Have you seen the August issue of Sky & Telescope magazine? If not, please check it out (click here). There is an article in it by someone from the Vatican Observatory! Who is that someone? Me!
I have been reading S&T since I was in eighth grade. The magazine has been in existence for well over 75 years, and it played a large role in forming my interest in, and career in, astronomy. It is also where I first learned about the Vatican Observatory — S&T carried news stories about the construction of the Vatican Advanced Technology Telescope on Mt. Graham in the early 1990s. I feel quite privileged to have an article in S&T. Br. Guy and I had an article in the October 2022 issue, but this article is my first that is “all my own”.
And it is on the cover of S&T. OK, it is maybe not “on the cover” in the manner that phrase brings to mind. It is not the cover article. But it is one of three articles featured on the top edge of the cover (indicated by the green arrow above) — “Other Worlds: Speculation Versus Science” refers to my article. So, my article is on the cover!
The article is a version of the paper I published in December in the International Journal for Astrobiology. That was titled “The Challenging History of Other Earths” (click here for a recent post on that). The S&T title, written for a broader audience, is “The Challenging History of New Worlds”. It is both more readable and a lot prettier than the IJA paper, since it benefits from the artistry and editorial guidance of the S&T staff. The opening spread is below.
I received a paper copy of the August S&T in the mail in June, at the same time as I had a copy of the book Star Struck: One Thousand Years of the Art and Science of Astronomy checked out from my local library. Star Struck, by Ronald Brashear and Daniel Lewis and published by the Huntington Library and the University of Washington Press, features a lot of historical astronomical artwork, very nicely reproduced. That artwork includes the image below from Thomas Wright’s 1750 book An Original Theory or New Hypothesis of the Universe — an image that ties in with my article.
In the image, A is the Sun, and our Solar System. The circles represent the orbits of the planets, and the ovals represent the orbits of comets. B is Sirius. C is Rigel. These have their own comets and planets. There are lots of unlabeled stars with their own planetary/cometary systems, much like our Sun and Solar System.
The theme of my “Challenging History” work has been that we human beings have tended to assume that the universe is like us, despite science always indicating otherwise. The Wright illustration is an example of this. As I discuss in my papers, astronomers in 1750 did not have any real science to support the idea that stars might be Suns, and in fact, people like Johannes Kepler and Jacques Cassini had used observations to argue that stars were not suns.
And indeed, Sirius and Rigel are arguably not suns. Sirius has over twenty times the power output of the Sun. Rigel? Over fifty thousand times. In the Wright illustration, Sirius and Rigel are about the same distance from the Sun. In reality, Rigel is approximately 80 times more distant than Sirius. Were Rigel at the distance of Sirius, it would appear significantly brighter than Venus. Were Rigel at the distance of the Sun, Earth would be toast.
The Sun, Sirius and Rigel are not all the same. The universe is not merely full of other Suns and other Solar Systems like Wright imagined. The universe is diverse. There are stars far dimmer than the Sun. There are stars far more powerful than Rigel (the cover story of the August Sky & Telescope, in fact, discusses just how powerful stars can be). If stars are not merely other Suns surrounded by other Solar Systems, then what does that say about other Earths? But you can read the August S&T for the whole discussion.
