Topic: Perihelion Today

[Garth Bock]

Today (Jan. 2) marks the time when the Earth is at perihelion, the point in its orbit at which it is closest to the sun.

During perihelion, the Earth is exactly 91,402,560 miles (147,098,161 kilometers) from the sun.In actuality, you most likely can't see any difference between the apparent size of the sun today and its appearance at aphelion (when the Earth will be farthest from the star).The difference is only 3.4 percent, too small to be detected with the naked eye.

(From www.space.com)

All I care about it that the days will be getting longer (I mean more daylight).

[SlowModem]

So if the earth is closest to the sun when it's winter in the northern hemisphere, does that mean summers in the southern hemisphere are warmer?  And if the earth is farthest away from the sun in July, does that mean winters in the southern hemisphere are colder?  Or does it matter?   

[Garth Bock]

Yes to both because it's all in the tilt.

" This perihelion effect is very minor compared to the effects of the tilt of our planet's axis. During December in the Northern Hemisphere, the North Pole is tilted away from the sun so that we receive less sunlight every day.

At the same time, the South Pole is tilted towards the sun, so the Southern Hemisphere receives more sun and experiences summer. In June, the situation is reversed and we have summer in the northern hemisphere and winter in the southern hemisphere.

The only effect of perihelion is that the winters in the Northern Hemisphere are very slightly milder than the winters in the southern hemisphere at the equivalent latitudes. Not as many people live as close to the South Pole as do close to the North Pole, so humanity isn't affected much."