Caoimhín's Content

Today we are going to look back in time. We have before looked far into the future, for example to at look at Halley’s Comet returning in the 2060s and other comets as they come and go. I believe we’ve looked into the past as well, but we are going to look quite far into the past for this video, we’re going to look 2,024 years ago.

First off we’re going to get rid of the light pollution. Light pollution is really a modern problem, it is street lights and all of the lights from houses and cars that give us the light pollution that we suffer with today. In the past, before electric lights, light pollution wasn’t much of a problem, torches and candles are not as capable of causing light pollution as the incandescent, fluorescent and LED electric lights that we have to day. Looking just a few decades into the past drastically reduces light pollution, and after a century or so it’s practically a non-issue. Going all the way back to year 0 leaves us a perfect dark sky.

We will be looking at year 0 on the 25th of December, so tomorrow. 2,024 years ago, the Sun was still pretty much its the lowest at midday, because we’re still very close to the winter solstice. Many things will be the exact same once night falls, if you go only 2,000 years into the past. We could see the Seven Sisters and Orion looking exactly the same and in the same places. Delphinus would be visible above the southwest, because we’re in a dark sky so it’s nice and easy to see. The summer triangle would be about to set because we’re not in summer, we wouldn’t be in summer two thousand years ago on the 25th of December either. Perseus would be up and we’d still have the square of Pegasus nice and clear. However, the planets are different. We would still see Venus and Saturn, which we see in the evening sky this year as well, but Mars would already up and Uranus would be much further across the sky. Jupiter is conspicuously missing from the evening sky. Of course Uranus is not really going to be visible to the naked eye, but that’s, that’s okay. The Moon of course would likely be in a different phase as well. Over the course of 2,000 years the phase of the Moon would probably be different, but there is a chance that it would be the exact same, I would have to double check. Eventually, Jupiter rises close to morning 2,000 years ago.

Overall, not too much has changed. The Geminids meteor shower would still have been occurring, or just after finishing on this date. They would have peaked back on the 13th of December, even 2,000 years ago. It seems that the Stellarium software doesn’t track the meteor showers for very distant dates, I only see the antihelion point and none of the other meteor showers, even on dates when they would have been peaking. The comets that leave behind the trails of dust that cause meteor showers were still orbiting the Sun 2,000 years ago. Interestingly, the Crab Nebula probably wasn’t around, or at least not visible, as it seems to have formed from a supernova we saw here on Earth in the 1300’s. Of course, with no telescopes 2,000 years ago, it would be difficult to check. We would see the stars are all in the same place, bar some of the ones with very high proper motion, and most of these aren’t visible to the naked eye anyway.

Venus is of course the brightest planet and one of the brightest objects in the sky second (or third) only to the Moon and the Sun. Venus was visible in the sky towards the southwest at sunset 2,024 years ago, as it is at the moment as well. We’re still seeing Venus at sunset this year but, it’s not exactly a coincidence. Venus in its orbit around the Sun will be at it’s extension like this on a given date any year. However, if we go through a few different years looking at sunset, you can see Venus isn’t there for all of the years. It is there regularly, Venus pops up a lot in the evening sky but it isn’t there every year on the 25th. The fact that we’re getting Venus in the evening sky this year when the Sun goes down and Venus was there in the evening sky 2,024 years ago when the Sun went down, it’s not exactly a coincidence, but is just what has happened based on the number of times that Venus goes around the Sun and how long it takes. If you count out a certain number of years, Venus will be in the evening sky every so many years, so it’s not exactly a coincidence, it’s just a point of commonality between this year and year 0.

Now of course the reason I’m mentioning this for this date and time is because of Christmas, the holiday of Christmas. We say that it is the year 2024 because year 0 was the birth of Christ, the figure in Christianity. Year 0 in astronomy is the same as 1 BC in the normal calendar, the year after 1 BC being 1 AD, or just year 1 in astronomy. Of course this didn’t happen in Ireland and we’re looking at the sky for here in Ireland. This event is purported, to have happened down in the Middle East. The location map in Stellarium is rather small, so it’s hard to pinpoint an exact location and I’m sure I am off by quite a lot, but it is meant to be the area of the Middle East around the Mediterranean coast, sometimes known as the Levant. We can see from this location that, for a good period of time, Venus is the Evening Star. Venus is often the Evening Star for quite a while when it is up in the evening, it takes awhile for Venus to move from one side of the Sun to the other, significantly longer than Mercury for example. For a month or so either side of December, Venus was visible over towards the southwest. If you were looking for a Christmas Star, it does just so happen that this year the same bright object, the Evening Star, which is of course a planet, is over in the southwest this year, 2024, as it was 2,024 years ago. This is true for every where in the world, if Venus is visible at sunset Venus is visible at sunset, it doesn’t really matter where you are.

This is a popular topic around this time of year, it is Christmas for many people and the story of Christmas does prominently feature a star. Of course the whole story of the nativity and when exactly it happened and where exactly different people were, those details are lost to time. The numbering system we use for years today, the AD or Anno Domini reckoning, originates from around 500 years after the year defined as 1 AD or 0. However, because it is a commonly talked about topic I thought it would be nice to show that this year Venus is in the same location, roughly, as it was 2024 years ago at year 0. Coming back up to the modern day, we can see that Venus’s location just after sunset, over in the southwest, is very similar. This year, Venus is the object roughly the right location. If you did want to point out a star as being the Christmas Star, Venus is this year in the right place to be it, of course on other years this will change.

Coming back to the modern day also reveals the Ursid meteor shower, which are still running at the end of December, though they peaked back on the 19th. I mentioned that Stellarium may not track the radiants of the meteor shower for points in time that are too far away from the present day and indeed that seems to be the case. Coming back to the modern day brought them back, so it’s not any other strange thing that’s after happening. I wasn’t after getting rid of them in the settings by accident, which I briefly thought I had while recording the accompanying video.

Moving back towards morning time for Christmas morning, we still have Mercury coming up nice and bright and early, another are nice thing to point out at this time of year. I’ll take any excuse to go pointing out a planet really, if there are children who are asking about the Christmas star, using that as an excuse to point out Venus and say “oh, that’s a planet in the sky, it’s not there every year”, you know, any excuse to talk about astronomy and point out planets to people. Especially if it means fostering an interest in astronomy from a young age, that’s always good. Glancing ahead to 2025 and Venus won’t be there when the Sun goes down. Back in 2023 Venus was also missing from the sunset on the 25th. If you celebrate Christmas, if you tell the story of the Christmas Star, then Venus will be there to be pointed out and even if you don’t, I think it is a good excuse to point out a planet at this time of year and any excuse, as I said, to talk about astronomy.

I hope that you did enjoy this little piece, even if we were looking at the distant past which we won’t be able to see, at least Venus will actually be there this year for us to see as well. If you did enjoy this video please do like it, you can also subscribe to this website and my YouTube channel if you’d like to see more of my content . Thank you for reading and hopefully I’ll see you back here next time.