Scientists Study Trajectories of Life-Bearing Earth Meteorites
Hugh Pickens writes "About 65 million years ago, Earth was struck by an asteroid some 10 km in diameter with a mass of well over a trillion tonnes that created megatsunamis, global wildfires ignited by giant clouds of superheated ash, and the mass extinction of land-based life on Earth. Now astrobiologists have begun to study a less well known consequence: the ejection of billions of tons of life-bearing rocks and water into space that has made its way not just to other planets but other solar systems as well. Calculations by Tetsuya Hara and his colleagues at Kyoto Sangyo University in Japan show that a surprisingly large amount of life-bearing material ended up not on the Moon and Mars, as might be expected, but the Jovian moon Europa and the Saturnian moon Enceladus also received tons of life-bearing rock from earth. Even more amazingly, calculations suggest that most Earth ejecta ended up in interstellar space and some has probably already arrived at Earth-like exoplanets orbiting other stars. Hara estimates that about a thousand Earth-rocks from this event would have made the trip to Gliese 581, a red dwarf some 20 light years away that is thought to have a super-Earth orbiting at the edge of the habitable zone, taking about a million years to reach its destination. Of course, nobody knows if microbes can survive that kind of journey or even the shorter trips to Europa and Enceladus. But Hara says that if microbes can survive that kind of journey, they ought to flourish on a super-Earth in the habitable zone (PDF). 'If we consider the possibility that the fragmented ejecta (smaller than 1cm) are accreted to comets and other icy bodies, then buried fertile material could make the interstellar journey throughout the Galaxy,' writes Hara. 'Under these circumstances fragments could continue the interstellar journey and Earth origin meteorites could be transferred to Gl 581 system. If we take it as viable, we should consider the panspermia theories more seriously.'"
If we take it is viable, we should consider the panspermia theories more seriously.
Only as a possible answer to the origin of Earth's life. It still doesn't answer the origin of life itself, wherever it may have started.
Those who do not learn from commit history are doomed to regress it.
humanoids walking on two feet with funny heads
so the culmination of mankind's civilization, scientific efforts, and technological achievements, is to go to some exoplanet, only to find some foot fungus some dinosaur had long before mankind ever appeared?
intellectual property law is philosophically incoherent. it is your moral duty to ignore it or sabotage it
Hmmm, made it to other Earth-like planets instead of randomly catching a closer strong gravitational field or drifting randomly into nothingness.
Even making Europa would be kind of like hitting a cockroach with a needle from across a football stadium.
Oh to be the house, if this scientist ever landed in Vegas with a wallet-load... Sounds like someone needs to re-fill the ol' grant jar.
*Repent!Quit Your Job!Slack Off!The World Ends Tomorrow and You May Die!
How do objects this size survive the trip through the destination planet's atmosphere?
There are those who believe that life out there began here
Flung far across the universe, before there were tribes of humans...
The next question has to be, was the Earth injected with life too? Is this how life started on our planet?
I've made a quick scan of the underlying academic article by Hara et al., along with one of my colleagues in a meeting here, who is closely involved in the issue of planetary protection (i.e. making sure that our spacecraft don't "pollute" the solar system bodies they fly to and land on).
Of course, this is a known issue in general: after all, there are meteorites on Earth which we know came from Mars, so the converse is obviously possible. But extending this to moons of Jupiter, Kuiper Belt objects, and even exoplanetary systems, and finding that a significant number of Earth rocks may have been dumped there is interesting. So, the article is worth a more careful read.
However, my antennae were sent into a state of high agitation when I saw that the article has been posted on the arXiV following its having been accepted to the infamous Journal of Cosmology. We've discussed that here before: I invite you to view the journal website (easily found by googling) and decide for yourselves how reputable it is.
Which raises the question of why Hara et al. chose to publish there. That I can't answer, obviously, but will keep it firmly in mind as I read the paper in more detail.
