Perihelion and Latest SunriseJanuary 3rd, 2013 at 2:46 pm by Bill Steffen under Bill's Blog, Weather
The sun is closer to the Earth in early January than at any other time of the year. The sun actually reached it’s closest point to Earth yesterday, January 2nd and that is called Perihelion. The sun is actually 3 million miles closer to Earth now than it is in the first week of July. Also, the sun’s light is actually 7% brighter in the first week of January than in the first week of July. Keep in mind that the sun is dimmer as it gets closer to the horizon and shines through a larger layer of air (and dust). You can look at a sunrise or sunset, because the sun isn’t as bright as it is when it has to come through the larger layer of air. I know what some of you are thinking…how come we have the coldest weather when the sun is closest to us? Our seasons are caused by the Earth tilting toward and away from the sun. Today, the sun climbs to only about 25 degrees above the horizon at solar noon (about 12:50 PM) and it stays out for 9 hours and 7 minutes. We’ve gained 7 minutes of daylight since the Winter Solstice back on 12/21. In the first week of July, when we have Aphelion (Earth farthest from the sun), the sun climbs to 70 degrees above the horizon at solar noon and it’s out for 15 hours and 6 minutes. If Perihelion and Aphelion were reversed, with the Earth closest to the sun in July, West Michigan would be 3 degrees colder in January and 3 degrees hotter in July. Today (Jan. 3) we also have our latest sunrise of the winter at 8:14 AM. We are now gaining about one minute of daylight each day. Interesting fact: If you could drive toward the sun continuously at 55 mph today, it would take you 196 years to reach the sun if it were 94.5 million miles away (roughly the time between World Series wins by the Chicago Cubs). Click the picture twice to super-size…picture from Wikipedia.