Astronomy

Can CME destroy planetary rings?

Can CME destroy planetary rings?


We are searching data for your request:

Forums and discussions:
Manuals and reference books:
Data from registers:
Wait the end of the search in all databases.
Upon completion, a link will appear to access the found materials.

Is Corona Mass Ejection able to reach the outer planets such as Jupiter and Saturn? If so can it blows away the icy rings or the distance is simply beyond the reach of maybe like Earth it is protected by a magnetic field?


Yes it can reach both Saturn and Jupiter. But it's not powerful enough to remove their rings. Even Earth's radiation belts don't get blown away.

Edit: Jupiter's magnetic field is $approx 770 mu T$ (at the surface of its equator) which is way more powerful than Earth's ($approx 40 mu T$ at the equator). Saturn's magnetic field on the other hand is a tad less powerful than that of the Earth ($approx 20 mu T$ at its equator). So Earth's magnetosphere shields it's particles from CMEs. Jupiter is further away and its magnetosphere is way stronger than Earth's. So it shields everything effectively. Saturn is even further away and although its magnetic field is comparable to that of the Earth, the distance from the Sun assures us that a CME wouldn't have a significant impact of any sort there.


I recently published an article in Answers in Genesis’ Answers Research Journal (ARJ) evaluating various astronomical young-age indicators that creationists have used over the years. One of the ones I discussed is the existence of planetary rings. Everyone knows that Saturn has a prominent ring system, but the other three Jovian planets have rings too, though they can’t be readily seen from earth. There are at least five mechanisms that destroy planetary rings. Given that planetary rings are fragile and contain relatively little mass, it has been known for some time that ring systems have relatively short lifetimes, at least compared to the supposed 4.5 billion-year age of the solar system. That Saturn’s rings are young doesn’t necessarily mean that Saturn itself or the rest of the solar system is young. Saturn and the rest of the solar system could be old, and Saturn could have acquired its rings very recently. How could a ring system form? The usual response is that Saturn’s strong tides disrupted a body that came too close to Saturn. Ditto for the other three ring systems. But this seems like an unlikely scenario. The most commonly invoked candidates for destruction to form Saturn’s rings are its natural satellites, or moons. But these bodies have reasonably stable orbits, and it would require multiple interactions to bring them so close to Saturn for tidal destruction to occur. Each of those interactions are exceedingly rare. Over the past 4 ½ billion years, this must have happened multiple times, yet Saturn has many satellites remaining. And what is the probability that all four Jovian planets recently underwent this process if the solar system is billions of years old?

As part of my conclusion of this possible young-age indicator, I wrote:

Well, we didn’t have to wait long. Even before my ARJ article was posted, a new study suggested that the rings of Saturn may be far older than generally thought. There are different ways to evaluate the age of Saturn’s rings, and each one involves some assumptions. This new study concentrated on the rate at which dusty and organic material are removed from Saturn’s rings. With a few different assumptions, the researchers concluded that Saturn’s rings could be billions of years old.

How well will this new result be received by other astronomers? It’s too early to tell. There has been much evidence amassed to the contrary, that Saturn’s rings are young, at most only millions of years old (and possibly far less). New studies that challenge the status quo typically don’t fare very well. On the other hand, most astronomers are committed to the solar system being billions of years old, and the low probability of tidal disruption events producing rings does call this into question. Therefore, many astronomers may welcome this new approach. As I said, we need to continue monitoring these sorts of developments as they arise.


15.3 Solar Activity above the Photosphere

Sunspots are not the only features that vary during a solar cycle . There are dramatic changes in the chromosphere and corona as well. To see what happens in the chromosphere, we must observe the emission lines from elements such as hydrogen and calcium, which emit useful spectral lines at the temperatures in that layer. The hot corona, on the other hand, can be studied by observations of X-rays and of extreme ultraviolet and other wavelengths at high energies.

