Printer Friendly
The Free Library
4,539,614 articles and books
Member login
User name  
Password 
 
Join us Forgot password?

Hubble: evidence of oceans on Titan?


Of all the solar system bodies other than Earth, planetary scientists believe just one may harbor oceans or lakes. Researchers have long debated whether Saturn's moon Titan, cloaked in a methane-rich atmosphere, contains hydrocarbon
alicyclic hydrocarbon  one that has cyclic structure and aliphatic properties.
aliphatic hydrocarbon  one in which no carbon atoms are joined to form a ring.
aromatic hydrocarbon  one that has cyclic structure and a closed conjugated system of double bonds.
 oceans or lakes.

[CHART OMITTED]

In penetrating much of Titan's haze, the Hubble Space Telescope has taken a new step in clearing up the mystery. Peering through a "window" that allows near-infrared light to escape through the smong and methane engulfing Titan, Hubble has imaged intriguing bright and dark patches that seem to lie on the moon's surface. One explanation for the dark patches: They represent oceans of hydrocarbons; the brightest patch could be a continent-size chunk of frozen water and ammonia ice.

Peter H. Smith of the University of Arizona in Tucson and his colleagues presented the findings last week in Bethesda, Md., at the annual meeting of the American Astronomical Society's Division for Planetary Sciences.

He cautions that the dark patches could have more mundane explanations. Hydrocarbon tars coating parts of the moon's surface, for example, could also lower Titan's reflectivity and account for the dark features.

Because the near-infrared wave-lengths at which Hubble observed don't penetrate all of Titan's haze, Smith and his colleagues had to subtract the murky atmosphere to produce the final images. Some astronomers express concern that the pictures may show a mix of surface and lower-atmosphere features rather than just the surface.

But Smith notes that the light and dark regions imaged by Hubble match several ground-based observations. Unlike Hubble, telescopes on Earth must contend with Earth's wavering atmosphere and for now can't resolve individual features on Titan. But near-infrared observations from Earth taken over several years reveal that the regions of Titan that reflect the most and least sunlight are the same ones in which Hubble finds the brightest and darkest patches, respectively.

"The real proof of the pudding that these are surface features is that our bright spot and our dark spot line up precisely with the ground-based measurements," Smith says.

Jonathan I. Lunine of the University of Arizona, a proponent of the ocean hypothesis, says the Hubble images suggest that the composition and topography of the moon's surface vary considerably. Both hydrocarbon tars and a small ocean might reside within the same dark patch, he notes.

Researchers proposed Titan's hydrocarbon ocean in order to solve a dilemma. They realized that to sustain the amount of methane found in Titan's atmosphere, the moon must have a reservoir of the hydrocarbon. Without it, sunlight would have long ago destroyed the atmospheric methane.

Given Titan's temperature and surface pressure, scientists suggested that the reservori took the form of methane and ethane oceans and lakes. Radar studies later ruled out an ocean covering the entire moon but allowed for individual lakes or seas.

Several developments may help identify what lies on Titan, even before a space probe space probe, space vehicle carrying sophisticated instrumentation but no crew, designed to explore various aspects of the solar system (see space exploration). Unlike an artificial satellite, which is placed in more or less permanent orbit around the earth, a space probe is launched with enough energy to escape the gravitational field of the earth and navigate among the planets. parachutes onto the moon in 2004. New techniques to compensate for Earth's blurry atmosphere should enable ground-based infrared telescopes to image individual features on Titan. Similarly, an upgrade of the Arecibo Arecibo (ärəsē`bō), city (1990 pop. 93,385), N Puerto Rico, a port on the Atlantic Ocean at the mouth of the Rio Grande de Arecibo. It has rum distilleries and is the commercial and industrial center of a region that produces coffee, tobacco, sugarcane, and pineapples. An important radio-astronomy installation is nearby. Observatory's radio telescope radio telescope: see radio astronomy. in Puerto Rico, to be completed in 1996, should provide higher-resolution radar images. In space, NASA plans to install a new infrared camera on Hubble in 1997. This should enable the telescope to get an even clearer view of Titan's surface.
COPYRIGHT 1994 Science Service, Inc.
No portion of this article can be reproduced without the express written permission from the copyright holder.
Copyright 1994, Gale Group. All rights reserved. Gale Group is a Thomson Corporation Company.

 Reader Opinion

Title:

Comment:



 

Article Details
Printer friendly Cite/link Email Feedback
Title Annotation:Hubble Space Telescope images Saturn moon Titan
Author:Cowen, Ron
Publication:Science News
Date:Nov 12, 1994
Words:552
Previous Article:One team, two clues in Alzheimer's puzzle. (Alzheimer's disease research findings)
Next Article:Nutrients may prevent blinding disease. (carotenoids may prevent age-related macular degeneration)
Topics:



Related Articles
Titan: no global ocean, maybe some seas.
Saturn's 18th moon linked to dusty object. (moon to be named Pan)
Greenhouses in space: unearthly findings. (Earth-like atmospheric conditions on Venus and Titan)
Saturn ring toss: Hubble finds more moons.(Amanda S. Bosh and Andrew S. Rivkin use the Hubble Space Telescope to observe two previously-undiscovered...
New Saturn moons or only transient debris? (objects detected by Hubble Space Telescope)(Science News of the Week)(Brief Article)
A clearer view of Titan.(Saturn's moon observed using Keck I Telescope)(Brief Article)
Titanic images, groovy shots: Cassini arrives at Saturn.(space probes)
Titan's lakes: evidence of liquid on Saturn's largest moon.
Lakes on Titan.(Brief article)
Rare Uranian eclipse.(Hubble Space Telescope )(Brief article)

Terms of use | Copyright © 2008 Farlex, Inc. | Feedback | For webmasters | Submit articles