Old 7th April 2005, 09:04   #1
taylormemer
made his slipknot mask in woodwork class
(Forum King)
 
taylormemer's Avatar
 
Join Date: Apr 2003
Location: Adelaide, Australia
Posts: 3,447
Send a message via ICQ to taylormemer Send a message via AIM to taylormemer Send a message via Yahoo to taylormemer
Habitable Planets





Habitable Planets: Disaster Zones and Safe Havens

By Robert Roy Britt

Senior Science Writer
posted: 05 April 2005
06:22 am ET

____________________________________________________________
New computer simulations of known extrasolar planetary systems suggest about half of them could harbor an Earth-like world, mathematically speaking.


All of the known planets orbiting other Sun-like stars -- there are at least 130 -- are very massive, most similar in heft to Jupiter. Earth-sized planets, if any exist, can't be found with present technology (with the exception of a handful discovered around a dying star). But several models by different groups have shown rocky planets about the size of Earth could exist in known systems where a giant planet orbits a Sun-like star.

In the new work, researchers created hypothetical giant planets and found that each creates two disaster zones -- one inside its orbit (closer to the star) and one outside. A fledgling Earth in either zone will either be lured into a collision with the larger planet, will hit the star, or will be tossed out to the cold, dead, far suburbs of the system.
____________________________________________________________
Images

An artist's impression of an Earth-like planet. Nobody knows if there are any for sure, however, or what they might look like...
____________________________________________________________

That's no surprise. But the specifics of the model bear attention: The disaster zones are governed by the giant planet's mass and the eccentricity of its orbit, or how noncircular it is.

"The larger its orbital eccentricity, the greater the gravitational reach of the giant," said Barrie Jones, an astronomy professor at the Open University in the UK.

The question was this: What sort of system with a large planet can support a rocky planet in a habitable zone, the region where temperatures are favorable for allowing liquid water to exist on an Earth-sized planet.

"If liquid water can exist, so could life as we know it," Jones said.

Other researchers caution that the presence of water does not mean life necessarily exists. Nobody knows how life begins or whether it has gotten started anywhere beyond Earth. But rocky, wet planets are a great place to start looking for biological activity.

To allow an Earth-sized planet in a stable orbit within a habitable zone, the giant must either be well outside that zone, as Jupiter and the other giants are in our solar system, or well inside, the modeling found.

"The more massive the giants the further their perturbing gravitational reach, and the more distant from the habitable zone they need to be," Jones told SPACE.com. "You can't be too near a giant or its gravity will wreak havoc with the 'Earth' orbit."

This is where the modeling gets interesting.

The scientists then applied these rules to real planetary systems. Several of the known extrasolar setups involve a "hot Jupiter," a planet roughly the mass of Jupiter in a very tight orbit around its star. These worlds see a year go by in less than a week.

The computer-generated disaster zones, particular to each actual star and its giant planet, were compared to that star's habitable zone to see if there were any safe havens -- stable orbital routes within habitable zones.

When the computer model was run, about half of the known systems allowed a safe haven over a long enough time period, including into the present, to possibly allow life to evolve, the researchers found.

A few other systems had habitable zones in the past or will have them in the future as their stars age and energy outputs change. Toss these in and the researchers come up with about two-thirds of the 130 systems they studied harboring habitable zones at some time in the past, present or future.

The research was to be presented today at the National Astronomy Meeting of the Royal Astronomical Society. Open University researchers Nick Sleep and David Underwood contributed to the work.

Scientists do not expect to discover Earth-sized planets until a new generation of space telescopes, such as NASA's Kepler mission, fly later in this decade.
____________________________________________________________
More Stories:____________________________________________________________

Image of the Day

5th April, 2005
On the Edge




Pandora is seen in this dramatic view, orbiting just beyond the outer edge of Saturn's F ring. Several bright areas are visible within the F ring. In the main rings, the Keeler gap and the Encke gap, with a bright ringlet, are also visible. Pandora is 52 miles (84 kilometers) across, about.025 times the diameter of the Moon.

Pandora, along with its partner Prometheus, is one of the “shepherd moons” for the F ring. The F-ring is a narrow, ribbon-like structure, with a width of about a few kilometers. The two moons exert a gravitational influence on particles that make up the ring, confining it and possibly leading to the formation of clumps, strands and other structures observed there.

Pandora prevents the F-ring from spreading out-ward and Prometheus prevents it from spreading inward. However, their interaction with the ring is complex and not fully understood. They are in chaotic orbits that can change unpredictably when the moons get very close to each other.

