Science Series Space

The Importance of the Moon

Earth's natural satellite - the moonThe Moon is something many of us take for granted. It doesn’t really do that much, it just sits up their in space.

When someone talks about the Moon what springs to mind? Werewolves? Cheese? Wallace and Gromit?

Maybe you think of Apollo 11 in 1969 and Neil Armstrong and Buzz Aldrin setting foot on the Moon.

I watched a very interesting BBC documentary recently called Do We Really Need the Moon? It explored how important the Moon has been to the development of life on Earth, and how important it may become in the future of space travel.

The Moon is likely to have been critical to the creation of life on Earth. It is believed that the Moon was formed when another planet crashed into Earth. At this point, the Earth was an uninhabitable, unstable lava wasteland. The collision created millions of pieces of molten rock which were sent into orbit. The biggest of these chunks of liquid rock grouped together (thanks to our old friend gravity) to form a new structure. Eventually all the pieces either became a part of the Moon, joined onto the Earth, or were flung off into space.

This massive collision reset Earth’s chemistry. Over the next 7 million years, it is thought that the Earth cooled, and water vapour condensed to form oceans. Oceans which the Moon controlled. The water nearest the Moon is affected by its gravitational pull more. This means that water recedes in other areas, amassing in the part of the ocean that is closest to the Moon. This is what creates the tides we know today, the same tides that are thought to have helped to create life – around 4 billion years ago.

Moon's gravity pulling the Earth
A picture from the BBC documentary Do We Really Need the Moon? showing how the Moon’s gravity pulls the oceans of the world towards it – creating tides.

So the Moon helped to create life, but that’s not all, it also helps to maintain it. The distance the Moon is away from the Earth, means that the tides are not too extreme. If the Moon were 20 times close than it is today then the Moon’s gravity would be 400 times stronger than it is today. This would create a huge tidal surge that would completely submerge all major cities around the world. At night, London would be underwater, and then a few hours later the waters would recede and flood New York. Evolution would not be able to adapt to changes that happened this quickly, and life on Earth would not exist.

The Moon also protects us in another way. Here is an image of the nearside of the Moon – the side we always see.

The nearside of the MoonNow here is an image of the farside, also known as the dark side of the Moon.

The farside of the MoonNotice a difference?

The farside is covered in a mass of craters, whilst the nearside is largely unscathed. Every crater on the farside of the Moon is a potential impact that the Moon has prevented for the Earth. Imagine that all meteoroids in space are chunks of iron, and the Moon is a giant magnet. The Moon pulls a lot of this space debris towards it.

Inevitably some meteoroids will collide with Earth, however the Moon does a pretty good job of shielding our planet from a lot of dangerous impacts.

We are pretty lucky really, if the Moon were much closer, or bigger, we wouldn’t be able to survive. Likewise, if it didn’t exist, we wouldn’t be here in the first place.

So next time you see the Moon, spare a thought for how integral it is to life on Earth.

That’s Not It!

Enjoyed this article? Feeling like you want a bit more Moon stuff? Next week I continue to look at the Moon, this time from the perspective of space travel!

Media Technology

A look into the technology used in live television

Around the world billions of people watched the Olympic Games last month. In this article I am going to explore the technology that is used in order to get the live action, be it aquatics, basket ball or shooting, from the event, onto our TV screens.

Live TV is a little different to recorded television. With recorded television, it has often been carefully chopped up and edited before it hits our screens. With live TV, the luxury of being able to remove mistakes isn’t there, as too much a delay would mean events were actually not live. There are a few seconds of delay between real events and what you see on your TV screen, like their is with radio, however this isn’t enough time for any extensive editing.

So imagine we are watching the men’s Olympic 100 metres final. Usain Bolt lines up along with two other Jamaicans, three Americans, a Trinidadian man and a Dutch man. The starters pistol blows and then what?

Well there is a lot more video broadcast equipment involved than you might think!