Plages and Prominences

As we saw, emission lines of hydrogen and calcium are produced in the hot gases of the chromosphere. Astronomers routinely photograph the Sun through filters that transmit light only at the wavelengths that correspond to these emission lines. Pictures taken through these special filters show bright “clouds” in the chromosphere around sunspots these bright regions are known as plages (Figure 15.18). These are regions within the chromosphere that have higher temperature and density than their surroundings. The plages actually contain all of the elements in the Sun, not just hydrogen and calcium. It just happens that the spectral lines of hydrogen and calcium produced by these clouds are bright and easy to observe.

Moving higher into the Sun’s atmosphere, we come to the spectacular phenomena called prominences (Figure 15.19), which usually originate near sunspots. Eclipse observers often see prominences as red features rising above the eclipsed Sun and reaching high into the corona. Some, the quiescent prominences, are graceful loops of plasma (ionized gas) that can remain nearly stable for many hours or even days. The relatively rare eruptive prominences appear to send matter upward into the corona at high speeds, and the most active surge prominences may move as fast as 1300 kilometers per second (almost 3 million miles per hour). Some eruptive prominences have reached heights of more than 1 million kilometers above the photosphere Earth would be completely lost inside one of those awesome displays (Figure 15.19).

Flares and Coronal Mass Ejections

The most violent event on the surface of the Sun is a rapid eruption called a solar flare (Figure 15.20). A typical flare lasts for 5 to 10 minutes and releases a total amount of energy equivalent to that of perhaps a million hydrogen bombs. The largest flares last for several hours and emit enough energy to power the entire United States at its current rate of electrical consumption for 100,000 years. Near sunspot maximum, small flares occur several times per day, and major ones may occur every few weeks.

Flares, like the one shown in Figure 15.21, are often observed in the red light of hydrogen, but the visible emission is only a tiny fraction of the energy released when a solar flare explodes. At the moment of the explosion, the matter associated with the flare is heated to temperatures as high as 10 million K. At such high temperatures, a flood of X-ray and ultraviolet radiation is emitted.

Flares seem to occur when magnetic fields pointing in opposite directions release energy by interacting with and destroying each other—much as a stretched rubber band releases energy when it breaks.

What is different about flares is that their magnetic interactions cover a large volume in the solar corona and release a tremendous amount of electromagnetic radiation. In some cases, immense quantities of coronal material—mainly protons and electrons—may also be ejected at high speeds (500–1000 kilometers per second) into interplanetary space. Such a coronal mass ejection (CME) can affect Earth in a number of ways (which we will discuss in the section on space weather).

Link to Learning

See a coronal mass ejection recorded by the Solar Dynamics Observatory.

Active Regions

To bring the discussion of the last two sections together, astronomers now realize that sunspots, flares, and bright regions in the chromosphere and corona tend to occur together on the Sun in time and space. That is, they all tend to have similar longitudes and latitudes, but they are located at different heights in the atmosphere. Because they all occur together, they vary with the sunspot cycle.

For example, flares are more likely to occur near sunspot maximum, and the corona is much more conspicuous at that time (see Figure 15.22). A place on the Sun where a number of these phenomena are seen is called an active region (Figure 15.23). As you might deduce from our earlier discussion, active regions are always associated with strong magnetic fields.

As an Amazon Associate we earn from qualifying purchases.

Want to cite, share, or modify this book? This book is Creative Commons Attribution License 4.0 and you must attribute OpenStax.

    If you are redistributing all or part of this book in a print format, then you must include on every physical page the following attribution:

  • Use the information below to generate a citation. We recommend using a citation tool such as this one.
    • Authors: Andrew Fraknoi, David Morrison, Sidney C. Wolff
    • Publisher/website: OpenStax
    • Book title: Astronomy
    • Publication date: Oct 13, 2016
    • Location: Houston, Texas
    • Book URL: https://openstax.org/books/astronomy/pages/1-introduction
    • Section URL: https://openstax.org/books/astronomy/pages/15-3-solar-activity-above-the-photosphere

    © Jan 27, 2021 OpenStax. Textbook content produced by OpenStax is licensed under a Creative Commons Attribution License 4.0 license. The OpenStax name, OpenStax logo, OpenStax book covers, OpenStax CNX name, and OpenStax CNX logo are not subject to the Creative Commons license and may not be reproduced without the prior and express written consent of Rice University.


