Ever wondered why the Easter date changes each year?

Sometimes the Easter date is in early April. Sometimes it’s in late April. There are other times the Easter date changes to late March.

It’s a great time of year. Children get exited for the arrival of the Easter Bunny. There’s often lots of chocolate and you might even do some egg shell painting at home.

There are traditions of fish for Easter Friday, Easter egg hunts on Sunday and special times to spend with family.

So why does the Easter date change each year?

Believe it or not, the reason the Easter date changes every year has a lot to do with astronomy!

It’s got nothing to do with a decision made churches, public holiday makers or governments.

Quite simply, Easter Sunday is deemed to be the first Sunday after the full Moon, following the March Equinox. Just so you now, the March Equinox is always on or around 22nd March each year. 

That raises another astronomical question! What is the March Equinox?

Easter date 2022

It’s a bit of a calculation and here it is for the Easter date 2022:

In 2022, the March Equinox is on 20th March. The full Moon after this date is on the 16th of April and therefore Easter Sunday is the following Sunday which is the 17th of April 2022!

Now you’ll be able to impress friends and relatives with your knowledge of why the Easter date changes each year! Or you’ll be able to predict when the Easter date will be for many years to come. All you need to know are the dates of the March Equinox and a full Moon chart.

Why does the Moon look so big near the horizon?

At about 6pm on the 17th of April, the Moon will rise from the east. Often times, a rising Moon appears to be far larger than normal, and it takes on a rich orange colour. Ever wonder why?

The Moon changes colour closer to the horizon as the light reflected off it has to travel through thick lower atmosphere longer before it reaches our eyes. Our atmosphere scatters blue light, known as Rayleigh scattering, leaving only the red/orange light of the Moon to reach our eyes.

The Moon appears larger on the horizon too! This is just an illusion, as our brains subconsciously compare the Moon to the size of objects closer to us such as trees, buildings or even hills. This is an effect known as the Ebbinghaus illusion and an example of it is shown below. Both orange circles are the same size, but when compared to the objects around them, our brain is tricked into thinking they are larger or smaller than they actually are!

To test whether the Moon has actually grown larger for yourself, measure the size of the Moon by extending an arm and covering the Moon with your pinky finger when the Moon is low to the horizon. Repeat the experiment a few hours later when it’s higher in the sky and see if the Moon has shrunk!

Speaking of the Easter Bunny...Here's one for the kids!

Did you know that you can make the shape of a rabbit on the Moon? This is a fun activity for children to try. Check out the latest Stargazing Forecast to find out when the next Full Moon rises. Then head outside to wait and watch. 

Easter Bunny on the Moon

First use the image above to find the rabbit.

Then imagine what it was like to travel in a spacecraft to land on the Moon in 1969.

Apollo 11, the first spacecraft to take humans to the Moon, landed in the Sea of Tranquillity, which is the large grey area that makes up the head of the rabbit. Apollo 11 landed towards the bottom of the rabbit’s left ear. That’s the rabbit ear on the right as we see it from Earth!

ready for some stargazing this easter?

It’s something you can do from home, it’s free and you’ll be surprised at what you’ll discover.