Asked by James (aged eight)

At 43 foot (13 metres) long and weighing up to nine tons (heavier than one and a half African elephants), Tyrannosaurus Rex was one of the largest meat-eating dinosaurs to have lived, but not the biggest dinosaur ever. Spinosaurus aegyptiacus was even longer at up to 59 feet (18 metres), and possibly twice as heavy. However, the largest dinosaurs were herbivores, not meat-eaters.

The largest dinosaur we know about from good fossils was the long-necked sauropod Argentinosaurus huinculensis, which was possibly 98 feet (30 metres) long (longer than three London buses end-to-end) and weighed over 90 tons (almost as much as 17 African elephants). Another sauropod dinosaur called Amphicoelias altus may have been larger, but the fossil bones of this creature are lost. Working out the size of dinosaurs is very difficult, because we very rarely find complete skeletons. Normally we only have a few bones available to estimate overall size and weight, so there may be many different estimates.

Dr Stig Walsh, Senior Curator of Vertebrate Palaeobiology, National Museums Scotland

Italian Paolo Nespoli, 54, has spent 174 days in space across two missions, travelling into Earth orbit on both NASA’s Space Shuttle and the Russian Soyuz spacecraft. We asked what it’s like to live in space, how it felt to witness the Space Shuttle docked to the ISS and more in our exclusive interview.

How It Works: Why did you decide to become an astronaut?

Paolo Nespoli: Ever since I was a little boy I wanted to become an astronaut. I was inspired by the Apollo missions, though not really Apollo 11. I was more interested in the later missions where they drove the rovers on the moon. I thought it was fascinating, with the astronauts jumping and driving around on the surface. Life was kind of different after that. I was drafted into the Italian army (they still had the draft back then) then figured out that I could make it as an astronaut. I applied twice to the European Space Agency (ESA) and didn’t make it, but on the third selection I made the cut.

HIW: Your first mission to space was on board STS-120. What was it like going to space for the first time?

PN: I was selected fairly young and got to fly after just nine years of training, which is somewhat of a short time to wait compared to many. People asked if I was scared but I wasn’t really. I’d trained so much, I knew what to expect. Feeling the acceleration in the Space Shuttle was amazing. The first couple of minutes it really shakes you. However, I was scared in space, because we’d trained for years and we only had 15 days to complete our mission. All I kept thinking to myself was, ‘You better not mess this up. People have been working on this for years!’ The fear of failure was the scariest thing about going into space.

HIW: What was the hardest part of going to space?

PN: I didn’t mind it so much in space, but my body felt really old when I came back to Earth; the gravity was so intense. I was fine in space, but I’m not exceptional or a superhero. Of the seven Shuttle crew members and three on the Soyuz I was the worst coming back by far. The micro-gravity environment does a lot to your body. You lose a lot of calcium in space; your bones and muscles can get quite weak.

HIW: How did you ensure your body stayed in shape? How did you adapt to life in space?

PN: We’d do about two hours of physical fitness every day. I would say you come back in better shape [in terms of fitness]. Doing two hours of exercise every day for six months, I came back with more muscles and less fat than when I left.

We did about one hour of cardiovascular exercise on a treadmill and another hour of resistance exercise. Obviously, you can’t lift weights in space, so a machine simulates the strain of lifting as on Earth.

There’s no training to prepare your body for its loss of balance. You get nausea and all sorts of things. Your skeleton also stretches (I was five or six centimetres taller than on Earth), and so muscles keep their strength but they are of a different length. Your body’s equilibrium shifts, and when you come back to Earth the muscles start contracting again, but they cannot find the equilibrium point so easily. I remember shaking constantly. Also I could be sitting and feel totally tired. Coming back to Earth is definitely the hardest aspect of being in space – for me, anyway!

On the station, you are isolated and confined, with only a few other people to talk to. You can’t just go out in the evening and see people. For some reason I discovered that whatever I was doing I was seeing pizzas all over the place, such as in clouds when looking at Earth. Freud would probably have a lot to say about that! I thought the food on the station was decent but far away from what an Italian would say is delicious. It was very good from a nutritional point of view, but a little horrific for an Italian. Maybe I was craving pizza because of food like that, or maybe I was just associating pizza with going out with friends and having a beer, maybe that is what I was missing. You are in isolation up there, and there are a lot of things you can’t do, a lot of things which aren’t normal.

