3 min read

NASA – Is the Moon Out Tonight?

Last month, the Hubble Space Telescope peered into the depths of space and sent back images of a new, mysterious planet-like body at the outer reaches of our Solar System. But it's what the telescope didn't see that is perplexing scientists.

Hubble composite images of Sedna

Image Left: Hubble took a total of 35 images of Sedna. The planetoid appeared to move slightly between exposures. Sedna is moving through space, but too slowly to be seen in this picture. The fact that the object shows this

parallax

shift between exposures demonstrates that Sedna is a member of the solar system, and closer to the Earth than the background star (at right) in the same field of view. Credit: NASA/ESA/M. Brown (Caltech)

In the weeks following the discovery, researchers expected Hubble to reveal images of a moon revolving around the newly found planetoid named Sedna. This is because Sedna appears to have a very slow rotation, which usually would mean the planetoid is slowed by the gravitational pull of a body revolving around it.

So far, any indication of a companion moon of any substantial size hasn't been seen.

"I'm completely baffled at the absence of a moon," said Mike Brown of the California Institute of Technology. "This is outside the realm of expectation and makes Sedna even more interesting. But I simply don't know what it means."

Sedna's rotation has been calculated to take 40 days compared to Pluto's six-day period. If in time this proves to be accurate, Sedna would be the slowest rotating object in the Solar System after Mercury and Venus.

NASA's Hubble Telescope, using its new Advanced Camera for Surveys, only showed Sedna in its observations. But there is still a small possibility that the planetoid has a moon that could be behind Sedna or in front of it.

Artist's concept of Sedna

In both cases, Hubble would not be able to see it. According to Brown, doing so would be like trying to see a soccer ball that is 900 miles away.

Image Right: This is an artist's impression of noontime on Sedna. The Sun is a brilliant pinpoint of light 100 times brighter than the full Moon. The dim spindle-shaped glow of dust around the Sun defines the ecliptic plane of the solar system. To the left the Milky Way stretches into the sky. Saturn is also visible as a dim star. Earth would be only half a degree from the Sun and only be visible with powerful binoculars. Click on image for larger view. Credit: NASA/ESA/ Adolf Schaller

NASA's ground and space telescopes - including the new James Webb Space Telescope (

JWST

), planned for launch in 2011 - will be focused on Sedna over the next 72 years, during its closest distance to Earth.

As Sedna continues to travel in its 10,500-year orbit around the Sun, only the highest-resolution, infrared-light-seeking instruments such as the JWST will have the ability to study the most frigid bodies in our Solar System.

For further information, visit:

http://science.msfc.nasa.gov/headlines/y2004/16mar_sedna.htm

and

http://www.gps.caltech.edu/~mbrown/sedna/

Elaine M. Marconi, KSC Staff Writer

NASA's John F. Kennedy Space Center and California Institute of Technology

Share

Details

Last Updated
Apr 17, 2023
Editor
NASA Hubble Mission Team

Related Terms

Explore More

A spiral galaxy, seen face-on to the viewer. The bright center of the galaxy is crossed by a glowing bar, and it is surrounded by tightly wound spiral arms, forming a circular shape with relatively clear edges. Faraway galaxies are visible around it, along with a few bright stars, on a dark background. One star to the right of the galaxy is very large and extremely bright with long diffraction spikes.
2 min read

Hubble Captures a Bright Galactic and Stellar Duo

Article6 hours ago
This is a Hubble Space Telescope image of the barred spiral galaxy UGC 12158. The majestic galaxy has a pinwheel shape made up of bright blue stars wound around a yellow-white hub of central stars. The hub has a slash of stars across it, called a bar. The galaxy is tilted face-on to our view from Earth. A slightly s-shaped white line across the top is a Hubble image is of an asteroid streaking across Hubble's view. It looks dashed because the image is a combination of several exposures of the asteroid flying by like a race car.
5 min read

Hubble Goes Hunting for Small Main Belt Asteroids

Article1 day ago
A spiral galaxy seen nearly face-on. The disk holds many tightly wound spiral arms. They contain small strands of reddish dust, near the center. On the left side, the disk features glowing patches of star formation. The whole right side, and part of the center, is obscured by a large cloud of dark grey gas which crosses the image.
2 min read

Hubble Spots a Galaxy Hidden in a Dark Cloud

Article1 week ago
Keep Exploring

Discover More Topics From NASA

James Webb Space Telescope

The image is divided horizontally by an undulating line between a cloudscape forming a nebula along the bottom portion and a comparatively clear upper portion. Speckled across both portions is a starfield, showing innumerable stars of many sizes. The smallest of these are small, distant, and faint points of light. The largest of these appear larger, closer, brighter, and more fully resolved with 8-point diffraction spikes. The upper portion of the image is blueish, and has wispy translucent cloud-like streaks rising from the nebula below. The orangish cloudy formation in the bottom half varies in density and ranges from translucent to opaque. The stars vary in color, the majority of which have a blue or orange hue. The cloud-like structure of the nebula contains ridges, peaks, and valleys – an appearance very similar to a mountain range. Three long diffraction spikes from the top right edge of the image suggest the presence of a large star just out of view.

Perseverance Rover

Parker Solar Probe

Juno