It’s winter solstice, so why is the sun sleeping in?

If you are feeling the pinch of the chilly, dark mornings, look on the bright side, after Sunday the mornings will become brighter… sort of.

This Sunday, 21 June is the winter solstice which means it is the day of the year that has the least daylight hours of any in the year.

But interestingly the Sun will continue to rise a bit later for a few weeks as it is actually the sunset time that moves forward.

In Ipswich the Sun will rise at 6.38am on Sunday with the winter solstice occurring at 7.43am and the Sun will set at 5.05pm.

For the following few weeks the Sun will get up as late as 6.40am until 7 July when it starts to creep back the other way with sunrise at 6.39am.

So why is the shortest day of the year in terms of sunlight, not have the latest sunrise or earliest sunset?

University of Southern Queensland professor Jonti Horner is an astrophysicist and he explains how telling time is not as simple as looking at a watch.

“The actual time of sunrise and sunset isn’t just set by the rotation of the earth in relation to the sun,” Professor Horner said.

“It also depends on our orbit around the Sun – we follow an elliptical path, so sometimes we are further from the Sun and travelling slower or close to the Sun and travelling faster.

“It’s a really small effect but the middle of the day drifts. Currently the sun is due north at 11.55am.

“As the Earth moves around the Sun we move a bit in our orbit which means we have to turn a little bit further which affects sunrise and set.”

Likewise this week is also not our coldest.

As the sunlight strikes the southern hemisphere at a steeper angle, the ground receives less heat during winter.

The heat from the oceans keeps us warm a little while longer with the coldest week of the year typically happening in July, some weeks after the solstice.

To take advantage of the longest night, the Australasian Dark Sky Alliance are running a world record attempt to measure light pollution around the globe – which people can get involved with here.

Read also:

>>> Dear winter solstice, I want my 3 hours and 29 minutes back

>>> How many weather records did Ipswich break in 2019?

Leave a Reply

Your email address will not be published.

Back to top button