If we share common ancestry, that means we might find alien life tasty and nutritious. ... to seek out new life and new civilizations, to eat.
ur never safe until you start making your own processors.
rewriting history since 2109
I had no idea the theory of an asteroid impact had been proven as fact. Glad I read slashdot so I can stay educated.
So, without realizing it, we're ALREADY colonizing our galaxy. Life bearing rocks from earth hit other planets, those planets also experience trauma sooner or later, ejecting their rocks into space millions of years later, after life had caught on, and so on and so on.
Therefore, Earth may be a colony of some other civilization from billions of years ago, or, we're creating colonies as we speak.
If telephones are outlawed, then only outlaws will have telephones.
Really? Is that like if you play it backwards you hear the voice of the devil or something
Noom eht yb despilce si nus eht tub enut si nus eht rednu gnihtyreve
Astounding! With just a few minutes of thought and your superior intuition, you've dismissed the result of careful calculation and decades of training on the part of this group of scientists. Imagine what a genius of your magnitude could accomplish from within the scientific system...it truly staggers my humble intellect! But I'm sure you're working on much more important things.
Yo dawg, I heard you like the Ackermann function, so OH GOD OH GOD OH GOD
I could believe that some simple life form could suvive on a rock travelling through space for millions of years, but I don't see how it would have survived the heat of the impact event that blasted it beyond escape velocity in the first place
(at least life as we know it, Jim)
So the implication is that if this is true then if life is one day to be discovered within the subsurface oceans of either Europa or Enceladus then it's possible that such life originated from Earth, and therefore from the same root single celled organism (the Eve cell) from which all terrestrial life came from. If so a mitochondrial DNA check would verify this.
How can we study the trajectory when we don't know:
When the asteroid hit?
The earth's position relative to the sun, the other planet, and the rest of the stars in the galaxy at the time of impact.
The direction from which the asteroid hit us.
The size of the asteroid.
For starters....
It's all so obvious now.
Panspermia is a very interesting/compelling theory. But I'd avoid telling anyone in academia that you're interested in an Earth genesis hypothesis other than evolution.
You may just as well have told them that you're a pro-lifer, who voted for Bush, are home schooling your kids, believe in a balanced budget, and are a racist all in one sentence.
All this talk about ejaculates and sperm theory, and NOBODY's made a joke about it yet?
Actually Martin Lo discovered low energy gravitational paths or "superhighways" that would allow objects like space probes and maybe rocks to travel all around the solar system without power. These calculations were used in the Genesis probe NASA project IIRC.
http://en.wikipedia.org/wiki/Interplanetary_Transport_Network
http://genesismission.jpl.nasa.gov/gm2/team/people/lo/interview1.htm
Assume we're just dealing with Carbon (molecular weight 12) here, and "well over 1 trillion tonnes" is actually 2 trillion tonnes:
number of molecules per gram = (Avogadro's Number) / 12 grams = 5.02E25 molecules/kg
2 trillion tonnes = 2E15 kg
(5.02E25 molecules / kg * 2E15 kg) = 1.004E41 molecules
Surface area of sphere with radius of 20 light years = 4.499E35 meters^2
1.004E41 molecules / 4.499 meters^2 = 223,091 molecules / meter^2 == 4.44 attograms of carbon per square meter.
This is a pretty thin layer of material to survive reentry on some 20 light year distant planet.
--------
Alternatively, from google: ((Avogadro's number / (12 grams)) * (2 trillion tonnes)) / (4 * pi * ((20 lightyears)^2)) = 0.223099739 kilometers per liter = 0.5 miles/US gallon, which means we totally need to collect some gas guzzler tax on this material
You should teach this in Tennessee!!
Don't forget that the movie WALL-E syncs up perfectly with Pink Floyd's "The Wall". A bloody obvious giveaway that you're trapped in The Matrix.
the preceding comment is my own and in no way reflects the opinion of the Joint Chiefs of Staff
Somewhere on Gliese 581's "Earth" is a Lex Luthor dinosauroid plotting the demise of Supersaur using radioactive fragments from his home world.