    Planetary Rings

    Planetary rings, once thought unique to the planet Saturn, are now known to exist around all large planets. These rings are not solid objects, but composed of countless particles with sizes from specks of dust to small moons. ΐ]

    All rings lie predominantly within their planet's Roche limit, where tidal forces would destroy a self-gravitating fluid body. They are also within the planet’s magnetosphere, and in the case of Uranus, they are within the upper reaches of the planetary atmosphere.

    For each planet, the rings are quite different. Jupiter's ring is thin and composed of dust-like small particles. Saturn's rings are broad, bright, and opaque. Uranus has narrow, dark rings among broad lanes of dust that are invisible from Earth. Neptune's rings include incomplete arcs restricted to a small range of their circumference.

    The ringed planets are not just objects of beauty, but complicated physical systems that provide a local laboratory and analogy for other cosmic systems like galaxies and planet-forming disks.

    Saturn's planetary ring system is believed to consist of shattered comets, moons and asteroids. Α]


    Key Concepts and Summary

    Near-Earth asteroids (NEAs), and near-Earth objects (NEOs) in general, are of interest in part because of their potential to hit Earth. They are on unstable orbits, and on timescales of 100 million years, they will either impact one of the terrestrial planets or the Sun, or be ejected. Most of them probably come from the asteroid belt, but some may be dead comets. NASA’s Spaceguard Survey has found 90% of the NEAs larger than 1 kilometer, and none of the ones found so far are on a collision course with Earth. Scientists are actively working on possible technologies for planetary defense in case any NEOs are found on a collision course with Earth years in advance. For now, the most important task is to continue our surveys, so we can find the next Earth impactor before it finds us.


    Planetary Magnetosphere

    Plasmas of different origins can have very different characteristic temperatures. Ionospheric plasma has a temperature on the order of ∼10,000 K or ∼1 eV, much higher than temperature of the neutral atmosphere from which it formed (<1000 K) but much lower than the ∼1 keV temperature characteristic of plasmas of solar wind origin, which are heated as they cross the bow shock and subsequently thermalized. Plasmas from satellite sources extract their energy from the planet's rotation through a complicated process. When the neutrals are ionized, they experience a Lorentz force as a result of their motion relative to the surrounding plasma this force accelerates both ions and electrons, which then begin to gyrate about the magnetic field at a speed equal to the magnitude of the neutral's initial velocity relative to the flowing plasma. At the same time, the new ion is accelerated so that its bulk motion (the motion of the instantaneous center of its circular orbit) moves at the speed of the incident plasma, close to corotation with the planet near the large moons of Jupiter and Saturn. Because the electric field pushes them in opposite directions, the new ion and its electron separate after ionization. Hence a radial current develops as the ions are “picked up” by the magnetic field and the associated Lorentz force at the equator acts to accelerate the newly ionized particles to the local flow speed. The radial current in the near equatorial region is linked by field-aligned currents to the planet's ionosphere where the Lorentz force is in the direction opposite to the planet's rotation (i.e., in a direction that slows (insignificantly) the ionospheric rotation speed). Thus, the planet's angular momentum is tapped electrodynamically by the newly ionized plasma.

