Horrible Consequences of Earth Losing His Magnetosphere
The study of the region of space near the Earth helps to determine changes in the Earth's magnetosphere, ionosphere, and upper atmosphere in order to enable specification, prediction, and mitigation of their effects. Heliophysics seeks to develop an understanding of the response of the near-Earth plasma regions to space weather. This complex, highly coupled system protects Earth from the worst solar disturbances while redistributing energy and mass throughout.
A key element involves distinguishing between the responses to external and internal drivers, as well as the impact of ordinary reconfigurations of environmental conditions, such as might be encountered when Earth crosses a magnetic sector boundary in the solar wind. This near-Earth region harbors spacecraft for communication, navigation, and remote sensing needs; conditions there can adversely affect their operation. Ground based systems, such as the power distribution grid, can also be affected by ionospheric and upper atmospheric changes. Key near-term investigations emphasize understanding the nature of the electrodynamic coupling, how geospace responds to external and internal drivers, and how the coupled middle and upper atmosphere respond to external forcings and how they interact with each other.
Plasmas and their embedded magnetic fields affect the formation, evolution and destiny of planets and planetary systems. The heliosphere shields the solar system from galactic cosmic radiation. Our habitable planet is shielded by its magnetic fi eld, protecting it from solar and cosmic particle radiation and from erosion of the atmosphere by the solar wind. Planets without a shielding magnetic field, such as Mars and Venus, are exposed to those processes and evolve differently. And on Earth, the magnetic field changes strength and configuration during its occasional polarity reversals, altering the shielding of the planet from external radiation sources.
How important is a magnetosphere to the development and survivability of life? The solar wind, where it meets the local interstellar medium (LISM), forms boundaries that protect the planets from the galactic environment. The interstellar interaction depends on the raw pressure of the solar wind and the properties of the local interstellar medium (density, pressure, magnetic field, and bulk flow). These properties, particularly those of the LISM, change over the course of time, and change dramatically on long time scales (1,000 years and longer) as the solar system encounters interstellar clouds.
How do these long-term changes affect the sustainability of life in our solar system? Understanding the nature of these variations and their consequences requires a series of investigations targeting the structure of the heliosphere and its boundaries and conditions in the LISM. Planetary systems form in disks of gas and dust around young stars. Stellar ultraviolet emission, winds, and energetic particles alter this process, both in the internal structure of the disk and its interaction with its parent star. The role of magnetic fields in the formation process has not been fully integrated with other parts of the process.
The study of similar regions in our solar system, such as dusty plasmas surrounding Saturn and Jupiter, will help explain the role of plasma processes in determining the types of planets that can form, and how they later evolve.
A magnetosphere is that area of space, around a planet, that is controlled by the planet's magnetic field. The shape of the Earth's magnetosphere is the direct result of being blasted by solar wind. It prevents most of the particles from the Sun, carried in the solar wind, from hitting the Earth. The Sun and other planets have magnetospheres, but the Earth has the strongest one of all the rocky planets. The Earth's magnetosphere is a highly dynamic structure that responds dramatically to solar variations. Life on Earth developed and is sustained under the protection of this variable magnetosphere.
Scientists have recently been able to identify many exoplanets that reside within a ‘Goldilocks Zone’, which is the region around a host star where it is thought possible a planet with sufficient atmospheric pressure could sustain liquid water on its surface. Though these planets are within the right orbit of the star, their ability to sustain life is not guaranteed; these exoplanets may be missing their magnetic shielding, which would make them susceptible to damaging radiation.
The magnetic field that protects Earth extends from the inner core to where it meets charged particles coming from the Sun, also known as solar wind. The magnetic field deflects most of these particles, which otherwise would strip off our ozone layer, the layer of our atmosphere responsible for protecting Earth from ultraviolet radiation. This field is generated and maintained through a rotating, convecting and electrically conducting fluid at its core called a geodynamo.
