Featured Research

from universities, journals, and other organizations

Hubble Captures A Rare Eclipse On Uranus

Date:
September 2, 2006
Source:
Space Telescope Science Institute
Summary:
A new Hubble Space Telescope image shows a never-before-seen astronomical alignment of a moon traversing the face of Uranus, and its accompanying shadow. The white dot near the center of Uranus' blue-green disk is the icy moon Ariel.

A new Hubble Space Telescope image shows a never-before-seen astronomical alignment of a moon traversing the face of Uranus, and its accompanying shadow. The white dot near the center of Uranus’ blue-green disk is the icy moon Ariel. The 700-mile-diameter satellite is casting a shadow onto the cloud tops of Uranus.
Credit: NASA, ESA, L. Sromovsky (University of Wisconsin, Madison), H. Hammel (Space Science Institute), and K. Rages (SETI)

A new Hubble Space Telescope image shows a never-before-seen astronomical alignment of a moon traversing the face of Uranus, and its accompanying shadow. The white dot near the center of Uranus’ blue-green disk is the icy moon Ariel. The 700-mile-diameter satellite is casting a shadow onto the cloud tops of Uranus. To an observer on Uranus, this would appear as a solar eclipse, where the moon briefly blocks out the Sun as its shadow races across Uranus’s cloud tops.

Though such "transits" by moons across the disks of their parents are commonplace for some other gas giant planets, such as Jupiter, the satellites of Uranus orbit the planet in such a way that they rarely cast shadows on the planet's surface. Uranus is tilted so that its spin axis lies nearly in its orbital plane. The planet is essentially tipped over on its side. During the course of its orbit around the Sun, first one pole and then the other is alternately illuminated. As a result, Uranus has extreme seasons during its 84-year orbit around the Sun. The moons of Uranus orbit the planet above the equator, so their paths align edge-on to the Sun only every 42 years.

This transit has never been observed before because Uranus is just now approaching its 2007 equinox when the Sun will shine directly over the giant planet’s equator. The last time a Uranian equinox occurred, when transits could have been observed, was in 1965. However, telescopes of that era did not have the image sharpness required to view satellite transits on Uranus. When Hubble was launched in 1990, the Sun was shining over Uranus’s far northern latitudes. Over the past decade Hubble astronomers have seen the Sun’s direct illumination creep toward equatorial latitudes and the moons' orbits approach an edge-on configuration.

Ariel, named for a mischievous airy spirit in Shakespeare's “The Tempest,” is only one-third the size of Earth's moon. Ariel is the nearest large satellite to Uranus. As Uranus approaches equinox, there will be additional eclipses by the large moons Umbriel, Titania, and Oberon, and by many smaller moons.

Lawrence A. Sromovsky of the University of Wisconsin-Madison, Heidi B. Hammel of the Space Science Institute, Boulder, Colorado, and Kathy A. Rages of the SETI Institute, Mountain View, California, created this color composite image from images at three wavelengths in near infrared light obtained with Hubble’s Advanced Camera for Surveys on July 26, 2006.


Story Source:

The above story is based on materials provided by Space Telescope Science Institute. Note: Materials may be edited for content and length.


Cite This Page:

Space Telescope Science Institute. "Hubble Captures A Rare Eclipse On Uranus." ScienceDaily. ScienceDaily, 2 September 2006. <www.sciencedaily.com/releases/2006/09/060901190042.htm>.
Space Telescope Science Institute. (2006, September 2). Hubble Captures A Rare Eclipse On Uranus. ScienceDaily. Retrieved July 29, 2014 from www.sciencedaily.com/releases/2006/09/060901190042.htm
Space Telescope Science Institute. "Hubble Captures A Rare Eclipse On Uranus." ScienceDaily. www.sciencedaily.com/releases/2006/09/060901190042.htm (accessed July 29, 2014).

Share This




More Space & Time News

Tuesday, July 29, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

Russia Saves Gecko Sex Satellite, Media Has Some Fun With It

Russia Saves Gecko Sex Satellite, Media Has Some Fun With It

Newsy (July 27, 2014) — The satellite is back under ground control after a tense few days, but with a gecko sex experiment on board, the media just couldn't help themselves. Video provided by Newsy
Powered by NewsLook.com
NASA EDGE: OCO-2 Launch

NASA EDGE: OCO-2 Launch

NASA (July 25, 2014) — NASA EDGE webcasts live from Vandenberg AFB for the launch of the Oribiting Carbon Observatory-2 (OCO) launch. Video provided by NASA
Powered by NewsLook.com
This Week @ NASA, July 25, 2014

This Week @ NASA, July 25, 2014

NASA (July 25, 2014) — Apollo 11 celebration, Next Giant Leap anticipation, ISS astronauts appear in the House and more... Video provided by NASA
Powered by NewsLook.com
Space to Ground: Coming and Going

Space to Ground: Coming and Going

NASA (July 25, 2014) — One station cargo ship leaves, another arrives, aquatic research and commercial spinoffs. Questions or comments? Use #spacetoground to talk to us. Video provided by NASA
Powered by NewsLook.com

Search ScienceDaily

Number of stories in archives: 140,361

Find with keyword(s):
 
Enter a keyword or phrase to search ScienceDaily for related topics and research stories.

Save/Print:
Share:  

Breaking News:
from the past week

In Other News

... from NewsDaily.com

Science News

Health News

Environment News

Technology News



Save/Print:
Share:  

Free Subscriptions


Get the latest science news with ScienceDaily's free email newsletters, updated daily and weekly. Or view hourly updated newsfeeds in your RSS reader:

Get Social & Mobile


Keep up to date with the latest news from ScienceDaily via social networks and mobile apps:

Have Feedback?


Tell us what you think of ScienceDaily -- we welcome both positive and negative comments. Have any problems using the site? Questions?
Mobile iPhone Android Web
Follow Facebook Twitter Google+
Subscribe RSS Feeds Email Newsletters
Latest Headlines Health & Medicine Mind & Brain Space & Time Matter & Energy Computers & Math Plants & Animals Earth & Climate Fossils & Ruins