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why is the earth closer to the sun during our winter in the northern hemisphere

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4 Answers

Sometime in February, our planet reaches it's farthest distance from the sun (Aphelion) with a distance of about 1.02 AU.

Sometime in August, our planet reaches it's closest distance from the sun (Perihelion) with a distance of about 0.98 AU.

Here, AU is short for "Astronomical Unit" which is defined as earth's average distance from the sun.

Thus 1 AU = 92.956×106 miles = 149.6×106 km

 

 

However, if we consider the earth as being a perfect sphere, and track the point on earth's surface that is closest to the sun, then it is a totally different matter. If you stand at this point, the sun will be directly above you in the sky.

Summer solstice = The moment when this point is furthest north.

Winter solstice = The moment when this point is furthest south.

Vernal equinox = The moment this point crosses the equator from the South to the North.

Autumnal equinox = The moment this point crosses the equator from the North to the South.

Your is on the right track and what she said about the axis positioned away in winter is true.

However, there are actually two factors that play into this question.

1.  ellipitical orbit = oval shaped

2.  tilt of the earth = 23.5 degrees

The earth is closest to the sun in early January; which makes no sense because it is winter.  However, if you track the sun's noontime position over the year it makes a figure eight or analemma. The combination of the sun's position and two factors above account for the fact that the sun is closer at a point during the winter.

Planetary orbits around our Sun are not perfect circles.  They're ellipses--a loose term to use is oval or ovoid.  At some point Earth gets to its closest point along its orbital path to the Sun .  6 months later it will be at its farthest away.  The distance from the Sun is not what causes the seasons.  The amount of direct sunlight hitting a certain hemisphere of Earth is what causes the seasons.  So, when the Earth's axis is tilted so that the Northern Hemisphere is titled toward the Sun, it's summer time in the Northern Hemisphere. When the Northern Hemisphere is tilted away, it's winter.  So, even though we are closer in distance during January through March, we in the Northern hemisphere are tilted away and it is winter for us.  Yes, that means it is summer in the Southern Hemisphere.

Well the Earth's orbit is actually an Ellipse so during our winter we may be closer to the sun but it is winter because of the tilt of the Earth (on its axis); so those are two separate things we're talking about.