The human brain isn't used to dealing with numbers which are either extremely large or extremely small. But those are exactly the types of numbers you encounter in science. In Astronomy, the distances between stars and galaxies are unimaginable. In the evolution of life, the time that has elapsed since life first started on Earth is unbelievable. In genetics, the size of the cells, of the chromosomes within them and of the DNA bases within those chromosomes are incredibly small. So, here are some facts and figures way outside the everyday experience of human life. I hope that they will inspire you to want to find out more.
Some of these statistics may blow your mind.
- The diameter of the sun is 865,000 miles. It's surface temperature is between 5,000 and 6,000 degrees Centigrade but at the core the temperature is an amazing 14,000,000 degrees.
- For every million hydrogen atoms in the sun, there are 63,000 of helium and only 700 of oxygen.
- The sun loses 4,000,000 tons of its mass every second.
- The Sun has a life of several thousand million years ahead of it, but eventually it will change. First the core will shrink and the outer layers will swell out, turning it into a red giant star. This will mean the end of the Earth. Then it will shed its outer layer and become a faint white dwarf, before finally losing the last of its light and heat and ending up a cold, dead globe.
- Our Galaxy contains about 100,000 million stars.
- There are a thousand million other known galaxies in the universe.
- The farthest we can see with the naked eye is 12 million million million miles. This is the distance of the Andromeda Spiral (2.2 million light years away) and is the most distant object that can be seen clearly with the naked eye.
- The most remote star systems are 13,000 million light years away from us. They are moving away from us at 90% of the speed of light!
- The age of the Universe is between 12 and 18 billion years.
- The Sun is thought to be 4.6 billion years old.
- The Earth is estimated to be 4 billion years old.
- The Big Bang theory claims to be able to account for everything that happened after the first 0.0001 of a second.
- The temperature of the Universe after 0.0001 of a second was 1,000 billion degrees.
- The density was 1014grams per cubic centimetre (the density of water is 1 gram per cubic centimetre).
Scientists keep changing their mind about when life first started on Earth. And each time they change their minds they push the date further and further back. Current estimates put the origin of life on earth at between three and four thousand million years ago.
For the first two thousand million years, life consisted of nothing more than single cells in the proverbial primeval swamp.
The DNA "book" which makes up a human being has three thousand million letters, all combinations of four bases, called A, C, G and T. This "book" exists in every single cell of the human body. Scientists are in the process of recording this "book" so that it can be read.
If all the DNA in all the cells in a single human being were stretched out, it would reach to the moon and back eight times.
There are thought to be 30,000,000 different species on Earth.
It has been estimated that the species which exist today constitute only 1% of all the species that have ever existed.
Every cell in your body contains the equivalent of 46 immense data tapes reeling off digital characters via numerous reading heads working simultaneously.
Genes are pure information -- information that can be encoded, recoded and decoded, without any degradation or change of meaning...Since it is digital copying the fidelity of the copying can be immense. They are copied down the generations with just enough occasional errors to introduce variety.
Hubble Telescope. Here you can see the latest photos sent back from the Hubble Telescope out in space.
Astronomy Picture of the Day
The Solar System. A guide to the planets.
Genetics and evolution
Richard Dawkins. This was an unofficial site which promoted the books, writings, and activities of one of today's most outspoken, and often humorous, scientists. It now operates as an archive of speeches and articles by Dawkins up to 2001.
Planet Science, the award-winning site of New Scientist magazine. You have to register but it is free.
The Why Files, a very chatty US site which gives you the background on science stories which are in the news.
And some books......
"River Out of Eden", "The Blind Watchmaker" "Climbing Mount Improbable" and "The Selfish Gene" by Richard Dawkins.
"The Language of Genes" by Steve Jones.
"In Search of the Big Bang", "In Search of the Double Helix" and "In Search of Schrodinger's Cat" (about Quantum Physics) by John Gribbin.
"The Origin of Humankind" by Richard Leakey
"Life -- an unauthorised biography (a natural history of the first four billion years of life on earth)" by Richard Fortey.