The image was taken in visible light with the Cassini spacecraft narrow-angle camera on Feb. 18, 2005, at a distance of approximately 746,000 miles (1.2 million kilometers) from Pandora. The moons were first viewed by the Voyager spacecraft, and were first spotted by Cassini in April of 2004.
Credit: NASA/JPL/Space Science Institute

April 06, 2005
Auroral Surprise




Solar storms ignite particles in Earth's upper atmosphere, triggering colorful light shows near polar regions known as the aurora. Scientists had thought the Southern Lights would mirror the Northern Lights.

A new study finds they don't.

Above is a 1991 view of the Aurora Australis, or Southern Lights, from the Space Shuttle Discovery. At right is data from simultaneous observations taken on Oct. 23, 2002 showing the two poles' auroras acting differently.

The study, based on satellite and ground-based observations, was announced yesterday.

According to scientists, the main cause behind the differences in location appears to be what occurs between the Sun's charged particles, known as the solar wind, and Earth's magnetic field.

Looking at the auroras from space, they look like almost circular bands of light. The new study found the bands at the two poles shift in opposite directions to each other depending on the orientation of the Sun's magnetic field, which travels toward the Earth with the solar wind flow. They also noted that the auroras shift in opposite directions to each other depending on how far the Earth's northern magnetic pole is leaning toward the sun.

What was most surprising was that both the northern and southern auroral ovals were leaning toward the dawn (morning) side of the Earth for this event. The scientists suspect the leaning may be related to "imperfections" of the Earth's magnetic field.

"This is the first analysis to use simultaneous observations of the whole aurora in both the northern and southern hemispheres to track their locations," said lead author Timothy Stubbs of NASA's Goddard Space Flight Center.

By knowing how auroras react to the solar wind, scientists can better determine the impacts of space weather in the future. The new discovery shows that auroras may be more complicated than previously thought.
Image: NASA
____________________________________________________________
CREDIT: SPACE.com



____________________________________________________________

DeviantART|¤¤|DS-Lair|¤¤|Dissectional|¤¤|Pearl Drums|¤¤|Viralsound|¤¤|PabUK
Hey you! Don't tell me there's no hope at all. Together we stand, divided we fall.My PLAYLIST

MSN: taylor.jake@hotmail.com
taylormemer is offline   Reply With Quote
Old 10th April 2005, 17:02   #2
webthing
Forum King
 
webthing's Avatar
 
Join Date: Sep 2002
Location: South Central Pennsylvania USA
Posts: 2,647
I'm about 99.9% sure there is more life out there.

Just look at the size of the universe. What a waste of space if we are the only planet with life.

If I was just told that a planet was found full of life it would not surprise me at all.

Bye-the-way taylormemer. What are your beliefs on the origin of the universe? Do you beleive that a God or supreme being created it? I do. It just didn't pop in to existence all by itself. You've made all these wonderful threads about the universe. Just curious what your thoughts were on the subject.


Have a nice day!
webthing is offline   Reply With Quote
Old 10th April 2005, 18:42   #3
ElChevelle
Moderator Alumni
 
ElChevelle's Avatar
 
Join Date: Jun 2000
Location: the MANCANNON!
Posts: 22,436
I'm a full 100% certain of habitable planets. Unfortunately, we'll never be able to explore them in my lifetime.
ElChevelle is offline   Reply With Quote
Old 11th April 2005, 02:11   #4
gaekwad2
Foorum King
 
gaekwad2's Avatar
 
Join Date: Jul 2003
Location: bar2000
Posts: 11,424
Quote:
To allow an Earth-sized planet in a stable orbit within a habitable zone, the giant must either be well outside that zone, as Jupiter and the other giants are in our solar system, or well inside, the modeling found.

"The more massive the giants the further their perturbing gravitational reach, and the more distant from the habitable zone they need to be," Jones told SPACE.com. "You can't be too near a giant or its gravity will wreak havoc with the 'Earth' orbit."

This is where the modeling gets interesting.

The scientists then applied these rules to real planetary systems. Several of the known extrasolar setups involve a "hot Jupiter," a planet roughly the mass of Jupiter in a very tight orbit around its star. These worlds see a year go by in less than a week.
The only problem with 'hot Jupiters' is that afaik they can't form so close to their sun (being so close to a young star their atmosphere would have been blasted away).

It's assumed that the gas giants that were found in close orbit formed further out and moved inward, destroying or hurling out of the solar system all possible inner planets.
gaekwad2 is offline   Reply With Quote
Reply
Go Back   Winamp & Shoutcast Forums > Community Center > Breaking News

Thread Tools Search this Thread
Search this Thread:

Advanced Search
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off

Forum Jump