The Stars That Know No Rest


Next week me and my mummy are off to visit Egypt, a trip I’ve been looking forward to for more than a year. Sadly, our jam-packed itinerary doesn’t include much computer time, so blogging from the field is not an option.

A guard watches over statues of Ramses II in Abu Simbel

—Photo by David Boyer/NGS

Never fear. For the next two weeks I leave you in the very capable hands of my two colleagues, Stephen and Susan.

Stephen Mather is the science and environment producer for

He tells me that his favorite planet is Venus, and that he has been known to build and launch—but rarely retrieve—model rockets. He’ll be keeping up with the latest planet news as well as reporting on a fun new project from National Geographic magazine that will launch next week, so stay tuned!

Susan Poulton is the vice president of programming and production for and a familiar face at space shuttle launches.

She’ll be keeping readers abreast of the latest developments leading up to the November 14 launch of the space shuttle Endeavour, which is headed to the ISS to deliver some new household goods, make a few repairs, and switch out a member of the crew. Susan will even be live blogging from the launch site—a first for Breaking Orbit.


A Soyuz spacecraft carrying crew headed for the ISS blasts off the Baikonur Cosmodrome in Kazakhstan on October 12, 2008

—Photo courtesy NASA/Bill Ingalls

In keeping with the spirit of my journey, I did a little snooping around on how the ancient Egyptians studied the planets.

Only five of the eight official planets are visible to the naked eye: Mercury, Venus, Mars, Jupiter, and Saturn.

Without the benefit of the telescope, which wasn’t invented until around A.D. 1600, these planets would have looked like stars that moved across the sky in odd ways compared to the rest of the firmament.

According to the home-study Web guide Egyptology Online, by the time of Egypt’s Middle Kingdom (roughly 2030 to 1640 B.C.) the five naked-eye planets were called “the stars that know no rest.”

These special stars were thought to be Egyptian gods sailing across the sky in ceremonial boats. Three—Jupiter, Mars, and Saturn—were associated with different incarnations of Horus, ruler of the living world.


An illustration shows Ramses II offering incense to the sun god Amun

—Illustration by H. Tom Hall/NGS

Mercury was Sebegu, a god that the Egyptology site says is linked to Set, ruler of the underworld, but one I can’t find any corroborating info on.

Venus, meanwhile, was an unnamed “god of the morning,” perhaps due to the fact that it appears brightest just before sunrise or just after sunset.

By the time the optical telescope finally burst on the scene in the 17th century, planets had already changed in definition from objects that moved across the sky to objects that orbit the Earth, and with Galileo’s first peek at the heavens through a refracting ‘scope, astronomy entered a brave new world.

Still, I find it remarkable, given the technological imitations, how much about the motions in the sky that ancient cultures like the Egyptians were able to decipher.

Egyptian priests, for example, could predict the summer solstice and thus the annual flooding of the Nile by tracking the star Sirius. In fact, from the Sphinx you can still see the sun setting on the solstice precisely between the two great pyramids of Giza.

While I won’t be there to witness a solstice of any kind, I will keep my camera poised to snap pictures of ancient astronomy sights I might find in my travels.

So welcome Stephen and Susan to the blog, and I’ll rejoin the fray in two weeks!

Human Journey