Question: In a recent programme, on astronomy, one of the scientist stated that our solar system has evolved over billions of years and is still evolving and will go on evolving into the future. To us the solar system’s evolution appears static because our life span is too short to be able to see appreciable changes to it. If I were able to view our solar in say a 10 million or even a billion years from now can you astronomers predict what our solar system would then look like? — David
Answer: Yes, as long as you consider only the evolution of our Sun and planets, and exclude unpredictable events such as collisions between asteroids and planets, for example. In about 1.1 billion years the Sun’s luminosity will be about 10% higher than it is now, which will result in an increased amount of solar heating for all planets. Orbital and rotational interactions between planets and their satellites will slow the rotation rate of many planets, including Earth. For us here on Earth, this will have the effect of increasing the length of the day by a few hours, and also will result in an increase in the Earth-Moon distance.