"the solar wind is gusty, ranging in speed from about 750,000 miles per hour (approximately 350 km/second) to 1.5 million miles per hour (700 km/second)."
https://www.nasa.gov/vision/universe/solarsystem/solar_wind_speed.html
"plasma. And it makes up 99.9% of the observable universe."
https://www.nasa.gov/mediacast/plasma-plasma-everywhere
"Plasma makes up nearly 100% of the interplanetary, interstellar and intergalactic medium. The Earth’s ionosphere is plasma."
https://www.plasma-universe.com/
"The Sun releases a constant stream of particles and magnetic fields called the solar wind. This solar wind slams worlds across the solar system with particles and radiation – which can stream all the way to planetary surfaces unless thwarted by an atmosphere, magnetic field, or both."
https://solarsystem.nasa.gov/resources/2288/the-solar-wind-across-our-solar-system/
"That hydrogen wall is the outer boundary of our home system, the place where our sun's bubble of solar wind ends and where a mass of interstellar matter too small to bust through that wind builds up, pressing inward. Our host star's powerful jets of matter and energy flow outward for a long stretch after leaving the sun — far beyond the orbit of Pluto."
https://www.livescience.com/63297-hydrogen-wall-glowing-interstellar-space.html
"If spacetime is a kind of fluid, then we must also take into account its viscosity and other dissipative effects, which had never been considered in detail".
Liberati and Maccione catalogued these effects and showed that viscosity tends to rapidly dissipate photons and other particles along their path, "And yet we can see photons travelling from astrophysical objects located millions of light years away!" he continues. "If spacetime is a fluid, then according to our calculations it must necessarily be a superfluid. This means that its viscosity value is extremely low, close to zero".
"We also predicted other weaker dissipative effects, which we might be able to see with future astrophysical observations."
https://phys.org/news/2014-04-liquid-spacetime-slippery-superfluid.html
"Drag is a force exerted on an object moving through a fluid, and it is oriented in the direction of relative fluid flow. Drag acts opposite to the direction of motion and tends to slow an object. As an example, think of running against a high wind and feeling the drag pushing you back in the direction of relative fluid flow. This same force acts on spacecraft and objects flying in the space environment."
https://www.swpc.noaa.gov/impacts/satellite-drag