    In the hot, tenuous plasmas of planetary magnetospheres , collisions between particles are very rare. By contrast, in the cold, dense plasmas of a planet's ionosphere, collisions allow ionospheric plasmas to conduct currents and cause ionization, charge exchange, and recombination. Cold, dense, collision-dominated plasmas are expected to be in thermal equilibrium, but such equilibrium was not originally expected for the hot, tenuous collisionless plasmas of the magnetosphere. Surprisingly, even hot, tenuous plasmas in space are generally found not far from equilibrium (i.e., their particle distribution functions are observed to be approximately Maxwellian, though the ion and electron populations often have different temperatures). This fact is remarkable because the source mechanisms tend to produce particles whose initial energies fall in a very narrow range. Although time scales for equilibration by means of Coulomb collisions are usually much longer than transport time scales, a distribution close to equilibrium is achieved by interaction with waves in the plasma. Space plasmas support many different types of plasma waves, and these waves grow when free energy is present in the form of non-Maxwellian energy distributions, unstable spatial distributions, or anisotropic velocity–space distributions of newly created ions. Interactions between plasma waves and particle populations not only bring the bulk of the plasma toward thermal equilibrium but also accelerate or scatter suprathermal particles.

    Plasma detectors mounted on spacecraft can provide detailed information about the particles’ velocity distribution, from which bulk parameters such as density, temperature, and flow velocity are derived, but plasma properties are determined only in the vicinity of the spacecraft. Data from planetary magnetospheres other than Earth's are limited in duration and spatial coverage so there are considerable gaps in our knowledge of the changing properties of the many different plasmas in the solar system. Some of the most interesting space plasmas, however, can be remotely monitored by observing emissions of electromagnetic radiation. Dense plasmas, such as Jupiter's plasma torus, comet tails, Venus's ionosphere, and the solar corona, can radiate collisionally excited line emissions at optical or UV wavelengths. Radiative processes, particularly at UV wavelengths, can be significant sinks of plasma energy. Figure 10 shows an image of optical emission from the plasma that forms a ring deep within Jupiter's magnetosphere near the orbit of its moon, Io (see Section 6 ). Observations of these emissions give compelling evidence of the temporal and spatial variability of the Io plasma torus. Similarly, when magnetospheric particles bombard the planets’ polar atmospheres, various auroral emissions are generated from radio to x-ray wavelengths and these emissions can also be used for remote monitoring of the system. [See Atmospheres of the Giant Planets.] Thus, our knowledge of space plasmas is based on combining the remote sensing of plasma phenomena with available spacecraft measurements that provide “ground truth” details of the particles’ velocity distribution and of the local electric and magnetic fields that interact with the plasma.

    FIGURE 10 . The ionization of an extended atmosphere of neutral atoms (yellow) around Jupiter's moon Io is a strong source of plasma, which extends around Jupiter in a plasma torus. Electrical currents generated in the interaction of Io with the surrounding plasma couple the moon to Jupiter's atmosphere where they stimulate auroral emissions. The main ring of auroral emissions is associated with currents generated as the plasma from the Io torus spreads out into the vast, rotating magnetosphere of Jupiter.


    The ring appears in the sky as a band of luminescent golden specks that varies in width and intensity depending on the time of the year: at the winter equinox, it is narrow and bright, but becomes wider and diffuse as the year goes on. As the ring is located above the equator, it appears on the southern sky in the northern hemisphere, and on the northern sky in the southern hemisphere. The ring is best seen at night, but it is visible in daylight hours. ΐ]

    The golden dragonshards are known as Siberys dragonshards and fall to Eberron along the equator, landing in Xen'drik and, it can only be speculated, Argonnessen. Α] The Ring of Siberys is sometimes associated with dragonmarks—Siberys dragonshards are used in the creation of dragonmark-specific magic items, and the most powerful of dragonmarks are called Siberys marks. ΐ]


    Secondary / 9-12 Assignments

    In 'The Hitch-hiker’s Guide to the Galaxy' created by Douglas Adams, the Vogons destroy the Earth to make way for the construction of a hyper spatial express route through the solar system.

    What if Vorgons had decided to do a cost-benefit analysis of all 8 planets before choosing which one to destroy?

    Scientists are often faced with difficult choices and must look at all the facts before making final recommendations. Which planet is the least valuable or the most valuable?  How would the removal of any one of the planets affect human life and our solar system in general?  