Sometimes you forget that you’re in space. It takes about a month and a half before you get out of your ‘Earth habits’, getting used to space, doing things in a different way. For example, we had a table in one of the nodes for eating in the evening. That table had been there for years. It was horizontal in respect to the floor of the deck, because that’s how a table is on Earth. It was protruding a lot, and you’d often hit it when going past. One day I was looking at it and I thought, ‘There must be a way to do this better. Why is this table parallel to the deck, when there’s no gravity?’ You use Velcro to stick things to the table anyway so that they don’t float away, so why not have it at an angle, like a technical drawing table? I kind of tilted it up a little bit, then more, and more, until finally, if you look at it now, it’s tilted at a steep angle because you don’t need a horizontal table and it’s much more out of the way. It was there for ten years before somebody thought to move it!

I would say that it is an environment that is closed, isolated and confined. At first, when I was told I would spend six months on the station before the mission, I thought, ‘Oh my God, six months, are you out of your mind?’ Looking back I realised that I did not have the time to do everything I wanted, like taking more pictures, looking at Earth, playing around more, calling people, doing video clips. You end up doing things up there that make sense, time flies and everything is nice, but you wish you could have done more.

HIW: What was your favourite aspect of living in space?

PN: I loved taking pictures, looking at the Earth and [re]discovering it. It was very enjoyable. You just go to the window and there you have it – a great and gorgeous view. However, when you go to the window randomly, more often than not you’re just going to see an ocean with clouds. It’s nice and blue, but that’s about it. Sometimes you see a piece of land going by and it’s not so recognisable. It’s not easy to figure out what’s what, except Italy! When you start talking about the UK and Ireland it gets complicated because of the angle, cloud coverage, time of day and sun reflection, etc. In the beginning you try to figure out where you are without using the software that tells us, but little by little you start to know what’s going on. By the second/third/fourth months you look out the window and you know where you are – the continent, information, features that are there that you might want to take pictures of, or if it’s boring you might spend a few minutes on something else.

I started using more and more powerful lenses to capture some interesting details that I could see from up there. First I tried to see the Egyptian pyramids, the Great Wall of China, and other landmarks. I wanted to see an aircraft carrier at sea, some volcanoes, special islands, and then I started looking around randomly, taking pictures of things that were astonishing and different. I had this feeling that I was a scientist peering down a microscope that allowed me to take pictures of this small sphere rotating below, discovering microscopic things. I’d look at the pictures and realise that those things were 20 kilometres [12.4 miles] in diameter. You can’t really see things that are any smaller than that.

I became really interested in taking photos of landmarks and countries. I started using social media like Twitter and Flickr because I thought those things were interesting. I decided to start tweeting them to see what people thought. That turned out to be a pretty good source of enjoyment: finding something special and tweeting it to people, asking them for quizzes or riddles from space and seeing all the comments. It turned out to be a very enjoyable way to spend time, letting everybody participate in this adventure.

HIW: Were you asked to take the pictures by NASA or the ESA?

PN: I wasn’t asked to do it by NASA or the ESA. Some of the other astronauts had done it before me. I was not the first. Several of them told me that it was enjoyable. I did not tweet before I went into space because I don’t have much time to do it. I see some people go around with phones all day, typing what they are doing, clicking, clicking, clicking, but I have so many things to do. However, in space it worked out pretty well. Sometimes when I was taking pictures I was asking for help from ESA to identify what I was looking at. Other times I would guess but sometimes I would make a mistake, and people would correct me, so I learned that it was better to verify what I was seeing before half of the world thinks, ‘What is that stupid astronaut doing up there?!’ One of the first weeks I was up I tweeted a picture of a European city and really thought it was London… Turns out it was Paris. How can you make a mistake between London and Paris? It was beyond me. But in space, you travel so fast that you pass by so quickly, and you only have a few seconds to snap a picture. You have no time to research, so mistakes do happen.

