How cold is space?

Hot things move quickly, cold things very slowly. If atoms come to a complete stop, they are at absolute zero. Space is just above that, at an average temperature of 2.7 Kelvin (about minus 455 degrees Fahrenheit).

How is our galaxy going to end?

Thats accounting for the increase in star formation when the Milky Way and the Andromeda Galaxy collide around that time. Thus, some 19 billion years after the Big Bang, the Milky Way will begin its slow but inexorable decline — and, a trillion years from now, the end will come as its last star fades from visibility.

What nationality is Replogle?

German German and French (Alsace): variant of German Reploegel, a compound of Repp rope + Middle High German lagel keg, also a linear measure.