    You will be part of a planetary delegation who will create a formal written argument in defense of preserving your home planet. You will present this to the Vogon Planning Council (aka your class). When all submissions have been presented, the council will meet to discuss and vote on which planet is to be blown up.  All decisions of the Council are final.

    After you have been assigned a planet, start to collect information that would prove your planet to be very valuable to human beings. Key your planet's name into this Wolfram Alpha computational search . More resources at bottom of page.

    There are two categories to cover.

    1.    Human-Habitable

    • Can humans live on your planet? What adaptations could make it more habitable? Costs?
    • In order to sustain human life, a planet needs to have the following: an energy source, liquid water, an atmosphere, carbon, hydrogen, nitrogen and oxygen, and a healthy distance from large-mass poisonous bodies (such as gas giants).

    2.    Not Habitable by Humans

    • Your planet can still be of great value (Many toxic materials are valuable and accessibility is vital.) What physical, chemical, geological or other resources does it have?
    • Consider other factors such as: place in solar system, mass, distance from sun, and earth, (advantages and disadvantages), axial tilt, gravity, proximity of asteroids and moon, day-night cycle, etc.

    Note-taking form: Save our planet because . . .

    Argument: planet supports human life

    EVIDENCE (proof: facts, statistics)

    * That prove planet supports life

    Source (citation information)

    Argument: planet has resources valuable to man

    Source (citation information)

    Now share your notes with your planet delegates. Pull out the strongest scientific evidence to prove how valuable your planet is.

    Anticipate what questions the Vogan council might ask you to put holes in your arguments (Remember, they are arguing to save their own planet and weakening your position could help them). Be prepared with counter arguments.

    EVIDENCE (proof: facts, statistics)

    Source (citation information)

    COUNTER ARGUMENTS (proof: facts, statistics)

    Source (citation information)

    Prepare a impassioned 5-minute speech to defend your planet. It must have a power beginning, strong arguments and a terrific ending. Choose one person to deliver it or all members can participate. Answers challenging questions with intelligence!   NO VISUALS PLEASE – Persuade the Council with strong emotions and scientific proof. (power point makes your audience sleepy)

    Step Four: Your job as part of the Vogon Planning Council

    Listen to all the planet delegate's speeches with an open mind. As a member of this democratic council it is your responsibility to make sure that the wrong planet does not get destroyed. (not unlike voting for the right person in government!). You get to question them, so the more you know about the the solar system, the better. Here are some criterion on which to judge them.

    Individual Planet Evaluation Sheet

    Circle score  (3 = Out of this World)

    Well developed argument with evidence.

    Group was well organized, ready to start.

    Value to Human Beings, list 1-8

    Exploring the Planets  online exhibit from 2002 "highlights the history and achievements of planetary explorations, both Earth-based and by spacecraft." It features information about tools of exploration and about the planets, asteroids, and comets in our solar system. Information for planets includes atmosphere, moons, magnetic fields, images, and more. From the Smithsonian National Air and Space Museum.


    Haughton-Mars Project, an international scientific research project conducted around the Haughton impact structure on Devon Island, a region that is similar to the surface of the planet Mars.

     The New Solar System: It's Not Just Planets Anymore
    An article (and a video lecture) about contemporary scientific views of the solar system. From the Institute for Astronomy, University of Hawaii.

    How Many Planets Do You Want in the Solar System?
    This blog post considers alternative ways to calculate the number of planets in our solar system. From the New York Times website.

    Welcome to Mars is a slide show of Mars as seen from Earth, from spacecraft, and up close and personal from the surface in pictures taken by the Mars Pathfinder vehicle. Includes audio clips and hyperlinks to a planet glossary. From the Jet Propulsion Laboratory of the California Institute of Technology, in conjunction with NASA.

    What Makes a Planet?  
    Brief introduction for the layperson about the definition of what is a planet and about the 2006 controversy about whether Pluto is a planet. This site notes "there are many things that make Pluto quite different from the [other eight] planets," so that it is "very hard to classify Pluto with the rest of the major planets." From a professor in the Department of Astronomy at Cornell University.

