We spoke to William Boynton on the show back in May about the mission so we decided to get back in touch with him to answer this question...

"We put the sample into a very small oven about the size of two drops of water and seal it to isolate it from the atmosphere.  We then flush out the atmosphere that was sealed in the oven with the sample with a flow of pure nitrogen gas.  The nitrogen gas is called a carrier gas and besides removing the atmosphere it is used to carry the evolved vapours generated during the heating over to the evolved gas analyser known as the sniffer.  This sniffer is a mass spectrometer – a machine that you can find in any chemistry lab back here on Earth.  This can accurately tell what molecules and atoms are in the sample."

Ben -  So if there was never a Big Bang, we’ve always had stars around - we know that what happens inside stars is hydrogen is converted into heavier elements like helium.  If there was no Big Bang then surely by now all the hydrogen would have been used up, is that right Sarah?

Sarah -  Well yes.  The idea that the universe has already existed is known as the Steady State theory.  This was developed in the 40s as an alternative to the Big Bang theory which is that the universe came into being and began to expand about 13.7 billion years ago.  The Steady State theory has lost favour since the 1960s because a lot of the evidence actually supports the Big Bang theory, particularly after the discovery of cosmic microwave background radiation which is the sort of thing that the James Webb telescope will be looking for.

Ben -   And it’s actually some of the stuff that you pick up on static on your TV.

Sarah -   Exactly, and on your radio as well.  You might think that even after 13.7 billion years the hydrogen might have all been converted but hydrogen still makes up about 75% of the normal matter in the universe.

Diana -  That’s quite a lot, isn’t it? Why is there so much still out there?

Sarah -  Most of it’s actually in low density, low temperature clouds of hydrogen where there just isn’t enough energy to fuse the nuclei to make helium or other elements.  This isn’t a spontaneous reaction.  It takes a serious amount of energy to do it which is why it did happen a second or so after the Big Bang and why it still happens in stars like our own sun.  The heat and the energy present is there to do it but it just isn’t there elsewhere in the universe.

Sarah -  Before Chris scampered off on his holidays he managed to pen an excellent answer to this on our forum and he says that basically the dish is full of holes to reduce the weight and the wind resistance aka the likelihood of it being blown away from your wall.  The dish works fine as a reflector despite it being full of holes because it’s picking up relatively long wavelength radio waves and microwaves.  Because the waves are longer than the diameter of the holes, they’re easily reflected by the mesh in the dish because the waves won’t fit through the holes.  What the waves see is effectively a smooth, flat surface which focuses the waves onto a point where the detector is positioned.  By doing this, gathering lots of waves over a large area and focussing them to a point you can get a much larger signal going to your TV.

Ben -  This is exactly what we did with our parabolic mirror in last week’s kitchen science.  What we were doing though, instead of focussing satellite signals, is actually focussing light and heat down onto a point.  You can actually use it the other way around and put the point source as your heat and use the dish to beam a jet of heat directly forward.  Dave did this to me in his garage and it really was quite uncomfortably warm.  Isn’t this the same reason why you have a gauze in the front of your microwave?

Sarah -  Yes, you know when you turn on your microwave you can see the light on inside but obviously the microwaves aren’t coming out at you.  It’s because the wavelength of the microwaves is much longer than the wavelength of visible light.  Although the light can get out through the mesh in the door the microwaves can’t.

Ben - And this is why you don’t cook your nose while you’re watching your food cooking!

Sarah -  We actually had some great responses to this on our forum from Paul.fr but basically the story is that thunderstorms are formed of what are known as cumulo-nimbus clouds.  These grow from the billowy cumulus clouds like the ones you see in cartoons and these grow upwards.  The reason they do this is because if the sun heats up the ground you get thermals which is like warm air and it rises, pushing up the clouds.

Ben -  Are these the same thermals that birds use to lift themselves really high up in the sky, and also in hang-gliders?

Sarah -  Yes. Big heavy birds like vultures, ones that live in quite hot areas, will wait for the thermals to rise before they can get up in the air because they’re quite heavy so they find it hard to take off.

Ben -  Once these thermals have lifted the clouds how do they get the flat top?

Sarah -  They keep growing upwards and then reach what is known as the tropopause which is the part of the atmosphere between the troposphere which is the bit nearest to the ground and the stratosphere which is the next layer up.

Ben -  What happens there?

Sarah -  What you get here is known as an inversion which is where you get cold air sitting over warm air.  What everyone’s used to is the warm air rising and therefore being above the cold air.  This doesn’t happen in the stratosphere because it gets colder and colder as you go up.  This means that the clouds can’t go any farther as it hits the wall of warm air.  It spreads out along the top and it’s very flat.  Obviously because the climate is very complicated there are other factors involved but that’s basically the story.