Is it necessary to Mars's magnetic field?

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Is it necessary to Mars's magnetic field?

Сообщение DARPA » 01 окт 2015, 03:11

Continue heading "Application terraforming." In the previous issue we have estimated reserves of Martian carbon dioxide ice, and human capacity to transform it into the atmosphere. Today let's talk about whether there is any sense to fill the atmosphere of Mars, in the absence of a magnetic field.

The theme of the magnetic field emerges in almost all discussions when it comes to transforming Mars into Earth-like planets. Many even learned to natural history, and the efforts of many popular science films and publications firmly memorized as truth: Earth's magnetic field protects us from solar radiation and the atmosphere from the solar wind blowing. Moreover, this "blowing" is widely perceived literally - as a mechanical process of removal of atmospheric gases flow of solar plasma.

The Earth's magnetic field, in such paintings depict heroic defender, who stands in the way of evil shield streams of fiery wind, the sun sent.



However, modern space research provides all the more reason to revise the picture towards the increasing complexity of interaction between the heliosphere and the geosphere. A more honest schemes already indicate that the magnetosphere does not protect against leakage of air from the poles, and perhaps even helps.



Let's start from the beginning. To begin to understand the reasons for the loss of the planet's atmosphere.

Dissipation (scattering) atmospheres into space has thermal and nonthermal origin. Thermally two mechanisms: the so-called Jeans and hydrodynamic. The first - is the heating of the molecules of the atmosphere by sunlight. As you know the temperature - is the intensity of the atoms and molecules. If you are around a lot of heated molecules neighbors, it gives them their energy and movement slows down. If the near molecules and atoms will not appear, and the energy flow does not stop, then at some point, the molecule is heated to such a state that it is, like a spaceship leaves the atmosphere by typing the escape velocity. About this occurs in the upper atmosphere - the so-called "thermosphere". The closer to the Sun, the planet, the greater the impact of this factor. But a lot depends on the mass of the planet. For example hydrogen and helium with ease to leave the atmosphere of Venus, but more massive molecules of CO2 retained strong enough gravity of the planet. On Earth, by the way, the same thing happens, but with less intensity, but 250 tons of hydrogen and helium 4 tons forever say goodbye to us every day.

Similar to the thermal process - photocatalyst when exposed to ultraviolet rays molecules decompose into single atoms such as water is split into hydrogen and oxygen, which promotes the volatilization of hydrogen.

Mars is farther from the Sun, so the atmosphere gets less light, but the mass of the planet below, so it loses every day on different data from 1 to 100 tons of atmosphere - mainly carbon dioxide.



But we remember that Mars has no magnetic field! We get up to him, and now look at another way to heat loss of the atmosphere - the hydrostatic.

If the heating of the atmosphere of the planet quite intense, and if there are any additional sources of heat beneath, the heavier gas molecules can be carried away by streams of light particles to heat up and gain the same second space, never to return to the planet. Probably for this reason quite volcanically active moon of Jupiter and Io massive does not have any significant atmosphere - it constantly blows powerful volcanic eruptions.



There is another way to get rid of the atmosphere, which is kind of similar to the previous hydrostatic - IMPACT. We all know how to look powerful explosions - a pillar of smoke rises into the sky, turning into a mushroom. If the explosion is of sufficient strength, then this post will rise to the space where the rarefied atmosphere of heated molecules can be dispersed enough to fly away forever. For planets with relatively strong gravitational field and a dense atmosphere like the Earth and Venus, this factor may be small, but for the loss of Mars may be much more significant, and it has got, it seems, more than the world - asteroid belt near. This factor plays against those who offer to bring down on Mars, an asteroid or comet is more - we must also consider whether there will be anything after the explosion.



How significant role in the loss of Mars' atmosphere has played a mechanism of impact is difficult to say. You can spend only a rough estimate, but even rough estimates I have not met. However, we should not forget that Mars is hardest hit, as well as the Moon and the Earth during the Late Heavy Bombardment about 3.8 billion years ago. But in those years on Mars was more dense atmosphere, because flowing river.

Important point to all these factors the magnetic field does not affect in any way. Therefore, the Earth, a couple of billion years, threatens the fate of Mars and Venus - a complete escape of hydrogen, ie, turning into a desert. There could be advertising SPA-salon or a seaside resort - enjoy liquid water while you can.



Maybe the atmosphere becomes thinner and without leaving the planet. Such proichodit when atmospheric gases to enter into chemical or physical interaction with the surface. Carbon and oxygen can effectively bind reacting with rocks. It is believed that if the Earth to release all the carbon, which is now linked to the hydrocarbon deposits and carbonate rocks, our atmosphere will not differ greatly from Venus. Therefore, we should say thank you to the millions of years of evolution, microorganisms that have turned our planet into a blooming garden. Hydrogen and oxygen can be effectively removed from the atmosphere by conversion into the water and the formation of the oceans and glaciers, and the farther from the sun all the more gas can be converted into ice.

