# Tag Info

## Hot answers tagged solar-flare

9

Yes, the basic mechanism is thought to be the same on red dwarfs and at least the hotter brown dwarfs, but the details can be different. As you say, magnetic reconnection in the corona is the starting point. Well, actually it is fluid motions at the magnetic loop footpoints that is the starting point. The B-field and partially ionised plasma are coupled and ...

8

The flare happens just outside the black hole. Matter which aproaches a black hole but not perfectly straight on doesn't fall into it immediately. It gets pulled around the black hole, just as a satellite is pulled around the Earth. If the object is a single small particle, that's almost the end of the story. Gravitational radiation and the precise ...

6

Coronal mass ejections consist of a very hot, but thin, plasma. Their very weak intrinsic emission would be dominated by ultraviolet and X-ray lines and bremsstrahlung continuum. There is very little optical radiation. However, CMEs can and are monitored at optical wavelengths using the light that they scatter from the Sun. The process is Thomson scattering ...

6

The point of my comment was that the connection between CMEs and flares would make for a good 20 page research paper in a college course. The connections are still only understood at a kind of cartoon level, after decades of concerted research. But I can tell you what the basic cartoon is, and you can think of that as a kind of operating hypothesis that ...

6

This was a coronal mass ejection. Those 1973 astronomers weren't looking at the picture correctly. They didn't have the tools at that time to look at the picture correctly. Coronal mass ejections (the term used now) were only discovered a couple of years prior to that picture taken from Skylab, via the Orbiting Solar Observatory 7 satellite. Those early ...

6

I should give credit here to @honeste_vivere, who pointed out to me today that there have been recent studies excited by some extremely large coronal mass ejections that were classed as "near misses" in terms of causing major disruption. Of particular interest to you would be the event of July 2012 discussed by Baker et al. (2013). I quote from the paper " ...

5

I remember that well. I presume you're referring to an episode of "The Outer Limits," which was based on a short story by Larry Niven. Having looked into the idea back when I read the story in the 1990s, I can say it's plausible in the sense that it's not strictly prohibited by any law of physics. That said, a solar flare would have to be of precisely the ...

4

You'd probably be most interested in the results of the Lunar Dust EXperiment (LDEX). A 2015 paper states LDEX data show no evidence for an electrostaticallylofted dust component at densities greater than a few per m3 I am assuming the solar flare stuff didn't pan out, otherwise it would be mentioned in the various LDEX summary papers. In addition, ...

4

All of these effects are related to the 11 year solar cycle. And while we know there are times when the sun is "active" versus "inactive" we aren't necessarily predicting exactly where sunspots or solar flares will occur, but how many we see in total.

4

Space Weather is the field within heliophysics that tries to understand this Sun-Earth relationship. When a Solar Flare occurs multiple things may happen and how it interacts with the Earth and our technology depend on different factors. The first effect, the X-ray radiation produced by an Solar Flare affects the ionosphere and therefore the radio ...

4

It's probably rare that moons have atmospheres to begin with. Planets don't generate solar flares. Planets emit thermal radiation as a result of their heat and during formation and collision planets can get significantly hot. Earth is believed to have glowed red hot following the theoretical giant impact and that heat actually may have helped give the Moon ...

4

First, I have provided some background on these phenomena at: https://astronomy.stackexchange.com/a/16786/13663 Solar flares and coronal mass ejections (CMEs) are not the same phenomena. I am aware that radiation from these solar events does not travel directly outward from the direction of the sun but follows magnetic lines of force and may be subject to ...

3

The Hinode satellite has an active x-ray telescope that is routinely used to image the sun. And the NuSTAR extreme x-ray telescope can also be used for sun imaging (although its main job is looking for black holes) Here is the latest XRT image of Hinode There are also Extreme Ultraviolet telescopes (at 171Å that is less than an octave away from the ...

3

No, but the magnetic dipole of Earth has a field strength that increases with closer distance. On the direct line between Earth and Sun the magnetic field strength is always $B(r) = M/r^3$ where $M$ is the magnetic moment of the terrestrial dipole and $r$ is the distance to the dipole, aka Earth. When the solar wind conditions change, the boundary between ...

3

I'd say it's an open question awaiting some observational evidence that it can happen. It presumably would depend a lot on what kind of situation you are looking for, and what would you call a flare on one star setting off a flare on the other. Certainly you'd need two stars that both have active atmospheres and are in a close binary, such that one mass ...

