Watch Moons of Mars 'Dance' in NASA Video (But There's a Trick)

Phobos and Deimos, the two moons of Mars, are rocky and odd, but they share a serene grace as they appear to dance by each other in this stunning video of NASA images. But don't be fooled: the moons aren't moving like the video suggests.

The new view of Phobos and Deimos is the work of NASA's Mars Odyssey spacecraft, which has been orbiting the Red Planet since 2002. The orbiter snapped 19 photos of the Martian moons during a 17-second time span on Feb. 19. NASA scientists then assembled the images into a short animation, which we looped into the video you see here. [See more photos of Phobos and Deimos here]

The animation shows Mars' smaller moon Deimos appear to move down and to the left, passing out of frame as the larger Phobos rises on the right. But that weird motion is really due to Odyssey's Thermal Emission Imaging System camera (known as THEMIS), and not the moons themselves, NASA officials said.

Phobos and Deimos, the two moons of Mars, are captured by NASA's Mars Odyssey orbiter in this video animation of 19 images taken by the spacecraft over 17 seconds on Feb. 18, 2018. The apparent motion is due to the camera itself, and not the moons.
Credit: NASA/JPL-Caltech/ASU/SSI

"This was the second observation of Phobos by Mars Odyssey; the first was on September 29, 2017," NASA officials wrote in an image description. "Researchers have been using THEMIS to examine Mars since early 2002, but the maneuver turning the orbiter around to point the camera at Phobos was developed only recently."

<> The views of Phobos and Deimos in the video were taken in the visible-light range of the spectrum, but Odyssey's THEMIS camera also recorded observations in the thermal-infrared wavelength range as well, NASA officials said.

The Mars moons Phobos (right) and Deimos appear to pass one another in this still from an animation of photos by NASA's Mars Odyssey orbiter captured on Feb. 18, 2018.
Credit: NASA/JPL-Caltech/ASU/SSI

Odyssey was about 3,489 miles (5,615 kilometers) from Phobos, and 12,222 miles (19,670 km) from Deimos, when it observed the two moons. Phobos is Mars' biggest moon, at about 14 miles (22 km) wide. Deimos, meanwhile, has a diameter of about 8 miles (13 km).

At 17 years and counting, Mars Odyssey is the longest-serving Mars mission of all time. NASA launched Odyssey in April 2001, with the orbiter arriving at Mars in October of that year.

Email Tariq Malik at tmalik@space.com or follow him @tariqjmalik and Google+. Follow us @Spacedotcom, Facebook and Google+. Original article on Space.com.