Now back to the solar wind and magnetic field. The solar wind - a stream of charged particles - electrons, protons and alpha particles. The particles have a different speed, and about the slow (speed of 300-500 km / s) of a particle saying "slow solar wind," fast (600-800 km / s) - "the fast solar wind", but about the high-speed (900 km / s and above ) - "solar radiation". The sun emits a lot of other "radiation": ultraviolet, X-ray, neutron, gamma up to, but now we talk about the one that has an electric charge, which affects the magnetic field.

Thus, the solar particles are carried from the Sun toward Earth. At a distance of about 10 Earth radii on them begins to affect our magnetic field, and to reject them. The lower the energy of the particles, the more effective they are deflected by the magnetic field. In place of the meeting, a shock wave. As a result, some particles slip through the magnetic lines, but rejected fly past Earth, some are absorbed by the atmosphere, but the vast majority are aligned along the magnetic lines and merge into existing Torus streams of charged particles around Earth, called "radiation belt". Hooray, the planet is saved, the magnetic field made its heroic deed ... But what is it? Why red and green light lit up our poles?



Auroras - a beautiful sight, until you wonder about the physics of processes that take place there. The following happens: the magnetic lines not only capture solar particles, but some of them direct to the poles. Newcomers particles, further accelerated by the magnetic field, and descend into the earth's atmosphere. They knock electrons from neutral atoms and molecules, they become charged and glow with indignation. Charged ions form an electric field, which starts as an accelerator and accelerates ions (molecules lose an electron) that they gain escape velocity and leave the planet. That is how the process of electromagnetic dissipation, from which supposedly saves us the magnetic field. Remember the flying away from Earth hydrogen and helium? Add to that, and oxygen, which is too heavy for the heat dissipation, and flies away from Earth only because of this "good" and "caring" to the magnetic field. It is not known the amount of oxygen loss from each beautiful nights in circumpolar regions, but the fact has already been proved by European satellites Cluster.



What will happen if the impact of the solar wind streams undergo a planet which has no magnetic field? There will be all the more dramatic - solar particles freely approach the planet at a distance of half its diameter, and will bombard the upper layers of its atmosphere. The gas molecules begin to lose electrons and acquire a charge ... the same charge repel solar wind streams. Ie here, too, the shock wave is formed as the magnetic field, which is closer to not let the bulk of solar particles. It is due to this effect, Venus has not lost its incredibly dense atmosphere of being much closer to the Sun than the Earth or Mars.



While scientists can not say how significant the contribution of electromagnetic dissipation in the degradation of the Martian atmosphere. In order to answer this question sent to Mars satellite MAVEN. Meanwhile, the loss of the Martian atmosphere, there are several facts:

Now a day lost less than 1 ton of atmosphere - it is learned spacecraft Mars Express, but the measurements were carried out in the solar minimum;

since the formation of the planet until today Mars lost so much of the atmosphere of hydrogen, as might be contained in an ocean depth of 110 meters, covering the entire planet - a learned astronomers of the European Southern Observatory, analyzing the change in the ratio of light and heavy isotope of hydrogen in the atmosphere of Mars;

all known Mars contain water ice, which would fill the planet by about 25 meters

under the influence of the solar wind Mars can lose oxygen is 100 times more intense than shown Mars Express - such data came from simulation results, but many dispute the accuracy of those results. Thus, even if Mars lost 100 tons of oxygen daily for 3.5 billion years, the loss would be equivalent to losing 10 meters of water in the ocean conditional on the planet.

of carbon dioxide associated with renowned carbonate in the soil of Mars, would be enough to increase the density of the current atmosphere of about 3 times, and Mars to collect atmospheric density comparable to the earth, then these stocks should be 30 times more.


It turns out today, scientists can only guess about the mechanisms that led to the loss of 1/3 of the Martian atmosphere, and do not know Where did even 2/3. It is not known how much this loss made arrangements electromagnetic (solar wind), hydrostatic (powerful eruption of supervolcano) and impact (falling asteroids) dissipation. The contribution of the solar wind in the depletion of the atmosphere is now being studied in the coming years will be a concrete answer to this question, volcanoes and asteroids to date may be excluded from the essential factors of degradation of the atmosphere of Mars.

To summarize: the example of Venus shows that the solar wind is not a factor volatilization atmosphere. For Mars its exposure is about four times less intense. Some of the factors that could lead to the loss of the atmosphere of Mars in the past, today are not essential: the fall of asteroids and powerful volcanic eruptions. Thermal radiation from the sun, because of the remote location of Mars, too, is not a decisive factor in the dissipation, at least for now, when the light of hydrogen and helium in the atmosphere is almost gone. So all that's left to do for the transformation of Mars into a blooming garden - is to wait for the results of the satellite MAVEN and find a few billion eksadzhoueley power to magically fill the atmosphere of Mars is unknown where the mined gas. And what magic can be applied here will be discussed in the next issue of "Applied terraforming." Do not switch.
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