# Tag Info

34

Venus has a strong ionosphere that protects it against violent solar winds. So, even though Venus has no intrisic magnetic field, it has an effective, induced magnetic field due to the interaction between the solar winds and the atmosphere, that protects it against solar winds. Venus atmosphere is thick enough to have a consequent ionosphere, that would be ...

15

The rate of loss of mass from a comet is perhaps surprisingly low. A paper The calculation of $Af\rho$ and mass loss rate for comets gives a rate for a "typical" comet at 1.29AU as 153kg/s. A typical comet has a mass of about $10^{13}kg$. Even if the comet is constantly active (and they are not) it would have enough material for over 2000 years. In fact ...

12

The solar neutrino luminosity is about 2.3% of its electromagnetic luminosity (i.e. light). So the extra mass lost in the form of neutrino energy is 2.3% of your original calculation. The average mass loss in the form of a wind and coronal mass ejections is about $4\times 10^{16}$ kg/year, but varies with the solar cycle (and from cycle to cycle) (Mishra et ...

10

You are right about the kinetic energy (ie the fast motion) of the particles being the reason, but wrong when you say They must be of almost the same energy if so there will be no relative kinetic energy, The individual particles are moving fast, but there is huge variation between them in just how fast and in what direction. In other words, the solar ...

9

Here is a way of getting a rough upper bound: the density $\rho$ of the solar wind is about 4 atoms per cm$^3$ (that we can assume are hydrogen), and it travels at $v=400-500$ km/s. That means that were the Earth to catch every atom directed at it it would gain $\pi R_\oplus^2 \rho v$ atoms per second, $2.0$ to $2.5\cdot10^{14}$. Which gives us a mass flow ...

8

We have very good data on the heavy metals in the solar wind from the Charge, Element, Isotope Analysis System (CELIAS) on SOHO: Some of these elements were previously known; others were observed for the first time. The new ones are phosphorus, chlorine, potassium, titanium, chromium, and nickel. They were detected in smaller amounts than, say, carbon, ...

7

When plasma moves in a magnetic field then the charged particles follow helical paths around the field lines, due to the $q\vec{v}\times \vec{B}$ Lorentz force. If the radius of gyration is small, then the plasma is effectively tied (or frozen) to the field lines. However to decide whether it is the motion of the magnetic field that enforces motion of the ...

7

Prelude It is now generally accepted in the planet formation community that planets form as a side-product of the star formation process in so-called protoplanetary discs. Protoplanetary discs have initial masses of few to tens of percent of their stellar host masses, are relatively cold (T<150K in about 95% or more of their mass, which is outside the ...

6

$$\left( \frac{4 \pi (6.96e10\,\text{cm})^{2}}{1} \right)$$ This is the primary source of your error. Your value of 6.96×1010 cm is the radius of the Sun. The problem specifically said "Assuming at the Earth ...". You need to calculate the flux through the surface of a sphere whose radius is about one astronomical unit rather than one solar radius. The ...

6

Technically, yes, the moon does have an atmosphere that gets ionized by the sun. NASA: Is There an Atmosphere on the Moon? our moon does indeed have an atmosphere consisting of some unusual gases, including sodium and potassium, which are not found in the atmospheres of Earth, Mars or Venus. It's an infinitesimal amount of air when compared to Earth's ...

5

The Sun erodes a planetary atmosphere through its solar wind. Presently, the solar wind passes Earth at 250-750 kps, which is roughly ten times the Sun's escape velocity from earth orbit. So atoms and molecules of gas eroded by the solar wind are carried right out of the Solar System into the beginnings of interstellar space. At that point (ca. 100 AU) ...

5

Okay we can state it as follow: Solar Radiation: It is the radiation from the sun which includes all wavelengths of electromagnetic radiation coming from the sun. Solar Wind The solar wind is a stream of charged particles (a plasma) released from the upper atmosphere of the Sun. It mostly consists of electrons and protons. And I can simplify it as like ...

5

The velocity and the density are at the earth position, so the area term must include the earth-sun distance instead of the solar radius.

4

What are the velocity, mass, and charge distribution of the solar wind. Velocity The solar wind speed has a large range of variation, between ~250–820 km/s [e.g., Chen et al., 2014; Gopalswamy, 2006; Jian et al., 2011, 2014; Kasper et al., 2012; Maksimovic et al., 1998; Marsch, 1983; McComas et al., 2013; Schwenn, 1983; Stverak et al., 2008, 2009] near the ...

