the_fungible_man

the_fungible_man t1_iuzr0jf wrote

Yes, humans for example. Any electric current will generate a magnetic field, and there is plenty of small electric currents flowing in your body right now. In your heart, your central and peripheral nervous systems, your muscles...

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the_fungible_man t1_iuc9n72 wrote

There's a difference between a solar flare, and a coronal mass ejection and the effects they produce on or above the Earth. The A, B, C, M, X classes of flares refer to the peak energy measured at a specific X-Ray wavelength. This is omnidirectional high energy electromagnetic radiation that travels at the speed of light. Such radiation does not pose a threat to electrical infrastructure or devices on the ground.

What do pose a threat are the CMEs often associated with solar flares. These are massive clouds of charged particles that generally spread out from site of a flare (a sunspot group) and expand out into the solar system at 1000 km/s or more. When these particles slam into and get trapped by Earth's geomagnetic field, huge electric currents can be produced which in turn can induce currents in transmission lines and other conductive paths on the surface. This can damage the electrical grid.

However, the location of the sunspot on the Sun largely determines the direction in which the CME expands out from the Sun. In reviewing the literature on the Halloween 2003 X28 (X45?) flare, I note that it occurred on November 4, when sunspot group 486 was nearing on the SW limb of the Sun. Any CME associated with that flare was aimed nearly 90° away from the Earth and would have delivered a glancing blow to the Earth, or none at all.

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the_fungible_man t1_itjpuom wrote

Deep space probes have radio transmitters and high -gain directional antennas aimed at Earth through which they send telemetry and science data, including the images captured by their onboard camera(s). These radio signals are received on Earth by the huge (70 m) radio antennas and sensitive receivers of NASA's Deep Space Network, with facilities located in Australia, Spain, and the US.

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the_fungible_man t1_itevk6p wrote

Sublimation of ice cools the ice left behind. Eventually the remaining ice will reach the temperature point in the ice/water/vapor pressure vs. temperature phase diagram at which ice is the equilibrium state. Below that temperature (somewhere below -100°C.) sublimation effectively stops.

This is why moons of the outer planets can have long-lived ice crusts exposed directly to the hard vacuum of space.

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the_fungible_man t1_irxqbeu wrote

Speaking generally, yes. Consider just the three body system of the Sun, Didymos, and Dimorphos. Despite the huge difference in their masses, Didy and Dimo revolve about their mutual barycenter – like the Earth and Moon, or Pluto and Charon, or even the Sun and the planets. This barycenter follows an elliptical orbit around the Sun.

Perturbing Dimo's orbit, by changing its mass, and its average distance from and period around Didy also changed the barycenter of the system. Therefore the impact on Dimorphos did change the heliocentric orbit of the Didy-Dimo pair. But in the real multi-body universe, the extent of this change is infinitesimally tiny compared to all the other forces constantly tugging on the Didy-Dimo system.

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the_fungible_man t1_irv8h4x wrote

The chances are 0.

The nearest star to the Sun, Proxima Centauri, is tiny, with about 12% of the mass of the Sun. The minimum mass for a star to sustain fusion in its core is ~8-9% of a solar mass, so this is a really small, cool, dim red star. And yet, from Earth, this star has a visual magnitude of 11, which is quite bright for a star less than 0.2% as luminous as the Sun.

Proxima Centauri could hardly be any smaller or dimmer and still be a star, and yet it can be easily observed with modest equipment. Any nearer star likewise would have already been detected.

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