    Chasing Venus: Observing the Transits of Venus, 1631-2004   
    This exhibit provides background information and history of transits of Venus, the astronomical events where "the planet Venus passes directly between Earth and the Sun, appearing as a small black dot on the Sun's disk." Features details about seven past transits of Venus (1631, 1639, 1761, 1769, 1874, 1882, 2004), and the upcoming transit in 2012. Includes links to related sites. From the Smithsonian Institution Libraries.

    Planetary Rings Node   
    A website "devoted to archiving and distributing scientific data sets relevant to planetary ring systems." In addition to technical data, the site features resources on the ringed planets (Jupiter, Saturn, Uranus, Neptune) and missions (such as Cassini and Voyager) involving planetary ring systems. A project of NASA Ames Research Center and the Center for Radar Astronomy at Stanford University. From the SETI Institute.

    Geology of Mars   
    "Here you can learn about the six geological processes that are either currently operating on Mars or have operated during Martian history. These include the aeolian, cratering, hydro, landslides, tectonic, and volcanic processes." Features essays accompanied by images of the surface of Mars

    Mars  
    This profile of Mars features facts, news, and photos. Includes information about missions, Canada's role in Mars exploration, the use of Canadian Arctic areas for space research, and an annotated timeline of Mars missions from the Soviet probes in the early 1960s to the present. Provides links to related stories and resources. From the Canadian Broadcasting Corporation (CBC).

    Saturn: Moons: Titan  


    Cooperative mining

    Multiple ships or a Wing can cooperate to mine more efficiently by specializing each ship's loadout. For example, one pilot can fly a speedy, low-mass ship such as the Asp Scout equipped only with Seismic Charge Launcher, Abrasion Blasters, and prospector limpets while the second pilot can fly a larger ship such as the Anaconda with ample cargo space, collector limpets, and a Refinery. ΐ]

    The miner ship should crack a suitable deep core asteroid, then use the Abrasion Blaster on any surface deposits. While the refinery ship collects and refines the ore, the miner ship can move on and locate another deep core asteroid with its prospector limpets. This process can be repeated until a ship runs out of cargo space, limpets, or ammunition. Cooperating pilots can then return to a station to split the cargo take care to avoid jettisoning cargo for this purpose within a station's jurisdiction to avoid penalties for littering. ΐ]


    Notes

    • The Detailed Surface Scanner cannot be used to map stars, even though the DSS interface can be activated while a star is targeted, as any probes fired at a star will simply vaporize from the intense heat. Stars can be analysed using the Discovery Scanner and Full Spectrum System Scanner.

    Pre-3.3 Detailed Surface Scanner

    The Detailed Surface Scanner was redesigned in Elite Dangerous: Beyond Chapter 4 (3.3). The old module's descriptions, stats, and functions are listed below for archival purposes.

    Advanced stellar body scanner used during exploration.

    — In-Game Description

    A Discovery Scanner is required for the DSS to be useful both modules must be present on the ship for this one to provide information. Use of this module increases the amount of credits that can be earned in stellar cartography by approximately 30%, and is considered essential for any pilot wanting to use exploration as their primary source of income.

    In order to use this module a pilot must select the unexplored entity from their navigation panel then fly to within range (varies due to entity diameter) just as with scanning with the discovery scanner and as such does not need to be bound to a firing group.

    The scan will take from 35 seconds down to 15 seconds depending upon the range at which the entity is scanned, 35 seconds for maximum range down to a minimum of 15 for close range. This difference in scan times may make it worthwhile to get closer to an entity being scanned to save a few seconds but risks the pilot being caught in the entity's gravity well.

    Upon completion of the scan the pilot will receive a message confirming the detailed scan.

    This scanner can be used in supercruise and normal space by being close to and targeting a stellar body first, then getting within range of the scanner. The scan will activate automatically when the ship is facing the planet and the above conditions are met. Completing a surface scan will yield higher monetary rewards for exploration data than discovering the stellar body alone.

    — Additional In-Game Description