Featured Research

from universities, journals, and other organizations

Comets Spread Earth-life Around Galaxy, Say Scientists

Date:
February 11, 2004
Source:
Cardiff University
Summary:
If comets hitting the Earth could cause ecological disasters, including extinctions of species and climate change, they could also disperse Earth-life to the most distant parts of the Galaxy.

If comets hitting the Earth could cause ecological disasters, including extinctions of species and climate change, they could also disperse Earth-life to the most distant parts of the Galaxy.

The "splash-back" from a large comet impact could throw material containing micro-organisms out of the planet's atmosphere, suggest scientists from Cardiff University Centre for Astrobiology.

Although some of this outflowing material might become sterilised by heat and radiation, they believe that a significant fraction would survive. As the Earth and the Solar system go round the centre of the galaxy every 240 million years, this viable bacterial outflow would infect hundreds of millions of nascent planetary systems on the way. Hence, they suggest, the transfer of Earth life across the galaxy is inevitable.

These ideas are discussed in detail in two papers appearing in the current issue of the Monthly Notices of the Royal Astronomical Society.

The authors of the two papers are Professor Chandra Wickramasinghe and Dr Max Wallis, of the Cardiff Centre for Astrobiology, and Professor Bill Napier, an astronomer at Armagh Observatory and an Honorary Professor at Cardiff University.

Interstellar routes for transmission of micro-organisms supports the view that life may not have originated on Earth but arrived from elsewhere, strengthening the "panspermia theory" that Professor Wickramasinghe and the late Sir Fred Hoyle had been developing since 1974.

It is known that boulders and other debris may be thrown from the Earth into interplanetary space. Professor Napier finds that collisions with interplanetary dust will quickly erode the ejected boulders to much smaller fragments and that these tiny, life-bearing fragments may be driven out of the solar system by the pressure of sunlight in a few years.

The solar system could, therefore, be surrounded by an expanding 'biodisc', 30 or more light years across, of dormant microbes preserved inside tiny rock fragments. In the course of Earth history there may have been a few dozen close encounters with star-forming nebulae, during which microbes might be injected directly into young planetary systems.

If planets capable of sustaining life are sufficiently common in the Galaxy, the Cardiff based scientists conclude that this mechanism could have infected over 10,000 million of them during the lifetime of our Galaxy.

Dr Wallis and Professor Wickramasinghe have also identified another potential delivery route. They point out that fertile Earth ejecta would, on impact, bury themselves in the radiation-shielded surface layers of frozen comets. A belt of such comets, the Edgeworth-Kuiper belt, lies beyond the planetary system. This belt gradually leaks comets into interstellar space, some of which will eventually reach proto-planetary discs and star-forming nebulae. There they are destroyed by collisions and erosion, releasing any trapped micro-organisms and seeding the formative planetary systems.


Story Source:

The above story is based on materials provided by Cardiff University. Note: Materials may be edited for content and length.


Cite This Page:

Cardiff University. "Comets Spread Earth-life Around Galaxy, Say Scientists." ScienceDaily. ScienceDaily, 11 February 2004. <www.sciencedaily.com/releases/2004/02/040211080129.htm>.
Cardiff University. (2004, February 11). Comets Spread Earth-life Around Galaxy, Say Scientists. ScienceDaily. Retrieved April 17, 2014 from www.sciencedaily.com/releases/2004/02/040211080129.htm
Cardiff University. "Comets Spread Earth-life Around Galaxy, Say Scientists." ScienceDaily. www.sciencedaily.com/releases/2004/02/040211080129.htm (accessed April 17, 2014).

Share This



More Space & Time News

Thursday, April 17, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

New Baby Moon 'Peggy' Spotted In Saturn's Rings

New Baby Moon 'Peggy' Spotted In Saturn's Rings

Newsy (Apr. 15, 2014) A bump in the rings could be a half-mile-wide miniature moon. It was found by accident in Cassini probe images. Video provided by Newsy
Powered by NewsLook.com
Americas Glimpse Total Lunar Eclipse

Americas Glimpse Total Lunar Eclipse

AFP (Apr. 15, 2014) A total lunar eclipse, the first since December 2011, took place early Tuesday morning with the Americas getting the best glimpse. Duration: 1:19 Video provided by AFP
Powered by NewsLook.com
NASA Showcases Lunar Eclipse

NASA Showcases Lunar Eclipse

AP (Apr. 15, 2014) Star gazers in parts of North and South America got a rare treat early Tuesday morning - a total eclipse of the moon. (April 15) Video provided by AP
Powered by NewsLook.com
Spacecrafts Could Use Urine As Fuel Source

Spacecrafts Could Use Urine As Fuel Source

Newsy (Apr. 15, 2014) New research says the urea from urine could be recycled for fuel. Urea is filtered out of wastewater when making drinking water. Video provided by Newsy
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