Fortunately rocks aren't light. Their atoms tend to stay clumped together instead of spreading out uniformly like photons.
To Serve Man
From my limited experience with mankind, more like " Silence of the Popplers ".
the preceding comment is my own and in no way reflects the opinion of the Joint Chiefs of Staff
Just once I'd like to see an origin-of-life article on Slashdot without atheists dragging religion into the discussion.
That's what she said.
that's how i roll
insensitive clod overlords obligatory xkcd car analogy russian reversals whoosh pedant fanbois ftfy in 3...2...1..PROFIT
Just a thought here, but I don't think re-entry would be that challenging for bacteria based life to survive. Most people think that what left of an asteroid is really hot when they land, but that just isn't the case. In fact asteroids have been touched right after landing and described as 'cool' in temperature.
http://impact.arc.nasa.gov/news_detail.cfm?ID=1
If bacteria were in the core part of the asteroid that survived impact it should be reasonable to assume that the part that is cool to the touch never got hot enough to kill any bacteria that were inside it. The other two questions than become what kind of shock (g-forces) can bacteria survive? We know they can survive the shock of being launched into space, and without the squishy bodies that we have they may well survive the shock of re-entry.
If we could determine the answers to those questions than really the only questions remaining are can bacteria adapt to their new home? We already know they live in places on earth that are very inhospitable by our standards. The only other real question is how long can they survive in space? We have documented cases of bacteria surviving in space for years at a time. If there is no real limit to how long they can survive in space than cross solar system colonization is all but inevitable.
I would expect they would decelerate pretty quickly, the mass / cross sectional area decreases as the 1/3 power of mass. Then they would fall at terminal velocity, which will be quite low for any reasonable atmospheric density, and wouldn't bother bacteria at all when they hit the ground.
Particularly if the ejecta are e.g frozen droplets of seawater, life could be distributed throughout, and you'd only need a tiny fraction of the ice to survive the decelration event.
I am amazed at comments by otherwise likely intelligent people here on Slashdot who still have absolutely no concept of just how complex even the simplest replicating organism is. Are the majority of people still so ignorant as to believe if you put a bunch of amino acids in a box and shake it long enough a simple replicating cell will emerge in time?
I am not a creationist, but I am also not purposefully ignorant about the issues surrounding life's origins. Perhaps someday by applying sciences like complexity theory we'll discover a way in which life an originate naturally and easily, but based on the extent of our knowledge right now life is far too complex to have arisen by chance in 500 million years on Earth.
To confidently say life arose naturally on Earth is a RELIGIOUS VIEW, an ARTICLE OF FAITH, akin to the creatioist view that God created life.
So what am I saying? That we need to be honest about the mystery of life's origin and not dogmatic that it somehow sprung magically from unliving matter on a young Earth just because we believe the only alternative is God and we don't want to believe in a God.
Personally, because I know how incredibly improbable it is that life could arise naturally in such a short time on a young Earth I feel the theory of panspermia (life everywhere) is the only current probable explanation. We used to think the Earth was the center of the Universe and people still haven't gotten over the prejudice that life must have arose on Earth because Earth must be the center of life. Stretch your knowledge people and don't be such dogmatic evolutionary fundamentalists.
We are alone in the universe, the only life is what we know here on the Earth.
This sig is not paradoxical or ironic.
How could organic matter survive ejection?
In order to reach such orbits these fragments have to be traveling at more than 10Km/s. In fact, considering the decceleration the atmosphere would cause they would have had to start at way more than that. Such speeds across the atmosphere would disintegrate any particle smaller than a few decimeters in size. I don't see how life could survive anything like that on a rock smaller than a few meters in diameter.
I tried to purchase a radioactive Carbon dating machine so I could age some rocks and bones, but unfortunately I could not find any such machines for sale. I have no way of aging rocks, bones, or fossils. Do you? So what scientific method, if any, was used to back up the claim that this event occurred "65 million years ago"?