SS-P Part 1: I am very pleased to have been interviewed by Daniel Whiteson and my dear friend Kelly Weinersmith for their podcast “Daniel and Kelly’s Extraordinary Universe”. In fact I am the first guest on this new podcast, which I would be honored about but then I remember Kelly studied parasites in fish that turn them into zombie robots under their will, and maybe I’m not so sure how I feel about it.

But anyway, come for us discussing asteroid impacts but stay for me monologuing ridiculously about solar storms.

Incidentally I got an email from a reader saying our power grid is actually not as vulnerable as I thought. I need to read more about that but I sure hope I am indeed wrong there and we’re doing a lot better battling potential spaceweather-induced blackouts.

(Thanks Daniel and Kelly for having me on!)

SS-P Part 2: I gave my “Under Alien Skies” talk — about touring Saturn and its weird moons, based on my book — at the Carnegie Science Neighborhood Lecture on October 14. They wrote up a nice little review of it, and there’s video if you want to watch! 

If you want more info on the book, visit the site! It’s out in paperback, and I recorded the audiobook, too.

Astronomers have found an object in a deep series of images by JWST that may be — may be — the most distant galaxy ever seen. It’s possible it’s something weird closer to us, but the scientists who analyzed the observations think that’s unlikely [link to journal paper].

JWST is like Hubble, but detects light in the infrared, where our eyes cannot see. Some astronomical objects emit infrared light, which is why JWST was built. One big research topic for the observatory is extremely distant galaxies. As the Universe expands, the light from objects that are far from Earth gets its wavelength lengthened, what’s called a redshift. We’ve known for a century or so that, in general, the higher the redshift of a galaxy, the farther away it is from us.

That’s important because light travels at a finite speed. Fast, but not infinitely so! So the more distant a galaxy is, the longer it takes its light to reach us, so the younger we see it. The Universe is about 13.8 billion years old, so if we see a galaxy where its light takes 13 billion years to reach us, we know we’re seeing it when the Universe itself was only 800 million years old.

We usually take spectra to measure redshift. Breaking the light of an incoming object up into thousands of individual wavelengths (colors) reveals a ton of info, like the temperature of an object, what it’s made of, and more. For distant galaxies, features in the spectrum appear at different wavelengths than they do for nearby galaxies due to their redshift. So we can read that right off the spectrum and get the galaxy’s distance.

But some galaxies are too far for that. They’re too faint to get a decent spectrum even if they show up in images. An image is like a pizza: there’s plenty of food (light, in this analogy) to go around if the number of people eating it is small. But if you try to feed a thousand people with it no one gets enough to do any good. Taking the light from an object and dividing it up into thousands of individual pieces means each bit is too faint to use well. 

So what’s an astronomer to do? Well, we can use what’s called photometric redshift: Take images using different filters to select out a series of broad ranges of colors from an object and examine those. They’re still images, so the object is still kinda bright, but you lose the exact nature of a detailed spectrum. It’s like taking a spectrum, but only breaking the light up into a few colors (so, the pizza can still feed five people).

Astronomers used JWST to take infrared observations that overlap with a series that Hubble took many years ago called the Ultra Deep Field, an extremely long exposure to look for very faint objects. JWST can look at those same objects and get more info on them, as well as discover new ones.

And that’s what happened. An extremely red object popped up in the JWST images, which the astronomers have nicknamed Cerberus. Hubble didn’t see it, and in fact it only barely shows up at all in the shorter wavelength JWST images. It only appears strongly in the reddest filters, indicating whatever this thing is, it’s extremely red.

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