Earth Day 22nd April 2012 – huge for us but insignificant in the universe?

The Earth is huge. It’s gigantic. Massive. It has a mass of 6,000 billion billion tonnes. It would take over a year to walk around it and we have only explored about 5% of the oceans, which cover 70% of the surface. There are 7 billion of us on the planet but we live in only about 1% of the Earth’s surface.

However, the Earth is less than a pin hole in the king sized double duvet cover of the Universe. There appears to be no end to the Universe - just like a double duvet cover. You can fit 1 million Earth’s in our Sun, and there are about 100 billion stars in the galaxy (with a lot of space in between) and over 100 billion galaxies in the observable Universe (with even more space in between and it’s expanding!)

So is the Earth insignificant? Certainly, we now know that there are many other planets in the universe – we are discovering them all the time – and we are probably not the only forms of life around. There may be many more Earth-like planets in the Universe – or even non-Earth-like that still have life. The crucial thing about the Earth though, is that it is the only one we have got. As astronauts find, as they look back at the Earth, we live in a thin blue line. Our atmosphere is like one outer layer of skin on an a big Earth onion and, although it’s still huge to us, we do have an effect on it. There is little debate now that man has changed the atmosphere – carbon dioxide levels have increased and pollutants are visible across the globe.

The image shows the levels of Nitrogen Dioxide present in the atmosphere. Nitrogen dioxide can cause eye, nose and throat irritation, and may cause impaired lung function and increased respiratory infections in young children. The main sources are cars and fossil fuel power stations. The global levels will continue to increase, with the industrialization across Asia.

The Earth Day Network have a Know Green, Go Green section on their website, with themed lesson plans for the day. I’ve also put together a list of resources from the National STEM Centre eLibrary with links to the Earth and its atmosphere.

Tom Lyons, ESERO Teacher Fellow, National STEM Centre