Daily Space: Bode’s Galaxy

Daily Space: Bode’s Galaxy

July 23, 2022 0 By Ellen Novack

In 2007, NASA and JPL directed the Hubble Space Telescope at M81 and took what was at the time the most detailed image of a galaxy that had ever been obtained.

Hubble image of Bode’s galaxy, M81. Released on May 28, 2007.

It may look nice above, but that’s scaled way down from the original. But, NASA being NASA, you can absolutely access the full 343 megapixel glory of the original right here. You can also download it in uncompressed TIF form from this page if you’re hankering for the best possible look at stars in one of the galaxies that’s considered quite similar to our own.

A lot of space images are pretty. This one, especially at scale, is simply majestic. I highly recommend it as a screen saver—though probably not at the full 22,000+ pixel width.

When it comes to Bode himself, he was an unlikely astronomer. He was born in Hamburg, Germany in 1747. As a young teenager, he suffered from an unspecified disease that caused damage in both eyes and left him mostly blind in the right eye. However, he still retained enough vision to wow his instructors with very impressive skills in math. Very impressive. 

One of his first works involved calculations about the specifics of an upcoming solar eclipse, which brought Bode to the attention of astronomers and got him access to both libraries and instruments. He used these to pull scattered observations together into more organized frameworks. At the age of 21, Bode published the first edition of Anleitung zur Kenntniss des gestirnten Himmels, Guide to Knowledge of the Starry Sky, which would go through ten editions and remain in print for a century. (‘Not bad, I guess,’ says the author, all of whose books went out of print within a decade).

At 25, Bode expanded on previous work to develop what’s now known as the Titius-Bode Rule, or just Bode’s Law, giving a formula to predict the positions of planets in a solar system. The rule predicted with fair precision the position of planets that were at that time unknown, as well as confirming that astronomers should take a good look at the area of the asteroid belt.

Bode’s Law was instrumental in pointing telescopes to the right place to find Uranus, just three years after the law was first published. In fact, Bode himself consulted records of past observations and pointed out what he believed to be a planet, mistaken for a star, in the records of other astronomers going back to 1690. With these observations in hand, Bode calculated the orbit of Uranus, before anyone officially recorded seeing Uranus.

As satellites like TESS have begun adding to the catalog of exoplanets orbiting distance stars, it also turns out that a modified form of Bode’s Law lines up with the positions of planets in other stellar systems. Or at least it does in systems where we’re able to tell enough about the structure. 

Bode went on to become a professor of mathematics, where one of his doctoral students was the mathematician Johann Pfaff, who pretty much set the direction for mathematics over the following century. Bode also published over 50 volumes of an “astronomical yearbook” listing new discoveries, and at age 54 began producing a great set of star maps that were republished and updated for over two decades.

He even began one of the first publications for the amateur astronomer. The Vorstellung der Gestirne, or “Star Knowledge,” explained the concepts of the stars, planets, and nebula as they were understood at the time. It also provided tables for those observing by eye, or with small telescopes, to find some of the objects in the night—including that big galaxy at the top of the page (Bode didn’t know it was a galaxy, but that’s another story). Every reader of Sky & Telescope owes Bode a tip of the hat.

These days, the tendency may be to refer to the object in the sky as M81, but it sounds to me like Bode deserves a galaxy. Or two.



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