The Camera

The first part of the chain is the cameras. These capture all the events first hand. At an event like the Olympics, there will usually be tens, and sometimes hundreds of cameras, and a good broadcaster will always try to keep them out of shot of each other – so you don’t get a camera panning to a shot which features another camera in it!

The camera may be free standing, or it could be on a dolly or a jib. A camera dolly is effectively a track that the camera sits on, so that it is able to move smoothly to capture moving action. A jib is a device which has a camera on one end and a counterweight on the other. A jib allows a camera to be moved freely around an area. When you see a swooping style shot on television, that will usually have been achieved by a jib.

A camera on a track
A camera dolly

The camera will have various different wires coming out of it which will ultimately lead to a monitor. Behind the monitor will be a director who decides how and where the camera is to move to get the best shot.

The Mixing Desk

The camera will then link into a mixing desk, which in a live event like the Olympics will usually be in a really big, extremely technical looking van. Inside the van will have a number of operators choosing which of the hundreds of buttons to press, and which shot should be used – don’t forget there will be loads!

This van will control the stream of visual and audio footage that is send to TV sets across the area, country and possible the world. Sometimes the format of the stream may have to be changed. To do this a digital media streamer is usually used. To see an example of what a digital media streamer looks like, have a look at the Sencore website – under the Signal Sources tab.

Once the finalised stream is ready, a great big satellite dish on top of the van (the one with the mixing equipment inside) will transmit the stream to a satellite high up above the earth.

The Satellite

The satellite then sends the signal to all the local masts where the stream will be broadcast from. These masts are usually called television masts and are often really tall thin metal structures with a flashing red light on top – to warn passing aircraft.

Your House

The television masts are transmitting the signal far and wide, and your areal on your roof will pick up this signal. It will then pass down the wires in your house and after an exchange box reach your TV, where thanks to either LEDs, plasma, or some other means, you will see Bolt steam to victory!

If you have a satellite dish the process is slightly different as you receive the feed directly from the satellite. Also if you have a portable aerial, you bypass all the wires in your house.

So, that is how a live event reaches your TV screen, and it does all of that in less that 30 seconds. Pretty amazing don’t you think?

Science Space Technology

Are We Reaching Satellite Saturation Point?

Satellites surrounding the earthWe all like our satellite navigation systems and mobile phones, Google maps and BBC World when we find ourselves in hotel rooms, but a report just published by the US National Research Council claims that we are on the brink of clogging up space to the point of no return.

A couple of years ago 2 satellites collided destroying both of them, one had already been decommissioned but the other was a communication carrier that was still in use. Also recently, astronauts had to get in to the emergency escape capsule on the International Space Station as debris passed close by.

There are about 22000 big pieces of debris floating round the Earth and many more smaller but potentially equally damaging pieces, and the problem is the lack of international agreement upon the use of near space. Almost everything from Sputnik onward is still floating about up there. The Chinese military destroyed one of their disused military satellites in an experiment in 2007 but that just created thousands more potentially dangerous pieces. More of a political action than a potential solution.

Now maybe we can live with the odd collision now and again, but a related and really serious problem and the underlying cause, is our reliance on this technology. Scientists talk about potential damage from solar flares and the likes, that might even knock the entire system out for an undefined period of time. This would have catastrophic effects on the world, no Satellite navigation means no aeroplanes, ships navigating by the stars, emergency services having to rush out and buy maps of the city, UPS and their competitors losing their way, and even worse than all this Sainsbury’s not being able to deliver Mrs French’s vegetables on time.

Easy to take lightly but really quite a serious problem.

Dependence is a difficult thing to overcome, but scientists are experimenting with bringing old satellites back to Earth. A sort of Kite is being trialled that once attached to its objective slows it down so that it enters the atmosphere and burns up, but this must be seen against a backdrop of more satellites being launched every month. They are both commercially and militarily extremely important.

Who has the right to govern space though? Competition rules and it is big business.

For a more detailed incite have a look at these postings on the Bassetti Foundation website.