HIW: Did it feel like you were travelling at 17,000mph?

PN: Well, it depends. If you are above an ocean, for example, which happened often, it doesn’t look like you are going very fast. But if you want to take a picture of something specific, then you understand how precise you need to be. I’m always on space time now. When I’m at home in the evening, and I look outside and see a sunset or moon. I see a nice picture and think, ‘Okay, I’m going to get my camera and I’ll take a picture in 30 minutes’. In space if you see the moon and you like it, you better take that picture in the next ten seconds because [otherwise] it’s gone. A good sunset is eight seconds and you think, ‘Oh, that’s a nice sunset, I’ll just get my camera… Holy cow, I need a picture now, where’s that camera!’ If you take out the card or wrong lens, then it’s gone. [This is how I mainly perceived speed on the ISS.]

You don’t feel anything physically on the ISS or the Soyuz capsule though. I remember when we detached from the station on Soyuz coming back to Earth, there is a moment in which the engine fires and you slow down and go into the atmosphere, and the capsule breaks up into three pieces. You are in the middle, the only one that gets to Earth; the others burn up in the atmosphere. At that point you are tumbling, finishing with a braking burn. The capsule has separated and you are waiting to be captured by the atmosphere. Then you look outside and realise you’re tumbling. It’s not a nice feeling. Are we supposed to be tumbling, you think. If you don’t look outside you don’t feel it, even at mach 25.

Kevlar is able to stop a bullet due to its molecular structure. It is a light, polyarylamide plastic fabric, which has a high tensile strength. this means it takes a huge amount of energy to make its fibres stretch even a little. Each Kevlar molecule looks like a long twisting coil. During polymerisation these coils of molecules become tangled, causing it to be hard to stretch.

Inside a bulletproof vest are many strips and layers of Kevlar. When a bullet hits the vest, it tries to force it through the layers, but to do this it must push the fibres apart. The fibres are woven and resist this very effectively. The movement is translated into a stretching force on the fibres. Some will break, but most will absorb the energy of the bullet by stretching a small amount.

Nathaniel Marten, Science Museum

In return for the amazing gadgets you see on this page, we want to find out what you think about How It Works magazine. Simply head on over to the How It Works survey and fill in our online questionnaire and ALL these goodies could be yours. Tell us what you like most about How It Works and you could walk off with £800 worth of swag under your arm.

At 58.5 metres (192 feet) the platforms at Hampstead station (opened 22 June 1907) are the deepest of all the London Underground stations. Hampstead also has the deepest lift shaft on the system at 55.2 metres (181 feet); that’s just 1.2 metres (four feet) less than the height of Nelson’s Column! On 11 April 1954, two new high-speed lifts, which travelled the 55-metre (181-foot) journey in 18 seconds (almost four times as fast as the 1907 lifts they replaced), came into service. They were then the fastest lifts anywhere in the UK.

Not surprisingly the station also has the longest spiral staircase on the system, with a total 310 steps. A notice advises passengers not to use them.

Answered by Caroline Warhurst, London Transport Museum.

Naked

The only asteroid in the main belt visible to the naked eye is Vesta, which has a mean diameter of 530km and contains nine per cent of the entire asteroid belt’s mass.

Coma

The way comets and asteroids are distinguished relies on visual appearance, with comets displaying a perceptible coma behind them while asteroids have none.

Naming

Once an asteroid has been discovered it can only be named under the consultation of the International Astronomical Union, who will approve or disapprove the proposition.

Photo

The first true asteroids to be photographed close up were Gaspra in 1991 and Ida in 1993. They were imaged by the Galileo space probe en route to Jupiter.

New

The latest asteroid to be landed on is Itokawa, an S-type asteroid that crosses the path of Mars. The Hayabusa space probe returned to Earth with a surface sample.

Human hair grows on average 1.25 centimetres (0.5 inches) per month, which is equivalent to about 15 centimetres (six inches) per year. There are several variables that can affect hair’s growth rate such as age, health and genetics. Each hair grows in three stages, the first being the anagen phase where most growth occurs. The longer your hair remains in this stage dictates how long and quickly it develops; this can last between two and eight years and is followed by the catagen (transitional) and telogen (resting) phases. Hair growth rates vary across different areas of the head, with that on the crown growing the fastest.