Mars and Venus do not have magnetic fields. Stellar winds are thought to have stripped away most of Mars’ atmosphere after the magnetic field dissipated. A comparison of the effect of the solar wind on Mars and Earth was possible when a planetary alignment occurred on 6 January 2008. Scientists compared the loss of oxygen from the two planets’ atmospheres when the same stream of solar wind hit them. Though the solar wind’s pressure increased at each planet by similar amounts, the increase in the rate of loss of Martian oxygen was ten times that of Earth’s increase. This difference in rates, over billions of years, helps explain the tenuous state of the Martian atmosphere today.
Venus may have had oceans deep in its past that were vaporised once the runaway greenhouse effect took hold. Any water would have been broken down by photons; with no magnetic field the free hydrogen was expelled into space by the solar wind. If an exoplanet had surface water, this water could get blasted away by stellar winds if the planet does not have a strong magnetic field.
A team of scientists, led by Jorge Zuluaga at the University of Antioquia in Colombia, used up-to-date dynamo scaling laws to calculate how long it would take for a rocky planet to cool so much that the geodynamo would stop working. They then compared these results against three well-known exoplanets believed to be potentially habitable: Gliese 581d, HD 40307g and GJ 667Cc . The team assumed an Earth-like composition for the three planets and found that the geodynamos of all of them would be extinct or close to being shut down. Gliese 581d was the best protected against the solar wind. GJ 667Cc has no protection from solar wind and has most likely suffered massive atmosphere loss. Any potential life on the planet is doomed.
Horrible Consequences of Earth Losing its Magnetic Field
There is so much about the Earth that we undervalue in our daily lives. Though human civilization has spread to every region of the world, our existence still depends on the alignment of natural phenomena that are beyond our control – Earth’s precise distance from the sun, which creates ideal temperatures for life, is a perfect example. Even the grandeur of our planet’s landscapes is the product of natural events – it was plate tectonics, after all, that forced the Himalayan Mountains to rise, created spectacular volcanoes like Mt. Fuji and Mt. Vesuvius, and shaped Earth’s oceans and continents. Our planet’s many peculiarities make it both beautiful and habitable, but what would happen if something changed? What if a single, elemental part of our planet was altered, and what would the consequences be for humanity and for all life? What if, for example, Earth’s magnetic field disappeared?Let’s conduct a thought experiment and imagine the Earth exactly as it is, but with no trace of geomagnetism. As it turns out, this seemingly simple change would have drastic consequences for humanity and all life on Earth. Some of the resulting effects would be plain weird – others would be utterly catastrophic. Of course, there is slight chance that this would ever actually happen, but that’s what makes for a good thought experiment. Let’s take a look:
1. COMPASSES WOULD DO STRANGE THINGS
Compasses are really nothing more than tiny magnets, and like all magnets, they align themselves with nearby magnetic fields. Conveniently, Earth’s magnetic field is strong enough to force compasses to align north-to-south – but with our planet’s magnetic field gone, compasses would point to any nearby source of magnetism. Even an outcrop of magnetic rock could do the trick.In fact, scientists have documented this effect before. Magnetic anomalies – places on Earth where nearby natural magnetism cause compasses to malfunction – are found around the world. In the Central African Republic, for example, unexplained magnetic variations in Earth’s crust cause compass needles to point in random directions, rendering them useless for navigation. If our planet’s magnetic field disappeared, “wandering compasses” could become the norm worldwide.
2. Birds Couldn’t Migrate for the Winter
Humans aren’t the only animals that exploit Earth’s magnetic field for navigation. Many birds, sea turtles, lobsters, honeybees, salmon, and even fruit flies have biological compasses – termed “magnetoreceptors” – built into their bodies. Birds use this ability to seek warmer climates during winter months, while sea turtles navigate the open ocean and seek beaches to lay their eggs. Scientists even think that most female sea turtles return to the same beaches every year – a feat made possible in part by their natural compasses.
If Earth’s magnetic field disappeared, many animals that depend on compass navigation could be in serious trouble. Sea turtles could literally get lost at sea. Migratory birds might fly in the wrong direction, threatening their survival. Honeybees might get lost trying to find their hives, which could impact the pollination of flowers and other plants. With their navigational abilities severely compromised, these and many other organisms could face extinction.
