Talking climate with relatives, the December solstice, and a pretty galaxy

December 25, 2023   Issue #660

Is it hot in here, or is it just anthropogenic global warming?

Climate change is real, y’all

This season means getting together with family and friends, and for a lot of us that means arguing over politics. I know, it’s a cliché, but it does happen, and it can ruin what should be a happy time for everyone.

What can you do?

In the case of climate change, my friend Katharine Hayhoe has some advice. She’s a climatologist, and talks to the public a lot about what global warming is doing to our planet. She writes books, make videos, has a newsletter… and her overall message is a relatively simple one: Find common ground first, and then use that to establish rapport. Use that to discuss how climate change affects the things you agree on, or back up even more and talk about how we understand climate change is real using the common ground you have.

As it happens, Katharine is a devout Christian. She and I would disagree about a lot of things when it comes to that, I expect, but it also puts her in a unique position to talk to other deeply religious folks about this topic. As she points out in an editorial she wrote for the journal Science, the strongest indicator for knowing climate change is real versus denying it is political stance. And in the US, most strongly religious Christians are conservative. That means they tend to deny the science of climatology. But it also means that while a group like that might reject what I have to say, they will be more willing to listen to Katharine (which is smart anyway; she knows way more about this than I do).

This exact relationship she has may not be mappable onto your own familial ties, but it does show that common ground is an effective way of at least getting a little headway with people who deny the science (and this goes for other things too, like vaccinations, for example). She’s not advocating tricking people or giving them false trust, but to simply show use that mutual tie to be able to get people to be more open.

She writes about this a lot, so if you want more info on how to do this for yourself go to her website and poke around, and especially read her FAQ about communicating to naysayers. She also gave a TED talk on this.

It may not save the holidays, but if you don’t try, you’ll never know.

SciAm What SciAm

Stuff I’ve written for Scientific American

As promised, I wrote about last week’s December solstice for Scientific American. Specifically, not that it’s the longest night of the year, but more about why it’s not the latest sunrise and earliest sunset. Give that a read.

Incidentally, it brings up an interesting point. We use the word day to mean both the roughly 24-hour period of Earths’ rotation, and colloquially the length of time the Sun is up. That’s confusing when talking about the solstices, especially the winter one.

Why/ Because that date is when the Sun is up for the least amount of time — we say it’s the shortest day — but in fact the length of the solar day is actually around the longest it is all year! The solar day is the time it takes for the Sun to go from due south (when it culminates, if you prefer, or is on the meridian) to due south once again, after setting and rising. That length of time changes over the yea due to Earth’s elliptical orbit, as I wrote in the SciAm article. Since Earth is moving fastest around the Sun at this time of year near perihelion, it takes an extra 30 seconds for the Sun to reach due south again after the previous day. Therefore it’s correct to say that this is one the longest days of the year, as long as it’s clear we mean the rotational period of Earth.

We have the shortest day (amount of time the Sun is up) on one of the longest days (the time it takes the Sun to go around the sky once, if you forgive the geocentric frame of reference there).

Terminology matters. There’s a term for the ~24-hour-long day/night period, nychthemeron. Of course no one uses or will use that clunky (though super cool) word. Too bad. It would make things a bit easier on us poor science communicators.

Pic o’ the Letter

A cool or lovely or mind-bending astronomical image/video with a description so you can grok it

NGC 941 is a slightly tipped spiral galaxy in the constellation of Cetus (the Whale or Sea Monster). I saw it in a recent image release from the European Space Agency Hubble site, and felt like I had to show it to you:

The link above has much larger versions, if you want to take a look (and you do). The release says it’s 55 million light-years away, but I looked up the redshift and got a distance of more like 75 million. That’s a big discrepancy, and I started digging more. Weirdly, Wikipedia (and the press release) gives its location as being in the constellation Triangulum, but it’s nowhere near there, lying about 30° south of that part of the sky! So I think somewhere someone messed up. It’s definitely in Cetus, and the coordinates given in the Wikipedia article also put it in Cetus despite what it says.

Weird. Anyway, my guess is they got the galaxy mixed up with another one, and it really is about 75 million light-years from us.

Anyway, Hubble took a peek at it to investigate the area in the galaxy around a star that went supernova there, the light from which reached us in 2005. The image release linked above has a nice write up of that part.

And in the end I just wanted to show you a picture of a pretty galaxy, because hey, we could all use that every now and again, right?

Et alia

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