MessageToEagle.com

Deception In The Universe –
Meteors Can Fool Us To Think Alien Worlds Are Inhabited With Life

18 September, 2012

Share this story:
Follow us:

MessageToEagle.com - In recent years, astronomers have detected hundreds of extrasolar planets.

Many of these exoplanets lie within habitable zones, the zones around their stars warm enough for liquid water to persist on a planet's surface, raising hopes that life as we know it might live on these distant worlds.

Ground-based observatories and proposed-but-cancelled spacecraft such as the European Space Agency's Darwin project or NASA's Terrestrial Planet Finder could scan the atmospheres of exoplanets for signs of extraterrestrial life. Molecules each absorb specific types of light, resulting in patterns known as spectra that allow scientists to identify what the molecules are.

Some chemicals or combinations of chemicals might be unique to life as we know it, and could thus serve as strong evidence of aliens.


Carbonaceous chondrites are thought to be a potential source of early Earth’s volatile elements - including hydrogen, nitrogen, and carbon - and possibly organic material. Artist concept Credit: NASA's Goddard Space Flight Center/Chris Smith


One key gas astrobiologists looking for extraterrestrial life would concentrate on would be oxygen, since researchers often think this molecule is too chemically reactive to remain for long in the atmosphere of a rocky planet like Earth without organisms to continuously produce it. Another possibility would be methane, a colorless, odorless, flammable organic gas that microbes on Earth produce.

Seeing both together in an exoplanet's atmosphere might be an especially significant sign of life, since they would both ordinarily remove each other from the atmosphere without something like life to constantly replenish them.

For more than 40 years, hints of methane have been seen on Mars, the first organic compound seen there. In the last decade, researchers have even suggested they have seen methane clouds that may have been forming over the red planet during the summer months in the last decade, raising the possibility of past or even extant organisms just below the surface, although these findings remain hotly contested.

Although life or the byproducts of life are responsible for nearly all the methane found in Earth's atmosphere, it is not the only source of the gas. For instance, volcanism can produce methane, as can chemical reactions between water, carbon dioxide and minerals.

Another potential source of methane are carbon-rich micrometeoroids that generate the gas as the compounds in them burn up while entering a planet's atmosphere. Our solar system's main asteroid belt happens to be dominated by carbonaceous asteroids.

Although the number of micrometeoroids hitting Mars would not explain the levels of methane seen there, exoplanets in much dustier systems could potentially have enough methane produced in this manner to give off a false atmospheric signature of life.

"This could pose a problem, since the search for life on these exoplanets is dependent on remote observations such as spectroscopic analysis of their atmospheres, as had been used to detect the methane in the atmosphere of Mars," said researcher Richard Court, a planetary geologist at Imperial College London. "There is no chance of spacecraft physically visiting these exoplanets many light years away in the foreseeable future."



Click on image to enlarge

This image shows concentrations of methane discovered on Mars. Credit: NASA


Past research suggests the only systems likely to possess debris disks dense enough to mimic a methane signature of life are either very young, or systems undergoing a massive set of collisions, such as was the case in our solar system during the Late Heavy Bombardment about 3.9 billion years ago, when millions of rocks cataclysmically blasted Earth and the rest of the inner solar system over a roughly 100-million-year period.

"Astronomers have been able to observe events analogous to the Late Heavy Bombardment occurring in other star systems," Court said.


Deception in the Universe - Meteors can fool us to think alien worlds are inhabited with life.


To see how much methane carbonaceous micrometeoroids might generate on exoplanets, scientists calculated what an early, dustier version of our solar system was like. Currently Earth receives about 40,000 metric tons of micrometeoroids annually, while Mars sees about 12,000 metric tons. The researchers estimate that during the Late Heavy Bombardment, Earth and Mars saw about 1,000 to 10,000 times more.

During the entire Late Heavy Bombardment, Earth may have received about 33 million billion metric tons of micrometeoroids, while Mars received 1.7 million billion metric tons. This all may be enough for an exoplanet to have enough methane to make it look as if it might have life.

"These are the first people to address exoplanet atmospheres as they relate to micrometeoroids that produce methane upon atmospheric entry — people working with exoplanets hadn't thought of this before, and it's cool and something we should be aware of," said planetary scientist Sara Seager at the Massachusetts Institute of Technology, who did not take part in this study.



Click on image to enlarge

When an exoplanet passes in front of its star from our point of view, atoms in its atmosphere absorb some of the starlight at specific wavelengths. These wavelengths form a unique fingerprint, allowing scientists to identify the presence of specific gases in an exoplanet's atmosphere. Credit: European Space Agency, with adaptations by David Sing


Court did caution that they assumed that the chemistry and abundance of the organic matter in micrometeorites falling to Earth is similar to that of micrometeorites in other star systems.

"While some differences are inevitable, it is likely to be a reasonable assumption, because a search for evidence of life on planets outside the solar system will naturally seek to investigate a star system as similar as possible to ours," he said.

So far astronomers have detected a number of exoplanetary systems that may possess both planets and debris disks.