4

First of all *not to consider me a conspiracy theorist(, but isn't landing on the moon a questionable issue? Only to conspiracy theorists. To everyone else, no, it's not a questionable issue. My father in law helped send men to the Moon. I have worked with a number of people who sent men to the Moon. I was once called on the carpet in Gene Kranz's office. I ...

4

Expanding on @Steve Lintons answer: In physics no quantity is just large, a quantity can only be large relative to some other quantity. So here we want to compare the kinetic energy to something, and that must be the binding energy of i.e. a hydrogen atom. The binding energy of the hydrogen atom is 13.6 eV. And this is much smaller than the keV energies ...

4

Yes and no. The question @JohnRennie links to in his comment Analogy between magnetic bottle and Van Allen's radiation belt contains a lot of relevant information, but packaged as an answer to this question. The question correctly concludes that, at least in the plane perpendicular to the magnetic field, particles will travel in circles, and those circles ...

4

Cosmic radiation (which consists of high-energy protons and atomic nuclei) comes from the sun, other stars, even other galaxies. Solar wind is a part of that - the part coming from the sun, which mostly consists of electrons, protons and alpha particles with kinetic energy between 0.5 and 10 keV

4

From going through the literature the paper by Wang et al. 2021 is citing, I am nearly certain that the term "Earth wind" must be a recent invention, perhaps by those authors themselves. It is however correct to call the solar wind a 'wind'. This is because a wind is a pressure-driven bulk motion of a collectively coupled gas. The solar wind, at ...

3

There is no difference in the number of cosmic particles. You seem to imagine that there are static clouds of gas in the universe that the sun is moving through. This is not the case. The gas in the galaxy is orbiting at roughly the same speed as the sun. The sun does have some proper motion relative to the interstellar medium, but the interstellar medium ...

3

Sort of, via radiation pressure and heating. The Sun emits photons, which carry with them energy and momentum. Any flux of photons applies pressure to an object it hits; this is the basic principle behind solar sails. In general, the larger the object, the more force it feels, since pressure is force per unit area. There are two main ways light from the Sun ...

3

At the moment, the Solar System is inside the Local Interstellar Cloud (which is itself within the Local Bubble). The LIC has a neutral hydrogen number density of $\sim0.1\text{ cm}^{-3}$, which is a bit lower than the mean galactic neutral hydrogen number density. The Local Bubble itself is less dense than the LIC, by about one or two orders of magnitude. ...

3

Conservation of mass? In a steady-state wind, the mass loss rate through each shell is the same. $$\frac{dM}{dt} = - 4\pi r^2 \rho(r) v(r),$$ where $\rho$ and $v$ would be the density and velocity of a spherically symmetric wind, with a fixed mass-loss rate $\dot{M}$. Thus for a fixed wind speed you expect the density to fall as the square of the radius ...

3

If you want to trigger outflows, there are two main processes that can help: magnetic field; radiation pressure. Magnetic fields is well-suited to launch such outflows, through magneto-centrifugal effects. Basically, if there is magnetic fields tighed to the disk surrounding the protostar and the angle between the field lines and the disk is right, a ...

3

Yes. After the charged particles that have distorted the magnetic field passed, it goes back to normal. Otherwise it could not have been doing this for the last few billion years. This then looks something like this (data from the ACE satellite): And look here for awesome real-time data. (Thanks Magic Octopus Urn for the comment!) Or see this video for a ...

3

If I understand your question correctly, it is about EPI-Lo which a part of the Integrated Science Investigation of the Sun (ISʘIS) . The picture is also taken from there: EPI-Lo stands for Energetic Particle Instrument-Low energy which indeed sounds confusing at first sight. The essential definition can be found in the instrument paper: EPI-Lo measures ...

3

Systems like this are known as colliding-wind binaries (CWBs), and they do produce some interesting effects. When winds collide, they create shocks, which in turn heats up gas. The most notable result is x-ray emission, which tends to happen whenever you have non-negligible shock heating in stellar winds; there is certainly additional thermal and non-thermal ...

2

From Wikipedia's article on solar winds: The solar wind is a stream of charged particles (a plasma) released from the upper atmosphere of the Sun. It mostly consists of electrons and protons with energies usually between 1.5 and 10 keV. Solar radiation would be everything in general, including solar wind. Everything else is electromagnetic ...

2

A major factor, is that Venus' volcanoes are still active. Mars's died millions of years ago. If they were still erupting, then Mars' atmosphere would be much thicker today. Edit: This may actually be true as referenced by a paper published July 20 2020 cited below. Gülcher, A.J.P., Gerya, T.V., Montési, L.G.J. et al. Corona structures driven by plume–...

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