Science & Technology

Galaxy Panspermia. How naturally can life spread in the galaxy like the Milky Way?

Can life spread throughout a galaxy like the Milky Way without technical intervention? That question is rarely answered. A new study is swinging to that question by using a simulated galaxy that resembles the Milky Way. They then investigated the model to see how organic compounds move between the systems.

Perhaps the central question in science is “how did life begin?” There are no more questions and no answers.The secondary question is more familiar: “Can life spread from star to star?” That’s the theory. PanspermiaIn a nutshell.

Regarding the Panspermia theory, the history of the earth raises an important issue. Scientists believe that there wasn’t enough time between the emergence of life after it had cooled enough to make the Earth habitable. Of course, not all scientists think so. There are various ideas about this issue. But the question remains. Was there enough time for DNA-based life to proceed independently on Earth, or did Panspermia play a role?

Many of the stories about the Panspermia theory are about simple life forms that move between stars, but the more serious ones are about the movement of organic compounds needed for life.Scientists have discovered some of them Comet compound And elsewhere in the universe. We now know that they are not always rare. So can those compounds move from the solar system to the solar system?

The title of the new study is “Panspermia theory of the galaxy like the Milky Way.. The lead author is Raphael Gobat of Instituto de Fisica in Valparaiso, Chile. This paper is available on the preprint site arxiv.org.

So what about Panspermia? In a solar system like us, that seems possible. A meteorite from Mars has landed on Earth. This is pretty solid proof. If rocks can travel, why not put chemicals in or on them? Can spores make intergalactic trips between systems?

A team of researchers set out to answer that question. They worked with MUGS’s simulated galaxy. McMaster Unbiased Galaxy Simulations.. MUGS is a set of 16 simulated galaxies created by researchers in the early 2000s. In 2016, Gobat et al. Added a modified galaxy habitability model called GH16.

The galaxy they chose g15784.. It is a little larger than the Milky Way and has a history of stationary mergers. It has not fused with the very large ones for a long time and is orbited by several spherical galaxies.

This is a simulated galaxy called g15784. Two spheroidal galaxies can be seen in the image. One is above the galactic plane and the other is below. Image credit: Gobat et al 2021.

The team calculated the level of habitability of the particles of each star in the galaxy. In this case, it means the number of low-mass stars in the main sequence with terrestrial planets in the habitable zone. They followed GH16 to do that. The GH16 takes into account the star’s metal content, minimum and maximum mass, formation history, and the inner and outer ranges of the habitable zone (HZ).

They also examined the impact of supernova explosions on habitability. The galactic center is the most densely populated part of the galaxy. So while there are more potentially habitable planets, there are also more deadly supernovae. The high density of stars in the core means that each habitable planet is likely to be uninhabitable by a supernova. According to the author, high metal content in the core also reduces habitability. This makes the central region a tough place for the Panspermia theory.

The group also focused on the g15784 spiral arm. It has a high density of stars and a high signal-to-noise ratio (SNR), but it did not affect habitability as it did in the bulge. They also saw the Galactic Disc and Hello.

Three-panel illustration of paper showing a row projected onto a 1 kpc wide slice passing through the center of g15784 at z = 0. The top shows the median natural habitability, the center shows the percentage of possible cradle in the simulated galaxy, and the bottom shows the percentage of possible colonization targets. The magenta star shows where the sun would be if it were the Milky Way. Image credit: Gobat et al 2021.
Three-panel illustration of paper showing a row projected onto a 1 kpc wide slice passing through the center of g15784 at z = 0. The top shows the median natural habitability, the center shows the percentage of possible cradle in the simulated galaxy, and the bottom shows the percentage of possible colonization targets. The magenta star shows where the sun would be if it were the Milky Way. Image credit: Gobat et al 2021.

This study shows that the Panspermia theory is at least possible, but there is no easy answer to the question. They found that the median habitability increased with the galactocentric radius, but the probability of the Panspermia theory was reversed. This is due to the high density of stars in the galactic bulge.

However, the Panspermia theory is unlikely on the central disc. This is because the proportion of supernovae is high and the amount of metal is high, so the escape rate is low. Natural habitability does not change much across galaxies, but the probability of the Panspermia theory varies by orders of magnitude.

The team found no correlation between the probability of the Panspermia theory and the habitability of the receptive particles. (In this study, the particles refer to a large number of stars due to the low resolution of the simulation.)

Finally, they found that Panspermia was less effective than the evolution of prebiotics on the fly, but they say it cannot be accurately quantified.

In conclusion, the author points out some warnings about this work. “… First, there are several factors that are considered to be unknown constants (eg, the rate of spore capture by the target planet, the relationship between habitability and the existence of life, the typical velocity of interstellar objects, etc.” And the absolute value of escape) some of the interstellar organic compounds from the source planet). ”As a result, they consider their results to be“… of course, qualitative rather than quantitative ”.

They also warn that real galaxies like the Milky Way are dynamic and changing, but simulated galaxies are just snapshots. “Therefore, these results apply only if the typical Panspermia timescale is much shorter than the galaxy’s dynamic timescale.”

There are other differences between the simulated galaxy and the Milky Way. “For example, our simulated galaxy has a higher ratio of bulge to disk light than the actual Milky Way, suggesting that the galactic bulge is suitable for the Panspermia theory.” Finally, MUGS is low. It is a resolution simulation and points out that high resolution simulations can make some differences in the results.

Recently, two interstellar objects have visited. ‘Oumuamua and 2L / Comet Borisov. Therefore, you can see that the object is moving between the systems. Perhaps there were more interstellar visitors who couldn’t be seen technically. And we know that organic building blocks exist in the universe.

It does not prove that organic building blocks can move between stars, but it seems possible. This study may give us a little more information about how likely it is and where it will happen in the galaxy.

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Galaxy Panspermia. How naturally can life spread in the galaxy like the Milky Way?

https://www.universetoday.com/152695/galactic-panspermia-how-far-could-life-spread-naturally-in-a-galaxy-like-the-milky-way/ Galaxy Panspermia. How naturally can life spread in the galaxy like the Milky Way?

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