We thought we’d start off by taking a look at emergency service vehicles. In the event of a disaster, the emergency services are always on hand to sort things out. From cop cars with high-tech tracking equipment to ambulances kitted out exactly like a hospital on wheels, you’ll learn everything you ever wanted to know about these life-saving vehicles in this bumper six-page feature.

With the launch of the iPad, we thought we’d open one up and take a look inside. Don’t worry, it’s not as gory as all that. In this clinical dissection you’ll see exactly what’s inside the iPad and discover how it works too.

We bring you yet another great space extravaganza this issue as we take an in-depth look at some of space exploration’s most amazing gizmos – space robots. Find out why developments in space robotics are so vital to the future of exploring our Solar System, and learn all about the robots of tomorrow in this four-page feature.

We asked our resident alternative fuel expert, HydroKevin, to set to work on a huge feature that ventures beneath the hood of hydrogen-powered cars and reveals just how these zero-emission vehicles work. Fully annotated and wonderfully explained, this feature is your one-stop shop for the answers to all your hydrogen-powered car questions.

And finally, because you keep telling us how much you all love discovering things you didn’t know about your own bodies, we thought it was about time we found out more about muscles – just how the dickens do they work? You’ll find out what muscles are made of, how an arm can flex as well as an insight to what affects muscle strength.

Of course, that’s not all. We also have plenty of nutritious edutainment on such essential subjects as smoke alarms, quicksand, coral reefs, fermentation, medieval armour, superchargers, Neptune, the Solar Impulse, dolphins, petrol pumps, rebreathers, brown dwarfs, the Spitzer Space Telescope, coal mining, vocal cords, fruit machines, understanding hieroglyphs and shed loads more. So as you can see, it’s all right here in issue 7 of How It Works – on sale 22 April and even earlier if you’re a subscriber. Enjoy the preview.

Professor Brian Cox: Wonders is a documentary about astronomy and physics. Since the BBC last made a documentary series about the solar system a decade ago, we have lived through what I believe is something of a golden age of exploration. We’ve confirmed that there was once water on Mars, and have seen evidence that there may still be liquid water beneath the Martian surface today. We are now virtually certain that Jupiter’s moon Europa has a liquid water ocean beneath its icy crust that is perhaps 100km deep, and therefore contains more water than all the oceans of Earth. We’ve seen fountains of ice erupting from Saturn’s tiny moon Enceladus, and parachuted to the surface of the giant moon Titan, on which we have discovered lakes of liquid methane, methane snow and methane rain.

To find out what else everyone’s favourite scientist had to say, including the rest of this answer, remember to get your copy of How It Works issue 7, which hits the shops on 22 April – earlier if you subscribe.

Images courtesy of the BBC

Saturn – The Roche lobe causes gravitational forces around Saturn to hold rocky particles

Inner rings – Inner rings are made up of rock particles that never formed into a moon

Outer rings – Outer rings are caused by geysers in the south pole of Saturn

Why does Saturn have rings but other planets do not? The answer has to do with something called the Roche lobe, named after a French astronomer. It seems when a planet orbits around a star (eg our Sun) and that planet has its own orbiting objects (eg a moon), a gravitational pull occurs between the objects. Around Earth, orbiting rocks formed into the moon. On Saturn, the rocks never coalesced and are still orbiting.

Interestingly, the rings are only a few miles in thickness because of the highly localised effects from the Roche lobe. Dr Steve Maran, a noted astronomer, says Galileo was the first to discover the rings, but could not explain them. Today, viewing angles from the Hubble Space Telescope reveal an enormous region extending widely around the planet. There’s also one distinct outer ring, which Maran attributes to geysers emitting from the icy southern polar region on Saturn, leaving a more distinct trail.