3

Magnetic fields are generated by currents - i.e. by the motion of charged particles. As you say, the Sun is full of freely moving charged particles, and these generate currents which in turn generate magnetic fields. No metals required. Most of the magnetic field generation is thought to occur at the interface between the radiative interior of the Sun and ...

3

Solar flares are observed at wavelengths right across the electromagnetic spectrum, not just H alpha. The basic model for a solar flare starts with the magnetic field in the corona. You can think of the topology of the magnetic field to consist of loops that poke up out of the photosphere and extend into the corona. However, the photosphere of the Sun is ...

3

It would be good business for the news industry: sky lights, plane crashes, exploding grid transformers, city blackouts, satellite damage, long, electricity-carrying wires would spark, start fires and and send signals when they are switched off. Burning buildings, dead people, everything. big flares occur about every 100 years. the last was the Carrington ...

3

Flares involve releasing huge amounts of potential energy that are stored in stressed magnetic structures in the solar corona. So-called reconnection events can release this stress but at the same time accelerate charged particles to high energies. These are trapped along the magnetic field lines, spiralling around them, but travelling until they hit the ...

3

What is the largest recorded solar flare? Since @Moriarty already dealt with historical records, I will focus on the modern observations. X-Ray Classification On April 2, 2001 the GOES spacecraft recorded an X20 flare (see the following for flare classification: https://en.wikipedia.org/wiki/Solar_flare#Classification). Most flares fall below C-class (i.e....

3

The following are largely excerpts from an answer I wrote at https://physics.stackexchange.com/a/258093/59023. What are the main differences between solar flares and coronal mass ejections? There are several differences between solar flares and coronal mass ejections (CMEs), the latter of which involve large amounts (i.e., upwards of billions of tons) of ...

3

How are these flares tracked after they've been detected? Since you already linked to https://astronomy.stackexchange.com/a/16786/13663, I won't belabor the differences between a solar flare and coronal mass ejection (CME). I will say that flares are short-lived phenomenon so they aren't really tracked so much as observed and their properties recorded. ...

3

Never drive a car which is larger than a football field during a solar storm Otherwise, don't worry about it. The answer to Does a geomagnetic storm visibly deflect a compass? shows the plot below which was a very large event. It looks like the fastest change was about 200 nT per minute or about 3 x 10-9 Tesla/second. For a 6 square meter car that's an ...

2

Magnetic activity depends on rotation due to the dynamo mechanism. Younger stars in general rotate faster. They (stars like the sun) spin down because their ionised winds interact with their magnetic fields and gradually remove angular momentum. A star like the Sun at 100 million years old may have had a rotation period of 0.5-5 days - much faster than the ...

2

As in the Earth and more than in the the giant gaseous planets the Sun's magnetic field is generated like in a dynamo. A few facts about it: The rotating plasma inside the Sun acts like a dynamo creating it's magnetic field. The plasma is ionized so all interact with the magnetic field and vice-versa. The sun as a fluid body also has Differential rotation, ...

2

I think we can broadly distinguish two classes of effects here: Flares directly affecting the planet The by-products of the flare affecting the planet I can loosely tell you what I know (although my knowledge here is far from being complete) Direct effects include: Magnetic field geometries: Far-away from their host star (>0.05AU) planets usually have ...

2

Satellites have been damaged before. GPS has been effected before. Power grids surge during magnetic disturbances. Pipelines energize too. March 13 1989 was a whopper. There's a lot of reporting online of this event. Some papers are still being written on the event. http://www.nasa.gov/topics/earth/features/sun_darkness.html So if a bigger, say a ...

2

Sun is more than one thousand times the mass of Jupiter, so it seems unlikely that even a very close approach by a "hot Jupiter" to its host star would cause a flare, and especially not a superflare.

2

Just going off the Wikipedia article you posted, it says the hot jupiter superflare theory was abandoned. The flares were initially explained by postulating giant planets in very close orbits, such that the magnetic fields of the star and planet were linked. The orbit of the planet would warp the field lines until the instability released magnetic ...

2

The most extreme solar flares are visible as bright marks on the face of the sun and the most extreme CME are apparent as aurorae even at low latitudes. Detecting CME as they leave the sun is difficult: you really need a spaceship to see that close to the sun. Detecting CME as they interact with the Earth's magnetic field is possible. You need to make a ...

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