It’s Perihelion Day!

Bill’s Blog

Posted: Jan 5, 2020 / 03:18 AM EST Updated: Jan 5, 2020 / 03:18 AM EST

It’s Perihelion Day! Today the Sun and Earth are closer than any other day of the year, 91,398,100 miles apart to be exact. The exact time that the Sun and Earth were closest was 2:47 am EST.

Perihelion (graphic from WJHL – Nexstar station in Johnson City TN)

The day when the Sun is farthest away from the Earth is July 4, when at 7:34 am, the Sun and Earth will be 94,577,635 miles apart. That’s a difference of 3,179,436 miles or 3.3%.

You might be asking…how come it gets much colder when the Sun is closest to the Earth? After all, January is usually the coldest month of the year and July is usually the warmest. The cold is caused by first, the low angle of the Sun’s rays at this time of year…and secondly by the length of day. When the sun is out 15 hours and 21 minutes at the Summer Solstice…you get a lot more energy (heat) than when the sun is out 9 hours and 31 seconds at the Winter Solstice.

Quadrantids Meteor Shower Graphic from WJHL

We have a meteor shower going on this weekend…this one the Quadrantids. I haven’t mentioned much about this…or other sky/astronomy topics because it’s been cloudy. Grand Rapids had 0% sunshine Friday and Saturday. We had 0% sunshine on 14 days in December and another 6 days with 1% to 8% sunshine.

When it is clear in the evening…look for the bright planet Venus in the west-southwest at and just after twilight. It’ll remain a bright evening “star” through the winter and into the spring. Venus through a telescope should be bigger than half – it’s on the far side of the sun right now. Mars is visible in the SE just before and during twilight. It’s fairly low in the sky and not very bright right now. Jupiter, Saturn and Mercury are all lost in the glow of the sun right now.