Astronomers call our farthest point fromt he sun Earth’s aphelion. Today, we’re about three million miles farther from the sun than we will be six months from now. That’s in contrast to our average distance from the sun of about 93 million miles (150 million km). Looking for Earth’s exact distance from the sun today? It’s at 94,508,959 miles. Last year, on July 4, 2012, the Earth at aphelion was a tiny bit closer, at 94,505,851 miles. We’re always farthest from the sun in early July during a Northern Hemisphere summer – and closest in January during a Northern Hemisphere winter – and that’s a good illustration of the fact that it’s not the Earth’s distance from the sun that creates the seasons on our world. Instead, the seasons result from Earth’s tilt on its axis. Right now, it’s summer in the Northern Hemisphere because the northern part of Earth is tilted most toward the sun. Meanwhile, it’s winter in the Southern Hemisphere because the southern part of Earth is tilted most away from the sun. So Earth’s varying distance from the sun doesn’t create the seasons. But it does affect the length of the seasons.
That’s because, at our farthest from the sun, like now, Earth is traveling most slowly in its orbit. That makes summer the longest season in the Northern Hemisphere and winter the longest season on the southern half of the globe. Conversely, winter is the shortest season in the Northern Hemisphere and summer is the shortest in the Southern Hemisphere – in each instance, by nearly 5 days.
You’ll probably need binoculars and a lot of luck to catch the planets Jupiter and Mars near the moon and in the glow of dawn on Saturday, July 6. Click here for a sky almanac
Waning crescent moon near Mars, Jupiter before sunrise July 6 The planets Mars and Jupiter are now very low in the east before dawn. You might need binoculars to see them, or at least to see Mars. Jupiter is brighter and therefore easier to see. For both objects, you’ll surely need an unobstructed eastern horizon before dawn breaks. On the morning of July 6, the waning crescent moon should help guide your eye to the two planets. Jupiter and Mars will appear higher in the predawn sky – and therefore will be easier to see – throughout July 2013. They’ll have a spectacular conjunction before the month ends. Bottom line: Friday, July 5, 2013, Earth is farthest from the sun for all of 2013. Astronomers call this yearly point in Earth’s orbit our aphelion. On Saturday, July 6, the waning crescent moon can guide your eye to Jupiter and Mars, which are now returning to the eastern predawn sky.
source and credit a earthsky
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