Answered by Laura Mead, Science Museum.

Imagine Publishing has launched a new digital-only, Multi-Touch ebook, iCloud For Beginners, specifically designed for Apple’s iBooks 2. Featuring slideshows, interactive images and more, it is one of the first ebooks of its type in the world.

Using iBooks Author’s revolutionary Multi-Touch technology, iCloud For Beginners teaches everything users need to know about iCloud, the free new back-up and sync service. From how to set-up your free iCloud account to sharing your information across your Apple devices, the ebook uses cutting-edge technology to deliver enhanced, easy-to-use tutorials.

“At Imagine, we’re always excited by cool new ways to deliver our world-leading content.” said Editor In Chief Aaron Asadi “iBooks Author is another great opportunity for us to create more products we love for a whole new type of audience. It’s this sort of game-changing innovation that makes us do what we do. ”

“With the speed that the publishing industry is changing, there’s nothing more exhilarating than grabbing hold of new technologies and seeing how we can get the most out of them to serve-up the content we’re so passionate about” added Ross Andrews, Head of Design “What could be better than going from saying ‘we should try that’ to a fully published product in just a few days? It’s hard to think of a more exciting time for the industry.”

iCloud For Beginners is available now on iTunes and iBookstore worldwide.

Imagine Publishing is one of the UK’s fastest-growing multimedia content producers. Formed in May 2005, Imagine now publishes 20 regular print magazines, 30 digital apps, 25 websites and thousands of articles every month in the technology, videogames, photography and knowledge/science markets. An Imagine magazine is purchased every ten seconds.

Imagine Publishing
01202 586200
www.imagine-publishing.co.uk

At the centre of every atom is a nucleus containing protons and neutrons. Together, protons and neutrons are known as nucleons. Around this core of the atom, a certain number of electrons orbit in shells. The nucleus and electrons are referred to as subatomic particles. The electrons orbit around the centre of the atom due to the charges present; protons have a positive charge, neutrons are neutral and electrons have a negative charge. It is the electromagnetic force that keeps the electrons in orbit due to these charges, one of the four fundamental forces of nature. It acts between charged objects – such as inside a battery – by the interaction of photons, which are the basic units of light.

An atom is about one tenth of a nanometre in diameter. 43 million iron atoms lined up side by side would produce a line only one millimetre in length. However, most of an atom is empty space. The nucleus of the atom accounts for only a 10,000th of the overall size of the atom, despite containing almost all of the atom’s mass. Protons and neutrons have about 2,000 times more mass than an electron, which results in the electrons orbit the nucleus at a large distance as they in turn have an extremely low mass.

An atom represents the smallest part of an element that can exist by itself. Each element’s atoms have a different structure. The number of protons inside a specific element is unique. For example, carbon has six protons whereas gold has 79. However, some elements have more than one form. The other forms – known as isotopes – will have the same number of protons but a different number of neutrons. For example, hydrogen has three forms which all have one proton; tritium has two neutrons, deuterium has one neutron and hydrogen itself has none.

As different atoms have different numbers of protons and neutrons, they also have different masses, which determine the properties of an element. The larger the mass of an atom the smaller its size, as the electrons orbit more closely to the nucleus due to a stronger electromagnetic force. For example an atom of sulphur, which has 16 protons and 16 neutrons, has the same mass as 32 hydrogen atoms, which each have one proton and no neutrons.

(Image credit: Science Photo Library)

Humans use the energy in food to live; this energy is measured in calories. If people consume lots of calories from food and don’t burn them up, they get converted to fat and stored in the body and so people gain weight. This was very important when humans were not always guaranteed access to food daily. They could use the stored fat in their bodies for energy until they could find food again. If people burn more calories than they consume through food, by doing lots of exercise etc, then their bodies use the fat stores instead and, as a result, they lose weight.

Answered by Kate Mulcahy, Science Museum.