Formation and evolution of the Solar System its current size. At the tip of the red giant branch, as a result of the vastly increased surface area, the Sun's surface will be much cooler (about 2600 K) than now and its luminosity much higher—up to 2,700 current solar luminosities. For part of its red giant life, the Sun will have a strong stellar wind that will carry away around 33% of its mass. During these times, it is possible that Saturn's moon Titan could achieve surface temperatures necessary to support life. As the Sun expands, it will swallow the planets Mercury and Venus. Earth's fate is less
Solar System model Solar System model Solar System models, especially mechanical models, called "orreries", that illustrate the relative positions and motions of the planets and moons in the Solar System have been built for centuries. While they often showed relative sizes, these models were usually not built to scale. The enormous ratio of interplanetary distances to planetary diameters makes constructing a scale model of the Solar System a challenging task. As one example of the difficulty, the distance between the Earth and the Sun is almost 12,000 times the diameter of the Earth. If the smaller planets are to be easily visible to