3. THE AURORA WOULDN’T BE THE SAME
Along with our biodiversity, the loss of Earth’s magnetic field could alter Earth’s auroras, known commonly as the Northern and Southern Lights. These beautiful phenomena are created when our planet’s magnetic field channels charged particles from the sun – known as the solar wind – into our planet’s upper atmosphere. The solar wind is usually deflected by our magnetosphere (the invisible “shell” created by Earth’s magnetic field), but around the north and south poles, the magnetosphere dips inward like a funnel, allowing the solar wind to interact with our upper atmosphere. The result of this interaction are the spectacular, multicolored bands of glowing plasma known as auroras.
Auroras on Earth have been known to shine so brightly, a person could literally read by them. But without Earth’s magnetic field, our entire upper atmosphere would be exposed to the solar wind, completely changing how our auroras might appear – they could even resemble auroras found on Venus and Mars. Since these two planets have no significant magnetic fields, they sometimes have faint, less colorful auroras scattered across their night sides. Thus, along with altering our polar skies, the disappearance of our magnetic field could forever dampen one of Earth’s most breathtaking natural wonders.
4. COSMIC RAYS COULD REACH EARTH’S SURFACE
Our magnetic field doesn’t just give us beautiful auroras: it keeps us alive. Cosmic rays and the solar wind are harmful to life on Earth, and without the protection of our magnetosphere, our planet would be constantly bombarded by a stream of deadly particles. The effects of cosmic rays on the body can be pretty terrifying. While on lunar missions, for example, astronauts often reported seeing flashes of light when they closed their eyes – the direct result of cosmic rays passing through their retinas. A few even developed cataracts years later.
Radiation and cosmic rays are a real concern for NASA, especially when it comes to long-term spaceflight. Astronauts on a mission to Mars could undergo up to 1000 times the exposure to radiation and cosmic rays that they would get on Earth. If Earth’s magnetic field disappeared, the entire human race – and all of life, in fact – would be in serious danger. Cosmic rays would bombard our bodies and could even damage our DNA, increasing worldwide risk of cancer and other illnesses. The flashes of light visible when we close our eyes would be the least of our problems.
5. WIDESPREAD POWER OUTAGES AND BROKEN SATELLITES
Human health is one issue, but without a geomagnetic field, our technology would also be at risk. Satellites can and do suffer damage from solar storms, and without Earth’s magnetic field, every electronic device could be exposed to high-energy particles from cosmic rays and the solar wind.
In fact, solar activity has caused such problems before. In 1989, a massive solar flare – an eruption of super-heated plasma from the surface of the sun – slammed into Earth’s magnetosphere and knocked out electricity in Quebec, Canada. The power grid for the entire province went offline for 12 hours, and other nearby regions scrambled to keep their grids working. Some satellites suffered damage, as their delicate electronics simply weren’t designed to handle a huge solar storm, and many tumbled out of control for hours after the flare struck.
While the Geomagnetic Storm of 1989 was unusually massive, the solar wind is always hitting our magnetosphere, even during normal solar activity. If Earth lost its magnetic field, there would be no magnetosphere – and no line of defense, even from weaker solar storms. Our power grids would be more vulnerable than ever, and even our computers and other electronics could suffer damage if a solar storm struck.
6. OUR ATMOSPHERE COULD BE STRIPPED AWAY
Perhaps the most horrifying effect of losing Earth’s magnetic field might be losing the air we breathe – and the solar wind would once again be the culprit. The sun’s natural wind is so powerful, it can easily rip gasses out of a planet’s atmosphere until there is little gas left at all. In fact, this likely happened to Mars.Mars was probably once a lot like Earth, with oceans of water and a thick atmosphere – but unlike our planet, its magnetic field disappeared billions of years ago. It’s atmosphere was left totally unprotected, causing it to be ripped away into space. Once its atmospheric pressure dropped low enough, its water began to evaporate until it too was taken by the solar wind. It’s quite possible that without our geomagnetic field, our atmosphere, our oceans, and life on Earth, could suffer the same terrible fate.
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SOURCE : http://science.nasa.gov/