This speed is the Specific Impulse which is a measure of how effective the fuel mass is used. It is equivalent to the effective exhaust velocity, which is basically the mean exhaust velocity as the real exhaust velocity depends on the position in the exhaust. The specific impulse is more often given in seconds like in the Wikipedia page for the thruster and this representation is connected to the speed-based representation by dividing the effective exhaust velocity by the standard gravitational acceleration at sea level. Mass is not present in both of these representations because this way they are the impulse per unit mass of propellant.

Electric thrusters reach very high exhaust velocities, but the fuel mass flow is limited which leads to low thrust. Chemical engines reach high thrust, but their exhaust velocities are quite low in comparison.

Yes, Cruelty Squad.

In SYNTHETIK there is a doomba! Ended many runs so far.

In The Expanse the group responsible for the attack stole the most advanced stealth coating in the Expanse universe to paint the asteroids, leaving Earth unable to detect them with anything but their most powerful sensors.

The kilogram is defined as the mass equivalent of a photon of a specific energy via the Planck constant h thus linking the speed of light and the frequency of the hyperfine level of caesium-133. The relative uncertainty of the measured value of the gravitational constant G is 10^-5 which would lead to a definition of the kilogram that has a worse relative uncertainty than using the former definition defined via an international prototype. The Wikipedka article is more detailed than this short summary.

To anyone curious, the link to the album. I absolutely love this, it has been playing on repeat this month.

https://youtu.be/voCRlFlj9yA

And if you hold, it scrolls faster, so you do not even have to pause too close to the frame.