Interstellar seeds could create oases of life

August 27, 2015, Harvard-Smithsonian Center for Astrophysics
In this theoretical artist's conception of the Milky Way galaxy, transluscent green "bubbles" mark areas where life has spread beyond its home system to create cosmic oases, a process called panspermia. New research suggests that we could detect the pattern of panspermia, if it occurs. Credit: NASA/JPL/R. Hurt

We only have one example of a planet with life: Earth. But within the next generation, it should become possible to detect signs of life on planets orbiting distant stars. If we find alien life, new questions will arise. For example, did that life arise spontaneously? Or could it have spread from elsewhere? If life crossed the vast gulf of interstellar space long ago, how would we tell?

New research by Harvard astrophysicists shows that if can travel between the stars (a process called panspermia), it would spread in a characteristic pattern that we could potentially identify.

"In our theory clusters of , grow, and overlap like bubbles in a pot of boiling water," says lead author Henry Lin of the Harvard-Smithsonian Center for Astrophysics (CfA).

There are two basic ways for life to spread beyond its . The first would be via natural processes such as gravitational slingshotting of asteroids or comets. The second would be for to deliberately travel outward. The paper does not deal with how panspermia occurs. It simply asks: if it does occur, could we detect it? In principle, the answer is yes.

The model assumes that seeds from one living planet spread outward in all directions. If a seed reaches a habitable planet orbiting a neighboring star, it can take root. Over time, the result of this process would be a series of life-bearing oases dotting the galactic landscape.

"Life could spread from host star to host star in a pattern similar to the outbreak of an epidemic. In a sense, the Milky Way galaxy would become infected with pockets of life," explains CfA co-author Avi Loeb.

If we detect signs of life in the atmospheres of alien worlds, the next step will be to look for a pattern. For example, in an ideal case where the Earth is on the edge of a "bubble" of life, all the nearby life-hosting worlds we find will be in one half of the sky, while the other half will be barren.

Lin and Loeb caution that a pattern will only be discernible if life spreads somewhat rapidly. Since stars in the Milky Way drift relative to each other, stars that are neighbors now won't be neighbors in a few million years. In other words, stellar drift would smear out the bubbles.

This research has been accepted for publication in The Astrophysical Journal Letters.

Explore further: A new approach in the search for extraterrestrial intelligence: targeting alien polluters

More information: arxiv.org/abs/1507.05614

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10 comments

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Rockguy
4 / 5 (2) Aug 27, 2015
If you modeled the stars with a computer simulation you should be able to re-create the pattern by adjusting for stellar drift.
Jeweller
3.5 / 5 (2) Aug 27, 2015
Panspermia.
Couldn't they have thought of another word ?
Interstellar pollination for instance.
viko_mx
1 / 5 (6) Aug 27, 2015
Again the endless "we think", "it could be", "probably" instead we found that, we did that and we checked that. The social status of speculators increase significantly in this fraudulent time.
JustAnotherGuy
4.2 / 5 (5) Aug 27, 2015
Again, hypotheses that are to be tested as hypothesis's definition says:
http://dictionary...pothesis

What is the claim the [people that "knows the only truth"] will throw at any incoming evidence? ......"LIES"
Consider this a prediction...
JustAnotherGuy
5 / 5 (6) Aug 27, 2015
Jeweller. Whatever other word, it has to be related to 'seeds'; not to pollen, which need an existing plant to receive it on another location.

Panspermia (from Greek πᾶν (pan), meaning "all", and σπέρμα (sperma), meaning "seed")
https://en.wikipe...nspermia
Egleton
1 / 5 (1) Aug 28, 2015
For your kind consideration.
Ummm. Not for Objective Materialists.

https://vimeo.com/39922720
Egleton
1 / 5 (1) Aug 28, 2015
https://vimeo.com/39922720

Not for the anally retentive.
Captain Stumpy
5 / 5 (4) Aug 28, 2015
"we think", "it could be", "probably"
@viko
still trolling with your religious stupidity? read this
The scientist has a lot of experience with ignorance and doubt and uncertainty, and this experience is of very great importance, I think. When a scientist doesn't know the answer to a problem, he is ignorant. When he has a hunch as to what the result is, he is uncertain. And when he is pretty darn sure of what the result is going to be, he is still in some doubt. We have found it of paramount importance that in order to progress we must recognize our ignorance and leave room for doubt. Scientific knowledge is a body of statements of varying degrees of certainty – some most unsure, some nearly sure, but none absolutely certain
-Feynman
until you learn about measurement and it's uncertainties, you will forever live blatantly stupid and without knowledge of reality and cling to your religious "certainties" which have proven false over and over again
NIPSZX
not rated yet Aug 28, 2015
We are still very, very far from this conclusion.
torbjorn_b_g_larsson
5 / 5 (4) Aug 28, 2015
Loeb does a good job, as always. [Disclaimer: I haven't checked the paper, but superficially the modeling reads as sound.]

@NIPSZX: Well, it is a speculative toy model approach to identify useful characteristics _if_ panspermia is at work, and if we can identify inhabited worlds. Just targeting mature, oxygenated atmospheres in local space is hard!

That is why the creationist trolls have flocked here. If there is a possibility of a religious bait-and-switch they like to demonstrate the innate lying-for-religion (and worse) immorality that appends to their magic beliefs. Silly things!

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