What happened before the Big Bang?
Q. What causes the seasons? A. The seasonal variation of weather on the Earth is affected by many things, but the principal factor is the tilt of the Earth’s axis with respect to its orbital plane. You often hear (correctly) that the Earth’s axis is tilted, at an angle of about 23.4 degrees. But–23.4 degrees from what? Up and down? Up and down from what? Up and down from the ecliptic plane. The Earth travels around the Sun in an almost circular ellipse, with a major axis (long diameter) of about 300 million kilometers (about 186 million miles). The average distance of the Earth from the Sun is thus half of that, or 150 million kilometers (about 93 million miles). The orbit is slightly elliptical, though, with the Sun not quite at the center of the ellipse, but offset by about 2.5 million kilometers (1.5 million miles) along the major axis. As a result, the actual distance at any time varies by about 5 million kilometers (3 million miles) throughout the year. It so happens that in our
