long chains, and part of the problem is that these chains are quite chemically unreactive.  They persist in the environment because the microorganisms can’t attack them and start to break them down, but there has been a lot of work recently on more biodegradable polymers.  So these are ones that still have the sort of mechanical properties to be a useful plastic, but can sort of be attacked on over time by the microbes and might rot away in the ground after a year or two.  And, certainly, they wouldn’t be as bad because eventually they would go from a landfill site, unlike the ones at the moment.

Kat - Stuart - what do you think?

Stuart - Well I think this is it.  So one of the things in our field - we were talking about plastic electronics earlier.  And one of the challenges we have to consider as we make things is what we’re going to do with all the plastic we’re using and generating.  So, I think further research into biodegradable plastics and how we process them if we can do recycling on them, is really important.

Kat - Yes.  I guess what you were saying about the flexible screens.  You know if you kind of throw it up, put it in your pocket and eventually it dies - just chuck it away!  Is there any progress in trying to recycle these kinds of electronics?

Stuart - Yes.  So, in general, you can recycle some electronics.  You kind try and recover the metals and things out of them, but this is very energy intensive.  It takes a lot of energy to do and so there’s always a trade off there, so maybe if we can look at ways of developing new techniques and new materials and biodegradable polymers - that would be a better approach.



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