One example may include Gliese 581 about 20 light years from Earth, which has one and maybe two "super-Earths" — rocky planets larger than our own that can reach up to 10 times Earth's mass — around the red dwarf of the system's habitable zone.

"As we observe more star systems, it will be possible to apply our work to more extrasolar planets," Court said.

MessageToEagle.com via Astrobio.net

See also:
Unusual Organisms Living On Pandora: A Fictional Alien World That Could Be Real

Follow MessageToEagle.com for the latest news on Facebook and Twitter !

Don't Miss Our Stories! Get Our Daily Email Newsletter

Enter your email address:


Once you have confirmed your email address, you will be subscribed to the newsletter.

Recommend this article:

Alien Life In The Multiverse - Are We Living In A "Rare Universe"?
A while back scientists announced that they had discovered what could possibly be considered as the first evidence of parallel universes. Many people are intrigued by speculative ideas about cosmology and find the idea of...

Unusual Pulsar Or Alien Signals?

Our Sun Does Not Originate From M 67

Super-Earth Discovered Orbiting Several Suns

Subscribe To Our News!

Grab the latest RSS feeds right to your reader, desktop or mobile phone.

Subscribe to RSS headline updates from:
Powered by FeedBurner

Related Posts Plugin for WordPress, Blogger...

Go to - MAIN PAGE

Copyright © MessageToEagle.com All rights reserved.
Go to - MAIN PAGE


Get our top stories
Follow MessageToEagle.com

 Subscribe in a reader

Join Us On Facebook!

Other Popular Articles

Universe:


A Lonely Galactic Island - Nine Million Light-Years Away From Our Solar System

Perfect Computer Simulation - 14 Billion Years Of Cosmic Evolution Recreated!

Massive Star Clusters On Collision Course In The Gigantic 30 Doradus Nebula

Extraordinary Phoenix Galaxy Cluster - One Of The Largest Objects In The Universe With Record-Breaking Star Formation

The Pipe Dark Nebula - Curious And Complex Astronomical Object

Gamma-Ray Photons Seen Emanating From The Center Of The Milky Way Could Be Evidence of Dark Matter

There Is Dark Matter Near The Sun - Astronomers Confirm Their Discovery

Sloan Digital Sky Survey III Presents: New 3-D Map Of The Sky!

Doomed Moons Of Uranus: Cupid And Belinda Are On Collision Course

Astronomical Mystery: Giant Alien Planet Orbiting Three Suns
Binary stars are well-known and even trinary systems may be common but most of them are crowded together and thus, difficult to find and study. Additionally, it has long been considered they are inhospitable to planets...

Radio Emission From Ultracool Dwarf Detected By Arecibo Telescope
The Arecibo Telescope in Puerto Rico has discovered sporadic bursts of polarized radio emission from the T6.5 brown J1047+21.
Because Arecibo is a single, fixed-dish telescope, it has a restricted practical sensitivity to weak, quiescent emission from radio sources...

Monster Star Thousand Times Bigger Than Our Sun Could Soon Explode - with video
Despite its enormous size, the star has not been identified as yellow hypergiant until recently...

Star Changes Into An Incredible Diamond Planet - with video
How can a star change into a diamond planet? Astronomical discoveries show that what sounds like science fiction is actually reality...

Invader From Another Galaxy
This alien intruder from another galaxy is in many ways different from other exoplanets observed by astronomers.
Located about 2000 light-years from Earth in the southern constellation of Fornax (the Furnace), the Jupiter-like planet orbits a dying star of extragalactic origin and risks to be engulfed by it.

Power To See Most Distant Objects In The Universe
The 3C294, is one of the most distant galaxies recorded by Chandra, the most sophisticated X-ray observatory ever built. The cluster 3C294 is even 40 percent farther (!) than the next most distant x-ray galaxy cluster. Chandra focus on X-rays from high-energy regions of the Universe and see the invisible. It is so sensitive that it can capture images of particles as they disappear into a black hole deep in outer space.

"Pillars Of Creation" Are Gone
Every time you look at the beautiful and famous image of the Pillars of Creation taken by Hubble back in 1995, you are actually admiring something that no longer exists.
In fact, the Pillars of Creation were already long gone by the time the image was captured!

New Unified Theory Alters Einstein's View Of Spacetime
The scientists suggest the law of energy and momentum conservation in spacetime is valid only when normal matter, dark matter and dark energy are all taken into account. For normal matter alone - they say - energy and momentum are no longer conserved...

Does Triton Have a Subsurface Ocean?
Triton was discovered in 1846 by the British astronomer William Lassell, but much about Neptune’s largest moon still remains a mystery. A Voyager 2 flyby in 1989 offered a quick peak at the satellite, and revealed a surface composition comprised mainly of water ice.

Teleportation Experiments Continue - Record-Breaking Distance of 143 Kilometers Achieved!
An international research team including several scientists from the University of Waterloo has achieved quantum teleportation over a record-breaking distance of 143 kilometres through free space.

W3Counter