Re-analysis of Mars Viking data "finds life"
http://news.discovery.com/space/mars...mkcpgn=rssnws1
And then there is this new analysis of the results of previous impacts on Earth of large meteorites:
http://www.technologyreview.com/blog/arxiv/27720/
Meteorites made of rocks blown off of Mars by impacts on its surface have been found on Earth. It is only reasonable to assume that ejecta from Earth impacts could send material out into space, the smaller stuff being assisted by the Solar wind. The escape velocity from Earth, v = sqrt(2GM/r), is 11.2 Km/sec, or 25,000 mph. To escape the Sun (solar system) you would have to achive 42.4 Km/sec velocity. This can be achieved by using the Earth's velocity around the Sun, 30 Km/sec and adding only 12.4 Km/sec to it in the direction the Earth is traveling.
The minimum impact velocity on Earth is 11 km/s, the same as the escape velocity. Typical impact velocities are 17 km/s for asteroids and 51 km/s for comets. The maximum Earth impact velocity for objects orbiting the sun is 72 km/s. (42Km/s + 30 Km/s). So, it is possible for ejecta to be propelled away from Earth at 42 Km/sec.
What this information establishes is that it would be impossible to claim that if life is discovered on any planet in this solar system that it is indigenous to that planet UNLESS it demonstrates a DNA pattern which is different from any that is or has been discovered on Earth. IOW, the Alpha Helix found anywhere else in this Solar system isn't going to count as proof of life evolving there. Further, considering the amount of material that could have ended up on planets revolving around stars that are 20 light years from Earth, and having taken only 1 million years to get there, assuming such organisms could survive that long in space, life found at that distance would be suspect as well, unless its basis for life is not the Alpha Helix.
New analysis of 36-year-old data, resuscitated from printouts, shows NASA found life on Mars, an international team of mathematicians and scientists conclude in a paper published this week.
http://www.technologyreview.com/blog/arxiv/27720/
About 65 million years ago, the Earth was struck by an asteroid some 10 km in diameter with a mass of well over a trillion tons. We now know the immediate impact of this event—megatsunamis, global wildfires ignited by giant clouds of superheated ash, and, of course, the mass extinction of land-based life on Earth.
But in recent years, astrobiologists have begun to study a less well known consequence: the ejection of billions of tons of life-bearing rocks and water into space. By some estimates, the impact could have ejected as much mass as the asteroid itself.
The question that fascinates them is what happened to all this stuff.
...
Their results contain a number of surprises. First, they calculate that almost as much ejecta would have ended up on Europa as on the Moon: around 10^8 individual Earth rocks in some scenarios. That's because the huge gravitational field around Jupiter acts as a sink for rocks, which then get swept up by the Jovian moons as they orbit.
But perhaps most surprising is the amount that makes its way across interstellar space. Last year, we looked at calculations suggesting that more Earth ejecta must end up in interstellar space than all the other planets combined.
Hara and co go further and estimate how much ought to have made its way to Gliese 581, a red dwarf some 20 light years from here that is thought to have a super-Earth orbiting at the edge of the habitable zone.
They say about a thousand Earth-rocks from this event would have made the trip, taking about a million years to reach their destination.
But in recent years, astrobiologists have begun to study a less well known consequence: the ejection of billions of tons of life-bearing rocks and water into space. By some estimates, the impact could have ejected as much mass as the asteroid itself.
The question that fascinates them is what happened to all this stuff.
...
Their results contain a number of surprises. First, they calculate that almost as much ejecta would have ended up on Europa as on the Moon: around 10^8 individual Earth rocks in some scenarios. That's because the huge gravitational field around Jupiter acts as a sink for rocks, which then get swept up by the Jovian moons as they orbit.
But perhaps most surprising is the amount that makes its way across interstellar space. Last year, we looked at calculations suggesting that more Earth ejecta must end up in interstellar space than all the other planets combined.
Hara and co go further and estimate how much ought to have made its way to Gliese 581, a red dwarf some 20 light years from here that is thought to have a super-Earth orbiting at the edge of the habitable zone.
They say about a thousand Earth-rocks from this event would have made the trip, taking about a million years to reach their destination.
The minimum impact velocity on Earth is 11 km/s, the same as the escape velocity. Typical impact velocities are 17 km/s for asteroids and 51 km/s for comets. The maximum Earth impact velocity for objects orbiting the sun is 72 km/s. (42Km/s + 30 Km/s). So, it is possible for ejecta to be propelled away from Earth at 42 Km/sec.
What this information establishes is that it would be impossible to claim that if life is discovered on any planet in this solar system that it is indigenous to that planet UNLESS it demonstrates a DNA pattern which is different from any that is or has been discovered on Earth. IOW, the Alpha Helix found anywhere else in this Solar system isn't going to count as proof of life evolving there. Further, considering the amount of material that could have ended up on planets revolving around stars that are 20 light years from Earth, and having taken only 1 million years to get there, assuming such organisms could survive that long in space, life found at that distance would be suspect as well, unless its basis for life is not the Alpha Helix.
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